3864681 is referenced by 12 patents and cites 3 patents.

A vehicle location system is provided for determining the coordinate location of a vehicle through radio transmission radiation from the vehicle and the system includes a plurality of receiver sites at known coordinate locations each having antenna-coupler means providing first and second signals whose phase difference is approximately linearly related to the azimuth angle of the receiver signal from the radiation source. The first and second signals are processed at each receiver site to translate the frequency of the signals to a lower frequency and to remove the common frequency variations therefrom. Thereafter, the signals are passed through a phase detector which provides a binary output expression which is linearly related to the phase difference between the first and second signals. The binary expressions from each of the respective receiver sites are then processed through an electronic data processing means which is programmed to determine the coordinates of the radiation source from the plurality of the binary expressions.

System and process for locating sources of radiation
Application Number
Publication Number
Application Date
February 28, 1973
Publication Date
February 4, 1975
Olive George A
Duffield Charles F
G01s 05/04
G08g 05/00
G01S 03/14
G01S 03/48
G01S 05/04
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