06046687 is referenced by 46 patents and cites 143 patents.

Apparatus and method for a location determination and reporting (LDR) system for clandestinely or surreptitiously 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 (preferably hidden on the vehicle) that receives LD signals and determines the LD unit present location, a specially configured cellular telephone, and a call interceptor. When the vehicle is reported missing, a central station or the vehicle operator interrogates the vehicle LDR system by transmitting a location interrogation signal, commanding the LD unit to transmit its present location. The vehicle phone does not signal receipt of 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 LD unit present location to a specified recipient. If the incoming call does not include a location interrogation signal, the cellular phone "rings" audibly or visually, after the initial time delay, and simulates behavior as a normal cellular phone for that call. The cellular phone simulates normal operation 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
Clandsetine location reporting for missing vehicles
Application Number
157726
Publication Number
6046687
Application Date
March 10, 1997
Publication Date
April 4, 2000
Inventor
James M Janky
Los Altos
CA, US
Agent
Donald S Cooper & Dunham Dowden
Assignee
Trimble Navigation
CA, US
IPC
G08B 25/01
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