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System and method for mobile location by proximity detection

  • US 9,331,798 B2
  • Filed: 01/07/2011
  • Issued: 05/03/2016
  • Est. Priority Date: 01/08/2010
  • Status: Expired due to Fees
First Claim
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1. A method of determining the location of a mobile device in a communications network having one or more base station transceivers and one or more proximity sensors, wherein the one or more proximity sensors are not co-located with any one of the one or more base station transceivers;

  • the method comprising the steps of;

    (a) receiving a request to locate the mobile device;

    (b) tasking, using a geolocation control system (“

    GCS”

    ), at least one of the proximity sensors to receive a signal transmission from the mobile device;

    (c) transmitting a first signal from at least one of the one or more base station transceivers to the mobile device;

    (d) transmitting by the mobile device the signal transmission from the mobile device, in response to receiving the first signal;

    (e) measuring one or more signal characteristics of the signal transmission from the mobile device by each tasked proximity sensor;

    wherein the signal transmission from which said signal characteristics are measured by each tasked proximity sensor is not received by said each tasked proximity sensor via the one or more base station transceivers;

    (f) collecting at said GCS the measured characteristics; and

    (g) determining at said GCS a location of the mobile device as a function of the measured characteristic, wherein the measured characteristic includes range information;

    wherein the step of measuring further comprises;

    (i) measuring by each tasked proximity sensor a transmit time of the first signal, a transmit time of a second signal transmitted by a repeater, or a transmit time of a third signal transmitted by a Distributed Antenna System (“

    DAS”

    ) antenna, wherein the second and third signal are each a repeated version of the first signal,(ii) measuring by the proximity sensor for a receive time of the first, second, or third signal,(iii) for estimating transceiver processing delay of the mobile device, and(iv) determining flight time of the signal transmission from the mobile device as a function of the measured transmit time, the measured receive time and the estimated delay.

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