Coherent Interference Detection via Statistical Cross-Correlation
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Solution Overview
Problem
Conventional GPS receivers face challenges in accurately detecting coherent interference, which can obscure real signals and reduce detection sensitivity, especially when multiple interferers are present, requiring detailed knowledge of interferer parameters that is impractical to maintain as more GNSS systems are deployed.
Innovation Solution
A method and system that use cross-correlation results to determine a statistical signature, allowing for the detection of non-negligible coherent interference without requiring detailed parametric knowledge of interferers, by comparing the measured statistical signature with an expected signature in the absence of interference, using a threshold value based on the mean and standard deviation of cross-correlation results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional GPS receivers use detailed parametric knowledge of interferers to detect and eliminate coherent interference, then detection accuracy improves, but device complexity and the need for continuous monitoring of all potential interferers increases
Solution Approach 1:
The patent extracts only the essential statistical characteristics (mean and variance) of the cross-correlation results that indicate coherent interference presence, rather than requiring complete parametric knowledge of all potential interferers. This extraction approach maintains detection accuracy while significantly reducing system complexity by focusing only on the critical features needed for interference identification.
Solution Approach 2:
The statistical signature detection method serves multiple functions: it detects coherent interference from any source (narrowband interferers, other GNSS signals, jammers) without requiring specific knowledge of the interferer type or parameters. This universal approach eliminates the need for separate monitoring systems for different interferer categories, reducing overall device complexity while maintaining comprehensive detection capability.
2Reliability
If GPS receivers continuously monitor all potential interferers to maintain accurate detection, then reliability improves, but loss of time and processing resources increases
Solution Approach 1:
The patent performs preliminary statistical analysis of the cross-correlation results during the normal signal acquisition process itself, rather than requiring separate pre-processing or continuous monitoring steps. By computing the mean and variance of cross-correlation values as part of the standard acquisition workflow, the system achieves reliable interference detection without adding time loss or processing overhead.
3Adaptability or versatility
If GPS receivers use statistical signature detection of cross-correlation results, then adaptability to unknown interferers improves, but measurement precision may be reduced compared to parametric methods
Solution Approach 1:
The patent changes the detection parameters from specific interferer characteristics (frequency, code phase, signal structure) to general statistical parameters (mean and variance of cross-correlation results). This parameter transformation enables the system to detect any coherent interference regardless of its specific characteristics, achieving high adaptability to unknown interferers while maintaining sufficient precision through the statistical signature threshold comparison.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables effective elimination of coherent interference during signal acquisition, improving detection sensitivity and resilience to unknown or future interferers, without the need for continuous monitoring of all potential interferers, thus scaling better with increasing GNSS systems.
Implementation Method 1
forming a set of cross-correlation results by at least cross-correlating the signal with a first known code for a plurality of code offsets
Data Source
AI summary
A method for detecting coherent interference includes the steps of: (a) receiving a signal at a first frequency, (b) forming a set of cross-correlation results by at least cross-correlating the signal with a first known code for a plurality of code offsets, (c) determining a statistical signature of the cross-correlation results, and (d) deciding, based on the statistical signature, whether non-negligible coherent interference is present within a search bin defined by the combination of the first frequency and the first known code.