04908629 is referenced by 148 patents and cites 5 patents.

An improved vehicle or other object-tracking and location system, preferably, though not essentially, of national scope, wherein transponder or transceiver-equipped stolen or missing vehicles or other objects may be located and/or tracked, as by appropriately-equipped police direction-finding tracking vehicles, through homing-in on periodic transponder reply radio transmissions automatically activated by command activation signals broadcast on the same carrier frequency as the transponder reply signals and with encoded vehicle identification information that causes the intended vehicle transponder so to reply, and with provision for modifying the command signals to require an increased rate of periodic transponder reply signal transmission to assist homing-in on the selected vehicle. In a preferred mode of operation, the verification of whether the reportedly missing vehicle is thus transponder-equipped is preferably established by querying the FBI-NCIC computer system, which will provide the said coded vehicle identification information and automatically cause the appropriate sector or area to broadcast said command activation signals.

Title
Apparatus for locating and/or tracking stolen or missing vehicles and the like
Application Number
847152
Publication Number
4908629
Application Date
December 5, 1988
Publication Date
March 13, 1990
Inventor
Norval D Stapelfeld
Brookline
MA, US
Sheldon P Apsell
Newton
MA, US
Agent
Rines and Rines Shapiro and Shapiro
Assignee
Lo Jack Corporation
MA, US
IPC
G01S 5/02
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