WO2000054008A1

WO2000054008A1 - Methods and apparatus for preventing vehicle accidents

Info

Publication number: WO2000054008A1
Application number: PCT/US2000/006236
Authority: WO
Inventors: David S. Breed; Wilbur E. Duvall; Wendell C. Johnson
Original assignee: Intelligent Technologies International, Inc.
Priority date: 1999-03-11
Filing date: 2000-03-10
Publication date: 2000-09-14
Also published as: AU3522500A

Abstract

System and method for preventing vehicle accidents in which the absolute position of the vehicle is determined, e.g., using a satellite-based positioning system (44) such as GPS, and the location of the vehicle relative to the edges of the roadway is then determined based on the absolute position of the vehicle and stored data (46) relating to edges of roadways on which the vehicle may travel. A system or component within the vehicle is initiated, e.g., an alarm or warning system (50), or the operation of a system or component is affected, e.g., an automatic guidance system (60), if the location of the vehicle approaches close to an edge of the roadway or intersects with an edge of the roadway.

Description

METHODS AND APPARATUS FOR PREVENTING VEHICLE ACCIDENTS 1. Background of the Invention 1.1 Field of the invention.

This invention is in the fields ot automobile safety, intelligent highway safety systems, accident avoidance, accident elimination, collision avoidance, blind spot detection, anticipatory sensing, automatic vehicle control, intelligent cruise control, automotive navigation and other automobile and truck safety, navigation and control related fields

There are two major efforts underway that will significantly affect the design of automobiles and highways The first is involved with preventing deaths and serious injuries from automobile accidents The second involves the attempt to reduce the congestion on highways In the first case there are approximately forty thousand (40.000) people killed each year in the United States by automobile accidents and another several hundred thousand are seriously injured In the second case, hundreds ot millions of man-hours are wasted every year by people stuck in traffic jams on the world's roadways There have been many attempts to solve both of these problems, however, no single solution has been able to do so When a person begins a trip using an automobile, he or she first enters the vehicle and begins to drive, first out of the parking space and then typically onto a local or city load and then onto a highway In leaving the parking space he or she may be at risk from an impact of a vehicle traveling on the road. The driver must check his or her mirrors to avoid such an event and several electronic sensing systems have been proposed which would warn the driver that a collision is possible Once on the local road, the driver is at risk of being impacted from the front side and rear, and electronic sensors are under development to warn the driver ot such possibilities Similarly, the driver may run into a pedestrian, bicyclist, deer or other movable object and various sensors are under development which will warn the driver ot these potential events These various sensors include radar, optical, ultrasonic, and d variety of others sensois, each of which attempts to solve a particular potential collision event It is important to note that in none of these cases is there sufficient confidence in the decision that the control ot the vehicle is taken away from the driver Thus, action by the driver is still always requned

In some proposed future Intelligent Transportation System (ITS) designs, hardware of various types is embedded into the highway and sensors which sense this hardware are placed onto the vehicle so that it can be accurately guided along a lane of the highway In various other systems, cameras are used to track lane markings or other visual images to keep the vehicle in its lane However, for successful ITS, additional information is needed by the driver, or the vehicle control system, to take into account weather, road conditions, congestion etc , which typically involves additional electronic hardware located on or associated with the highway as well as the vehicle From this discussion it is obvious that a significant number of new electronic systems are planned for installation onto automobiles However, to date, no product has been proposed or designed which combines all ot the requirements into a single electronic system This is the intent of this invention

The safe operation of a vehicle can be viewed as a process in the engineering sense To achieve safe operation, first the process must be designed and then a vehicle control system must be designed to implement the process The goal of a process designer is to design the process so that it does not fail The fact that so many people are being seriously injured and killed in traffic accidents and the fact that so much time is being wasted in traffic congestion is proof that the current process is not working and requires a ma|or redesign To design this new process the information required by the process must be identified, the source of that information determined and the process designed so that the sources of information can communicate effectively to the user of the information, which will most often be the vehicle control system Finally, the process must have feedback that self-corrects the process when it is tending toward failure

Although it is technologically feasible, it is probably sociallv unacceptable at this time for a vehicle safety system to totally control the vehicle The underlying premise of this invention, therefore, is that people will continue to operate their vehicle and control of the vehicle will only be seized by the control system when such an action is required to avoid an accident or when such control is needed for the orderly movement of vehicles through potentially congested areas on a roadway When this happens, the vehicle operator will be notified and given the choice of exiting the road at the next opportunity In some implementations especially when this invention is first implemented on a trail basis, control will not be taken awav from the vehicle operator but a warning system will alert the driver of a potential collision, road departure or other infraction

Let us consider several scenarios and what information is required for the vehicle control process to prevent accidents In one case a driver is proceeding down a country road and falls asleep and the vehicle begins to leave the road perhaps heading toward a tree In this case, the control system would need to know that the vehicle was about to leave the road and for that it must know the position of the vehicle relative to the road One method of accomplishing this would be to place a wire down the center of the road and to place sensors within the vehicle to sense the position of the wire relative to the vehicle An alternate approach would be tor the vehicle to know exactly where it is on the surface of the earth and to also know exactly where the edge of the road is

These approaches are fundamentally different because in the former solution every road in the world would require the placement of appropriate hardware as well as the maintenance of this hardware This is obviouslv impractical In the second case, the use ot the global positioning satellite system (GPS), augmented by additional systems to be described below, will provide the vehicle control system with an accurate knowledge of its location Whereas it would be difficult to install and maintain hardware such as a wire down the center of the road for every road in the world, it is not difficult to survey every road and record the location of the edges, and the lanes for that matter, of each road This information must then be made available through one or more of a variety of techniques to the vehicle control system

Another case might be where a driver is proceeding down a road and decides to change lines while another vehicle is in the driver's blind spot Various companies are developing radar, ultrasonic or optical sensors to warn the driver if the blind spot is occupied The driver may or may not heed this warning, perhaps due to an excessive false alarm rate, or he or she may have become incapacitated, or the system may fail to detect a vehicle in the blind spot and thus the system will fail

Consider an alternative technology where again each vehicle knows precisely where it is located on the earth surface and additionally can communicate this information to all other vehicles within a certain potential danger zone relative to the vehicle Now when the driver begins to change lanes, his or her vehicle control system knows that there is another vehicle in the blind spot and therefore will either warn the driver or else prevent him or her from changing lanes thereby avoiding the accident

Similarly if a vehicle is approaching a stop sign or red traffic light and the operator fails to bring the vehicle to a stop, if the existence of this traffic light or stop sign has been made available to the vehicle control system the system can warn the driver or seize control of the vehicle to stop the vehicle and prevent a potential accident Additionally, if an operator of the vehicle decides to proceed across an intersection without seeing an oncoming vehicle, the control system will once again know the existence and location and perhaps velocity of the oncoming vehicle and warn or prevent the operator from proceeding across the intersection Consider another example where water on the surface of a road is beginning to freeze Probably the best way that a vehicle control system can know that the road is about to become slippery, and therefore that the maximum vehicle speed must be significantly reduced, is to get information from some external source This source can be sensors located on the highway that are capable of determining this condition and communicating it to the vehicle Alternately, the probability of icing occurring can be determined analytically from meteorological data and a historical knowledge of the roadway and communicated to the vehicle over a LEO satellite system or an FM sub-carrier or other means

Studies have shown that a combination of meteorological and historic data can accurately predict that a particular place on the highway will become covered with ice This information can be provided to properly equipped vehicles so that the vehicle knows to anticipate shpperv roads For those roads that are treated with salt to eliminate frozen areas, the meteorological and historical data will not be sufficient Numerous systems are available todav that permit properly equipped vehicles to measure the coefficient of friction between the vehicle's tires and the road It is contemplated that police vehicles will be equipped with such a friction coefficient measuring apparatus and can serve as probes for those roadways that have been treated with salt Information from these probe vehicles will be fed into the information system that will then be made available to control speed limits in the those areas

Countless other examples exist however from those provided above it can be seen that for the vehicle control system to function without error, certain types of information must be accurately provided These include information permitting the vehicle to determine its absolute location and means for vehicles near each other to communicate this location information to each other Additionally, map information that accurately provides boundary and lane information of the road must be available Also, critical weather or road-condition information is necessary The road location information need only be generated once and changed whenever the road geometry is altered This information can be provided to the vehicle through a variety of techniques including prerecorded media such as CDRO or DVD disks or through communications from transmitters located in proximity to the vehicle, satellites, radio and cellular phones Consider now the case of the congested highway Many roads in the world are congested and are located in areas where the cost of new road construction is prohibitive or such construction is environmentally unacceptable It has been reported that an accident on such a highway typically ties up traffic for a period of approximately four times the time period required to clear the accident Thus, by eliminating accidents, a substantial improvement in the congested highway problem results This of course is insufficient On such highways each vehicle travels with a different spacing, frequently at different speeds and in the wrong lanes If the proper spacing of the vehicles could be maintained, and if the risk of an accident could be substantially eliminated, vehicles under automatic control could travel at substantially higher velocities and in a more densely packed configuration thereby substantially improving the flow rate of vehicles on the highway by as much as a factor of 3 to 4 times This not only will reduce congestion but also improve air pollution Once again, if each vehicle knows exactly where it is located, can communicate its location to surrounding vehicles and knows precisely where the road is located, then the control system in each vehicle has sufficient information to accomplish this goal

Again the intent of the system and process described here is to totally eliminate automobile accidents as well as reduce highway congestion This process is to be designed to have no defective decisions The process employs information from a variety ot sources and utilizes that information to prevent accidents and to permit the maximum vehicle throughput on highways

The information listed above is still insufficient The geometry of a road or highway can be determined once and for all until erosion or construction alters the road Properly equipped vehicles can know their location and transmit that information to other properly equipped vehicles There remains a variety ot objects whose location is not fixed, which have no transmitters and which can cause accidents These ob|ects include broken down vehicles animals such as deer which wander onto highways, pedestrians, bicycles, objects which fall otl ot trucks, and especially other vehicles which are not equipped with location determining systems and transmitters for transmitting that information to other vehicles Part of this problem can be solved for congested highways by restricting access to these highways to vehicles that are properly equipped Also, these highways are typically in urban areas and access by animals can be effectively eliminated Heavy fines can be imposed on vehicles that drop objects onto the highway Finally, since every vehicle operator becomes part of the process, each such operator becomes a potential source of information to help prevent catastrophic results Thus, each vehicle should also be equipped with a system ot essentially stopping the process in an emergency Such a system could be triggered by the operator strongly applying the brakes, lapidly turning the steering wheel or by activating a manual switch when the operator observes a critical situation but is not himself in immediate danger An example of the latter case is where a driver witnesses a box falling off of a truck in an adjacent lane

To solve the remaining problems, therefore, each vehicle should also be equipped with an anticipatory collision sensing system, or collision forecasting system, which is capable of identifying or predicting and reacting to a pending accident As the number of vehicles equipped with the control system increases, the need for the collision forecasting system will diminish

Once again, the operator will continue to control his vehicle provided he or she remains within certain constraints These constraints are like a corridor As long as the operator maintains his vehicle within this allowed corridor, he or she can operate that vehicle without interference from the control system That corridor may include the entire width of the highway when no other vehicles are present or it may be restricted to all East-bound lanes, for example In still other cases, that corridor may be restricted to a single line and additionally, the operator may be required to keep his vehicle within a certain spacing tolerance from the preceding vehicle If a vehicle operator wishes to exit a congested highway, he could operate his turn signal that would inform the control system of this desire and permit the vehicle to safely exit from the highway It can also inform other adjacent vehicles of the operator's intent, which could then automatically cause those vehicles to provide space for lane changing, for example The highway control system is thus a network of individual vehicle control systems rather than a single highway resident computer system

1.2 Limitations of the prior art

Previous inventions have attempted to solve the collision avoidance problem for each vehicle independently of the other vehicles on the roadway Systems that predict vehicle trajectories fail because two vehicles can be on a collision course and within the last 1 second a slight change of direction avoids the collision This is a common occurrence that depends on the actions of the individual drivers and no collision avoidance system now in existence can differentiate this case from an actual collision In the present invention, every equipped vehicle will be confined to a corridor and to a position within that corridor where the corridor depends on sub-meter accurate digital maps Only if that vehicle deviates from the corridor will an alarm sound or the vehicle control system take over control of the vehicle sufficiently to prevent the vehicle from leaving its corridor if an accident would result from the departure from that corridor

Additionally, no prior art system has successfully used the GPS navigational system, or an augmented DGPS to locate a vehicle on a roadway with sufficient accuracv that that information can be used to prevent the equipped vehicle from leaving the roadway or striking another similarly equipped vehicle

Prior art systems in addition to being poor at locating potential hazards on the roadway, have not been able to ascertain whether they are in fact on the roadway of off on the side whether they are threatening vehicles, static signs over overpasses etc In fact no credible attempt to date has been made to identify or categorize objects which may impact the subject vehicle The RtZF svstem also contemplates a different kind of interrogating svstem It is based on scanning infrared laser radar with range gating This system, when used in conjunction with accurate maps, will permit a precise imaging of an object on the road in front of the vehicle, for example, permitting it to be identified (using neural networks) and its location, velocity and the probability of a collision to be determined This will be part of the Phase One I VI Program 1.3 Summary and Objects of the invention

