05629693 is referenced by 158 patents and cites 10 patents.

Apparatus and method for a location determination and reporting (LDR) system for clandestinely determining and reporting a missing vehicle present location. The vehicle may be stationary or moving and may be anywhere within reach of a cellular central station to which the location is reported. The vehicle is equipped with a location determination (LD) unit, including an LD signal antenna and receiver/processor (preferably hidden on the vehicle) that determines the LD antenna present location, a specially configured cellular telephone, and a controller. When the vehicle is reported missing, the central station interrogates the vehicle LDR system to determine the vehicle present location. A location interrogation signal is transmitted, commanding the LD unit to transmit the LD antenna present location. The vehicle phone does not signal an incoming call for an initial time period of selected length .DELTA.t.sub.d, awaiting possible receipt of a location interrogation signal. If the incoming call includes a location interrogation signal, the cellular phone does not "ring" but transmits information on the vehicle's present location to the central station. If the incoming call does not include a location interrogation signal, the cellular phone "rings" audibly or visually, after the initial time delay, and behaves as a normal cellular phone for that call. The cellular phone functions normally if a vehicle occupant attempts to use the phone. An unauthorized user of the vehicle receives no indication that the innocuous cellular phone is used to track the vehicle present location.

Title
Clandestine location reporting by a missing vehicle
Application Number
157726
Publication Number
5629693
Application Date
May 17, 1995
Publication Date
May 13, 1997
Inventor
James M Janky
Los Altos
CA, US
Agent
John Schipper
Assignee
Trimble Navigation
CA, US
IPC
G08G 1/123
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