A personal data unit (PDU) is operable to collect video information via a camera (12) and audio information via a microphone (14). The PDU (10) utilizes a cellular link for transmission of the collected information to a central station (27). Position/time information is received from a GPS satellite...http://www.google.es/patents/US5726660?utm_source=gb-gplus-sharePatente US5726660 - Personal data collection and reporting system