The first phase of this invention can be practiced with only minor retrofit type additions to the vehicle These include the addition of a differential GPS system and an accurate map database In this first phase the driver will only be warned when he or she is about to depart from the load surface During the second phase of practicing this invention, the earning system will be augmented with a system which will prevent the operator from leaving the assigned corridor and in particular leaving the road at high speed In further phases of the implementation of this invention, additional systems will be integrated which will scan the roadway and act to prevent accidents with vehicles that do not have the system installed Also communication systems will be added to permit the subject vehicle to communicate its position, velocity etc to other nearby vehicles which are also equipped with a system A primary preferred embodiment of the system, therefore, is to equip a vehicle with a DGPS system, an laser gyro inertial guidance system vehicle steering and brake control apparatus, a sub-meter accurate digital map svstem with the relevant maps, a scanning sub-nanosecond pulsed infrared laser radar, a system for sensing or receiving signals from a highway based precise position determination system, and communications svstems for ( 1 ) sending and receiving data from similarly equipped vehicles, (2) receiving updated maps and map status information, and (3) receiving weather and road condition information A preferred embodiment for the infrastructure enhancements includes a DGPS system, a micropower impulse radar precise position determining system and local weather and road condition determination and transmission system This invention is a method and apparatus for preventing vehicle accidents A vehicle is equipped with a differential GPS (DGPS) navigational system as well as an inertial navigation subsystem Part of the system can be an array of infrastructure stations that permit the vehicle to exactly determine its position at various points along its path Such stations would typically be located at intervals such as every 50 miles along the , or more or less frequently depending on requirements as described below These stations permit the vehicle to become its own DGPS station and thus to correct for the GPS errors and to set the position ot the vehicle based initial guidance system It also provides sufficient information for the vehicle to use the carrier frequency to determine its absolute position to within less than a meter Data is also available to the vehicle that provides information as to the edges of the roadway at the location of the vehicle so that the vehicle control system can continuously determine its location relative to the roadway edges In the initial implementation, the operator operates his or her vehicle and is unaware of the presence of the accident avoidance system If, however, the operator falls asleep or for some other reason attempts to run off of the roadway at high speed, the system will detect that the vehicle is approaching an edge of the roadway and will either sound an alarm or prevent the vehicle from leaving the roadway when doing so would lead to an accident In some cases the system will automatically reduce the speed of the vehicle and stop it on the shoulder ot the roadwav

It is important to note that the invention as described in the above paragraph is in itself a significant improvement to automotive safety Approximately half of all fatal accidents involve only a single vehicle that typically leaves the roadway and impacts with a roadside obstacle This typically happens when the driver in under the influence of alcohol or drugs, has a medical emergency or simply falls asleep If this cause ot accidents could be eliminated, the potential exists for saving many thousands of deaths per year when all vehicles are equipped with the system of this invention This would make this the single greatest advance in automotive safety surpassing both seatbelts and airbags in fesaving potential

A first improvement to the basic invention is to provide the vehicle with a means using radar, lidar, optical or infrared imaging, or a similar technology, to determine the presence, location and velocity of other vehicles on the roadwav which are not equipped with the accident avoidance system The accident avoidance system (RtZF™) of this invention will not be able to avoid all accidents with such vehicles for the reasons discussed above, but will be able to provide the level of protection at least equal to the prior art systems Some improvement over prior art systems will result from the fact that the equipped vehicle knows the location of the roadway edges, as well as the lane boundaries, not only at the location of the equipped vehicle but also at the location of the other nearby vehicles Thus, the equipped vehicle will be able to determine that an adjacent vehicle has already left its corridor and warn the driver or initiate evasive action In prior art systems, the location of the roadway is not known leading to significantly less discrimination ability A second improvement to the RtZF™ of this invention is to provide communication ability to other nearby similarly equipped vehicles permitting the continuous transmission and reception of the locations of all equipped vehicles in the vicinity With each vehicle knowing the location, and thus the velocity, of all potential impacting vehicles which are equipped with the RtZF™, collisions between vehicles can be reduced and eventually nearly eliminated when all vehicles are equipped with the RtZF™ A third improvement comprises the addition of software to the system that permits vehicles on especially designated vehicle corridors for the operator to relinquish control of the vehicle to the vehicle based system, and perhaps to a roadway computer system This then permits vehicles to travel at high speeds in a close packed formation thereby substantially increasing the flow rate of vehicles on a given roadway Naturallv in order to enter the designated corridors a vehicle would be required to be equipped with the RtZF™ Similarly, this then provides an incentive to vehicle owners to have their vehicles so equipped so that thev can enter the controlled corridors and thereby shorten their travel time

Prior art svstems require expensive modifications to highways to permit such controlled high speed close packed travel Such modifications also require a substantial infrastructure to support the system The RtZF™ of the present invention, in its simplest form does not require any modification to the roadway but rather relies primarily on the GPS or similar satellite system The edge and lane boundary information is either present within the vehicle RtZF™ memory or transmitted to the vehicle as it travels along the road The permitted speed of travel is also communicated to the vehicles on the restricted corridor and thus each vehicle travels at the appointed speed Since each vehicle knows the location of all other vehicles in the vicinity, should one vehicle slow down due to an engine malfunction for example. appropriate action can be taken to avoid an accident Vehicles do not need to travel in groups as suggested and required by some prior art svstems Rather each vehicle mav independently enter the corridor and travel at the system defined speed until it leaves

Another improvement involves the transmission of additional data concerning weather conditions, traffic accidents etc to the equipped vehicle so that the speed of that vehicle can be limited to a safe speed depending on road conditions, for example If moisture is present on the roadway and the temperature is dropping to the point that ice might be building up on the road surface, the vehicle can be notified by the roadway information system and prevented from traveling at an unsafe speed

Principle objectives and advantages of the RtZF™ system of this invention include

1 To provide a system based partiallv on the global positioning system (GPS) or equivalent that permits an onboard electronic system to determine the position of a vehicle with an accuracv of 1 meter or better

2 To provide a system which permits an onboard electronic system to determine the position of the edges and/or lane boundaries of a roadway with an accuracy of 1 meter or less m the vicinity of the vehicle To provide a system which permits an onboard vehicle electronic system to determine the position of the edges and/or lane boundaries of a roadway relative to the vehicle with an accuracy of less than 2 meters To provide a system that substantially reduces the incidence ot single vehicle accidents caused by the vehicle inappropriately leaving the roadway at high speed To provide a system which does not require modification to a roadway which permits high speed controlled travel of vehicles on the roadway thereby increasing the vehicle flow rate on congested roads To provide a collision avoidance system comprising a sensing svstem responsive to the presence of at least one other vehicle in the vicinity of the equipped vehicle and means to determine the location ot the other vehicle relative to the lane boundaries of the roadway and thereby determine if the other vehicle has strayed from its proper position on the highway thereby increasing the risk ot a collision, and taking appropriate action to reduce that risk To provide a means whereby vehicles near each other can communicate their position and/or their velocity to each other and thereby reduce the risk of a collision

8 To provide a means tor accurate maps of a roadway can be transmitted to a vehicle on the roadwav

9 To provide a means tor weathei road condition and/or similar information can be communicated to a vehicle traveling on a roadway plus means within the vehicle tor using that information to reduce the risk of an accident

10 To provide a means and apparatus tor a vehicle to preciselv know its location at certain positions on a road by passing through or over an infrastructure based local subsystem thereby permitting the vehicle electronic systems to self correct for the satellite errors making the vehicle for a brief period its own DGPS station 1 1 To utilize government operated navigation aid systems such as the WAAS and LARS as well as other available or to become available systems to achieve sub-meter vehicle location accuracies 12 To utilize the OpenGIS™ map database structure so as to promote open systems for accurate maps for the RtZF™ system

In contrast to some prior art systems, with the RtZF™ system of this invention, especially when all vehicles are appropriately equipped, automatic braking of the vehicle should rarely be necessary and steering and engine control should in most cases be sufficient to prevent accidents In most cases, braking means the accident wasn't anticipated

It is important to understand that this is a process control problem The process is designed so that it should not fail and thus all accidents should be eliminated Events that are troublesome to the system include a deer running in front ot the vehicle, a box falling off of a truck, a rock rolling onto the roadway and a catastrophic failure of a vehicle Continuous improvement to the process is thus required before these events are substantially eliminated Each individual driver is part of the system and upon observing that such an event has occurred he or she should have the option of stopping the process to prevent or mitigate an emergency All equipped vehicles therefore have the capability of communicating that the process is stopped and therefore that the vehicle speed, for example, should be substantially reduced until the vehicle has passed the troubled spot or until the problem ceases to exist In other words, each driver is part of the process

The RtZF™ system ot this invention will thus start simple by reducing single vehicle accidents and evolve The system has the capability to solve the entire problem by eliminating automobile accidents

This invention is a method and apparatus for eliminating accidents by accurately determining the position of a vehicle, accurately knowing the position of the road and communicating between vehicles and vehicle and the infrastructure People get into accidents when they go too fast for the conditions and when they get out of their corridor This invention eliminates these and other causes of accidents In multilane highways, this system prevents people from shifting lanes if there are other vehicles in the blind spot, thus, solving the blind spot problem The vehicle would always be traveling down a corridor where the width of the corridor may be a lane or the entire road width or something in between depending on road conditions and the presence of other vehicles

The invention is implemented through the use of both an inertial navigation system (INS) and a DGPS ion some cases with carrier frequencv enhancement Due to the tact that the signals from at least four GPS or GLONASS satellites are not always available and to errors caused bv multiple path reception from a given satellite, the DGPS svstems cannot be totally relied upon Therefore the INS is a critical part of the system This will improve as more satellites are launched and additional ground stations are added It will also significantlv improve when the WAAS system in implemented and refined to work with land vehicles as well as airplanes

Other improvements will now be obvious to those skilled in the art The above features are meant to be illustrative and not definitive 1.4 Brief review of the drawings

Fig 1 illustrates the GPS satellite system with the 24 satellites revolving around the earth Fig 2 illustrates four such satellites and a pseudohte transmitting position information to a vehicle and to a base station which in turn transmits the differential correction signal to the vehicle

Fig 3 is a logic diagram showing the combination of the GPS system and an inertial navigation system

Fig 4 illustrates a vehicle traveling on a roadway in a defined corridor

Fig 5 illustrated two adjacent vehicles traveling on a roadway and communicating with each other

Fig 6 illustrates the use of three micropower impulse radar transmitters in a configuration to allow a vehicle to accurately determine its position

Fig 7 is a schematic illustration of the system in accordance with the invention Fig 8 is a flow chart ot the method in accordance with the invention

2. Description of GPS system

2.1 Background of GPS

Referring to Fig 1 the presently implemented Global Positioning System with its constellation of 24 satellites 102 is truly revolutionizing navigation throughout the world The satellites orbit the Earth in six orbits 104 However, in order to reach its full potential for airline navigation, GPS needs to be augmented both to improve accuracy and to reduce the time needed to inform an aircraft pilot of a malfunction of a GPS satellite, the so-called integrity problem

The Global Positioning System (GPS) is a satellite-based navigation and time transfer system developed by the U S Department of Defense GPS serves marine, airborne and terrestrial users, both military and civilian Specifically, GPS includes the Standard Positioning Service (SPS) that provides civilian users with 100 meter accuracy as to the location or position of the user It also serves military users with the Precise Positioning Service (PPS) which provides 20 meter accuracy tor the user Both of these services are available worldwide with no requirement for any local equipment Differential operation of GPS is used to improve the accuracy and integrity of GPS Differential

GPS places one or more high quality GPS receivers at known surveyed locations to monitor the received GPS signals This reference statιon(s) estimates the slowly varying components of the satellite range measurements, and forms a correction for each GPS satellite in view The correction is broadcast to all DGPS users within the coverage area of the broadcast facilities For a good discussion of DGPS. for following paragraphs are reproduced from OMNISTAR

The new OMNISTAR Model 6300A offers unprecedented versatility for portable, real-time, DGPS positioning It can improve the accuracy of a GPS receiver by as much as 100 times If your product or service needs precise positioning information, then chances are good that OMNISTAR can supply that need, and at a reasonable cost OMNISTAR is a Differential GPS (DGPS)System It is capable of improving regular GPS to sub-meter accuracy GPS computes a user's position by measuring ranges (actually, pseudoranges. which are ranges that are calculated by an iterative process) to three or more GPS satellites simultaneously The Department of Defense (DOD) is intentionally limiting the accuracy of the calculation by continuously changing the onboard clock on the satellites This process is called Selective Availability, or "SA" This appears as a continuous variation in the user's position Using GPS in an unconⁿected (stand-alone) mode, a user s calculated position will continuously move around the true position in a near-random pattern The indicated position may move out as far as 100 meters from the true position The randomness makes it impossible to predict If a user samples the position data over a long period of time, such as 24 hours, the average or mean will likely be within a meter of the true position. In statistical terms, the standard deviation will be approximately 15 to 20 meters in each horizontal coordinate A DGPS System generates corrections for SA and other errors This is accomplished by the use of one or more GPS "Base Stations" that measure the errors in the GPS system and generate corrections A "real-time" DGPS System not only generates the corrections, but provides some methodology for getting those corrections to users as quickly as possible This always involves some type of radio transmission system They may use microwave systems for short ranges, low frequencies for medium ranges and geostationary satellites for coverage of entire continents

The method of generating corrections is similar in most DGPS systems A GPS base station tracks all GPS Satellites that are in view at its location The internal processor knows the precise surveyed location of the base station antenna, and it can calculate the location in space of all GPS satellites at any time bv using the epheremis that is a part of the normal broadcast message from all GPS satellites From these two pieces of information, an expected range to each satellite can be computed at any time. The difference between that computed range and the measured range is the range error. If that information can quickly be transmitted to other nearby users, they can use those values as corrections to their own measured GPS ranges to the same satellites. The key word is "quickly", because of the rapid change in the SA errors. In most radio systems, bandwidth is a finite limitation which dictates how much data can be sent in a given time period. That limitation can be eased somewhat by having the GPS base station software calculate the rate of change of the errors and add that information as part of the correction message. That term is called the range rate value and it is calculated and sent along with the range correction term. The range correction is an absolute value, in meters, for a given satellite at a given time of day. The range rate term is the rate that correction is changing, in meters per second. That allows GPS user sets to continue to use the "correction, plus the rate-of-change" for some period of time while it's waiting for a new message. The length of time you can continue to use that data without an update depends on how well the range rate was estimated. In practice, it appears that OMNISTAR would allow about 12 seconds before the DGPS error would cause a one meter position error. In other words, the ""age of data" can be up to 12 seconds before the error from that term would cause a one meter position error. OMNISTAR transmits a new correction message every two and one/half seconds, so even if an occasional message is missed, the user's "age of data" is still well below 12 seconds.

