GNSS Receiver Spoofing Detection via Timing Analysis
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Solution Overview
Problem
Conventional GNSS receivers struggle to detect spoofing signals without zone identifier information, leading to difficulties in distinguishing between genuine and spoofed position information.
Innovation Solution
A GNSS receiver configuration that includes a demodulation module, position calculation module, and determination module, which analyzes the timing difference and propagation delay of GNSS signals to differentiate between normal and spoofed signals, utilizing a storage for reference timing and assist GNSS information to determine the authenticity of received signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If zone identifier information is required for detecting spoofing signals, then position confirmation capability is improved, but device complexity and operational difficulty increase when information cannot be obtained
Solution Approach 1:
The GNSS receiver uses its own internal resources (timing generation unit, navigation message processing unit) to create and verify timing information without requiring external zone identifier data. The receiver autonomously determines spoofing by comparing expected versus actual message timing, making the system self-sufficient and eliminating dependency on external confirmation data.
Solution Approach 2:
The invention extracts the essential spoofing detection capability from the zone identifier requirement. By removing the dependency on zone identifier information and focusing solely on timing analysis of navigation messages, the system achieves spoofing detection without the operational complications introduced by zone-based methods.
2Measurement precision
If timing difference analysis is performed to detect spoofed signals, then spoofing detection accuracy is improved, but processing time and computational complexity increase
Solution Approach 1:
The receiver continuously monitors and records actual reception timing of navigation messages as they arrive. This preliminary timing data is stored and immediately available for comparison with expected timing calculations, eliminating the need for post-processing delays. The timing difference analysis can begin as soon as the next navigation message is received, minimizing processing latency.
Solution Approach 2:
Instead of performing comprehensive analysis of all signal parameters, the system focuses solely on timing difference analysis of navigation messages, which is the most critical indicator of spoofing. This partial action approach concentrates computational resources on the single most effective detection method, improving accuracy without excessive processing overhead.
3Reliability
If propagation delay analysis is used to distinguish normal and spoofed signals, then signal authentication reliability is improved, but measurement precision requirements increase
Solution Approach 1:
The invention uses navigation message timing as an intermediary indicator rather than directly measuring propagation delay. The timing difference between expected and actual message reception serves as a proxy that reflects propagation characteristics without requiring direct, high-precision measurement of the propagation delay itself, thereby reducing measurement precision requirements while maintaining authentication reliability.
Data Source
AI summary
A GNSS receiver includes a demodulation module, a position calculation module, a storage, and a determination module. The demodulation module receives the GNSS signal and acquires a navigation message. The position calculation module performs positioning calculation based on a propagation delay which is a time until a GNSS signal transmitted from a GNSS satellite reaches an antenna. The storage stores reception timing (reference timing) of a message of a predetermined type in the navigation message. The determination module determines that a GNSS signal including the navigation message is a spoofed GNSS signal when the difference between the reception timing of the next and subsequent messages of the same type predicted from the reference timing and the reception timing of the same type of message received after the reference timing is outside the scope of the time threshold.