System and method for enhanced data decode in a GPS receiver
First Claim
1. A data decoding system for a satellite-based navigation system comprising:
- a data prediction subsystem adapted to provide predicted data bits for a satellite;
a differential data decoding subsystem adapted to provide decoded data bits from the satellite for data bits other than the predicted data bits;
a data parity check and correction subsystem adapted to perform parity check and to correct bit errors in the decoded data bits from the differential data decoding subsystem and the predicted data bits from the data prediction subsystem to provide equivalent data words for a plurality of frames; and
a frame combination subsystem adapted to compare the equivalent data words for the plurality of frames to provide a decoded data word.
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Accused Products
Abstract
Systems and methods are disclosed herein for improving the sensitivity of satellite data decode in a satellite navigation receiver. The low signal ephemeris data decoding system of the present disclosure achieves a 5 db improvement in decoding sensitivity over conventional system by operating down to a CN0 of 21 dB-Hz. The improved sensitivity is achieved through a combination of reducing the number of data bits to be decoded, overcoming the inherent differential decoding problem of an all data bit polarity inversion, improving the probability of seeing single bit decoding error in an ephemeris word, running the parity correction algorithm, and reducing the undetected word error rate. The improved sensitivity makes it possible to predict the orbit of the satellite and to determine the receiver'"'"'s location with higher accuracy even when operating in challenging signal conditions.
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Citations
28 Claims
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1. A data decoding system for a satellite-based navigation system comprising:
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a data prediction subsystem adapted to provide predicted data bits for a satellite; a differential data decoding subsystem adapted to provide decoded data bits from the satellite for data bits other than the predicted data bits; a data parity check and correction subsystem adapted to perform parity check and to correct bit errors in the decoded data bits from the differential data decoding subsystem and the predicted data bits from the data prediction subsystem to provide equivalent data words for a plurality of frames; and a frame combination subsystem adapted to compare the equivalent data words for the plurality of frames to provide a decoded data word. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of decoding data bits from satellites of a satellite-based navigation system, comprising:
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predicting data bits for the satellites to form predicted data bits; reducing number of data bits to be decoded by using the predicted data bits; performing a plurality of differential phase decoding between a data bit to be decoded and a plurality of data bits surrounding the data bit to be decoded to form a decoded data bit; performing data parity checking and error correction on a data word comprising a plurality of predicted data bits and a plurality of decoded data bits to form equivalent parity checked and corrected data words for a plurality of frames; comparing the equivalent parity checked and corrected data words for the plurality of frames to form a decoded data word. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A data decoding system for a satellite-based navigation system comprising:
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a data prediction subsystem adapted to provide predicted data bits for a satellite; a differential data decoding subsystem adapted to provide decoded data bits from the satellite for data bits other than the predicted data bits; and a data parity check and correction subsystem adapted to perform parity check and to correct bit errors in the decoded data bits from the differential data decoding subsystem and the predicted data bits from the data prediction subsystem to provide a decoded data word for a frame.
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Specification