Interferometry Spoofing Detection for ADS-B Aircraft
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Solution Overview
Problem
Air traffic control systems, particularly ADS-B, face challenges in accurately determining the location of aircraft due to potential spoofing, where a target transmits incorrect GPS data, which can be caused by malfunctions or malicious intent, leading to safety and capacity issues in air traffic management.
Innovation Solution
The system uses interferometry by collecting signals at two or more ground stations to determine the angle to the target, comparing the phase difference signals with reported positions to identify spoofing, ensuring the target's actual location matches possible locations determined from the signals received at these stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If ADS-B system uses GPS signals to determine aircraft location, then location information can be obtained, but the system is vulnerable to spoofing where incorrect GPS data is transmitted
Solution Approach 1:
The patent introduces an interferometry-based verification system as an intermediary between the GPS signal and the air traffic control system. By using multiple ground stations to measure the phase difference of signals and comparing it with the reported position, the system creates an independent verification mechanism that mediates the trust between GPS data and control decisions, thereby detecting spoofing attempts without completely rejecting the ADS-B system.
2Reliability
If multiple ground stations are used to collect signals for interferometry, then spoofing detection capability is improved, but system complexity increases
Solution Approach 1:
The patent makes the ground stations multi-functional by having them serve both as traditional ADS-B receivers and as interferometry-based spoofing detection devices. The same ground station infrastructure collects signals for position determination while simultaneously measuring phase differences for spoofing detection, eliminating the need for separate dedicated detection systems and reducing overall complexity.
3Measurement precision
If phase difference signals are compared with reported positions to detect spoofing, then location accuracy is enhanced, but processing time increases
Solution Approach 1:
The patent performs preliminary calculations by pre-determining the expected phase difference signals based on the reported positions before receiving the actual signals from multiple ground stations. This allows the system to quickly compare expected versus actual phase differences without performing complex position calculations in real-time, thereby enhancing location accuracy while minimizing processing time delays.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively detects and prevents spoofing by comparing the phase difference signals with reported positions, enhancing the accuracy and reliability of aircraft location determination, thereby improving air traffic control and reducing frequency congestion in the 1090 MHz spectrum.
Implementation Method 1
A signal transmitted by the target is collected at two or more different locations to determine the angle to the target. As the target moves through space, it traverses through peaks and troughs in the generated antenna pattern that can be compared to the reported positions to identify spoofing of the target.
Data Source
AI summary
Methods and apparatus for preventing spoofing of targets, such as aircraft, in an air traffic control system. In one embodiment, first and second antennas at respective ground stations can be used to receive a signal transmitted by an aircraft from which a phase signal can be generated. A position of the aircraft generate can be generated from peaks and troughs in the phase signal due to movement of the aircraft. The determined position can be compared to a position reported by the aircraft to identify spoofing of the target.