The OMNISTAR DGPS System was designed with the following objectives: ( 1 ) continental coverage; (2) sub-meter accuracy over the entire coverage area: and (3) a portable system (backpack). The first objective dictated that the transmission system had to be from a geostationary satellite. We purchased a transponder on satellite Spacenet 3. which is located at 87 degrees West longitude. It has an antenna pattern that covers most of North America; specifically, all of the 48 states, the northern half of Mexico and the southern half of Canada. It also has sufficient power within that footprint that a tiny omnidirectional antenna can be used at the user's receiver.

The methodology developed by John E. Chance & Assoc. of using multiple GPS base stations in a user's solution and reducing errors due to the GPS signal traveling through the atmosphere, met the second objective. It was the first widespread use of a "Wide Area DGPS Solution". It is able to use data from a relatively small number of base stations and provide consistent accuracy over extreme distances. A unique method of solving for atmospheric delays and weighting of distant base stations, achieves sub-meter capability over the entire coverage area - regardless of the user's proximity to any base station. This achieves a truly nationwide system with consistent characteristics. A user can take the equipment anywhere within the coverage area and get consistent results, without any intervention or intimate knowledge of GPS or DGPS. The units being sold today are sufficiently portable that they can used in a backpack. They can include an internal GPS engine (optional) that will provide a complete solution in a single system package. All that is needed is a data collector or notebook computer for display and storage of corrected GPS data.

The OMNISTAR Network consists of ten permanent base stations that are scattered throughout the Continental US, plus one in Mexico. These stations track all GPS Satellites above 5 degrees elevation and compute corrections every 600 milliseconds. The corrections are in the form of an industry standard message format called RTCM- 104, Version II. The corrections are sent to the OMNISTAR Network Control Center in Houston via lease lines, with a dial back-up. At the NCC these messages are checked, compressed, and formed into a packet for transmission up to our satellite transponder. This occurs approximately every 2 to 3 seconds. A packet will contain the latest data from each of the 1 1 base stations. All OMNISTAR user sets receive these packets of data from the satellite transponder The messages are first decoded from the spread-spectrum transmission format and then uncompressed At that point, the message is an exact duplicate of the data as it was generated at each base station Next, the atmospheric errors must be corrected Everv base station automatically corrects tor atmospheric errors at it s location but the user is not at any of those locations so the corrections are not optimized for the user - and OMNISTAR has no information as to each individual s location If these errors are to be optimized for each user then it must be done in each user's OMNISTAR For this reason each OMNISTAR user set must be given an approximation of its location The approximation only needs to be within 50 to 100 miles of its true position Given that information, the OMNISTAR user set can remove most of the atmospheric correction from each Base Station message and substitute a correction for his own location In spite of the loose approximation of the user s location, this information is crucial to the OMNISTAR process It makes the operation totally automatic and it is necessary for sub-meter positioning If it is totally ignored errors of up to ten meters can result

Fortunately this requirement of giving the user s OMNISTAR an approximate location is easily solved If OMNISTAR is purchased with the optional internal GPS receiver installed the problem is taken care of automatically bv using the position output of the GPS receiver as the approximation It is wired internally to do exactly that An alternate method - when the internal GPS receiver is not present - is to use the user s external GPS receiver tor this function In that case the user s receiver must have an output message in one of the approved formats (NMEA) and protocols that OMNISTAR can recognize

That output can be connected back to the OMNISTAR set by using the same cable that normally supplies the RTCM-104 from OMNISTAR to the user's GPS receiver This method works perfectly well when all the requirements on format and protocol are met There is a third method where a user uses a notebook computer to type in an estimated location into the OMNISTAR user set Any location entered by this method is preserved - with an internal battery - until it is changed This method works fine where the user does not intend to go more than 50- 100 miles from some central location After the OMNISTAR processor has taken care ot the atmospheric corrections it then uses it's location versus the eleven base station locations in an inverse distance-weighted least-squares solution The output of that least-squares calculation is a synthesized RTCM-104 Correction Message that is optimized for the user's location It is always optimized for the user s location that is input from the user's GPS receiver or as an approximation that is typed in from a notebook computer This technique is called the ' Virtual Base Station Solution" It is this technique that enables the OMNISTAR user to operate independently and consistently over the entire coverage area without regard to where he is in relation to our base stations As far as we have determined users are obtaining the predicted accuracy over the entire area '

The above description is provided to illustrate the accuracy which can be obtained from the DGPS system It is expected that the WAAS svstem when fully implemented will provide the same benefits as provided by the OMNISTAR system However when the standard deviation of approximately 5 meter is considered, it is evident that this WAAS system is insufficient by itself and will have to be augmented by other systems to improve the accuracy GLONASS is a Russian system similar to GPS This system provides accuracy that is better than GPS with SA on and not as good as GPS with SA off It is expected that SA will be removed before the system described herein is implemented

The Projected Position Accuracy ot GPS and GLONASS, Based on the Current Performance is Horizontal Error (m) Vertical Error (m)

(50%) (9 (95%)

GPS (SA off) 7 18 34

GPS (SA on) 27 72 135

GLONASS 10 26 45

GGPPSS++GGLLOONNAASSSS 99 2200 38

The system described here will achieve a higher accuracy than reported in the above table due to the combination of the inertial guidance system that permits accurate changes in position to be determined and through multiple GPS readings In other words, the calculated position will converge to the real position over time The addition of DGPS will provide an accuracy improvement of at least a factor of 10, which, with the addition of a sufficient number of pseudohte and DGPS stations in some cases is sufficient without the use of the carrier frequency correction A further refinement where the vehicle becomes its own DGPS station through the placement of infrastructure stations at appropriate locations on roadways will further significantly enhance the system accuracy to the required level

Multipath is the situation where more than one signal from a satellite comes to a receiver with one of the signals resulting from a reflection off of a building or the ground, for example Since multipath is a function of geometry, the system can be designed to eliminate its effects based on highway surveying and appropriate antenna design Multipath from other vehicles can also be eliminated since the location of the other vehicles will be known 2.2 DGPS As discussed below, the Wide Area Augmentation System (WAAS) is being installed by the US

Government to provide DGPS for airplane landings The intent is to cover the entire continental U S (CONUS) This may be useful for much of the country tor the purposes of this invention Another alternative would be to use the cellular phone towers, since there are so many of them, if they could be programmed to act as pseudohtes An important feature of DGPS is that the errors from the GPS satellites change slowly with time and therefore, only the corrections need be sent to the user from time to time Using reference receivers separated by 25-120 km, accuracies from 10 cm to 1 m are achievable using DGPS which is marginal for RtZF™ Alternately, through the placement of appropriate infrastructure transmitters as described below even better accuracies are obtainable A type of wide area DGPS system has been developed spans the entire US continent which provides position RMS accuracy to better than 50 cm This system is described in the Bertiger, et al, "A Prototype Real-Time Wide Area Differential GPS System " Proceedings ot the National Technical Meeting, Navigation and Positioning in the Information Age, Institute of Navigation, January 14-16, 1997 pp. 645-655 A RMS error of 50 cm would be marginally accurate for RtZF™ Many of the teachings of this invention especially it the road edge and lane location error were much less which could be accomplished using more accurate surveving equipment

A similar DGPS system which is now being implemented on a nationwide basis is described in " "DGPS Architecture Based on Separating Error Components Virtual Reference Stations and FM Subcarrier Broadcast" by Differential Corrections Inc , 10121 Miller Ave Cupertino CA 95041 The system described in this paper promises an accuracy on the order of 10 cm

Suggested DGPS update rates are usually less than twenty seconds DGPS removes common- mode errors, those errors common to both the reference and remote receivers (not multipath or receiver noise) Errors are more often common when receivers are close together (less than 100 km) Differential position accuracies of 1-10 meters are possible with DGPS based on C/A code SPS signals

Using the Cnet commercial system, 1 foot accuracies are possible if base stations are no more than 30 miles from the vehicle unit This would require approximately 1000 base stations to cover CONUS Alternately, the same accuracy is obtainable if the vehicle can become its own DGPS system every 30 miles as descπbed below Untortunatelv the respective error sources mentioned above rapidlv decorrelate as the distances between the reference station and the vehicle increases Conventional DGPS is the terminology used when the separation distances are sufficiently small that the errors cancel The terms single-reference and multi- reference DGPS are occasionally used in order to emphasize whether there is a single reference station or whether there are multiple ones It it is desired to increase the area of coverage and, at the same time, to minimize the number of fixed reference receivers, it becomes necessary to model the spatial and temporal variations of the residual errors Wide Area Differential GPS (WADGPS) is designed to accomplish this In addition, funds have now been appropriated for the US Government to deploy a national DGPS system

2.3 Pseudolites

Pseudolites are artificial satellite like structures, can be deployed to enhance the accuracy of the DGPS svstem Such structures could become part ot the RtZF™ svstem

2.4 WAAS

The Wide Area Augmentation System (WAAS) is being deployed to replace the Instrument Landing System used at airports across the country The WAAS system provides an accuracy of from 1 to 2 meters for the purpose ot aircraft landing If the vertical position of the vehicle is known, as would be in the case of automobiles at a known position on a road, this accuracy can be improved significantly Thus, for many of the purposes of this invention, the WAAS can be used to provide accurate positioning information for vehicles on roadways The accuracy of the WAAS is also enhanced by the fact that there is an atomic clock in every WAAS receiver station that would be available to provide great accuracy using carrier phase data With this system sub-meter accuracies are possible for some locations The WAAS is based on a network of approximately 35 ground refeience stations Signals from

GPS satellites are received by aircraft receivers as well as by ground reference stations Each of these reference stations is precisely surveyed enabling each to determine any error in the GPS signals being received at its own location This information is then passed to a wide area master station The master station calculates correction algorithms and assesses the integrity of the system This data is then put into a message format and sent to a ground earth station tor uplink to a geostationary communications satellite The corrective information is forwarded to the receiver on board the aircraft, which makes the needed adjustments The communications satellites also act as additional navigation satellites for the aircraft, thus, providing additional navigation signals for position determination This system will not meet all of FAA's requirements For category III landings, the requirement is

1 6-m vertical and horizontal accuracy To achieve this, FAA is planning to implement a network of local area differential GPS stations that will provide the information to aircraft This system is referred to as the Local Area Augmentation System (LAAS)

The WAAS system, which consists of a network of earth stations and geo-synchronous satellites, is currently being funded by the U S Government for aircraft landing purposes Since the number of people that die yearly in automobile accidents greatly exceeds those killed in airplane accidents, there is clearly a greater need for a WAAS type system for solving the automobile safety problem using the teachings of this invention Also, the reduction in required highway funding resulting from the full implementation of this invention would more then pay for the extension and tailoring of the WAAS to cover the nations highways

2.5 LAAS

The Local Area Augmented System (LAAS) is also being deployed in addition to the WAAS system to provide even greater coverage for the areas surrounding major airports According to Newsletter of the Institute of Navigation. 1997, "the FAA's schedule for (LAAS) for Category II and III precision instrument approaches calls for development of standards by 1998 that will be sufficient to complete a prototype system by 2001 The next step will be to work out standards for an operational system to be fielded in about 2005, that could serve nationwide up to about 200 runways for Cat 11— 111 approaches "

