METHOD AND APPARATUS FOR GNSS SIGNAL TRACKING

摘要

A GNSS receiver to track low power GNSS satellite signals. The GNSS receiver includes a frequency locked loop (FLL) that measures a current doppler frequency of the satellite signal. A delay locked loop (DLL) measures a current code phase delay of the satellite signal. A current operating point corresponds to the current doppler frequency and the current code phase delay of the satellite signal. A grid monitor receives the satellite signal and the current operating point, and measures a satellite signal strength at a plurality of predefined offset points from the current operating point. The FLL and the DLL are centered at the current operating point. A peak detector is coupled to the grid monitor and processes the satellite signal strengths at the plurality of predefined offset points and re-centers the FLL and the DLL to a predefined offset point with the satellite signal strength above a predefined threshold.

主权项

1. A GNSS receiver comprising:
a frequency locked loop (FLL) configured to receive a satellite signal and configured to measure a current doppler frequency of the satellite signal; a delay locked loop (DLL) configured to receive the satellite signal and configured to measure a current code phase delay of the satellite signal, wherein a current operating point corresponds to the current doppler frequency and the current code phase delay of the satellite signal; a position computation unit coupled to the FLL and the DLL and configured to compute a position of the GNSS receiver using the current doppler frequency and the current code phase delay; a grid monitor configured to receive the satellite signal and the current operating point, and configured to measure a satellite signal strength at a plurality of predefined offset points from the current operating point, wherein the FLL and the DLL are centered at the current operating point; and a peak detector coupled to the grid monitor and configured to process the satellite signal strengths at the plurality of predefined offset points and configured to re-center the FLL and the DLL to a predefined offset point of the plurality of predefined offset points, with the satellite signal strength above a predefined threshold.