Satellite Receiver Phase Offset Correction After Discontinuity
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Solution Overview
Problem
Satellite positioning system (SPS) receivers face inaccuracies during signal search discontinuities, such as when a tracking session is paused or restarted, due to assumptions of linear movement and stale prior state information, leading to inaccuracies in position calculations.
Innovation Solution
The method involves integrating satellite positioning system signals for a period T2, sampling observable signal metrics at an earlier time T1, identifying peaks, and solving for a common code phase offset to correct for phase offsets and improve accuracy in location determination after a search discontinuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior state information is used to improve position calculation accuracy during continuous tracking, then accuracy is improved, but after a search discontinuity the prior state information becomes stale or non-existent leading to inaccuracy
Solution Approach 1:
The patent performs preliminary actions by integrating the satellite positioning system signal for a longer period T2 after a search discontinuity to build up sufficient signal energy and establish accurate phase information before normal tracking resumes. This preliminary integration ensures that when tracking restarts, the receiver has reliable phase data to work with, preventing the degradation that would otherwise occur during the discontinuity period.
Solution Approach 2:
The patent dynamically adjusts the signal integration period based on the tracking state. During continuous tracking, normal integration periods are used to maintain efficiency. After a search discontinuity, the integration period is extended to T2 to re-establish accurate phase information. This dynamic adjustment allows the system to optimize between speed and accuracy depending on the current tracking condition.
2Use of energy by moving object
If the satellite positioning system receiver pauses or restarts a tracking session, then power consumption is reduced or session management is improved, but signal search discontinuity occurs leading to position calculation inaccuracy
Solution Approach 1:
Before pausing the tracking session to save power, the patent performs preliminary signal integration to accumulate sufficient phase information. When the tracking session restarts, this pre-acquired information is used to quickly re-establish accurate positioning without requiring a full signal search, thus minimizing the impact of the discontinuity on position calculation accuracy while still achieving power savings during the pause period.
Solution Approach 2:
The patent maintains continuity of useful action by performing signal integration continuously even during periods when full tracking is suspended. The integration process continues to accumulate phase information during the pause, ensuring that when tracking resumes, the receiver has up-to-date phase data. This approach allows the system to reduce power consumption during pauses while maintaining the continuity of signal processing to prevent accuracy degradation.
3Device complexity
If assumption of linear movement is made to simplify position calculation during discontinuity, then calculation complexity is reduced, but inaccuracy is introduced into position calculation
Solution Approach 1:
The patent performs preliminary signal integration for an extended period T2 after a search discontinuity to establish accurate phase information before resuming normal tracking. This preliminary action provides sufficient data to calculate accurate position and velocity without relying on linear movement assumptions, thereby maintaining high accuracy while avoiding the need for complex real-time trajectory modeling during the discontinuity period.
Data Source
AI summary
Disclosed is an apparatus, system and method for location determination following a search discontinuity utilizing early sampling of a satellite positioning system signal to determine a common code phase offset, pseudorange rate and mode of location calculation.