In a country like the United States, which has many airfields, a WAAS can serve a large market and is perhaps most effective for the control of airplane landings The best way for other countries, with fewer airports, to participate in the emerging field of GPS-based aviation aids may be to build LAAS In countries with a limited number of airports. LAAS is not very expensive while the costs of building a WAAS to get Category I type accuracy is very expensive However, with the added benefit of less highway construction and greater automobile safety, the added costs for a WAAS system may well be justified for much of the world For the purposes of the RtZF™ system, both the WAAS and LAAS would be useful but probably insufficient Unlike an airplane, there are many places where it might not be possible to receive LAAS and WAAS information or even more importantly the GPS signals themselves with sufficient accuracy and reliability Initial RtZF™ systems may therefore rely on the WAAS and LAAS but as the system develops more toward the goal of zero fatalities road based systems which permit a vehicle to pinpoint its location are preferred However, there is considerable development ongoing in this field so that all systems are still candidates for use with RtZF™ and only time will determine which are the most cost effective

2.6 Carrier Phase Measurements

An extremely accurate form of GPS is Carrier Based Differential GPS This form of GPS utilizes the 1.575 GHz carrier component of the GPS signal on which the Pseudo Random Number (PRN) code and the data component are superimposed Current versions ot Carrier Based Differential GPS involve generating position determinations based on the measured phase differences at two different antennas, a base station or pseudolite and the vehicle, for the carrier component of a GPS signal This technique mitiallv requires determining how manv integer wave-lengths of the carrier component exist between the two antennas at a particular point in time This is called integer ambiguity resolution A number of approaches currently exist for integer ambiguity resolution Some examples can be found in U S Patents 5.583,513 and 5,619.212 Such systems can achieve sub-meter accuracies and in some cases, accuracies of 1 cm U S Pat 5 477,458 discloses a DGPS system that is accurate to 5 cm with the base stations located on a radius of 3000 km With such a system very few base stations would be required to cover the continental United States This system still suffers from the availability ot accurate signals at the vehicle regardless of its location on the roadway and the location of surrounding vehicles and objects Nevertheless the principle ot using the carrier frequency to preciseK determine the location of a vehicle can be used with the highway based systems described below to provide extreme location accuracies Using the svstem described below where a vehicle becomes its own DGPS system, the carrier phase ambiguity problem also disappears 2.7 Other Aids

There are other sources of information that can be added to increase the accuracy of position determination The use of GPS with tour satellites provides the three dimension location of the vehicle plus time Of the dimensions the vertical is the least accurately known, yet. if the vehicle knows where it is on the roadway the vertical dimension is not only the least important but it is also already accurately known from the roadmap information plus the inertial guidance system

Another aid is to provide markers along side the roadway which can be either visual, passive or active transponders reflectors, or a variety of other technologies which have the property that as a vehicle passes the marker it can determine the identity of the marker and from a data base it can determine the exact location of the marker If three or more of such markers are placed along side ot the roadway, a passing vehicle can determine its exact location by tπangulation Although it may be impractical to initially place such markers along all loadways, it would be reasonable to place them in particularly congested areas or places where it is known that a view of one or more of the GPS satellites is blocked A variation of this concept will be discussed below Although initially it is preferred to use the GPS navigational satellites as the base technology, the invention is not limited thereby and contemplates using all methods by which the location of the vehicle can be accurately determined relative to the earth surface The location of the roadway boundaries and the location of other vehicles relative to the earth surface are also to be determined and all relevant information used in a control system to substantially reduce and eventually eliminate vehicle accidents Only time and continued system development will determine the mix of technologies that provide the most cost effective solution All forms of information and methods of communication to the vehicle are contemplated including direct communication with stationary and moving satellites, communication with fixed earth based stations using infrared, optical, radar, radio and other segments of the electromagnetic spectrum Some additional examples follow A pseudo-GPS can be delivered from cell phone stations, in place of or in addition to satellites DGPS corrections can be communicated to a vehicle via FM radio via a sub-carrier frequency for example An infrared or radar transmitter along the highway can transmit road boundary location information. A CD-ROM or other portable mass storage can be used at the beginning of a controlled highway to provide road boundary information to the vehicle Finally, it is contemplated that eventually a satellite will broadcast periodically, perhaps every five minutes, a table ot dates covering the entire CONUS that provides the latest update date ot each map segment If a particular vehicle does not have the latest information for a particular region where it is operating, it will be able to use its cell phone to call and retrieve such road maps perhaps through the Internet Emergency information would also be handled in a similar manner so that if a tree fell across the highway, all nearby vehicles would be notified 2.8 Other Location Fixing Systems

It is expected, especially initially, that there will be many holes in the DGPS or GPS and their various implementations that will leave the vehicle without an accurate means of determining its location The inertial navigation system described below will help in filling these holes but its accuracy is limited to a time period significantly less than an hour and a distance of less than 50 miles before it needs correcting That may not be sufficient to cover the period between DGPS availability It is therefore contemplated that the RtZF™ system will also make use ot low cost systems located along the roadways that permit a vehicle to accurately determine its location One example of such a system would be to use a group of three Micropower Impulse Radar (MIR) units such as developed by Lawrence Livermore Laboratory A MIR operates on very low power and periodically transmits a very short spread spectrum radar pulse. The estimated cost of a MIR is less than $10 even in small quantities If three such MIRs, 51, 52 and 53, as shown in FIG 6, are placed along the highway and triggered simultaneously, and it a vehicle has an appropriate receiver system, the time of arrival of the pulses can be determined and thus the location of the vehicle relative to the transmitters determined The exact location of the point where all three pulses arrive simultaneously would be the point that is equal distant from the three transmitters and would be located on the map information Thus it would not even be necessary to have the signals contain identification information since the vehicle would not be so far off in its position determination system to confuse different locations By this method, the vehicle would know exactly where it was whenever it approached and passed such a tπple-MIR installation Naturally, several such readings and position determinations can be made with one approach to the MIR installation, the vehicle need not wait until they all arrive simultaneously Also the system can be designed so that the signals never arrive at the same time and still provide the same accuracy as long as there was a sufficiently accurate clock on board One way at looking at FIG 6 is that transmitters 51 and 52 fix the lateral position of the vehicle while transmitters 51 and 53 fix the location of the vehicle longitudinally The three transmitters need not be along the edges on one lane but could span multiple lanes and they need not be at ground level but could be placed sufficiently in the air so that passing trucks would not block the path of the radiation from an automobile Particularly in congested areas it might be desirable to code the pulses and to provide more than three transmitters to further protect against signal blockage or multipath The power requirements for the MIR are sufficiently low that a simple photoelectric cell array can provide sufficient power for most if not all CONUS locations With this exact location information, the vehicle can become its own DGPS station and determine the corrections necessary for the GPS It can also determine the integer ambiguity problem and thereby know the exact number of wave lengths between the vehicle and the satellites or the vehicle and the last MIR installation

MIR is one of several technologies that can be used to provide precise location determination Others include the use of an RFID tag that is designed in cooperation with its interrogator to provide a distance to the tag measurement and radar or other reflectors where the time of flight can be measured

Once a vehicle passes a precise positioning station such as the MIR triad described above, the vehicle can communicate this information to surrounding vehicles If the separation distance between two communicating vehicles can also be determined by some type of time-of-flight method, then the vehicle that has just passed the triad can in effect become a satellite equivalent or moving pseudolite This then begins the process of eventually eliminating the dependence on the GPS satellites Finally if many vehicles are communicating their positions to many other vehicles along with an accuracy of position assessment each vehicle can use this information along with the measured separation distances to improve the accuracy that its position in known In this manner as the number of such vehicles increases the accuracy ot the whole svstem increases and dependence on the GPS satellites decreases until an extremely accurate positioning svstem for all vehicles results Such a system since in combines many sources of position information is tolerant of the failure of any one or even several such sources Thus, the RtZF™ system becomes analogous to the Internet in that it can't be shut down and the goal of perfection is approached Some of the problems associated with this concept will be discussed in more detail below 2.9 Inertial Navigation Svstem

In many cases especially before the svstem implementation becomes mature and the complete infrastructure is in place, there will be times when the system is not operational This could be due to obstructions hiding a clear view ot a sufficient number of GPS satellites such as when a vehicle enters a tunnel It could also be due to a lack ot road boundary information due to construction or the fact that the road has not been surveyed and the information recorded and made available to the vehicle, or a variety of other causes It is contemplated therefore, that each equipped vehicle will contain a warning light that warns the driver when he is at a position where the system is not operational If this occurs on one of the especially designated highway lanes the vehicle speed will then also be reduced until the system again becomes operational

When the system is non-operational for a short distance, the vehicle will still accurately know its position if there is in addition a laser gyroscope, micromachined angular rate sensor or equivalent, and some other velocity or position measuring system which together is referred to as an Inertial Navigation System (INS)

In implementations where control of the vehicle steering is assumed by the system at least to the extent that the vehicle is prevented from leaving its assigned corridor the vehicle should also have a yaw rate sensor rather than reiving on a steering wheel angle sensor which can be less accurate As more sensors which are capable of providing information on the vehicle position, velocity and acceleration are added onto the vehicle, the system can become sufficiently complicated as to require a neural network system to permit the optimum usage of the available information This becomes even more important when information from outside the vehicle other than the GPS related systems becomes more and more available For example, a vehicle may be able to communicate with other vehicles that have similar systems and learn their estimated location If the vehicle can independently measure the position of the other vehicle for example through the use of the scanning impulse laser radar system descπbed below, and thereby determine the relative position of the two or more vehicles, a further improvement of the position can be determined for all such vehicles Adding all such additional information into the system would probably require a computational method such as neural networks or a combination of a neural network and a fuzzy logic system 2.10 Conclusion - How Used

One way to imagine the system operation is to consider each car and roadway edge to behave as if it had a surrounding "force field" that would prevent it from crashing into another vehicle or an obstacle along the roadwav A vehicle operator would be prevented from causing his or her vehicle to leave its assigned corridor This is accomplished with a control system that controls the steering, acceleration and perhaps the vehicle brakes based on its knowledge of the location of the vehicle highway boundaries and other nearby vehicles In a preferred implementation, the location of the vehicle is determined by first using the GPS L I signal to determine its location within approximately 100 meters Then using DGPS and corrections which are broadcast whether by FM or downloaded from geo-synchronous or Low Earth Orbiting (LEO) satellites or obtained from road based transmitters to determine its location within less than 10 centimeters Finally the use of a MIR or similar system periodically permits the vehicle to determine its exact location and thereby determine the GPS corrections eliminate the carrier cycle ambiguity and set the INS system If this is still not sufficient then the phase of the carrier frequency provides the required location information to a few centimeters Dead reckoning, using vehicle speed, steering angle and tire rotation information and/or inertial guidance, is used to fill in the gaps Where satellites are out ot view, pseudolites. or other systems, are placed along the highway A pulsed scanning infrared laser radar system, or an equivalent system, is used for near obstacle detection Communication to other vehicles is by short distance radio or by spread spectrum time domain pulse radar as descπbed by Time Domain Incorporated One problem which will require addressing as the system becomes mature is satellite temporary blockage by large trucks or other movable objects whose location cannot be foreseen by the system designers Another concern is to prevent vehicle owners from placing items on the vehicle exterior that block the GPS and communication antennas 3. Communication with other vehicles - Collision Avoidance MIR might also be used tor Vehicle to vehicle communication except that it is line of sight An advantage is that we can know when a particular vehicle will respond by range gating Also the short time of transmission permits many vehicles to communicate at the same time 3.1 Description - Requirements The communication between vehicles tor collision avoidance purposes cannot solely be based on line-of-sight technologies as this is not sufficient since vehicles which are out of sight can still cause accidents On the other hand, vehicles that are a mile away but still in sight, need not be part of the communication svstem Messages sent by each vehicle ot the subiect invention would contain information indicating exactlv where it is located and perhaps information as to what type ot vehicle it is The subject vehicle can therefore eliminate all of those vehicles that are not potential threats even if such vehicles are very close, but on the other side of the highway barrier

The use of an Ethernet protocol will satisfy the needs of the network, which would consist of all threatening vehicles in the vicinity of the subject vehicle Alternately a network where the subject vehicle transmits a message to a particular vehicle and waits for a response could be used From the response time, the relative position of other vehicles can be ascertained which provides one more method of position determination Thus, the more vehicles that are on the road with the equipped system, the greater accuracy of the overall system and thus the safer the system becomes as described above

To prevent accidents caused by a vehicle leaving the road surface and impacting a roadside obstacle requires onlv an accurate knowledge of the position of the vehicle and the road boundaries To prevent collisions with other vehicles requires that the position ot all nearby automobiles must be updated continuously But just knowing the position of a threatening vehicle is insufficient The velocity, size and orientation ot the vehicle is also important in determining what defensive action may be required Once all vehicles are equipped with the svstem ot this invention, the communication of all relevant information will take place via a radio communication link In addition to signaling its absolute position, each vehicle will send a message identifying the approximate mass, velocity orientation and other relevant information This has the added benefit that emergency vehicles can make themselves known to all vehicles in their vicinity and all such vehicles can then take the appropriate action The same system can also be used to relay accident or other hazard information from vehicle to vehicle 3.2 Preferred System

