Fast Acquisition Engine for GPS Power Optimization
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Solution Overview
Problem
Conventional GPS receivers in battery-operated devices face power consumption challenges, limiting their ability to maintain continuous location calculations due to the need for frequent re-acquisition of position signals, which affects accuracy and efficiency.
Innovation Solution
A fast acquisition engine method that automatically powers up a radio receiver and correlators, buffers position signals, searches for code sequences within a subset of the search space, and generates location signals based on found sequences, optimizing power usage and maintaining accuracy through coherent or non-coherent integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS receivers are enabled continuously to maintain location accuracy, then positioning accuracy is improved, but power consumption increases
Solution Approach 1:
The system implements periodic duty-cycling of the GPS receiver, automatically powering it up at scheduled intervals to re-acquire position signals. This periodic operation maintains positioning accuracy by regularly updating location data while significantly reducing power consumption compared to continuous operation.
2Use of energy by moving object
If GPS receiver is powered down to save power, then power consumption is reduced, but signal re-acquisition time increases
Solution Approach 1:
The system performs preliminary actions by maintaining correlation with satellite code sequences during active periods and using predicted satellite positions to pre-calculate expected signal parameters. When powered down and subsequently reactivated, this preliminary preparation enables faster signal re-acquisition compared to conventional cold starts.
Solution Approach 2:
The system dynamically adjusts search parameters such as Doppler frequency range and code phase search window based on predicted satellite motion and previous signal characteristics. This parameter optimization reduces the search space and accelerates signal re-acquisition after power-down periods.
3Reliability
If full search space is searched for code sequences, then signal acquisition reliability is improved, but processing time increases
Solution Approach 1:
The system optimizes search parameters by adjusting Doppler frequency ranges and code phase windows based on predicted satellite positions and relative motion. This parameter tuning reduces the effective search space while maintaining reliable signal acquisition by focusing computational resources on the most probable signal locations.
Solution Approach 2:
The system uses feedback from previous signal acquisition attempts and tracked satellite ephemeris data to refine search parameters for subsequent acquisitions. This adaptive feedback mechanism improves acquisition reliability by learning from past performance while reducing processing time through intelligent parameter selection.
Data Source
AI summary
A method of fast acquisition of a location of a device is disclosed. The method generally includes the steps of (A) repeatedly powering up automatically (i) a radio receiver and (ii) a given subset of a plurality of correlators in some of a plurality of search engines in the device, (B) buffering first data of a plurality of position signals received through the radio receiver over a first period, each of the position signals comprising a respective one of a plurality of code sequences, (C) searching through the first data with the correlators to find at least one of the code sequences, each of the correlators using a search window comprising a fraction of a code length of the code sequences and (D) generating an output signal carrying a location of the device based on the position signals corresponding to the code sequences that were found.