Method and system for determining time in a satellite positioning system
First Claim
Patent Images
1. A method of receiving an estimate of time in a satellite signal receiver comprising:
- requesting and receiving an estimate of time from a server using a time transfer protocol;
compensating for error of a clock in the satellite signal receiver using the estimate of time;
designating the output of the compensated clock as an a-priori estimate of absolute time; and
employing the a-priori estimate of absolute time in a mathematical model that updates the a-priori estimate of absolute time to compute a position of the satellite signal receiver and an absolute time.
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Abstract
Method and apparatus for receiving an estimate of time in a satellite signal receiver receives an estimate of time from a server and compensates for error of a clock in the satellite signal receiver using the estimate of time. The output of the compensated clock is used when computing a position of the satellite signal receiver. The estimate of time is received using a network time protocol (NTP), a simple network time protocol (SNTP), or by one-way broadcast from the server.
58 Citations
23 Claims
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1. A method of receiving an estimate of time in a satellite signal receiver comprising:
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requesting and receiving an estimate of time from a server using a time transfer protocol; compensating for error of a clock in the satellite signal receiver using the estimate of time; designating the output of the compensated clock as an a-priori estimate of absolute time; and employing the a-priori estimate of absolute time in a mathematical model that updates the a-priori estimate of absolute time to compute a position of the satellite signal receiver and an absolute time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of receiving an estimate of time in a satellite signal receiver comprising:
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requesting and receiving an estimate of time from a server using a time transfer protocol; compensating for error of a clock in the satellite signal receiver using the estimate of time; designating the output of the compensated clock as an a-priori estimate of absolute time; employing the a-priori estimate of absolute time in a mathematical model that updates the a-priori estimate of absolute time to compute a position of the satellite signal receiver and an absolute time; providing an a-priori estimate of absolute time from a time source; computing a position of the satellite signal receiver and an absolute time using a mathematical model that updates the a-priori estimate of absolute time; and comparing the computed absolute time with the output of the compensated clock. - View Dependent Claims (13, 14)
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15. A method of receiving an estimate of time in a satellite signal receiver comprising:
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requesting and receiving an estimate of time from a server using a time transfer protocol;
which comprises;determining a time of last compensation of the clock; comparing the time of last compensation with a threshold; and requesting the estimate of time from the server in response to the time of last compensation exceeding the threshold; and compensating for error of a clock in the satellite signal receiver using the estimate of time; designating the output of the compensated clock as an a-priori estimate of absolute time; and
employing the a-priori estimate of absolute time in a mathematical model that updates the a-priori estimate of absolute time to compute a position of the satellite signal receiver and an absolute time.
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16. A method for determining a position of a satellite signal receiver comprising:
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computing pseudoranges that estimate the range of the satellite signal receiver to a plurality of satellites in a satellite constellation; requesting and receiving an estimate of time from a server using a time transfer protocol; receiving ephemeris data relating to the satellite constellation; designating the estimate of time as an a-priori estimate of absolute time; and employing the designated a-priori estimate of absolute time in a mathematical model that update the a-priori estimate of absolute time to determine the position of the satellite signal receiver and an absolute time. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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23. A method for determining a position of a satellite signal receiver comprising:
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computing pseudoranges that estimate the range of the satellite signal receiver to a plurality of satellites in a satellite constellation; requesting and receiving an estimate of time from a server using a time transfer protocol; receiving ephemeris data relating to the satellite constellation; providing an a-priori estimate of absolute time from a time source; computing a position of the satellite signal receiver and an absolute time using a mathematical model that updates the a-priori estimate of absolute time; and comparing the computed absolute time with the estimate of time.
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Specification