One preferred method of communication between vehicles uses that portion of the electromagnetic spectrum that permits only line ot sight communication In this manner, only those vehicles that are in view can communicate In most cases, a collision can only occur between vehicles that can see each other This system has the advantage that the "communications network" only contains nearby vehicles This would require that when a truck, for example, blocks another stalled vehicle that the information from the stalled vehicle be transmitted via the truck to a following vehicle An improvement in this system would use a rotating aperture that would only allow communication from a limited angle at a time further reducing the chance for multiple messages to interfere with each other Each vehicle transmits at all angles but receives at only one angle at a time This has the additional advantage of confirming at least the direction of the transmitting vehicle An infrared rotating receiver can be looked at as similar to the human eye That is, it is sensitive to radiation from a range of directions and then focuses in on the particular direction, one at a time, from which the radiation is coming It needn't scan continuously In fact the same transmitter which transmits 360 degrees could also receive from 360 degrees with the scanning done m software A alternate preferred method is to use short distance radio communication so that a vehicle can receive position information from all nearby vehicles such as the DS/SS system The location information received from each vehicle can then be used to eliminate it from further monitoring if it is on a different roadway or not in a potential path of the subject vehicle Many communications schemes have been proposed for inter-vehicle and vehicle to road communication At this time the suggested approach utilizes DS/SS communications in the 2 4 GHz INS band Experiments have shown that communications are 100 percent accurate at distances up to 200 meters At a closing velocity of 200 KPH. at 5 g deceleration, it requires 30 meters for a vehicle to stop Thus, communication accurate to 200 meters is sufficient to cover all vehicles that are threatening to a particular vehicle

A related method would be to use a MIR system in a communications mode Since the width of the pulses typically used by MIR is less than a nanosecond, many vehicles can transmit simultaneously without fear of interference

With either system other than the MIR system, the potential exists that more than one vehicle will attempt to send a communication at the same time and there will then be a data collision If all of the communicating vehicles are considered as being part of a local area network the standard Ethernet protocol can be used to solve this problem In that protocol when a data collision occurs each of the transmitting vehicles which was transmitting at the time of the data collision would be notified that a data collision had occurred and that they should retransmit their message at a random time later When several vehicles are in the vicinity and there is the possibility of collisions of the data each vehicle can retain the coordinates last received fiom the surrounding vehicles as well as their velocities and predict their new locations even though some data was lost

If a line of sight svstem were used an infrared or MIR svstem would be good choices In the infrared case and if an infrared system were also used to interrogate the environment for non-equipped vehicles, pedestrians animals etc as will be discussed below both systems could use some of the same hardware

If point to point communication can be established between vehicles, such as described in U S Pat 5,528,391 to Elrod. then the need for a collision detection svstem like Ethernet would not be required If the receiver on a vehicle, for example, only has to listen to one sender from one other vehicle at a time, then the bandwidth can be considerably higher since there will not be any interruption

When two vehicles are communicating their positions to each other, it is possible through the use of range gating or the sending of a clear to send signal and timing the response to determine the seperation of the vehicles This assumes that the properties of the path between the vehicles in know which would be the case if the vehicles are within view of each other If on the other hand there is a row ot trees between the two vehicles, a false distance measurement would be obtained if the radio waves pass through a tree If the communication frequency is low enough that it can pass through a tree in the above example it will be delayed If it is a much higher frequency such that is blocked by the tree then it still might reach the second vehicle through a multi-path Thus, in both cases an undetectable range error results If a range of frequencies is sent as in a spread spectrum and the first arriving pulse contains all of the sent frequencies then it is likely that the two vehicles are in view of each other and the range calculation is accurate If any of the frequencies are delayed then the range calculation can be considered inaccurate and should be ignored

3.3 Enhancements In the accident avoidance system of the present invention, the information indicative of a collision could come from a vehicle that is quite far away from the closest vehicles to the subject vehicle This is a substantial improvement over the prior art collision avoidance systems which can only react to a few vehicles in the immediate vicinity The system described herein also permits better simultaneous tracking of several vehicles For example if there is a pileup of vehicles down the highway then this information can be transmitted to control other vehicles that are still a significant distance from the accident This case cannot be handled by prior art systems Thus, the system described here has the potential to be part of the U S Pat 5.572.428 to Ishida. for example

The network analogy can be extended if each vehicle receives and retransmits all received data as a single block of data In this way. each vehicle is assured in getting all of the relevant information even if it gets it from manv sources Even with many vehicles the amount of data being transmitted is small relative to the bandwidth of the infrared optical or radio technologies Naturally, in some particular cases, a receiver and retransmitter can be part of the highwav infrastructure Such a case might be on a hairpin curve in the mountains where the oncoming traffic is not visible

In some cases it may be necessary for one vehicle to communicate with another to determine which evasive action each should take This could occur in a multiple vehicle situation when one car has gone out of control due to a blowout, for example In such cases, one vehicle may have to tell the other vehicle what evasive actions it is planning The other vehicle can then calculate whether it can avoid a collision based of the planned evasive action of the first vehicle and if not it can inform the first vehicle that it must change its evasive plans The other vehicle would also inform the first vehicle as to what evasive action it is planning Several vehicles communicating in this manner can determine the best paths for all vehicles to take to minimize the danger to all vehicles

If a vehicle is stuck in a corridor and wish to change lanes in heavy traffic, the operator's intention can be signaled by the operator activating the turn signal This could send a message to other vehicles to slow down and let the signaling vehicle change lanes This would be particularly helpful in an alternate merge situation

4. Communication with highway - Maps

4.1 Statement of the Problem

The initial maps showing roadway lane and boundary location for the CONUS should preferably be installed within the vehicle at the time of manufacture The vehicle thereafter would check on a section by section basis whether it had the latest update information for the particular and surrounding locations where it is being operated One method of verifying this information would be achieved if a satellite periodically broadcasts the latest date and time that each segment had been most recently updated This matrix would amount to a small transmission requiring perhaps one minute of airtime Any additional emergency information could also be broadcast in between the periodic transmissions to cover accidents, trees falling onto roads etc If the periodic transmission were to occur everv five minutes and if the motion of a vehicle were somewhat restricted until it had received a periodic transmission, the safety of the system can be assured If the vehicle finds that it does not have the latest map information, the cell phone in the vehicle can be used to log onto the Internet, for example and the missing data downloaded An alternate is for the LEOs to broadcast the map corrections directly

It is also possible that the map data could be off loaded from a transmitter on the highway itself In that manner the vehicles would only obtain that map information which it needed and the map information would alwavs be up to the minute As a minimum, temporary data communication stations can be placed before highway sections that are undergoing construction or where a recent blockage has occurred and where the maps have not yet been updated Such an emergency data transfer would be signaled to all approaching vehicles to reduce speed and travel with care Naturally such information could also contain maximum and minimum speed information which would limit the velocity of vehicles in the area

There is other information that would be particularly useful to a vehicle operator or control svstem including in particular the weather conditions especially at the road surface Such information could be obtained by road sensors and then ti ansmitted to all vehicles in the area by a peπnanentlv installed system Alternately there have been lecent studies that show that icing conditions on road surfaces, for example, can be accurately predicted bv local meteorological stations and broadcast to vehicles in the area In such a svstem is not present then, the best place to measure road friction is at the road surface and not on the vehicle The vehicle requires advance information of an icmg condition in order to have time to adjust its speed or take other evasive action The same road based or local meteorological transmitter system could be used to warn the operators of traffic conditions construction delays etc and to set the local speed limit 4.2 Maps All information regarding the road both temporary and permanent should be part of the map data base, including speed limits presence ot guard rails width of each lane width of the highwav width of the shoulder exactly where the precise position location apparatus is located etc The Speed limit associated with particular locations on the maps should be coded in such a way that the speeds limit can depend upon the time of day and the weather conditions In other words, the speed limit is a variable that will change from time to time depending on conditions It is contemplated that there will be a display for various map information present which will always ba in view for the passenger and for the driver at least when the vehicle is operating under automatic control Additional user information can thus also be displayed such as traffic conditions weather conditions advertisements, locations of restaurants and gas stations etc

A map showing the location of road and lane boundaries can be easily generated using a specially equipped survey vehicle that has the most accurate position measurement svstem available In some cases, it might be necessary to set up one or more temporary local DGPS base stations in order to permit the survey vehicle to know its position within a few centimeters The vehicle would drive down the roadway while operators, using specially designed equipment sight the road edges and lanes This would probably best be done with laser pointers and cameras Transducers associated with the pointing apparatus record the angle of the apparatus and then by tπangulation determine the distance of the road edge or lane marking from the survey vehicle Since the vehicle's position would be accurately known, the boundaries and lane markings can be accurately determined It is anticipated that the mapping activity would take place continuously such that all roads in a particular state would be periodically remapped in ordei to pickup up any changes which were missed by other monitoring systems and to improve the reliability ot the maps by minimizing the chance for human error

The above described method depends on human skill and attention and thus is likely to result in many errors A preferred approach is to carefully photograph the edge of the road and use the laser pointers to determine the location of the road lines relative to the pointers and to determine the slope of the roadwav through tπangulation In this case several laser pointers would be used emanating from above, below and to the sides of the camera The reduction of the data is then done later using equipment that can automatically pick out the lane markings and the reflected spots from the laser pointers

In some cases where the roadway is straight, the survey vehicle could travel at moderate speed while obtaining the boundary and lane location information In other cases, where the road in turning rapidly more readings would be required per mile and the survey vehicle would need to travel more slowly In anv case the required road information can be acquned semi-automatically with the survey vehicle traveling at a moderate speed Thus, the mapping of a particular road would not require significant time or resources It is contemplated that a tew such survey vehicles could map all ot the major roads in the United States in less than one vear The mapping effort could be supplemented and cross-checked though the use of accurate detailed digital photogrammetic svstems which for example, can determine the road altitude with an accuracy to <50 cm Efforts are underway to map the earth with 1 meter accuracy The generated maps could be used to check the accuracy of the road determined maps

Another improvement that can be added to the system based on the maps is to use a heads up display for in-vehicle signage As the vehicle travels down the road, the contents of road side signs can be displayed on a heads up display providing such a display is available in the vehicle, or on a specially installed LCD display This is based on the inclusion in the map database the contents of all highway signs A further improvement would be to include signs having varying messages which would require that the message be transmitted to the vehicle and received and processed for in vehicle display As the roadway is being mapped, the availability of GPS satellite view and the presence of multipath reflections from fixed structures can also be determined This information can then be used to determine the advisability of locating a local precise location system at a particular spot on the roadway Cars can also be used as probes for this process and for continuous improvement to check the validity of the maps and report anv errors Multipath is the situation where more than one signal from a satellite comes to a receiver with one of the signals resulting from a reflection off of a building or the ground, for example Since multipath is a function of geometry, the system can be designed to eliminate its effects based on highway surveying and appropriate antenna design Multipath from other vehicles can also be eliminated since the location of the other vehicles will be known 4.3 Privacy

People do not necessarily want the government to know where they are going and therefore will not want information to be transmitted that can identify the vehicle The importance of this issue may be overestimated Most people will not object to this minor infraction if they can get to their destination more efficiently and safely

On the other hand, it has been estimated that there are 100 000 vehicles on the road, many of them stolen, where the operators do not want the vehicle to be identified If an identification process that positively identifies the vehicle were made part of this system it could thus cut down on vehicle theft Alternately, thieves might attempt to disconnect the system thereby defeating the full implementation of the system and thus increasing the danger on the roadways and defeating the RtZF objective The state of the system would therefore need to be self-diagnosed 5. Sensing of non-RtZF equipped objects

5.1 Problem Statement

Vehicles with the RtZF™ system of this invention must also be able to detect those vehicles that do not have the s stem as well as pedestrians animals, bicyclists, and other hazards that may cross the path of the equipped vehicle

5.2 Prior Art

Although, there appears not to be any significant prior art involving a vehicle communicating safety information to another vehicle on the roadway, several of the prior art patents discuss methods of determining that a collision might take place using infrared and radar U S Pat 5.249, 128 to Markandey et al , for example, discusses methods of using infrared to determine the distance to a vehicle in front and U.S Pat 5,506.584 to Boles discloses a radar based system Both systems suffer from a high false alarm rate and could be substantially improved if a pattern recognition system such as neural networks were used

5.3 Description Systems based on radar have suffered from the problem ot being able to sufficiently resolve the images which are returned to be able to identify the other vehicles, bridges etc One method used for adaptive cruise control systems is to ignore everything that is not moving This, of course, leads to accidents if this were used with the instant invention The problem stems from the resolution achievable with radar unless the antenna is made very large Since this is impractical for use with automobiles, only minimal collision avoidance can be obtained using radar

Optical systems can provide the proper resolution but may require illumination with a bright light or laser If the laser is in the optical range, there is a danger of causing eye damage to pedestrians or vehicle operators As a minimum it will be found distracting and annoying to other vehicle operators A laser operating in the infrared part of the electromagnetic spectrum avoids the eye danger problem and, since it will not be seen, it will not be annoying Infrared also has the proper resolution so that pattern recognition technologies can be employed to recognize various objects, such as vehicles, in the reflected image Infrared has another advantage from the object recognition perspective All objects radiate and reflect infrared The hot engine of a moving vehicle in particular is a recognizable signal Thus, if the area around a vehicle is observed with both passive and active infrared, more information can be obtained than from radar, for example Infrared is less attenuated by fog than optical frequencies, although it is not as good as radar Infrared is also attenuated by snow but at the proper frequencies it has about five times the range of human sight

