GNSS Receiver Power Management via Dynamic Search Window Adjustment
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Solution Overview
Problem
Global Navigation Satellite System (GNSS) receivers in mobile devices face power consumption challenges due to limited battery size, especially in environments with obstructed signals, where conventional methods to reduce accuracy do not uniformly manage power effectively.
Innovation Solution
A method that derives a GNSS search window based on position and time uncertainties, selects a search mode from low and high uncertainty modes based on available resources, and conducts the search to estimate the device's position while ensuring power consumption does not exceed a specified limit, using additional sources like terrestrial transceivers and sensors when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional GNSS receiver reduces accuracy requirements to reduce power consumption, then power consumption is reduced, but positioning accuracy deteriorates and may not meet application requirements
Solution Approach 1:
The patent implements dynamic adjustment of GNSS search parameters including search window size, Doppler frequency range, and integration time based on current signal conditions and power availability. The receiver adapts its search strategy in real-time, expanding search windows when signals are weak and reducing them when signals are strong, thereby optimizing the balance between power consumption and positioning accuracy under varying operational conditions
Solution Approach 2:
The system changes multiple GNSS receiver parameters simultaneously including search window duration, Doppler frequency offset range, signal integration time, and correlation threshold levels. By coordinating changes across these parameters, the system achieves power reduction while maintaining sufficient positioning accuracy for the application
2Reliability
If GNSS receiver increases search window and Doppler frequency range to improve signal acquisition in obstructed environments, then signal acquisition capability is improved, but power consumption increases
Solution Approach 1:
The system performs preliminary assessments of signal conditions using initial correlation searches and signal strength measurements before committing to full-scale searches with expanded windows and Doppler ranges. This preliminary action allows the receiver to identify promising signal candidates and focus subsequent processing only on those candidates, avoiding exhaustive searches across entire expanded parameter spaces
Solution Approach 2:
The patent implements partial searches where the receiver examines only a subset of the full search space based on preliminary indications. When signal conditions suggest weak signals, the system expands the search window and Doppler range but processes only selected frequency bins and time offsets that show promise, rather than exhaustively searching all possible combinations, thereby achieving improved acquisition capability with controlled power increase
3Reliability
If GNSS receiver performs exhaustive search to ensure position determination in poor signal conditions, then positioning reliability is improved, but power consumption exceeds available power budget
Solution Approach 1:
The system continuously monitors signal acquisition progress, correlation peak strengths, and power consumption levels, using this feedback to dynamically adjust the search strategy. When feedback indicates that sufficient satellites are being acquired with adequate signal strength, the system reduces the search window and Doppler range to lower power consumption. Conversely, when feedback shows insufficient acquisitions, the system temporarily expands parameters to improve reliability, creating a closed-loop control system that balances power and performance
Solution Approach 2:
The receiver dynamically transitions between different operational states including aggressive search mode, conservative search mode, and maintenance mode based on real-time conditions. In aggressive mode, expanded parameters are used temporarily to acquire initial satellite locks. Once locks are established, the system transitions to conservative mode with reduced parameters to conserve power while maintaining the acquired satellites, and may switch to maintenance mode with minimal searching to sustain positioning
Data Source
AI summary
Techniques for managing power consumption of a Global Navigation Satellite System (GNSS) receiver of a mobile device are provided. These techniques include a method that includes deriving a GNSS search window for the GNSS receiver based on a position uncertainty (PUNC) and a time uncertainty (TUNC), selecting a GNSS search mode based on the GNSS search window and resources available for searching for signals from GNSS satellite vehicles (SVs), wherein an estimated power consumption associated with execution of a GNSS search associated with the GNSS search mode does not exceed a power consumption limit specified for the GNSS receiver conducting the GNSS search using the GNSS search mode, and estimating a position of the mobile device.