05225842 is referenced by 444 patents and cites 3 patents.

A tracking system employing global positioning system (GPS) satellites provides extremely accurate position, velocity, and time information for vehicles or any other animate or inanimate object within any mobile radio communication system or information system, including those operating in high rise urban areas. The tracking system includes a sensor mounted on each object, a communication link, a workstation, and a GPS reference receiver. The sensor operates autonomously following initialization by an external network management facility to sequence through the visible GPS satellites, making pseudo range and delta range or time difference and frequency difference measurements. No navigation functions are performed by the sensor, thereby permitting significant reductions in the cost thereof. The raw satellite measurements, with relevant timing and status information, are provided to the communication link to be relayed periodically back to the workstation. Differential corrections may also be provided at the workstation to increase the accuracy of the object location determination. In normal operation, three satellite measurements are required to compute the location of the object, but for a short time period a minimum of two satellite measurements are acceptable with time, altitude, and map aiding information being provided by the workstation.

Title
Vehicle tracking system employing global positioning system (GPS) satellites
Application Number
7/697754
Publication Number
5225842
Application Date
May 9, 1991
Publication Date
July 6, 1993
Inventor
Mark A Sturza
Woodland Hills
CA, US
Alison K Brown
Monument
CO, US
Agent
William E Hein
Assignee
NAVSYS Corporation
CO, US
IPC
G01S 5/02
H04B 7/185
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