Global positioning system receiver
First Claim
1. A global positioning system (GPS) receiver comprising:
- a demodulator for obtaining ephemeris data and almanac data from a navigation message sent by a plurality of satellites;
a calculator for calculating a plurality of almanac correction parameters according to coordinate differences between a plurality of ephemeris-based coordinates of said satellites and a plurality of almanac-based coordinates of said satellites and according to clock differences between a plurality of ephemeris-based clock drifts of said satellites and a plurality of almanac-based clock drifts of said satellites; and
a satellite position calculator for calculating said ephemeris-based coordinates according to said ephemeris data, for calculating said almanac-based coordinates according to said almanac data, and for calculating a plurality of positions of said satellites according to said ephemeris data, said almanac data and said almanac correction parameters,wherein said calculator verifies validity of said ephemeris data, said almanac data and said almanac correction parameters and calculates a new plurality of almanac correction parameters if previous almanac correction parameters are invalid and said ephemeris data and said almanac data are valid.
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Accused Products
Abstract
A GPS receiver includes a demodulator for obtaining ephemeris data and almanac data from a navigation message sent by satellites, and includes a calculator. The calculator is used for calculating almanac correction parameters according to coordinate differences between ephemeris-based coordinates of the satellites and almanac-based coordinates of the satellites. The GPS receiver also includes a satellite position calculator for calculating the ephemeris-based coordinates of the satellites according to the ephemeris data, for calculating the almanac-based coordinates of the satellites according to the almanac data, and for calculating positions of the satellites according to the ephemeris data, the almanac data and the almanac correction parameters.
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Citations
23 Claims
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1. A global positioning system (GPS) receiver comprising:
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a demodulator for obtaining ephemeris data and almanac data from a navigation message sent by a plurality of satellites; a calculator for calculating a plurality of almanac correction parameters according to coordinate differences between a plurality of ephemeris-based coordinates of said satellites and a plurality of almanac-based coordinates of said satellites and according to clock differences between a plurality of ephemeris-based clock drifts of said satellites and a plurality of almanac-based clock drifts of said satellites; and a satellite position calculator for calculating said ephemeris-based coordinates according to said ephemeris data, for calculating said almanac-based coordinates according to said almanac data, and for calculating a plurality of positions of said satellites according to said ephemeris data, said almanac data and said almanac correction parameters, wherein said calculator verifies validity of said ephemeris data, said almanac data and said almanac correction parameters and calculates a new plurality of almanac correction parameters if previous almanac correction parameters are invalid and said ephemeris data and said almanac data are valid. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for positioning global positioning system (GPS) receiver, comprising:
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obtaining ephemeris data and almanac data from a navigation message sent by a plurality of satellites; calculating a plurality of ephemeris-based coordinates and a plurality of ephemeris-based clock drifts of said satellites according to said ephemeris data; calculating a plurality of almanac-based coordinates and a plurality of almanac-based clock drifts of said satellites according to said almanac data; calculating a plurality of almanac correction parameters according to coordinate differences between said ephemeris-based coordinates and said almanac-based coordinates and according to clock differences between said ephemeris-based clock drifts and said almanac-based clock drifts; calculating a plurality of positions of said satellites according to said ephemeris data, said almanac data and said almanac correction parameters; verifying validity of said ephemeris data, said almanac data and said almanac correction parameters; and calculating a new plurality of almanac correction parameters if previous almanac correction parameters are invalid and said ephemeris data and said almanac data are valid. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A GPS (global positioning system) comprising:
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an acquisition and track device for acquiring and tracking a plurality of satellites and obtaining a navigation message from said satellites; a demodulator for obtaining ephemeris data and almanac data from said navigation message; a calculator for calculating a plurality of almanac correction parameters according to coordinate differences between a plurality of ephemeris-based coordinates of said satellites and a plurality of almanac-based coordinates of said satellites and according to clock differences between a plurality of ephemeris-based clock drifts of said satellites and a plurality of almanac-based clock drifts of said satellites; and a satellite position calculator coupled to said acquisition and track device and for calculating said ephemeris-based coordinates and said ephemeris-based clock drifts according to said ephemeris data, for calculating said almanac-based coordinates and said almanac-based clock drifts according to said almanac data, and for calculating a plurality of positions of said satellites respectively according to said ephemeris data, said almanac data and said almanac correction parameters, wherein said calculator verifies validity of said ephemeris data, said almanac data and said almanac correction parameters and calculates a new plurality of almanac correction parameters if previous almanac correction parameters are invalid and said ephemeris data and said almanac data are valid. - View Dependent Claims (21, 22, 23)
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Specification