Patent ID: 8259012

Claim:
A Global Navigation Satellite System (GNSS) receiver onboard a satellite, comprising: an antenna for generating analog Global Positioning System (GPS) signal data in response to detection of analog GPS signals; front-end circuitry connected to receive said analog GPS signal data from said antenna, said front-end circuitry comprising an analog-to digital converter which converts analog GPS signal data to digital GPS signal data; and a computer processor programmed to perform the following steps: (a) buffering digital GPS signal data outputted by said front-end circuitry over a time interval that is greater than the duration of a bit of a navigation message; (b) calculating a respective set of parameters based in part on the digital GPS signal data remaining after navigation data wipe-out for each frequency/time data point in a search array, and based in part on modeled clock errors calculated by using a periodic function corresponding to a periodic thermal profile of said satellite to model clock errors; (c) calculating time-domain averaged I and Q signal components as a function of said respective set of parameters for each frequency/time data point in said search array; (d) calculating respective correlation magnitudes based on said time- domain averaged I and Q signal components for each frequency/time data point in said search array; and (e) determining an orbit state correction based in part on said correlation magnitudes.