Scanning correlator for global navigation satellite system signal tracking
First Claim
1. A Global Navigation Satellite System (GNSS) receiver, the receiver comprising:
- a front end configured to receive GNSS signals;
a code and carrier remover coupled to the front end;
a carrier numerically controlled oscillator coupled to the code and carrier remover and generating a first oscillating signal,a code numerically controlled oscillator coupled to the code and carrier remover and generating a second oscillating signal,wherein the code and carrier remover comprises;
a carrier remover configured to down convert a received GNSS signal based on the first oscillating signal,a correlator block comprising at least a scanning correlator; and
a Pseudo Random Noise generator coupled to the correlator block, the Pseudo Random Noise generator producing a local Pseudo Random Noise sequence based at least in part on the second oscillating signal,wherein the scanning correlator is configured to estimate at least two points of an autocorrelation function of the received GNSS signal based on a plurality of scanning values derived from sampling the received GNSS signal, wherein the at least two points of the autocorrelation function are based on scanning values of the plurality of scanning values that are captured during different integration periods, wherein each scanning value of the plurality of scanning values has a respective time offset variably controlled such that at least one first time offset of the plurality of scanning values is not equal to at least one second time offset of the plurality of scanning values;
wherein the scanning correlator calculates an alignment between the received GNSS signal and the Pseudo Random Noise sequence based on the autocorrelation function estimate; and
a control block coupled to the code numerically controlled oscillator and the carrier numerically controlled oscillator;
wherein the correlator block further includes a reference correlator that generates a second value by processing the received GNSS signal; and
wherein the respective time offset for each scanning value of the plurality of scanning values is varied by the control block either forward or backward by a fraction of a code chip with respect to a fixed reference point provided by a time offset of the reference correlator.
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Accused Products
Abstract
Systems and methods for a scanning correlator for global navigation satellite system signal tracking are provided. In one embodiment, a method for Global Navigation Satellite System (GNSS) receiver tracking comprises: receiving a GNSS navigation signal; generating a local Pseudo Random Noise (PRN) sequence; sampling the GNSS navigation signal over a plurality of integration periods to produce a plurality of scanning values, wherein each scanning value has a respective time offset such that at least one first time offset is not equal to at least one second time offset; estimating at least two points of an autocorrelation function for the GNSS navigation signal based on the plurality of scanning values; and calculating an alignment between the GNSS signal and the local PRN sequence based on the autocorrelation function estimate.
29 Citations
18 Claims
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1. A Global Navigation Satellite System (GNSS) receiver, the receiver comprising:
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a front end configured to receive GNSS signals; a code and carrier remover coupled to the front end; a carrier numerically controlled oscillator coupled to the code and carrier remover and generating a first oscillating signal, a code numerically controlled oscillator coupled to the code and carrier remover and generating a second oscillating signal, wherein the code and carrier remover comprises; a carrier remover configured to down convert a received GNSS signal based on the first oscillating signal, a correlator block comprising at least a scanning correlator; and a Pseudo Random Noise generator coupled to the correlator block, the Pseudo Random Noise generator producing a local Pseudo Random Noise sequence based at least in part on the second oscillating signal, wherein the scanning correlator is configured to estimate at least two points of an autocorrelation function of the received GNSS signal based on a plurality of scanning values derived from sampling the received GNSS signal, wherein the at least two points of the autocorrelation function are based on scanning values of the plurality of scanning values that are captured during different integration periods, wherein each scanning value of the plurality of scanning values has a respective time offset variably controlled such that at least one first time offset of the plurality of scanning values is not equal to at least one second time offset of the plurality of scanning values; wherein the scanning correlator calculates an alignment between the received GNSS signal and the Pseudo Random Noise sequence based on the autocorrelation function estimate; and a control block coupled to the code numerically controlled oscillator and the carrier numerically controlled oscillator; wherein the correlator block further includes a reference correlator that generates a second value by processing the received GNSS signal; and wherein the respective time offset for each scanning value of the plurality of scanning values is varied by the control block either forward or backward by a fraction of a code chip with respect to a fixed reference point provided by a time offset of the reference correlator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for Global Navigation Satellite System (GNSS) receiver tracking, the method comprising:
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receiving a GNSS navigation signal; generating a local Pseudo Random Noise (PRN) sequence; sampling the GNSS navigation signal over a plurality of integration periods to produce a plurality of scanning values, wherein each scanning value of the plurality of scanning values has a respective time offset variably controlled by a control block such that at least one first time offset is not equal to at least one second time offset; estimating at least two points of an autocorrelation function for the GNSS navigation signal based on scanning values of the plurality of scanning values captured during different integration periods; calculating an alignment between the GNSS signal and the local PRN sequence based on the autocorrelation function estimate; and applying the received GNSS signal to a reference correlator to generate a second value; wherein the respective time offset for each scanning value of the plurality of scanning values is varied by the control block either forward or backward by a fraction of a code chip with respect to a fixed reference point provided by a time offset of the reference correlator. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification