Directly acquiring precision code GPS signals
First Claim
1. A method comprising:
- receiving acquisition assistance data from an assist server; and
determining a time offset for a P-code pseudorandom code sequence associated with a signal from a satellite based on the acquisition assistance data.
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Accused Products
Abstract
In general, the invention is directed to techniques for directly acquiring P-codes without first acquiring C/A-codes. For example, in one embodiment, a system comprises an assist server to track a P-code signal from a Global Positioning System (GPS) satellite and generate acquisition assistance information from the signal. The system further comprises a mobile unit to receive the acquisition assistance data from the assist server, and to acquire the P-code signal from the satellite based on the acquisition assistance data. The acquisition assistance data may include time-of-week data indicating an initial time offset into a P-code pseudorandom code sequence for the satellite. The mobile unit may include a reference generator to locally generate a reference pseudorandom code sequence based on the time-of-week data.
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Citations
71 Claims
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1. A method comprising:
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receiving acquisition assistance data from an assist server; and
determining a time offset for a P-code pseudorandom code sequence associated with a signal from a satellite based on the acquisition assistance data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 25, 30)
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23. A method comprising:
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receiving acquisition assistance data from an assist server, wherein the acquisition assistance data identifies a set of satellites and includes time-of-week data indicating an initial time offset into a P-code pseudorandom code sequence for each of the satellites;
receiving signals from the satellites;
digitizing the signals to produce a stream of digital data;
buffering an amount of the digital data;
locally generating reference P-code pseudorandom code sequences for the satellites based on the respective initial time offsets for the satellites;
correlating the digital data with the reference code sequences to identify correlation peaks having respective time offsets; and
determining a position for a mobile unit based on the time offsets. - View Dependent Claims (24, 26, 27, 28, 29, 31)
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32. A method comprising:
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receiving acquisition assistance data from server; and
directly acquiring a P-code signal from a satellite based on the acquisition assistance data without first acquiring a C-code signal from the satellite. - View Dependent Claims (33, 34, 35)
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36. A system comprising:
an assist server to track a signal from a Global Positioning System (GPS) satellite and generate acquisition assistance information from the signal; and
a mobile unit to receive the acquisition assistance data from the assist server, and to acquire a P-code signal from the satellite based on the acquisition assistance data. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43)
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44. An apparatus comprising:
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an antenna to receive a signal from a satellite;
a wireless modem to receive acquisition assistance data from an assist server;
a reference generator to generate a reference pseudorandom code sequence based on the acquisition assistance data; and
a processor to determine a time offset for a P-code pseudorandom code sequence associated with the signal based on the acquisition assistance data. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60)
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61. A computer-readable medium comprising instructions for causing a programmable processor to:
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receive acquisition assistance data from an assist server; and
determine a time offset for a P-code pseudorandom code sequence associated with a signal from a satellite based on the acquisition assistance data. - View Dependent Claims (62, 63, 64, 65, 66, 67, 68, 69, 70)
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71. A method comprising:
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receiving acquisition assistance data from an assist server;
directly acquiring a P-code signal from a satellite based on the acquisition assistance data without first acquiring a C-code signal from the satellite; and
determining a time offset for a P-code pseudorandom code sequence associated with said P-code signal.
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Specification