DAPS based adaptive tracking system for high-assurance air traffic surveillance

With the rapid increase in air traffic demands, the more accurate and reliable tracking systems for aircraft surveillance are required to improve the capacity, safety and efficiency of air traffic control (ATC) services. As a considered part of the surveillance infrastructure, Secondary Surveillance Radar (SSR) Mode S has been widely utilized in the ATC applications. In the Mode S Enhanced Surveillance (EHS), the Downlink Aircraft Parameters (DAPs) are available for obtaining updated and detailed information from aircrafts. For the performance evaluation of Mode S EHS, Electronic Navigation Research Institute (ENRI) has constructed an aircraft surveillance system which is composed of two SSR Mode S radars. And compared with the Kalman filter and IMM (Interacting Multiple Model) estimator, the α-β filter has low computation cost and configuration complexity. If the maneuvers of aircrafts can be detected in real time, it is possible to select appropriate gains to make a trade-off between good noise reduction and good tracking through maneuvers. In this paper, a DAPs based adaptive tracking system which consists of a simple α-β filter with several different models and a maneuver detector is proposed. The system enables dynamically selecting the optimal filter model according to the different motions of aircrafts. Moreover, as the availability and certification of DAPs cannot be guaranteed, the integration of the elementary surveillance and the enhanced surveillance is also implemented. The results of computer simulations and practical experiments show the effectiveness of proposed system by comparing with the standard IMM estimator.