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Local clock frequency calibration using low earth orbit (LEO) satellites

  • US 7,859,455 B2
  • Filed: 01/06/2009
  • Issued: 12/28/2010
  • Est. Priority Date: 01/06/2009
  • Status: Active Grant
First Claim
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1. A method of transferring frequency stability from a satellite to a device, the method comprising:

  • receiving a signal from the satellite;

    determining a code phase from the satellite signal, wherein;

    the satellite is a low earth orbit (LEO) satellite having a clock frequency,the signal comprises a plurality of message frames each having an ordinal number, and at least one time transfer structure message having a unique pseudorandom code, andthe code phase corresponds to the ordinal number of the message frame whose time transfer structure message is identified through its unique pseudorandom code;

    receiving aiding information; and

    calibrating a frequency of a local clock of the device to substantially synchronize the local clock frequency with the satellite clock frequency, wherein the calibrating comprises measuring a frequency of the satellite signal using the code phase and the aiding information.

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