05293645 is referenced by 128 patents and cites 10 patents.

A system for locating a movable radio terminal within a cellular telephone network, or other radio network, which includes a plurality of base stations that transmit synchronized timing reference signals. A receiver in the network receives transmissions from the radio terminals to be located that include information compiled at the radio terminal indicating relative propagation delays in receipt of the timing reference signals from at least three base stations. A processor coupled with the receiver, processes the transmissions indicating relative propagation delays to identify a geographic location of the radio terminal. A complementary radio terminal receives the timing reference signals from base stations, including a designated base station and compiles information indicating propagation delays, relative to the propagation delay of the timing reference signal from the designated base station, from at least two additional base stations. The radio terminal transmits the information compiled so that a station receiving the transmission may locate the radio terminal in response to the information and the known locations of base stations in the network.

Title
Apparatus and method for locating mobile and portable radio terminals in a radio network
Application Number
7/771195
Publication Number
5293645
Application Date
October 4, 1991
Publication Date
March 8, 1994
Inventor
Prem L Sood
Vancouver
WA, US
Agent
Martin C Fliesler
Assignee
Sharp Microelectronics Technology
WA, US
IPC
H04B 17/02
H04B 7/005
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