Satellite Navigation Interference Detection via Phase Dispersion
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Solution Overview
Problem
Existing satellite radio-navigation signal receivers face delays in detecting interference, leading to measurement errors and positioning inaccuracies due to the time required to detect aberrant signals.
Innovation Solution
A method that measures phase dispersion between correlation measurements at different time shifts to quickly identify interference by calculating the standard deviation of phase differences and comparing it to a detection threshold, allowing for timely corrective processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional detection methods based on aberrant measurement detection are used, then interference can be detected, but detection time is too long causing measurement errors and positioning inaccuracies
Solution Approach 1:
Instead of detecting interference by identifying aberrant measurements after they occur, the invention inverts the approach by detecting the presence of narrow-band interfering signals through their characteristic effect on phase dispersion before significant measurement errors accumulate. The method calculates phase dispersion from correlation measurements at different time shifts, and interference is detected when phase dispersion exceeds a threshold, enabling earlier and more accurate interference detection.
Solution Approach 2:
The invention changes the detection parameter from measuring signal amplitude or correlation strength to measuring phase dispersion between correlation measurements at different time shifts. This parameter change allows the system to detect narrow-band interfering signals based on their distinctive phase modulation characteristics, enabling faster and more reliable detection compared to conventional methods that rely on detecting aberrant measurements after they have already degraded signal quality.
Data Source
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AI summary
Method of detecting interference in a satellite radio-navigation signal, characterized in that it comprises the following steps: determining a first temporal position for which the correlation between the said signal and a local spreading code, offset by the said position, is maximum; determining a plurality of measurements of correlation between the said signal and a local spreading code offset by a plurality of secondary temporal positions, the said plurality of secondary temporal positions and the said first temporal position being regularly spaced; determining, for a plurality of correlation measurement pairs formed by two measurements at two consecutive temporal positions, the phase difference between the two correlation measurements of the said pair; calculating an item of information representative of the standard deviation of the said phase difference; and comparing the said item of information with a detection threshold configured at least as a function of the ratio of the powers of the signal and of the interference.