GNSS Temporal Shift Estimation via GPS-GLONASS Frame Alignment
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Solution Overview
Problem
Global Navigation Satellite Systems (GNSS) face challenges in accurately estimating location due to differences in clock systems between GPS and GLONASS, where GLONASS accounts for leap seconds, while GPS does not, leading to temporal shifts that affect signal alignment and location estimation accuracy.
Innovation Solution
The method estimates the temporal shift by analyzing frame features of GPS and GLONASS signals, allowing for the determination of cumulative leap-second adjustments, which enables conversion between GPS and GLONASS system times, thereby improving clock accuracy and location estimation by synchronizing both systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS and GLONASS signals are analyzed together for location estimation, then location accuracy is improved, but temporal misalignment due to leap-second adjustments degrades signal synchronization
Solution Approach 1:
The patent applies parameter changes by detecting and compensating for temporal shifts in GLONASS signal frame features caused by leap-second adjustments. The system monitors the timing of GLONASS frame features (such as string numbers and subframe boundaries) and adjusts the temporal parameters of signal processing accordingly, allowing GPS and GLONASS signals to be synchronized and analyzed together accurately despite the leap-second discrepancy between the two systems.
2Measurement precision
If full GPS and GLONASS signal frames are analyzed to determine temporal shift, then estimation accuracy is improved, but processing time increases
Solution Approach 1:
The patent extracts only the critical frame features from the GPS and GLONASS signals that are necessary for determining temporal shift, rather than analyzing the entire signal frames. By focusing on specific identifiable elements such as frame onset, string number, and subframe boundaries, the system achieves accurate temporal alignment while significantly reducing the computational burden and processing time required.
Solution Approach 2:
The system performs partial analysis of the signal frames by examining only the essential frame features needed for temporal shift determination. This partial action approach provides sufficient information for accurate synchronization without the excessive processing that would result from analyzing complete signal frames in detail.
Data Source
AI summary
Techniques are provided to quickly estimate a temporal shift of a GPS signal based on an analysis of a GLONASS signal. The shift can be a result of applied leap-second adjustments affecting GLONASS signals but not GPS signals. By identifying this shift, GPS and GLONASS signals can be considered together in order to estimate locations. The temporal shift can be determined, e.g., by estimating a separation between a GPS-signal frame feature (e.g., frame onset) and a GLONASS-signal frame feature (e.g., frame onset), or identifying coinciding frame features (e.g., a GPS-signal subframe coinciding with a GLONASS-signal string number). The techniques allow the temporal shift to be estimated based on an analysis of just a portion of the GPS-signal and GLONASS-signal frames, such that a speed of location estimations can be improved.