An example of such an instrument is made by Sumitomo Electric and is sufficient for the purpose here The Sumitomo product has been demonstrated to detect leaves of a tree at a distance of 300 meters The product operates at a 1 5 micron wavelength

This brings up a philosophical discussion about the trade-offs between radar with greater range and infrared laser radar with more limited range but greater resolution At what point should driving duπng bad weather conditions be prohibited⁰ If the goal of zero fatalities is to be realized, then people should not be permitted to operate their vehicles during dangerous weather conditions This may require closing roads and highways prior to the start of such conditions Under such a policy a system which accurately returns images of obstacles on the roadway that are five times the visual distance should be adequate In such a case, radar would not be necessary These and other similar design trade-off issues will be resolved prior to the submission of a proposal for a Phase One IVI effort

Laser Radar scanning svstem

The digital map can be used to define the field that the laser radar scanner will interrogate The laser radar scanner will return information as to distance to an object in the scanned field This will cover all objects that are on or adjacent to the highway The laser pulse can be a pixel that is one inch in diameter at 100 feet, for example The scanner must scan the entire road at such a speed that the motion of the car can be considered significant Alternately, a separate aiming system that operates at a much lower speed, but at the speed to permit compensation for the car angle changes Such an aiming system is also necessary due to the fact that the road curves up and down Therefore two scanning methods one a slow, but for large angle motion and the other fast but for small angles are required The large angular svstem requires a motor drive while the small angular system can be accomplished through the use of an acoustic wave system, such as Lithium Niobate (LiNbO ), which is used to drive a crystal which has a large refractive index such as Tellurium dioxide

The laser radar scanner can be set up in conjunction with a range gate so that once it finds a object the range can be narrowed so that only that object and other objects at the same range, 65 to 75 feet for example, are allowed to pass the receiver In this way an image of a vehicle can be separated from the rest of the scene for identification by pattern recognition software Once the image of the particular object has been captured , the range gate is broadened, to 20 to 500 feet for example, and the process repeated for another object In this manner all ob|ects in the field of interest to the vehicle can be separated and individually imaged and identified The field of interest, of course, is the field where all objects with which the vehicle can potentially collide reside Particular known features on the highway can be used as aids to the scanning system so that the pitch and perhaps roll angles ot the vehicle can be taken into account

Prior to the time that all vehicles are equipped with the RtZF™ system described above, roadways will consist of a mix of vehicles In this period it will not be possible to totally eliminate accidents. It will be possible to minimize the probability of having an accident however, if a laser radar system similar to that described in Shaw US Pat 5.529, 138 with some significant modifications is used It is correctly perceived by Shaw that the dimensions of a radar beam are too large to permit distinguishing various objects which may be on the roadway in the path of the instant vehicle Laser radar provides the necessary resolution that is not provided by radar Laser radar as used in the piesent invention however would acquire significantly more data than anticipated by Shaw Sufficient data in fact would be attained to permit the acquisition of a 3-dιmensιonal image of all objects in the field of view The X and Y dimensions of such objects would, ot course, be determined knowing the angular orientation of the laser radar beam The longitudinal or Z dimension would be obtained by the time-of-flight of the laser beam to a particular point on the object and reflected back to the detector At least two methods are available for resolving the longitudinal dimension for each of the pixels in the image In one method, a laser radar pulse having a pulse width of say one nanosecond would be transmitted toward the area of interest and as soon as the reflection was received and the time-of-flight determined a new pulse would be sent at a slightly different angular orientation The laser, therefore, would be acting as a scanner covering the field of interest A single detector could then be used since it would know the pixel that was being illuminated The distance to the reflection point could be determined by time-of-flight thus giving the longitudinal distance to all points in view on the object

Alternately the entire area of interest can be illuminated and an image focused on a CCD or CMOS array By checking the time-of-flight to each pixel, one at a time, the distance to that point on the vehicle would be determined A variation of this would be to use a garnet crystal as a pixel shutter and only a single detector In this case the garnet crystals would permit the illumination to pass through one pixel at a time through to a detector

Other methods of associating a distance to a particular reflection point, ot course, can now be conceived by those skilled in the art In the laser scanning cases the total power required of the laser if significantly less than in the area of illuminated design However, the ability to correctly change the direction of the laser beam in a sufficiently short period of time complicates the scanning design The system would work approximately as follows The entire area in front of the instant vehicle, perhaps as much as a full 180 degree arc in the horizontal plane would be scanned for objects Once one or more objects had been located the scanning range would be severely limited to basically cover that particular object and some surrounding space Based on the range to that object a range gate can be used to eliminate all background and perhaps interference from other objects In this manner, a very clear picture or image of the object of interest can be obtained as well as its location and through the use of a neural network pattern of recognition system, the identity of the object can be ascertained as to whether it is a sign, a truck, an automobile or other objects The identification ot the object will permit an estimate to be made of the object's mass and thus the seventy of any potential collision Once a pending collision is identified this information can be made available to the driver and if the driver ceases to heed the warning control of the vehicle could be taken from him or her by the system The actual usurpation ot vehicle control, however, is unlikely since there are many situations on the highway where the potential for a collision cannot be accurately ascertained Consequently, this system can be thought of as an interim solution until all vehicles have the RtZF™ system described above To use the laser radar in a scanning mode requires some means ot changing the direction of the emitted pulses of light One method ot using a ultrasonic wave to change the difraction angle of a Tellurium dioxide crystal was disclosed above This can also be done in a variety of other ways such as through the use of a spinning mirror, such as is common with laser scanners and printers This mirror would control the horizontal scanning, for example, with the vertical scanning controlled though a stepping motor Alternately, one or more piezoelectric materials can be used to cause the laser radar transmitter to rotate about a pivot point A rotating system, such as described in Shaw is the least desirable available methods due to the difficulty in obtaining a good electrical connection between the laser and the vehicle while the laser is spinning at a very high angular velocity Another promising technology is to use MEMS mirrors to deflect the laser beam

Although the system described above is intended for collision avoidance or at least the notification of a potential collision, when the roadway is populated by vehicles having the RtZF™ system and vehicles which do not. its use is still desirable after all vehicles are properly equipped It can be used to search for animals or other objects which may be on or crossing the highway, a box dropping off of a truck for example, a person crossing the road who is not paying attention to traffic naturally motorcycles, bicycles, and other vehicles can also be monitored

One significant problem with all previous collision avoidance systems which use radar or laser radar systems to predict impacts with vehicles, is the inability to know whethei the vehicle that is being interrogated is located on the highway or is off the road In the system of the present invention, the location of the road at any distance ahead of the vehicle would be known precisely from the sub-meter accuracy maps, thus the scanning system can ignore, for example, all vehicles on lanes where there is a physical barrier separating the lanes from the lane on which the subject vehicle is traveling This, of course, is a common situation on super highways Similarly, a parked car on the side of the car would not be confused w ith a parked car that is in the lane of travel of the subject vehicle when the road is curving This permits the subject invention to be used for automatic cruise control In contrast with radar systems, it does not require that vehicles in the path of the subject vehicle to be moving thus high speed impacts into stalled traffic can be avoided

If we use a system with a broader beam to illuminate a larger area on the road in front of the subject vehicle, and the subsequent focusing of this image onto a CCD or CMOS array, this has an advantage of permitting a comparison to be made of the passive infrared signal and the reflection of the laser radar active infrared Metal objects, for example appear cold to passive infrared This permits another parametei to be used to differentiate metallic objects from non-metallic objects such as foliage or animals such as deer The breadth of the beam can be controlled and thereby a particular object can be accurately illuminated With this system, the speed with which the beam steering is accomplished can be much slower Naturally, both systems can be combined into the maximum amount of information to be available to the system

Through the use of range gating, objects can be relatively isolated from the environment surrounding it other than for the section of highway For many cases, a properly trained neural network can use this data and identify the objects An alternate approach is to use the Fourier transform of the scene as input to neural network The advantages of this latter approach are that the particular location of the vehicle in the image is not critical for identification

In the future, when the system can take control of the vehicle, it will be possible to have much higher speed travel In such cases all vehicles on the controlled roadway will need to have the RtZF™ system as described above Fourier transforms of the objects of interest can be done optically though the use of a diffraction system The Fourier transform of the scene can then be compared with the library of the Fourier transforms of all potential objects and through a system used in military target recognition, multiple objects can be recognized and the system then focus onto one at time to determine the degree of threat that it poses 6. ITS + Adaptive Cruise Control

6.1 Problem - Traffic Congestion

The world is experiencing an unacceptable growth in traffic congestion and attention is increasingly turning to smart highway systems to solve the problem It has been estimated that approximately S240 billion will be spent on smart highways over the next 20 years All of the initiatives currently being considered involve a combination of vehicle mounted sensors and sensors and other apparatus installed in or on the roadway Such systems are expensive to install difficult and expensive to maintain and will thus only be used on major highways if at all Although there will be some safety benefit from such systems, it will be limited to the highways which have the system and perhaps to only a limited number of lanes The RtZF™ of this invention eliminates the shortcomings of the prior art by providing a system that does not require modifications to the highway The information as to the location of the highway is determined, as discussed above, by mapping the edges of the roadway using a process whereby the major roads of the entire country can be mapped at very low cost Thus the system has the capability of reducing congestion as well as saving lives on all major roads, not just those which have been chosen for high speed guided lanes

6.2 Description

According to U S Pat 5.506.584 the stated goals of the US DOT 1VHS system is

• improving the safety ot surface transportation

• increasing the capacity and operational efficiency of the surface transportation system • enhancing personal mobility and the convenience and comfort of the surface transportation system

• reducing the environmental and energy impacts of the surface transportation system

The RtZF™ of the present invention satisfies all of these goals at a small fraction of the cost of prior art systems The safety benefits have been discussed above The capacity increase is achieved by confining vehicles to corridors where they are then permitted to travel at higher speeds This can be achieved immediately where carrier phase DGPS is available or with the implementation of the highway located precise location systems as shown in FIG 6 An improvement is to add the capability for the speed of the vehicles to be set by the highway This is a simple additional few bytes of information that can be transmitted along with the road edge location map, thus, at very little initial cost To account for the tolerances in vehicle speed control systems, the scanning laser radar, or other technology system, which monitors for the presence of vehicles without RtZF™ is also usable as an adaptive cruise control system Thus, if a faster moving vehicle approaches a slower moving vehicle, it will automatically slow down to keep a safe separation distance from the leading vehicle Thus, although the system is not planned for platoo ng, that will be the automatic result in some cases Thus the maximum packing of vehicles is automatically obtained and thus the maximum vehicle flow rate is also achieved with a very simple system. For the Intelligent Highway System (ITS) application, provision is required to prevent unequipped vehicles from entering the restricted lanes In most cases, a barrier will be required since if an errant vehicle did enter the controlled lane, a serious accident could result Vehicles would be checked while traveling down the road or at a tollbooth. or similar station, that the RtZF™ system was in operation without faults and with the latest updated map for the region Only those vehicles with the RtZF™ system in good working order would be permitted to enter The speed on the restricted lanes would be set according to the weather conditions and fed to the vehicle information system automatically as discussed above

For ITS use, there needs to be a provision whereby a driver can signal an emergency, for example, by putting on the hazard lights This would permit the vehicle to leave the roadway and enter the shoulder when the vehicle velocity is below some level Once the driver provides such a signal the roadway information system, or the network ot vehicle based control systems, would then reduce the speed of all vehicles in the vicinity until the emergency has passed This roadway information system need not be actually associated with the particular roadway and also need not require any roadway infrastructure It is a term used here to represent the collective system as operated by the network of nearby vehicle and the inter- vehicle communication system Eventually, the occurrence of such emergency situations will be eliminated by vehicle based failure prediction systems 6.3 Enhancements - Vehicle

There will be emergency situations develop on intelligent highways It is difficult to access the frequency or the results The industry has learned from airbags that if a system is developed which saves many lives but causes a tew deaths the deaths will not be tolerated The ITS system, therefore, must operate with a very high reliability, that is approaching zero fatalities Since the brains of the system will reside in each vehicle, which is under the control of individual owners, there will be malfunctions and the system must be able to adapt without causing accidents The spacing of the vehicles is the first line of defense Secondly, each vehicle with a RtZF™ has the ability to automatically communicate to all adjacent vehicles and thus immediately issue a warning when an emergency event is occurring Finally, with the addition of a total vehicle diagnostic system, such as disclosed in U S Pat No 5.809,437. " On Board Vehicle Diagnostic System", potential emergencies can be anticipated and thus eliminated with high reliability Although the application for ITS envisions a special highway lane and high speed travel, the potential exists in the present invention to provide a lower measure of automatic guidance where the operator can turn control of the vehicle over to the RtZF™ for as long as the infrastructure is available. In this case, the vehicle would operate on normal lanes but would retain its position in the lane and avoid collisions until a decision requiring operator assistance is required At that time the operator would be notified and if he or she did not assume control of the vehicle, an orderly stopping of the vehicle on the side of the road would occur

