WO2001023839A1

WO2001023839A1 - Method and system for a real-time distributed navigation system

Info

Publication number: WO2001023839A1
Application number: PCT/US2000/026921
Authority: WO
Inventors: Haiping Jin
Original assignee: Televigation, Inc.
Priority date: 1999-09-27
Filing date: 2000-09-27
Publication date: 2001-04-05
Also published as: AU7624500A

Abstract

An interactive real-time distributed navigation system (1) is disclosed. In the present invention a user's location is determined by generating a position signal at the user's location. Through wireless communication (2) between the user and distributed navigation servers (5), the user is presented with a list of candidate locations. The user's choice from the candidate list is then used by the navigation servers (5) to obtain an accurate measurement of the user's location. Having established a user's location, the system (1) proceeds to provide navigational prompts to the user to reach a final destination.

Description

METHOD AND SYSTEM FOR A REAL-TIME DISTRIBUTED NAVIGATION SYSTEM

I. Field of Invention

This invention relates to navigation systems and location based information delivery Specifically, this invention provides means for delivering interactive and real time navigation information using distπbuted navigation information processing systems

II. Background of Invention

Currently, the most advanced navigation systems are largely based upon global positioning system (GPS) devices which have been applied in automobile navigation systems, see, e.g., U.S. Patent Nos. 5,938,720, 5,928,307, 5,922,042, 5,912,635,

5,910,177, 5,904,728, 5,902,350, all incorporated herein by reference for all purposes Such automobile navigation systems, however, are expensive and inconvenient to use Therefore, there is a great need m the art to incorporate navigation systems in personal data assistant, cellular phone or other small handheld electronic devices However, there are several technical obstacles that prevent the incorporation of navigation capabilities in handheld devices for providing turn-to-tum real time navigation services One such obstacle is the amount of geographic data needed to provide reasonable detailed navigation information. In the existing automobile navigation systems, the GPS system is employed to provide location and movement information about a user. Geographic information is usually stored in a geographic mapping database stored in the CD-ROM or a hard-disk drive device. In a small (handheld) device, such as a cellular phone, however, the amount of embedded memory is limited and is impractical to store the large amount of geographic information

Another obstacle is that the lack of information processing power of small de\ ices such as a cellular phones The information processing power of a cell phone is usually provided by an embedded microprocessor with limited memory While the information processing power of embedded microprocessors is generally increasing, those processors are still not suitable for processing CPU intensive real time navigation

An additional obstacle is that the location accuracy provided by current technology, either Enhanced GPS based (SNAPTRACK), network based system (TRUEPOINT) The inaccuracy of the GPS based systems is either imposed by the U.S Department of Defense (Selective Availability or S/A) or due to atmospheπc and timing errors limiting the accuracy of a single GPS receiver to -<-/- 50 meters There are methods which can be use to enhance accuracies to -r/- 5 meters. These methods use a known position, such as a surveyed control point, as a reference point to correct the GPS position error. These methods of correcting GPS positions are referred to as Differential GPS or DGPS The DGPS corrections can be applied to the GPS data in real-time using data telemetry (radio modems) The U.S.A. and Canadian Coast Guard are establishing a seπes of radio beacons to transmit the DGPS corrections for accurate navigation along the Great Lakes, the Mississippi River and tπbutaπes. the Gulf Coast, and the Eastern and Western coasts of North Ameπca Such radio beacons are not available to consumers traveling in most m-land locations Current automobile GPS navigation system uses other sensors, such as accelerometers, or speedometers, etc. and plus some sophisticated fϊlteπng technology to improve the accuracy (See. e.g , U.S Patent Number 5,912,635, previously incorporated by reference for all purposes). In addition, many use map-aidmg technology as well However, for handheld device (such as cellular phone) based navigation system, it is impractical to have the handheld devices connected to external sensors Especially when people use it while they are walking Therefore, there is a great need m the art for a navigation system that overcomes the above mentioned obstacles III. Summary of the Invention

Accordingly, it is the objective of the invention to provide a real time navigation system for small wireless devices, such as cellular phones

