Interferometrics Incorporated

Associated Rt, Inc.

Curtis A Knight

John C Webber

Louise A Stilp

Louis A Stilp

A system for determining the location of a mobile transmitter is disclosed. The mobile transmitter receives a message signal and responds to the message signal by transmitting a responsive signal, wherein the responsive signal is indicative of the identity of the mobile transmitter. One preferred embodiment comprises at least three antenna site systems 10, a central site system 12, a database processor for use in connection with various applications, and a map system 16. The system may be employed to locate cellular telephones and/or like devices emitting bursty transmissions, e.g., over messaging or control channels.

System for locating a source of bursty transmissions cross reference to

In a method and system for locating an unknown transmitter which emits an interfering signal, multiple signals, including a phase-calibrating signal and the interfering signal, are simultaneously observed within a passband. These signals are then simultaneously cross-correlated. The phase-calibrating signal is then isolated from the cross-correlated signals and processed to determine an amount of offset to compensate for frequency fluctuations between local oscillators in satellites, which receive and retransmit the phase-calibrating signal and the interfering signal.

Method and system for locating an unknown transmitter using calibrated

A satellite tracking system, including a terrestrial transmitter, a plurality of terrestrial receivers, and a controller/analyzer, operates in two modes. In an active mode, the transmitter emits a tracking signal within a spread spectrum to a satellite and at least one of the receivers receives the signal retransmitted by the satellite. The controller/analyzer then determines the satellite position and velocity from the received signal. In a passive mode, at least two receivers each receive a signal transmitted from the satellite during normal operation and the controller/analyzer determines the satellite position and velocity from the received signals. The satellite position and velocity can be used to determine the position of an unknown transmitter that causes interference at the satellite.

Method and system for tracking satellites to locate unknown transmitting

A cellular telephone location system for automatically recording the location of one or more mobile cellular telephones comprises three or more cell site systems 12. Each cell site system is located at a cell site of a cellular telephone system. Each cell site system includes an antenna that may be mounted on the same tower or building as the antenna employed by the cellular telephone system and equipment that may be housed in the equipment enclosure of the corresponding cell site. The cell site systems are coupled via T1 communication links 14 to a central site 16. The central site may be collocated with the cellular telephone system's MTSO. The central site 16 is further coupled to a database 20, which may be remotely located from the central site and made available to subscribers.

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Washington, DC, United States of America

Curtis A Knight