Duty-Cycled GNSS Receiver Snapshots for Delay and Doppler Estimation
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Solution Overview
Problem
GNSS receivers face challenges in reducing power consumption while maintaining accurate estimation of delays and Doppler shifts, as conventional tracking loops quickly deplete battery power.
Innovation Solution
A GNSS receiver operates in a power-saving mode, taking snapshots of GNSS signals in duty cycles to estimate delays and Doppler shifts, reducing power consumption by shutting down functionality during non-processing periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed tracking loops (DLL, PLL, FLL) are used to continuously track GNSS signals, then accurate estimation of delays and Doppler shifts is achieved, but power consumption increases rapidly
Solution Approach 1:
The patent applies periodic action by implementing a duty cycle mechanism where the GNSS receiver alternates between active measurement periods and sleep periods. During active periods, the receiver performs signal acquisition and estimates delays and Doppler shifts using correlation-based methods. During sleep periods, the receiver shuts down functionality modules to reduce power consumption. This periodic operation maintains measurement accuracy while significantly reducing average power consumption compared to continuous tracking.
2Use of energy by moving object
If the GNSS receiver shuts down functionality modules to reduce power consumption, then battery life extends, but continuous tracking of delays and Doppler shifts is lost
Solution Approach 1:
The patent applies preliminary action by performing signal acquisition and obtaining coarse estimates of delays and Doppler shifts before entering sleep mode. The receiver prepares measurement data during active periods and uses this preliminary information to maintain positioning accuracy during sleep periods. This approach allows the receiver to shutdown functionality modules while preserving the reliability of positioning through pre-acquired signal characteristics.
Solution Approach 2:
The patent applies copying by using correlation-based estimation methods that capture essential signal characteristics during active periods. Instead of continuously tracking the actual GNSS signals, the receiver creates computational models (correlation results) of the signal properties during active periods and uses these models to maintain positioning accuracy during sleep periods, effectively copying the essential measurement information.
Data Source
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AI summary
A method for receiving and processing GNSS signals is performed by a GNSS receiver featuring a power saving mode. The method comprises, in the power saving mode: receiving and taking a snapshot of a GNSS signal in a duty cycle, wherein the duty cycle is part of a cycle; computing, in the duty cycle, respective correlations between the snapshot and different delays of a PRN code sequence; computing, in the duty cycle, respective frequency spectra of the correlations; estimating, in the duty cycle, a delay and a Doppler shift of the GNSS signal based on the frequency spectra; and reducing power consumption for the rest of the cycle; wherein an accuracy of the estimated delay and the estimated Doppler shift is in a same order of magnitude as an accuracy of a delay and a Doppler shift estimated in a full power mode without reducing power consumption.