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Positioning system

  • US 20040212531A1
  • Filed: 02/17/2004
  • Published: 10/28/2004
  • Est. Priority Date: 02/28/2003
  • Status: Active Grant
First Claim
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1. A positioning system for determining a position P of a positioning terminal, the system including a plurality of first signal sources each emitting a respective first signal, and one or more second signal sources each emitting a respective second signal, the first signals being synchronous to each other and the second signals being non-synchronous with the first signals, for, based on a signal propagation time and signal propagation speed of the first signals, determining a distance from the positioning terminal to the first signal sources so as to determine a position of the positioning terminal, said positioning system comprising:

  • a measurement device for receiving the signals from the first signal sources to determine the position P and a time of measurement when the measurement device receives the first signals and for, based on the time of measurement, measuring a receiving time (TR) of a predetermined event of the second signals;

    a control device for determining a signal propagation time (t) between the measurement device and one of the second signal sources by calculating a relative distance |P−

    Q| between the measurement device and the one second signal source based on the position P measured by the measurement device and a position (Q) of the one second signal source and by dividing the resulting distance by the signal propagation speed, and for determining a time (TT) at which the one second signal source originates the predetermined event by solving TR

    t;

    the positioning terminal having a receiving device for receiving the signals from the first and second signal sources; and

    a communication device for communicating between the control device and the positioning terminal, wherein the positioning terminal uses the time TT as a reference to receive the signals from the first signal sources for positioning.

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