GPS receiver using a radio signal for improving time to first fix
DCFirst Claim
1. A global positioning system (GPS) receiver apparatus, comprising:
- a radio signal receiver for receiving a radio signal having a standard time, decoding said standard time from said radio signal, and providing information for said standard time in a radio receiver output signal; and
a GPS signal receiver for receiving a GPS signal having data bits and coupled to the radio signal receiver for using said standard time information for resolving a GPS-based time for a time of arrival of one of said data bits.
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Abstract
A global positioning system (GPS) receiver apparatus using time and frequency information derived from a radio signal other than the GPS satellite signal for improving the time to first fix (TTFF). The GPS receiver apparatus includes a GPS signal receiver for receiving a GPS satellite signal modulated with data bits and a radio signal receiver for receiving a radio signal having a standard time and/or a standard frequency. The radio signal receiver provides standard time information to the GPS signal receiver. The GPS signal receiver uses the standard time information to resolve a GPS time for a time of arrival of a data bit. The GPS signal receiver includes a propagation delay calibrator for correcting the standard time for the travel time due to the path length for the radio signal. The radio signal receiver uses a reference clock signal provided by the GPS signal receiver for determining a frequency error between a frequency of the reference clock signal and the standard frequency. The GPS signal receiver uses the frequency error for pre-tuning to the carrier frequency of the GPS satellite signal.
312 Citations
17 Claims
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1. A global positioning system (GPS) receiver apparatus, comprising:
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a radio signal receiver for receiving a radio signal having a standard time, decoding said standard time from said radio signal, and providing information for said standard time in a radio receiver output signal; and a GPS signal receiver for receiving a GPS signal having data bits and coupled to the radio signal receiver for using said standard time information for resolving a GPS-based time for a time of arrival of one of said data bits. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 10)
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9. A global positioning system (GPS) receiver apparatus, comprising:
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a radio signal receiver for receiving a radio signal having an accurate carrier frequency and for providing frequency error information for a difference between said carrier frequency and a multiple of a frequency of a reference clock signal; and a GPS signal receiver coupled to the radio signal receiver, including; a) a reference oscillator for providing said reference clock signal; b) a microcomputer for using said frequency error information for providing a frequency adjustment; and c) a digital signal processor for using said frequency adjustment for pre-tuning to a frequency for acquiring a GPS signal. - View Dependent Claims (11, 12, 13, 14)
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15. A method for improving time to first fix in a global positioning system (GPS) receiver apparatus for receiving a GPS signal, comprising steps of:
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receiving a radio signal having a standard time; decoding said standard time from said radio signal; receiving said GPS signal having data bits; and using said standard time for resolving a GPS-based time for a time of arrival of one of said data bits.
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16. A method for improving time to first fix in a global positioning system (GPS) receiver apparatus for receiving a GPS signal, comprising steps of:
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receiving a radio signal having an accurate carrier frequency; providing a reference clock signal; determining a frequency error for a difference between said carrier frequency and a multiple of a frequency of said reference clock signal; using said frequency error for computing a frequency adjustment; and using said frequency adjustment in a digital signal processor in said GPS receiver for pre-tuning to a frequency for acquiring said GPS signal. - View Dependent Claims (17)
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Specification