One aspect of the invention provides an interactive, real-time and distπbuted navigation system Accurate navigation information is generated by the server based upon location information provided by the location sensing technology such as EGPS or network based system and the information obtained by interacting with the user In some embodiments, an ambiguous location of a user. 1 e . the location information about a user which is ambiguous for navigation purpose, is determined A user is then presented with a plurality of candidate locations to chose, wherein the candidate locations are m close proximate of said location After the user selects one or more of the candidate locations, the user's location is calculated based upon the chosen candidate locations and optionally in combination with the ambiguous location to determine a more accurate location of the user in some embodiments employing GPS type technology, location of a user is first partially determined based upon GPS signals. In addition, the user interacts with the system and provides related location information, such as the street name, landmarks, etc , observed by the user, to enhance the accuracy of location determination and provide a better navigation quality The user will interact with the system to enhance the navigation quality This invention utilizes fully the existing sensor- user's eyes to help to improve the location determination accuracy. For example, when the user requests navigation guidance to the server, the server will compare the direct location measurement with map Because of the location determination accuracy is normally not good enough, the user's real location may be different from what the location measurement indicates In order to determine the location of the user, the server will provide a few possible choices, such as several street names, to the user and let user to choose based on what the user sees on the road. Therefore, the navigation system of the invention employs user's eyes are used as additional sensors to the whole system to improve the location determination accuracy and navigation quality In some embodiments, the user is presented with several choices of landmarks which can be a building, a street address, a bookstore or any other easily identifiable objects The landmarks presented are determined based upon the user^'s location information (such as GPS or network based location information) The user can select the closest landmark to assist the server to locate the user accurately. Once the location of the user is determined, different kind of digital filteπng processes can be used so the interaction with the use is only necessary when the confidence level of the server in determine the user location is below the level previously set. The confidence level can be obtained by compaπng the location position after processing and map database

Another aspect of the invention provides enhanced and simplified dynamic real time navigation system based upon distπbuted computing and database systems In some embodiments, geographic map information databases are stored in servers remote from a user Navigation information is also calculated in servers remote from the user When the user requests navigation guidance, a request (including destination information) and the location of the user is sent to the remote server. The location of the user can be determined by a third paπy system or at the device. Or the raw measurements can be sent to the remote server, where the raw measurements will be processed and the location of the user determined. After obtaining the user location, the remote server accesses the geographic map information and generates navigation guidance, which is sent to the user to fulfill the request. In some other embodiments, depending upon the capability of the user device, data storage and navigation calculation load are dynamically distπbuted between the server and the device. In one paπicularly preferred embodiment, a user sends a request to navigate from current location (or point A) to point B. A server, after receiving the request (including destination information) and user's location, generates a global navigation route across several small geographic areas The server then sends information relating to the first small geographic area and navigation guidance information to the user device and the user devices performs navigation m this area. Once the user moves out of the area, the information will be updated by the server either at the request of the user device or initiated by the server based the location of the user Another aspect of the invention provides navigation guidance based on the real time traffic condition. The traffic information can be obtained from group of the navigation service users, by observing their speeds and compare with the street nominal speed limit in the map data base This traffic information will help the system to determine the best route for its users m real time At each juncture, the system will dynamically determine the best way to get to the destination based on the traffic information The best route can be defined based on the user's request, for example, it can be either time or gas consumption that will be minimized

Another aspect of the invention is that this system will also give directions m a queue ahead of time This is particularly important for wireless device navigation, because of the small screen size For example, the server will indicate either by voice or text "you are going to see University Ave in about 5 minutes (or 500 yards), where you should turn πght" In the mean time, if not necessary, the communication link can be stopped to reduce the server traffic

IV. Brief Description of the Drawings The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the descπption, serve to explain the pπnciples of the invention

Figure 1 is a schematic showing One Embodiment of the Interactive Real

Time Distπbuted Navigation System- User end Item 1 is Mobile wireless devices with position capabilities For example, the position capability can be built in the device or comes from attached devices or network based solution

Item 2 is Interactive portion with its users The interaction with users will be used to improve the position accuracy Both text or/and voice can be used for interaction

Item 3 is Ahead of time and real time navigation part The system will provide navigation guide ahead of time, so the user can use his/her eyes to confirm the navigation guide from the system Both voice and test will be used for this function as well Item 4 is the graphics part The navigation guide, user location can also be shown on the screen Figure 2 is a schematic showing an embodiment of the Interactive Real Time Distπbuted Navigation System- Architecture A (Internet)

Item 1 Same as Item 1 m Figure 1

Item 2 Wireless earners Wireless earners will provide part of the connectivity for the wireless devices and distπbuted navigation servers Some earners will also have a function to provide the location for the wireless devices Examples of these wireless earners include wireless service resellers, wireless ISPs (Internet Service Provider), or satellite wireless earners