For all cases where vehicle steering control is assumed by the RtZF™. the algorithm for controlling the steering should be developed using neural networks or neural fuzzy systems This is especially true for the emergency cases discussed above where it is well known that operators frequently take the wrong actions and at the least they are slow to react Algorithms developed by other non-pattern recognition techniques do not in general have the requisite generality or complexity and are also likely to make the wrong decisions When the throttle and breaking functions are also handled by the system, an algorithm based on neural networks is even more important For the ITS, the driver will enter his designation so that the vehicle knows ahead of time where to exit. Alternately, if the driver wishes to exit he merely turns on his turn signal, which tells the system and other vehicles that he or she is about to exit the controlled lane 7. Other Features

7.1 Blind spot Detection The RtZF™ system of this invention also can eliminate the need for blind spot detectors such as disclosed in U S Pat 5.530.447 to Henderson Alternately, if a subset of the complete RtZF™ is implemented, as is expected in the initial period, the RtZF™ can be made compatible with the blind spot detector described in the '447 patent

7.2 Incapacitated Driver As discussed above, the RtZF™ system of this invention also handles the problem of the incapacitated driver thus eliminating the need for sleep sensors that appear in numerous U S Patents. Such systems have not been implemented because of their poor reliability The RtZF™ system senses the result of the actions of the operator, which could occur for a vaπety of reasons including old age. drunkenness, heart attacks, drugs as well as falling asleep 7.3 Emergencies - car jacking, crime

Another enhancement that is also available is to prevent car jacking in which case the RtZF™ can have the functions of a Lojack system In the case where a car jacking occurs, the location of the vehicle can be monitored and if an emergency button is pushed, the location of the vehicle with the vehicle ID can be transmitted 7.4 Headlight Dimmer

The system also solves the automatic headlight dimmer problem Since the RtZF™ equipped vehicle knows where all other RtZF™ equipped vehicles are located in its vicinity, it knows when to dim the headlights Since it is also interrogating the environment in front of the vehicle it also knows the existence and approximate location of all non RtZF™ equipped vehicles This is one example of a future improvement to the system The RtZF™ is a system which lends itself to continuous improvement without having to change systems on an existing vehicle 7.5 Rollover It should be obvious from the above discussion that rollover accidents should be effectively eliminated by the RtZF™ In the rare case where one does occur, the RtZF™ has the capability to sense that event since the location and orientation of the vehicle is known

For large trucks that have varying inertial properties depending on the load that is being hauled, sensors can be placed on the vehicle that measure the angular and linear acceleration of a part of the vehicle Since the geometry of the road is known, the inertial properties of the vehicle w ith load can be determined and thus the tendency of the vehicle to roll over can be determined Again since the road geometry is known the speed of the truck can then be limited to prevent rollovers

8. Anticipatory sensing - Smart Airbags, Evolution of the Svstem The RtZF™ is also capable of enhancing other vehicle safety systems In particular, through knowing the location and velocity of other vehicles, tor those cases where an accident cannot be avoided, the RtZF™ will in general be able to anticipate a crash and make an assessment of the crash severity using neural network technology Even with a limited implementation of RtZF™ a significant improvement in smart airbag technology results when used in conjunction with a collision avoidance system such as described in Shaw U S Patents 5.3 14 037 and 5 529 138 and a neural network anticipatory sensing algorithm such as disclosed in co-pending U S Patent application 08 247.760 to Breed A further enhancement would be to code the signal from RtZF™ vehicles with information that includes the size and approximate weight of the vehicle Then if an accident is inevitable the severity can be accurately anticipated and the smart airbag tailored to the pending event It can be seen by the above discussion that the RtZF™ will evolve in solving many safety, vehicle control and ITS problems Even such technologies as steering and drive by wire will be enhanced by the RtZF™ of this invention since it will automatically adjust for failures in these systems and prevent accidents

9. Other advantages & Enhancements 9.1 GPS and Other Measurement Improvements

One ot the problems with the RtZF™ is operation in large cities such as downtown New York In such locations, unless there are a plurality of local pseudolites or precise position location system installations, the signals from the GPS satellites can be significantly blocked Also there is a severe multipath problem A solution is to use the LORAN system as a backup for such locations The accuracy of LORAN can be comparable to DGPS Naturally, the use of multiple roadway located triple precise positioning systems would be a better solution or a complementary solution

The use of geo-synchronous satellites as a substitute for earth bound base stations in a DGPS system, with carrier phase enhancements for sub-meter accuracies, is also a likely improvement to the RtZF™ system that can have a significant effect in downtown areas Another enhancement that would be possible with dedicated satellites and/or earth bound pseudolites results from the greater control over the information transmitted than is available from the GPS system Recognizing that this system could save up to 40.000 lives per year in the U S alone, the cost of deploying such special purpose stations can easily be justified For example, say there exists a modulated wave that is 10000 kilometers long, another one which is 1000 km long etc down to 1 cm It would then be easy to determine the absolute distance from one point to the other Other types of modulation are of course possible to achieve the desired result of simply eliminating the carrier integer uncertainty that is discussed in many U S patents and other literature This is not meant to be a recommendation but to illustrate that once the decision has been made to provide information to every vehicle that will permit it to always know its location within 10 cm, many technologies will be there to make it happen The cost savings resulting from eliminating fatalities and serious injuries will easily pay the cost of such technologies many times over

9.2 Vehicle Enhancements

The RtZF™ system can now be used to improve the accuracy of other vehicle based instruments The accuracy of the odometei and yaw rate sensors can be improved over time, for example, by regression against the DGPS data

9.3 Highway Enhancements

Enhancements to the roadways that result from the RtZF™ include traffic control The timing of the stoplights can now be automatically adjusted based on the relative traffic flow The position of every vehicle within the vicinity of the light will be known When all vehicles have the RtZF system, many stoplights will no longer be necessary since the flow of traffic through an intersection can be accurately controlled to avoid collisions

Since the road conditions will now be known to the system, an enhanced RtZF™ system will be able to advise an operator not to travel oi. alternately, it can pick an alternate route if certain roads have accidents or iced over roadways, for example Some people may decide not drive if there is bad weather or congestion The important point here is that sensors will be available to sense the road condition as to both traffic and weather this information will be available automatically and not require reporting from a weather station which has only late and inaccurate information The system lends itself to time and congestion based allocation of highway facilities A variable toll can automatically be charged to vehicles based on such considerations since the vehicle can be identified In fact, automatic toll systems now being implemented will become obsolete as will all toll booths

Finally it is important to recognize that the RtZF system is not a " sensor fusion' system Sensoi fusion is based on the theory that you can take inputs from different sensors and combine them in such a way as to achieve more information from the combined sensors than from treating the sensor outputs independently in a deterministic manner The ultimate sensor fusion system is based on artificial neural networks, sometimes combined with fuzzy logic to form a neural fuzzy system Such systems are probabilistic Thus there will always be some percentage of cases where the decision reached by the network will be wrong The use ot such sensor fusion, therefore, is inappropriate for the Zero Fatalities goal 9.4 Map Enhancements

Once the road edge and lane locations are being transmitted to the operator it requires very little additional bandwidth to include other information such as the location of all businesses that a traveler would be interested in such as gas stations, restaurants etc which could be done on a subscription basis This concept was partially disclosed in the '482 patent discussed and partially implemented in existing map databases

Naturally, the communication of information to the operator could be done either visually or orally as described in U S Pat 5.177.685 Finally, the addition ot a route guidance system as disclosed in other patents becomes even more feasible since the exact location ot a destination can be determined The system can be configured so that an operator could enter a phone number, for example, or an address and the vehicle would be automatically and safelv driven to that location Since the system knows the location of the edge of every roadway, very little if nay operator intervention would be required Even a cell phone number can be used if the cell phone has the SnapTrack GPS location system as soon to be provided vy Qualcom

9.5 Other Uses

The RtZF™ can even replace other sensors now on or being considered for automobile vehicles including Pitch, roll and yaw sensors This information can be found by using carrier phase GPS and by adding more antennas to the vehicle Additionally once the system is in place for land vehicles, there will be manv other applications such as surveying, vehicle tracking and aircraft landing which will benefit from the technology and infrastructure improvements The automobile safety issue and ITS will result in the implementation of a national system which provides any user with low cost equipment the ability to know precisely where he is within centimeters on the face of the earth Many other applications will undoubtedly follow 10. The RtZF™ System

The design of this system is only beginning From the above discussion two conclusions should be evident There are significant advantages in accurately knowing where the vehicle, the roadway and other vehicles are and that this information is the key to reducing fatalities to zero Secondly, there are many technologies that are already in existence that can provide this information to each vehicle Once there is a clear direction that this is the solution then many new technologies will emerge There is nothing inherently expensive about these technologies and once the product life cycle is underway the added cost to vehicle purchasers will be minimal Roadway infrastructure costs will be minimal and system maintenance costs almost non-existent

Most importantly, the system has the capability of reducing fatalities to zero' 10.1 Technical Issues

The accuracy of DGPS has been demonstrated numerous times in small controlled experiments most recently by the University of Minnesota

The second technical problem is the integrity of the signals being received and the major cause of the lack of integrity is the multi-path effect Considerable research has gone into solving the multi-path effect and Trimble claims that this problem is no longer an issue

The third area is availability ot GPS and DGPS signals to the vehicle as it is driving down the road The system is designed to tolerate temporary losses ot signal, up to a few minutes That is the prime function of the inertial guidance system (INS) Prolonged absence of the GPS signal will significantly degrade system performance There are two primary causes of lack of availability, temporary and permanent Temporary causes result from a car driving between two trucks for an extended period of time, blocking the GPS signals The eventual solution to this problem is to change the laws to prevent trucks from traveling on both sides of the automobile If this remains a problem a warning will be provided to the driver that he/she is losing system integrity and therefore he/she should speed up or slow down to regain a satellite view

Permanent blockage ot the GPS signals, as can come from operating the vehicle in a tunnel or in the downtown of a large city, can be corrected through the use of pseudolites or other guidance systems such as the SnapTrack system This is not a serious problem since very few cars run off the road in a tunnel or in downtown Manhattan The final technical impediment is the operation of the diagnostic system that verifies that the system is operating properly This requires an extensive failure mode and effect analysis and the design of a diagnostic system that answers all of the concerns of the FMEA 10.2 Cost Issues

The primary cost impediment is the cost of the DGPS hardware A single base station and roving receiver that will give an accuracy ot 2 centimeters ( 1 σ) cuπently costs about S25 000 This is a temporary situation brought about by low sales volume Since there is nothing exotic in the receiving unit, the cost can be expected to follow typical automotive electronic life-cycle costs and therefore we project that in high volume production the electronics for the DGPS receivers will be below $ 100 per vehicle In the initial implementation of the system, an OmmSTAR DGPS system will be used providing an accuracy of 6 cm

A similar argument can be made for the inertial navigation system A considerable research and development effort is ongoing to reduce the size, complexity and cost ot these systems Three technologies are vying for this rapidly growing market laser gyroscopes fiber-optic lasers, and MEMS systems The cost of these units today range from a few hundred and ten thousand dollars each, however once again this is due to the very small quantity being sold Substantial improvements are being made in the accuracies of the MEMS svstems and it now appears that such a system will be accurate enough for RtZF purposes We expect the cost of these systems in high-volume production will be below ten dollais each This includes at least a yaw rate sensor with three accelerometers and probably three angular rate sensors The accuracy of these units is currently approximately 003 degrees per second This is a random error which can be corrected somewhat by the use of multiple vibrating elements A new laser gyroscope has recently been announced by Intel sense Corpoiation which should pi ovide a dramatic cost reduction and accuracy improvement

Eventually when most vehicles on the road have the RtZF system then communication between the vehicles can be used to substantially improve the location accuracy of each vehicle as described above The cost of mapping the continental United States (CONUS) is largely an unknown at this time

OnmiStar has stated that they will map any area with sufficient detail at a cost ot $300 per mile They have also indicated the cost will drop substantially as the number of miles to be mapped increases This mapping would be done by helicopter using their laser ranging system We propose that the initial mapping be done using this system However a task of the Phase Zero project will be to investigate alternate and potentially substantially less expensive mapping strategies One such strategy, for example, would be to outfit a ground vehicle w ith the equipment that will determine the location of the lane and shoulder boundaries of road Such a system has been used for mapping a Swedish highway One estimate is that the mapping ot a road will be reduced to approximately $50 per mile tor ma|or highways and rural roads and a somewhat higher number for urban areas The goal of this program is to map as much of the country as possible to an accuracy of 2 centimeters ( 1 σ)

