Navigation Receiver Signal Pair Analysis for Spoofing Mitigation
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Solution Overview
Problem
Existing radio navigation systems are vulnerable to emulator spoofer signals, which can deceive receivers into generating erroneous navigation information, leading to navigation errors, and conventional encryption methods are compromised.
Innovation Solution
A navigation receiver system that selects authentic signals by analyzing characteristics of signal pairs, including relative amplitude, phase, and frequency, to differentiate them from emulator spoofer signals, using a method that includes pre-screening and candidate screening tests, and leverages receiver motion to confirm signal authenticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If signal encryption is used to protect navigation signals, then security against spoofing is improved, but encryption keys may be compromised and computational complexity increases
Solution Approach 1:
The patent extracts the authentication function from the signal content itself and places it in the signal structure characteristics. By analyzing geometric relationships between multiple signals (time differences, frequency differences, phase differences), the system authenticates signals without requiring encryption keys, thus removing the vulnerability to key compromise while reducing computational complexity compared to encryption/decryption operations.
Solution Approach 2:
Instead of trying to protect the signal content through encryption, the patent inverts the approach by using the signal structure and geometric relationships as the authentication mechanism. The authenticating information is embedded in the spatial-temporal-frequency relationships between signals from different satellites, not in the encrypted payload, making spoofing detection possible through structural analysis rather than content decryption.
2Reliability
If emulator spoofer signals are generated to disrupt navigation, then electronic warfare capability is improved, but navigation accuracy deteriorates
Solution Approach 1:
The patent implements feedback by continuously monitoring the geometric relationships between multiple received signals and comparing them against expected relationships based on satellite ephemeris and receiver position. When spoofed signals are detected through inconsistency in time differences, frequency differences, or phase differences, the system can identify and reject them, maintaining navigation accuracy despite the presence of emulator spoofers.
Solution Approach 2:
The patent uses a composite approach by combining multiple signal characteristics (amplitude, phase, frequency, time of arrival) from multiple satellites to create a robust authentication mechanism. Rather than relying on a single signal property, the system analyzes the composite geometric relationships between signals, making it difficult for spoofers to replicate all characteristics simultaneously and maintain navigation accuracy.
3Measurement precision
If multiple signals from multiple satellites are processed to determine position, then navigation accuracy is improved, but vulnerability to spoofing increases
Solution Approach 1:
The patent adds a new dimension to signal authentication by incorporating spatial-geometric relationships between multiple satellites and the receiver. Instead of only analyzing signal content in the time-frequency domain, the system extends authentication to the spatial domain by verifying geometric consistency of signal arrivals from multiple satellites, creating an additional layer of verification that spoofers must replicate across multiple dimensions simultaneously.
Data Source
AI summary
The present invention is a method and system to mitigate emulator spoofer signals. In an embodiment of the invention, the system of the present invention may be a navigational receiver which may acquire authentic signals in the presence of spoofer signals whereby the authentic navigational signals may be processed to determine a correct position of the receiver. The receiver of the present invention may execute a mitigation method of the present invention whereby characteristics of pairs of signals of received signals may be determined. The mitigation method may also include selection of an authentic signal based upon the characteristics of signal pairs. Characteristics of signal pairs may include relative amplitude, phase and frequency.