Item 3 Gateways to Internet connecting the user to the Internet Gateways can be provided by earners, ISPs or other providers

Item 4 Internet

Item 5 Distnbuted Navigation Servers These servers will carry street map information and point of interest information It will also process location specific information, such as traffic information, to help its customers (users) to do real time optimal navigation It will also carry navigation guide algoπthm

Figure 3 is a schematic showing another embodiment of the Interactive Real Time Distπbuted Navigation System- Architecture B (Direct links)

Item 1 Same as Item in Figure 1

Item 2 Same as Item 2 in Figure 2 Item 3 Direct links between earner and Distπbuted Navigation Servers This direct link can be dedicated lines Or it can means that the Servers are collocated with earner systems

Item 4 Distπbuted Navigation Servers In addition to the functions mentioned in Item 5 of Figure 2. these servers may include some conversion functions For example, converting HDML or WML to HTML and vice versa

Figure 4 is a schematic showing one embodiment of the interactive real time distπbuted navigation system of the invention

Figure 5 is a schematic showing a process of Navigation using the interactive real time distπbuted navigation system of the invention \ . Detailed Descπption of the Embodiments

Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings While the invention will be descπbed in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to these embodiments On the contrary, the invention is intended to cover alternatives, modifications and equπ alents which may be included within the spiπt and scope of the invention as defined by the appended claims

As will be appreciated by one of skill m the art, the present invention may be embodied as a method, data processing system or program products Accordingly, the present invention may take the form of navigation systems, navigation methods, navigation devices, navigation software and etc Software wπtten according to the present invention is to be stored in some form of computer readable medium, such as memory, or CD ROM, or transmitted over a network, and executed by a processor

A. Interactive Location Determination and Navigation Service

A key component of a navigation system is the determination of the location (or position) of a user It is intended that the term location (referred to herein as the measurement^ ) of a geographic location) includes information related to the position of an object A location may contain three dimensional information that completely define the exact position of an object In some embodiments, a location may contain two dimensional information to define an object in a two dimensional space In some additional embodiments, a location may contain information that is not sufficient to define completely the position of an object Broadly defined location, as used herein, also may include speed, direction of movement, etc of an object

One of skill in the art would appreciate that the format of location information is not cπtical to some embodiments of the invention For example, m some embodiments, location information is presented m the format of (x, y). where x and y are two ordmates define the geographic location of an object, l e., a user There are both satellite and terrestrial positioning systems useful for some embodiments of the invention A location, however, contains vaπous degrees of inaccuracies For example, most GPS receivers can provide the location of object withm a range of around 50 meters. 1 e . an inaccuracy of around 50 meters There are a number of well know factors that mav affect the accuracy of a location determination For example, weather conditions may affect the accuracy of a GPS location determination In some embodiments of the invention, a location

(measurements), m addition to information defining the position of an object, is also associated with an estimated error and a range One of skill in the art would appreciate that the error of a location determination may be estimated based upon the characteπstics of the positioning device, weather and a number of other factors One aspect of the invention provides methods, software and devices for determining whether a location is ambiguous for navigation purposes Whether or not a location is ambiguous may be dependent upon many factors including, but not limited to

1 ) The accuracy associated with the location In general, the more accurate a location is. the less likely it is ambiguous

2) Attπbutes of road network For example, if one is traveling in a high way a remote area without any exits, a location associated with error of around 50 meters is not ambiguous for navigation purpose, because the navigation direction will be "going along the highway" In contrast, a location associated with an error of 50 meters is clearly ambiguous if the location is within a business distπct of a downtown where street blocks are less than 10 meters away In some embodiments of the invention, whether a location is ambiguous is also dependent upon traffic regulations For example, if there are only two roads (Road A and B) withm the range of a location (locatιon-/-error), the user is traveling at a speed of 55-80 miles/hr and road A has speed limit of 25 miles/hr, the location is unambiguous for the purpose of navigation because the user's location can be determined to be in Road B with high confidence m general

