05929752 is referenced by 58 patents and cites 8 patents.

Apparatus and method for a location determination and reporting (LDR) system for clandestinely determining and reporting a missing vehicle present location. The vehicle is equipped with a handheld cellular phone unit and controller that are accepted and held by a cellular phone cradle that can include electrical power and/or a location determination (LD) unit to determines the LD unit present location. The cellular phone unit can operate on one cellular channel or on two distinct cellular channels. 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 its present location. The cellular phone does not signal receipt of an incoming call for an initial time period of selected length .DELTA.td, awaiting possible receipt of a location interrogation signal on the first cellular channel. 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 on the second cellular channel. 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.

Clandestine missing vehicle location reporting using cellular channels
Application Number
Publication Number
Application Date
March 11, 1997
Publication Date
July 27, 1999
John F Schipper
Palto Alto
Hamid Najafi
Los Altos
James M Janky
Los Altos
Donald S Cooper & Dunham Dowden
Trimble Navigation
B60R 25/10
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