ADS-B Integrity Monitoring

Automatic Dependent Surveillance-Broadcast (ADS-B) system is an electronic equipment onboard an aircraft which automatically broadcasts the location of the aircraft by using a digital data link. ADS-B determines its position using GPS. Aircraft transponders receive GPS signals and use them to determine the aircraft's position in the sky. A transmitter then broadcast that position at rapid intervals, along with identity, altitude, velocity and other data. Dedicated ADS-B grounds stations receive the broadcast and relay the information to air traffic control for precise tracking of the aircraft. It offers more precision than and provide more service, such as weather and traffic information. Both pilot and controllers will see the same real-time displays of air traffic and improve safety. In the future, ADS-B will be the prime means of surveillance. However, since ASD-B depends on accurately data from GPS, there are some potential risks due to GPS weakness and error source. Multilateration has a high accuracy performance and is believed to be an ideal back-up strategy for ADS-B systems. Thus, in this study, develop the ADS-B and multilateration sensor fusion algorithm for aircraft tracking applications in ATC. The algorithm contains a fault detection function for ADS-B information monitoring by using Trajectory Change Points reports from ADS-B and numerical vectors from a hybrid estimation algorithm. We consider two types of faults in the ADS-B measurement model to show that the algorithm is able to deal with the bad data from ADS-B systems and automatically select good data from multilateration systems. We apply fuzzy logic concepts and generate time variant parameters during the fusion process. The parameters play a role of weights for combining data from different sensors. The algorithm performance is validated through aircraft tracking examples.