3) Recent traveling history may also be a relevant factor

4) Map accuracy Ambiguous locations present a challenge to a navigation system because good navigation direction can not be directly generated using an ambiguous location To overcome this problem, one aspect of the invention provides methods, software and devices for interactively determining the location of a user In some embodiments, one a location is determined to be ambiguous (Figure 5. 2) A map database is searched, using the ambiguous location and the associated eπor, for candidate locations (usually some visible landmarks, such as a building, a hospital, a hotel, a street intersection, street names, etc ) One of skill in the art would appreciate that v arious types of database structures can be useful for at least some embodiments of the invention Many map databases, search methods, algoπthms, software are either well known or commercially available Once a list of candidate locations is generated, if the list is too large and inappropπate for presenting to the user, the list may be consolidated (Figure 5, 4) For example, a list of 400 candidate locations (occasionally refeπed to as candidates) is too large for display in the LCD screen of a typical cellular phone, without scrolling One of skill m the art would appreciate that there are many ways to consolidate such a list of candidate locations Optionally, the list of candidate locations may be ranked based upon the probability of their being the closest to the user (or the actual locatιon)(Fιgure 5, 5) The list of candidate location is presented to a user (Figure 5, 7 and 8) and the user can select the one that is closest to the user The user's selection is then used to calculate the actual location of the user (9, 10) In some embodiments, the user's location is calculated as the selected candidate location In some other embodiments, the user^'s location is the middle of the ambiguous location and the selected candidate location One of skill m the art would appreciate that other methods of calculating the actual location is also withm the scope of the invention

One of skill in the art would also appreciate that the user may also be asked to select candidate locations according to cπtena other then closest distance For instance, a user may be asked to select the candidate location in a specific direction, such as "selecting the candidate location direct in front of you " It is also apparent to one of skill m the art that the user may also be asked to select multiple candidate locations in response to a question such as "Select candidate locations in front of vou " The process for interactive determination of a location may be repeated a number of times to obtain unambiguous locations (see. figure 5) The process may be performed in a single device that contains at least one processor and a memory In some preferred embodiments, the process is executed in a device that contains a processor, a mam memory, a hard dm e and a data storage space for stoπng a map database Code executing the process descπbed

e is loaded from the hard dπve into the memory and executed by the processor As it is apparent to one of skill in the art other data processing architectures may also be suitable for some embodiments of the invention In some most preferred embodiments, the interactive real time determination of a location and navigation service is performed in a distπbuted svstem containing a client, a remote server and a wireless communication between the two (Figure 4 and

B. Distributed Navigation Service

One aspect of the invention provides distnbuted navigation services which may be used m conjunction with the interactive real time navigation descπbed above In some embodiments, this new navigation architecture (Figure 2 and 3) employs \\ ireless and communication (Internet) infrastructure and server technology In particularly prefeπed embodiments, most navigation data storage, maintenance, retπeval and real time processing are conducted at the server level The full navigation w orkload are distπbuted among servers, devices, depending the locations of the users, capability of the wireless devices and real time situation at the user end

In another aspect of the invention, the data storage and computation workloads are distπbuted between servers and local devices In some embodiments, if the local device has an excessive memory and computation power, servers can download more information into the device and give more autonomous function to the device That is the reason it is called distπbuted navigation system

In yet another aspect of the invention, the navigation system of the invention provides real time navigation information Specifically, m some embodiments, the navigation system is a dynamic system (unlike map or many dnving directions provided by Internet portals, such as YAHOO. MAPQUEST, etc), it will provide real time turn by tum navigation guidance It will utilize voice, text and graphics in aiding its users to navigate It is also an interactive navigation system Given that none of the location technology can pinpoint the user location 100% and street condition may change, it is possible that the user get lost because of the user location error or the new street change The new interactive navigation system utilize the users vision and ask for the user input (what he/she saw) and compare with the options generated by the server based on the map data base to improve the location accuracy and hence improve the navigation accuracy Basically it is an intelligent system, it leams real time about the location by including its user in the loop

This navigation system will deπve the real time (or close to real time) traffic information based on its user group (location, speed, and time) information. The traffic information will be used in determining the optimal route (minimum time, or minimum gas as desired by its user) for the user to get to his/her destination This optimal routing will be dynamic as well. It is not necessary the one the system set when its user first request the navigation aid. The system will dynamically determine the route real time based on the real time traffic and weather situation at each con_juncture he/she meets. Of course if third party traffic information is available, it can also utilize that as well. Wireless devices can be any mobile devices with capability of communicating to other places. The locations of these devices are available, through its own function or earner's function or combined function of the device and earners. For example, the wireless device can use GPS (Global Position System) to determine its location, or it can use earner network based method to determine its location This patent does not constraint to any particular location determination technology The wireless devices can be any portable devices with wireless communication capability. For example, it can be cellular phones, satellite phone, Personal Digital Assistance and mobile computers, etc

