Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Patent
1997-12-19
2000-03-07
Eisenzopf, Reinhard J.
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
342463, H04M 720, G01S 302
Patent
active
060352027
ABSTRACT:
A system for locating a mobile transceiver is disclosed. A first receiver associated with a mobile transceiver detects signals transmitted from fixed transmitter locations broadcasting, for example, FM signals. A demodulated audio portion of the received FM signals, along with an encoded representation of the channel of the transmitted FM signal, are transmitted to a second receiver at a known location. The second receiver is tuned to the channel indicated by the channel data. A correlator time-shifts the received audio portion of the FM signal until a correlation with the received signal at the second receiver is achieved. This process may be repeated for several transmitted FM signals. The time differences between the signals received at the first and second receivers along with the known location of the FM transmitters are used to determine the location of the mobile unit.
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Project #19, Rural Mayday/800 Call-In System Feasibility, Enabling Technologies for Mayday Systems, Updated Technical Report, May 21, 1997, Mobile & Portable Radio Research Group, Center for Transportation Research, Virginia Polytechnic Institute and State University, pp. 18-19.
Appiah Charles N.
Eisenzopf Reinhard J.
Ericsson Inc.
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