GNSS Delta Range Synchronization for Spoofing Detection
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Solution Overview
Problem
Navigation systems face challenges in ensuring reliable and accurate GNSS measurements due to potential spoofing attacks, which can lead to incorrect location calculations, particularly in safety-critical applications like aviation, where distinguishing fake GNSS signals from authentic ones is difficult.
Innovation Solution
Implementing a navigation system with multiple GNSS receivers that synchronize delta range measurements using synthetic clock steering to enhance measurement reliability and detect spoofing by synchronizing measurement times across receivers, leveraging standards like ARINC 743A for communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple GNSS receivers are used to improve measurement reliability and detect spoofing, then the reliability and accuracy of navigation data are improved, but the device complexity and synchronization requirements increase
Solution Approach 1:
The system divides the navigation measurement task across multiple independent GNSS receivers, each collecting delta range measurements separately. This segmentation allows parallel data collection while maintaining individual receiver reliability, resolving the contradiction by distributing the reliability function across multiple simple units rather than one complex receiver
Solution Approach 2:
A processing unit acts as an intermediary that receives measurements from multiple receivers, synchronizes their measurement times, and combines the data. This intermediary handles the complexity of coordination and synchronization, allowing individual receivers to remain simple while achieving collective reliability through centralized processing
2Difficulty of detecting and measuring
If measurement synchronization is implemented across multiple receivers, then spoofing detection capability is improved, but the measurement processing complexity and time requirements increase
Solution Approach 1:
The system performs preliminary synchronization of measurement times from multiple receivers before combining the data. By pre-synchronizing the timing information and organizing measurements into aligned time epochs, the system enables efficient spoofing detection without requiring complex real-time synchronization during the detection process itself
Solution Approach 2:
The patent replaces complex hardware-based synchronization mechanisms with computational time-synchronization methods. Instead of using precise hardware clock synchronization, the system uses software-based time tagging and post-processing alignment of measurements, reducing hardware complexity and processing time while maintaining spoofing detection capability
Data Source
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AI summary
Systems and methods for calculating single delta range differences using synthetic clock steering are provided. In certain embodiments, a system includes a first GNSS receiver that provides first delta range measurements and first measurement times associated with a plurality of GNSS satellites. The system further includes a second GNSS receiver that provides second delta range measurements and second measurement times associated with the plurality of GNSS satellites. Additionally, the system includes a processing unit that executes instructions that cause the processing unit to synchronize the second delta range measurements with the first delta range measurements to create synchronized delta range measurements. The executable instructions also cause the processing unit to calculate a single difference of the first delta range measurements and the synchronized delta range measurements for at least one satellite in the plurality of GNSS satellites.