The wireless device does not need to carry map information. But it can carry minimum amount of map information, depending on the oπgmal design of these devices, for example its storage size If the wireless device has voice function, it can tell the user certain location specific commands or suggestions, for example, it can tell the customer turn by turn driving or walking navigation guide It can also take the voice message from the customer to the distnbuted nav igation server, which can process the request and provide coπesponding suggestions or guidance

The wireless device can also show graphically the navigation information on the display of the device or on a displav connected to the device

Wireless earners will provide part of the connectivity for the wireless devices and distributed navigation servers Examples of these wireless earners are wireless service resellers, wireless ISPs (Internet Service Provider), or satellite wireless earners W^τιreless earners or third parties may provide the location capability for wireless devices

The system will need some kind of link for the distπbuted navigation servers and carriers They can either be through Internet or direct links (For example. Tl , Frame Relay etc or collocated at the earner site linked by LAN) The direct link architecture is applicable where Internet infrastructure is not well established or fast response is desired for user navigation or other location specific information services

The Distπbuted Navigation Server will store the street map and other location specific information When requested by the wireless user or any other authoπzed user, the server will use the user^'s location information and process the information, then provide corresponding guide to the user The user will get the guide through voice or display (for example, text or graphics) These servers also distπbute certain tasks between the server and the wireless devices, depending on what kind of the devices the users use For example, for a less powerful device, the server will carry major tasks, while for quite powerful devices, the server may let the devices do certain locahzable tasks, for example, stoπng some location information for quick response These Distnbuted Navigation Servers can be centralized, in case of limited number of users In most cases, they will be distπbuted in different regions to respond to local request faster Figure 4 shows one embodiment of the interactive navigation system of the invention The navigation system compπses a wireless device (1 , such as a PDA. Cell Phone, or any wireless device with location determining capability) and a server (7^s) which contains at least one central process unit and a map database This location information may be ambiguous due to a number of factors discussed above A location is ambiguous if navigation directions can not be generated For example, if the user is dπving in a downtown area with many close streets, a GPS location with -r/- 50 meters is not adequate to give turn by tum direction in some embodiments of the invention The GPS location information is thus considered as ambiguous m such embodiments In other situations, a GPS location with +/- 50 meiers is adequate for navigation purpose For example, if a user is dπving in a highway in a remote area without any close exits, the GPS location is sufficient for calculating further navigation directions for the user In such a situation, the GPS location is not ambiguous in these embodiments

The location information is transmitted to the server which determines whether the location information is ambiguous If it is ambiguous, the server will search the map database to locate several candidate locations (or candidates or candidate landmarks) around the ambiguous location (6) The candidate locations can be a street address, a high building, a gas station or other landmarks The candidate locations (5) are transmitted to the wireless device (1 ) for display The user can choose the candidate location that is closest to the user The user's chosen location is then sent to the server The server can determine, according to the most recent user/device location information and the closest candidate location, the user's actual location This process may be repeated to enhance the accuracy of the user location measurements One the location measurements satisfy the requirement of further navigation Further navigation information is transmitted to the user The foregoing descπptions of specific embodiments of the present invention have been presented for purposes of illustration and descπption They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and vanations are possible m light of the above teaching The embodiments were chosen and descπbed in order to best explain the pnnciples of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and vaπous embodiments with vaπous modifications as are suited to the particular use contemplated

Claims

What is claimed is:

1 A method for determining the location of a user compπsing a) determining an ambiguous location of a user, wherein said location is ambiguous for navigation, b) presenting to said user a plurality of candidate locations, wherein said candidate locations are in close proximate of said location, c) receiving from said user's chosen location from said plurality of candidate locations, d) adjusting said location according to said chosen location

2 The method of claim 1 wherein said chosen location is the most possible location among said plurality of said candidate locations of said user

3 The method of claim 1 wherein said step of determining an ambiguous location is conducted in a device wherein said device compnses a satellite based location determination svstem

4 The method of claim 3 wherein said satellite based location determination system is a global positioning system

5 The method of claim 1 wherein said step of determining an ambiguous location is determined using a terrestπal based location determination system

6 The method of claim 1 wherein said method is conducted in a single device.

7 The method of claim 1 wherein said step of determining an ambiguous location further compπses transmitting location information to a server via wireless transmission

8. The method of claim 4 wherein said step of presenting further compπses the steps of: a) calculating said plurality of candidate locations in a single device or a remote server; ranking said plurality of candidate locations; and transmitting said plurality of candidate locations to device.

9. The method of claim 8 wherein said device is a cellular phone.

10 The method of claim 9 wherein said device is a PDA.