GNSS Receiver Spoofing Detection Using Error State Estimates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Global Navigation Satellite Systems (GNSS) are susceptible to spoofing, which can lead to unacceptably large errors in navigation solutions, compromising the integrity of GPS receivers, particularly in environments where test signals unintentionally mimic true satellite signals.
Innovation Solution
A satellite spoofing detection system using error state estimates, incorporating a controller with monitors to analyze pseudorange measurements, inertial navigation system (INS) data, and GPS data to detect anomalies indicative of spoofing, employing filters like Kalman filters to correct and compare state estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spoofing signals are transmitted to test GPS receiver equipment, then the receiver can be validated for signal processing capabilities, but the test signals may unintentionally reach external receivers and cause spoofing situations
Solution Approach 1:
The patent introduces an intermediary detection system that monitors GPS signals for authenticity. This intermediary layer (the spoofing detection apparatus) analyzes signal characteristics and compares them against expected satellite signal patterns, acting as a mediator between the potential spoofing source and vulnerable receivers. The system uses multiple satellites' signals cross-validation to identify and reject spoofed signals before they can corrupt navigation solutions.
Solution Approach 2:
The patent implements feedback mechanisms where the GPS receiver continuously monitors its own signal acquisition and tracking performance. By analyzing residuals, measurement uncertainties, and consistency across multiple satellites, the system provides real-time feedback on signal integrity. When anomalies are detected that suggest spoofing, the system can alert operators or automatically switch to alternative navigation methods, creating a closed-loop feedback system for spoofing mitigation.
2Ease of operation
If traditional GPS signal monitoring is used, then basic signal reception is achieved, but detection of spoofed signals is insufficient leading to navigation solution errors
Solution Approach 1:
The patent segments the GPS signal processing into multiple independent verification layers: signal acquisition, signal tracking, pseudorange measurement, velocity measurement, and cross-satellite consistency checking. Each layer independently validates signal authenticity, and the system requires consistency across all segments to accept navigation solutions. This segmentation allows basic signal reception to continue while adding sophisticated spoofing detection capabilities at each processing stage.
Solution Approach 2:
The patent employs a composite approach combining multiple detection methods: geometric consistency checks (satellite geometry validation), kinematic consistency (velocity and position relationship verification), signal quality metrics (carrier-to-noise ratio analysis), and cross-validation among multiple satellites. This composite detection strategy integrates various measurement types and analysis techniques to create a robust spoofing detection system that maintains ease of operation while achieving high measurement precision.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A system for detecting satellite signal spoofing using error state estimates is provided. The system includes at least one satellite receiver to receive satellite signals, at least one memory and at least one controller. The at least one memory is configured to store at least operation instructions. The at least one controller is in communication with the at least one satellite receiver and the at least one memory. The at least one controller is configured to determine state estimates from the received satellite signals. The at least one controller is further configured to determine error state estimates based at least in part on differences in current state estimates and differences in delayed state estimates. The controller further configured to determine if spoofing is occurring in one more of the received satellite signals when the error state estimates are greater than a select threshold.