06111541 is referenced by 158 patents and cites 31 patents.

A positioning system includes the ability to receive GPS signals and to receive and transmit packet radio signals. The positioning system receives GPS transmissions to determine its pseudo position. The positioning system also receives differential corrections relative to its pseudo position using packet radio. By combining the GPS transmissions and the differential corrections, the positioning system calculates its actual position. A user has the ability to obtain information relevant to their actual position by transmitting a request to a reference station, using packet radio. The reference station maintains an information system and will transmit the requested information back to the user. The information system includes a data storage memory and retrieval system and a direct link to the internet. The user is able to provide information for storage within the information system or on the internet in order to compile the information available from the reference station. The positioning system also includes the ability to automatically transmit its position periodically allowing the reference station to track and monitor its actual position. Information relative to its location, signals and alerts are transmitted to predetermined locations based on the position of the positioning system relative to a predetermined location or another positioning system. Alternatively, the positioning system determines its position using only packet radio. Reference stations at known locations transmit signals having predetermined amplitudes and signal strengths. A positioning system determines its position relative to the reference stations based on the amplitude and strength of the signals received from the reference stations.

Positioning system using packet radio to provide differential global positioning satellite corrections and information relative to a position
Application Number
Publication Number
Application Date
September 24, 1997
Publication Date
August 29, 2000
Clayton R Karmel
San Jose
Haverstock & Owens
Sony Electronics
Sony Corporation
G01C 21/00
H04B 7/185
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