GNSS Spoofing Detection Network for Protected Airspace Alerts
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Solution Overview
Problem
Aircraft operations are hindered by the increasing presence of GNSS jammers and spoofers, which introduce interference and errors into Global Navigation Satellite Systems (GNSS), leading to inflated protection levels that reduce navigational and landing operations' availability, with no models for predicting spoofer/jammer presence in airspace.
Innovation Solution
A system for Local Area Detection and Alerting of GNSS Spoofing (LDAS) is implemented, comprising receiver stations and a master control station that determine GNSS-driven absolute positions, detect anomalies, and transmit updates to aircraft, allowing them to adjust protection levels based on detected spoofing probabilities, with directional information of spoofer sources and confidence bounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conservative protection levels are assumed to always account for spoofer/jammer presence, then system reliability is improved, but navigational and landing operations availability deteriorates
Solution Approach 1:
The system performs preliminary detection of spoofer/jammer presence in the airspace before aircraft operations commence. Ground-based receivers continuously monitor for spoofing signals and predict the probability of spoofer/jammer presence in advance, allowing operations to proceed at normal protection levels when the airspace is clean, thus resolving the contradiction between maintaining high reliability and ensuring operational availability
Solution Approach 2:
The system establishes a feedback loop where ground-based receivers continuously monitor for spoofing attempts, update the probability assessment of spoofer/jammer presence, and communicate this information to aircraft. This real-time feedback allows dynamic adjustment of protection levels based on actual threat conditions rather than conservative static assumptions, simultaneously maintaining reliability and improving availability
2Measurement precision
If higher protection levels are used to account for potential spoofing threats, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces ground-based receiver stations as intermediary components that perform the complex spoofing detection and probability assessment computations. Instead of requiring each aircraft to independently compute protection levels against spoofing threats (which would increase onboard device complexity), the ground infrastructure acts as an intermediary that pre-processes threat information and provides simplified guidance to aircraft, thereby maintaining position accuracy while reducing computational complexity
Data Source
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AI summary
A local area detection and alerting system, LDAS, (100) for detecting potential GNSS spoofing within a protected airspace includes a ground-based control station (102) and several RF interference (RFI) control stations (106) spaced to define the protected airspace. Each RFI control station (106) includes two or more reference GNSS signal receivers (108) in communication with two or more reception (Rx) antennas (110), each antenna having a surveyed true location and distinct height. The reference receivers (108) continually determine GNSS-derived absolute positions of each antenna (110), which are compared to their true locations to determine if GNSS spoofing is responsible for measurement anomalies. Any detection of potential spoofing is forwarded to the control station (102), which broadcasts regular LDAS updates indicating the presence or absence of potential spoofing to all aircraft (116) operating within a transmission range surrounding the protected airspace.