04359733 is referenced by 171 patents and cites 22 patents.

A system for determining the positions of a plurality of vehicles traveling on or above a defined sector of the earth's surface comprises a transponder carried by each vehicle for transmitting a uniquely coded beacon signal in response to a general interrogation signal, at least three repeater-carrying satellites at spaced orbital locations above the earth for receiving and retransmitting the beacon signals produced by the vehicles, and a ground station for periodically transmitting the general interrogation signal and for receiving and processing the beacon signals retransmitted by the three satellites in order to determine vehicle position. In order to avoid signal overlap and equipment saturation at the ground station, each vehicle transponder includes means responsive to the general interrogation signal for inhibiting the transmission of further beacon signals by the transponder for a predetermined time interval following the response of the transponder to the general interrogation signal. In a preferred embodiment of the invention, the inhibited interval of the vehicle transponders may be varied automatically in response to a command signal transmitted by the ground station.

Satellite-based vehicle position determining system
Application Number
Publication Number
Application Date
September 23, 1980
Publication Date
November 16, 1982
Gerard K O Neill
127 McCosh Cir., Somerset County, Princeton, 08540
Robbins & Laramie
G01S 13/78
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