GNSS Anti-Spoofing via Residual Score Outlier Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Global navigation satellite systems (GNSS) are vulnerable to spoofing attacks, where attackers transmit signals that deceive receivers into incorrect position and time measurements, posing safety and financial risks.
Innovation Solution
A GNSS receiver system that identifies spoofing signals by calculating residual scores based on variability in position calculations using signals from multiple satellite systems, excluding potential spoofing signals and alerting users or ignoring them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the GNSS receiver processes all received signals to calculate position data, then the position calculation uses maximum available data, but the system becomes vulnerable to spoofing attacks that can deceive the receiver
Solution Approach 1:
The patent segments the signal processing by dividing all received signals into multiple signal types (e.g., GPS L1 C/A, GPS L2C, GLONASS, Galileo, SBAS) and processes each type separately. This segmentation allows the system to calculate position data using different subsets of satellites for each signal type, enabling independent validation and identification of spoofed signals without requiring complete reprocessing of all signals.
Solution Approach 2:
The patent introduces residual scores as an intermediary metric to assess the quality and reliability of position calculations for each signal type. These residual scores serve as a mediator between the raw position calculations and the final position determination, allowing the system to identify and exclude compromised signal types based on abnormal residual values before finalizing the position data.
2Reliability
If the system excludes certain signal types to mitigate spoofing, then anti-spoofing reliability improves, but the quantity of usable signals decreases
Solution Approach 1:
The patent implements a dynamic signal selection mechanism where the set of usable signals is not fixed but adaptively adjusted based on real-time assessment of each signal type's reliability through residual score analysis. The system dynamically excludes only those signal types that exhibit abnormal residual scores indicative of spoofing, while maintaining all other legitimate signals, thus optimizing the balance between reliability and signal quantity.
Solution Approach 2:
The patent changes the parameter of signal inclusion/exclusion based on the calculated residual scores. Instead of using a fixed set of signals, the system adjusts which signal types are included in the final position calculation by comparing residual scores against threshold values, thereby adapting the signal composition to current spoofing conditions while maximizing the use of legitimate signals.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
Systems and methods for identifying which of a plurality of signal types received by a global navigation satellite system (GNSS) receiver includes a spoofing signal. One method may include, for each particular signal type of the plurality of signal types, excluding the particular signal type, calculating a parameter of a GNSS receiver based on the received wireless signals having a plurality of remaining signal types, and calculating a residual score based on a variability associated with calculating the parameter, the residual score being one of a plurality of residual scores. The method may also include identifying an outlier of the plurality of residual scores and identifying which of the plurality of signal types includes a spoofing signal based on the outlier.