Method and apparatus for GNSS signal tracking

Abstract

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.

Description

CROSS REFERENCES TO RELATED APPLICATIONS[0001]This application claims priority from India provisional patent application No. 3407 / CHE / 2013 filed on Jul. 30, 2013, which is hereby incorporated by reference in its entirety.TECHNICAL FIELD[0002]Embodiments of the disclosure relate to wireless receivers and more particularly to global navigation satellite system (GNSS) receivers.BACKGROUND[0003]Global navigation satellite systems (GNSS) are broadly defined to include GPS (U.S.), Galileo (proposed), GLONASS (Russia), Beidou (China), IRNSS (India, proposed), QZSS (Japan, proposed) and other current and future positioning technologies using signals from satellites, with or without augmentation from terrestrial sources. Information from GNSS is being increasingly used for computing a user's positional information (e.g., a location, a speed, a direction of travel, etc.).[0004]In GNSS, multiple satellites may be present, with each transmitting a satellite signal. A received signal at a GNSS r...

AI Technical Summary

Benefits of technology

The patent describes a GNSS receiver that includes a frequency locked loop (FLL) and a delay locked loop (DLL) to measure the current doppler frequency and code phase delay of the satellite signal. The receiver uses a current doppler frequency and a PN code sequence to compute the position. The receiver also includes a grid monitor that measures the satellite signal strength at multiple predefined offset points. The technical effect of this invention is to improve the accuracy and efficiency of GNSS navigation by accurately tracking the satellite signal and compensating for any errors or limitations.

Problems solved by technology

However, if a user suddenly accelerates or the GNSS satellite signal is obstructed because of building, tunnels, sub-ways etc, then the GNSS receiver would lose track of the satellite signal.

Thus, acquisition of the GNSS satellite signal is more power intensive process than the tracking of the GNSS satellite signal.

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