Related to the costs of mapping is the cost of converting the taw data acquired either by helicopter or by ground vehicle into a usable map database The cost tor manually performing this vectoπzation process has been estimated at $100 per mile by Om STAR This process can be substantially simplified through the use of raster to vector conversion software Such software is currently being used for converting hand drawings into CAD systems, for example The lntergiaph Corp provides hardware and software for simplifying this task It is therefore expected that the cost for vectoπzation of the map data will follow proportionately a similar path to the cost of acquiring the data and will eventually reach $10 to $20 per mile for the rural mapping and $25 to a $50 per mile tor urban areas Considering that there are approximately four million miles of roads in the CONUS. and assuming we can achieve an average of $150 for acquiring the data and converting the data to a GIS database, the total cost for mapping all of the roads in United States will amount to $600 million This cost would obviously be spread over a number of years and thus the cost per year is manageable and small in comparison to the $215 billion lost every year due to death, injury and lost time from congestion Another cost is the lack of DGPS base stations The initial analysis indicated that this would be a serious problem as using the latest DGPS technology required a station every 30 miles Upon further research, however, it has been determined that the OmmSTAR company has now deployed a nationwide DGPS system with 6 cm accuracy The initial goal of the RtZF system was to achieve 2 cm accuracy for both mapping and vehicle location The 2 cm accuracy can be obtained in the map database since temporary differential base stations will be installed for the mapping purposes By relaxing the 2 cm requirement to 6 cm. the need for base stations every 30 miles disappears and the cost of adding a substantial number of base stations is no longer a factor

The next impediment is the lack of a system for determining when changes are planned for the mapped roads This will require communication with all highway and road maintenance organizations in the mapped area

A similar impediment to the widespread implementation of this RtZF system is the lack of a communication system for supplying map changes to the equipped vehicles 10.3 Educational issues

A serious impediment to the implementation of this system that is related to the general lack of familiarity with the system, is the belief that significant fatalities and injuries on the U S highways are a fact of life This argument is presented in many forms such as "'the perfect is the enemy of the good" This leads to the conclusion that any system which portends to reduce injury should be implemented rather than taking the viewpoint that driving an automobile is a process and as such it can be designed to achieve perfection As soon as it is admitted that perfection cannot be achieved, then any fatality gets immediately associated with this fact. This of course was the prevailing view among all manufacturing executives until the zero defects paradigm shift took place. The goal of Zero Fatalities is not going to be achieved in a short period of time. Nevertheless to plan anything short of zero fatalities is to admit defeat and to thereby allow technologies to enter the market that are inconsistent with a zero fatalities goal. 10.4 Potential Benefits When the System is Deployed. 10.4.1 Assumptions for the Application Benefits Analysis

The high volume incremental cost of an automobile will be $200

The cost of DGPS correction signals will be a onetime charge of $50 per vehicle.

The benefits to the vehicle owner from up-to-date maps and to the purveyors of services located on these maps to cover the cost of updating the maps from as the roads change.

The cost of mapping substantially all roads in the Continental U.S. will be $600 million.

The effects of phasing in the system will be ignored.

There are 15 million vehicles sold in the U.S. each year.

Of the 40.000 plus people killed on the roadways, at least 10 % are due to road departure, yellow line infraction, stop sign infraction, excessive speed and other causes which will be eliminated by the Phase

Zero deployment.

• $ 165 billion are lost each year due to highway accidents.

• The cost savings due to secondary benefits will be ignored. 10.4 Initial System Deployment The initial implementation of the RtZF system would include the following services:

1. A warning is issued to the driver when the driver is about to depart from the road.

2. A warning is issued to the driver when the driver is about to cross a yellow line.

3. A warning is provided to the driver when the driver is exceeding a safe speed limit for the road geometry. 4. A warning is provided to the driver when the driver is about to go through a stop sign without stopping.

5. A warning is provided to the driver when the driver is about run the risk of a rollover.

6. A warning will be issued prior to a rear end impact by the equipped vehicle.

7. In-vehicle signage will be provided for highway signs. 8. A recording will be logged whenever a warning is issued.

11. Detailed Description of the Illustrations

Fig. 1 shows the current GPS satellite system associated with the earth and including 24 satellites 102, each satellite revolving in a specific orbital path 104 around the earth. By means of such a GPS satellite system, the position of any object can be determined with varying degrees of preciseness. Fig. 2 shows an arrangement 202 of four satellites SV 1.SV2.SV3 and SV4 of the GPS satellite system shown in Fig. 1 and a pseudolite 230 transmitting position information to receiver means of a base station 220, such as an antenna 222, which in turn transmits a differential correction signal via transmitter means associated with that base station, such as a second antenna 216, to a vehicle 218. Fig 3 is a logic diagram of the system 210 in accordance with the invention (illustrated in greater detail in Fig 7) showing the combination of the GPS system 300 and an inertial navigation system 306 The GPS system includes a unit 302 for processing the received information from the satellites 301 of the GPS satellite system and data from an inertial leference unit (IRU) 304 Additional details relating to Figs 1 -3 can be found in U S Pat No 5,606 506 to Kyrtsos

Fig 4 shows the implementation of the invention in which a vehicle 10 is traveling on a roadway in a defined corridor in the direction X Each corridor is defined by lines 14 If the vehicle is traveling in one corridor and strays in the direction Y so that it moves along the line 22, e , the driver is falling asleep, the system on board the vehicle in accordance with the invention will be continually detecting the position of the vehicle, such as by means of the GPS system, and have stored the locations of the lines 14 defining the corridor Upon an intersection of the position of the vehicle and one of the lines 14 as determined by a processor, the svstem may be designed to sound an alarm to alert the driver to the deviation or possibly even correct the steering of the vehicle to return the vehicle to within the corridor defined by a pair of lines 14 Fig 5 shows the implementation of the invention in which a pair of vehicles 26.30 are traveling on a roadway each in a defined corridor delineated by lines 14 and each is equipped with a system in accordance with the invention The system will receive data informing it of the position of the other vehicle and prevent accidents from occurring

Fig 6 shows the implementation of the invention in which a pair of vehicles 26 30 are traveling on a roadway each in a defined corridor delineated by lines 14 and each is equipped with a system in accordance with the invention The system will receive data informing it of the position of the other vehicle as well as the position of trees 51 52,53 on the side of the roadway and prevent accidents between the vehicles and between the vehicle and the trees 51.52,53 from occurring

Fig 7 is a schematic representation of the system 210 in accordance with the invention System 210 detects the absolute position of the vehicle such as by means of the GPS system 44 and has stored the locations of the edges of the roadways (the lines 14 defining the corridor as shown in Figs 4-6) in a memory unit 46 Upon intersection of the position of the vehicle and the edges of the roadway as determined by a processor 48 the system may be designed to sound an alarm to alert the driver to the deviation or possibly even correct the steering of the vehicle to return the vehicle to within the corridor defined by a pair of lines 14 (the alarm and steering guidance unit being represented as reactive system 50) The position determining means 44 may include an optional inertial navigation system 54

Means for determining the presence, location and/or velocity of other vehicles 56 on the roadway (any known type of detection system such as those using radar, electromagnetic radiation, etc ) are coupled to the processor 48 which can then determine the location of the other vehicles relative to the edges of the roadway and provide a signal to alert means 52 (e g , an alarm) to alert the other vehicles if the location of the other vehicles approach close to an edge of the roadway or intersect with an edge of the roadway

A communications unit 58 is also coupled to the processor 48 to enable communication of data regarding, e g , the location and velocity of the vehicle, between vehicles equipped with the same or a compatible system An automatic driving system 60 can be integrated with the steering unit and acceleration unit of the vehicle and coupled to the processor 48 to guide the vehicle in the roadway, i.e., such that the position of the vehicle does not come close to or intersect the edges of the roadway.

Fig. 8 is a flow chart of the method in accordance with the invention. The absolute position of the vehicle is determined at 62. e.g., using a GPS system, and compared to the edges of the roadway at 66 which is obtained from a memory unit 64. Based on the comparison at 66, it is determined whether the absolute position of the vehicle is approaching close to or intersects an edge of the roadway at 68. If not, then the position of the vehicle is again obtained and the process continues. If yes, an alarm will sound, a warning light will be illuminated or the system will take control of the vehicle (at 70) to guide it to a shoulder of the roadway or other safe location.

Claims

Claims: We Claim:

1 A system tor preventing vehicle accidents, comprising position determining means for determining the absolute position of the vehicle. memory means for storing data relating to edges of roadways on which the vehicle may travel, processing means coupled to said determining means and said memory means for determining the location of the vehicle relative to the edges of the roadway, and reaction means coupled to said processing means for affecting a system within the vehicle if the location of the vehicle approaches close to an edge of the roadway or intersects with an edge of the roadway

2 The system of claim 1 wherein said position determining means comprise a unit which cooperates with a satellite svstem

3 The system ot claim 1 further comprising means for determining at least one of the presence, location and velocity ot other vehicles on the roadwav

4 The system ot claim 3 wherein said processing means are structured and arranged to determine the location of the other vehicles relative to the edges of the roadway

5 The system ot claim 1 , further comprising communication means for enabling the vehicle to communicate with other vehicles similarly equipped with the accident preventing system such that the location and optionally velocity of the other vehicles is communicated to the vehicle

6 The system of claim 1. further comprising automatic driving means coupled to said memory means and a steering unit and acceleration unit of the vehicle for guiding the vehicle within the edges of the roadway

7 The system of claim 1 , wherein said processing means are structured and arranged to receive data on at least one of weather conditions and traffic accidents and control operation of the vehicle based thereon

8 The system of claim 1 , wherein said position determining means comprise at least one earth-based station

9 A method for preventing vehicle accidents, comprising the steps of determining the absolute position of the vehicle. storing data relating to edges of roadways on which the vehicle may travel, determining the location of the vehicle relative to the edges of the roadway, and affecting a system within the vehicle if the location of the vehicle approaches close to an edge of the roadway or intersects with an edge of the roadway

10 The method of claim 9 further comprising the step of determining at least one of the presence, location and velocity of other vehicles on the roadway

1 1 The method of claim 10, further comprising the step of determining the location of the other vehicles relative to the edges of the roadway

12 The method of claim 9, further comprising the step of enabling the vehicle to communicate with other vehicles similarly equipped with the accident preventing system such that the location and optionally velocity of the other vehicles is communicated to the vehicle

13 The method of claim 12 wherein the vehicles communicate with each other by utilizing a portion of the electromagnetic spectrum that permits only line of sight communication

14 The system of claim 2, wherein the satellite system includes base stations for generating a differential correction signal to the vehicle

15 The system of claim 1 wherein said position determining means further comprises an inertial navigation system

16 The system of claim 4 further comprising alert means for alerting the other vehicles if the location of the vehicle approaches close to an edge of the roadway or intersect with an edge of the roadway

17 The system ot claim 1 , wherein said processing means are structured and arranged to receive data on at least one of weather conditions and traffic accidents and display such data to the driver

18 The system of claim 1 wherein said processor is structured and arranged to receive data on at least one of weather conditions and traffic accidents and control operation of the vehicle based thereon

19 The system of claim 1. wherein said reaction means comprise an alarm

20 The system of claim 1 wherein said reaction means comprise vehicle guidance system for automatically guiding the vehicle

21. The method of claim 10, further comprising the step of: alerting the other vehicles if the location of the vehicle approaches close to an edge of the roadway or intersects with an edge of the roadway.

22. A system for preventing vehicle accidents, comprising a positioning system arranged in a vehicle for determining the absolute position of the vehicle, a memory unit for storing data relating to edges of at least one lane of the roadway on which the vehicle may travel, a processor coupled to said positioning system and said memory unit for determining the location of the vehicle relative to the edges of at least one lane of the roadway based on the absolute position of the vehicle and the data relating to edges of the roadway, and a reactive component or system arranged in the vehicle and coupled to said processor, said component or system being arranged to initiate an action or change its operation if the location of the vehicle approaches close to an edge of at least one lane of the roadway or intersects with an edge of at least one lane of the roadway.

23. The system of claim 22, wherein said positioning system comprises a unit which cooperates with a satellite system.

24. The system of claim 23. wherein the satellite system includes base stations for generating a differential correction signal to the vehicle.

25. The system of claim 22, wherein said positioning system further comprises an inertial navigation system.

26. The system of claim 22, further comprising a determination system arranged on the vehicle for determining at least one of the presence, position and velocity of other vehicles on the roadway.

27. The system of claim 26, wherein said determination system determines the position of the other vehicles on the roadway relative to the vehicle, said processor being structured and arranged to determine the position of the other vehicles relative to the edges of at least one lane of the roadway based on the data relating to edges of at least one lane of the roadway.

28. The system of claim 27, further comprising a warning system for alerting the other vehicles if the location of the other vehicles approach close to an edge of the roadway or intersect with an edge of the roadway.

29. The system of claim 22, further comprising a communication unit for enabling the vehicle to communicate with other vehicles similarly equipped with the accident preventing system such that the location and optionally velocity of the other vehicles is communicated to the vehicle.

30. The system of claim 22. further comprising an automatic driving and guidance unit arranged in the vehicle and coupled to the memory unit and a steering unit and acceleration unit of the vehicle for guiding the vehicle within the edges of at least one lane of the roadway.

31. The system of claim 22, wherein said processor is structured and arranged to receive data on at least one of weather conditions and traffic accidents and control operation of the vehicle based thereon.

32. The system of claim 22, wherein said processor is structured and arranged to receive data on at least one of weather conditions and traffic accidents and display such data to the driver.

33. The system of claim 22, wherein said positioning system comprises at least one earth- based station.

34. The system of claim 22, wherein said reactive component or system is an alarm.

35. The system of claim 22, wherein said reactive component is a vehicle guidance system for automatically guiding the vehicle.