05003317 is referenced by 174 patents and cites 4 patents.

A stolen vehicle recovery system (20) in which a vehicle transceiver (30) is disposed on each vehicle (28) for cyclically transmitting a pulsed signal which is modulated by a data stream comprising a verification code, a unique identity code associated with the vehicle (28), and a code which corresponds to whether the detected vehicle (28) is moving or stationary. The vehicle transceiver (30) is automatically activated if a proper authorization signal is not provided to the transceiver (30) by a verification unit. A scanning receiver (42) decodes the pulsed signal and provides the information to a control processor (40) which, in turn, sets remote direction finding receivers (44, 46, 48), set up in a triangulation antenna array, to the appropriate channel. The D.F. receivers (44, 46, 48) measure the bearing, signal strength and time variation, as well as the vehicle identity code, and pass it back to the control processor (40) which, after verification of the identity code, passes this positional information on to a mapping and display computer (50) at the central station (22) which, thereafter, provides a digitized street or terrain map display with the vehicle position and identity code being dynamically displayed thereon. The map may be zoomed through a hierarchical geographical display. The system (20) may be used with multiple vehicles in the same detection area with the channel being divided into a plurality of sub-channels and a composite map display dynamically showing all stolen vehicles (28) in the detection area. Mobile tracking (110, 112, 114, 116, 118, 120, 122) may al be used. In addition, the transceiver (30) can be remotely activated or deactivated, and overlapping detection areas can be provided to cover a larger area. When the transceiver (30) is initially activated, the verification code is set to an unverified state and is changed to a verified state, after confirmation of stolen status, by a command sent from the command transmitter (52).

Title
Stolen vehicle recovery system
Application Number
7/378593
Publication Number
5003317
Application Date
July 11, 1989
Publication Date
March 26, 1991
Inventor
Robert L Gendler
Tamarac
FL, US
Donald R Gray
Carmel
IN, US
Agent
Bryan Cave McPheeters & McRoberts
Assignee
Mets
IN, US
IPC
G01S 3/02
View Original Source