ADS-B signal separation based on blind adaptive beamforming

The automatic dependent surveillance-broadcast (ADS-B) is a surveillance system for air traffic management where aircrafts asynchronously broadcast the position and other information on the same frequency band. However, this simple transmission protocol will result in inevitable overlapping among multiple ADS-B signals. In this paper, with the inherent characteristics of the ADS-B signal, an algorithm is proposed to separate the overlapping ADS-B signals. First, a nonconvex blind adaptive beamforming problem is formulated where the constraints are different from those in common beamforming algorithms. Especially, for the non-overlapping snapshot, the relationship between the output of the beamformer and that of the first array element is constrained. After that, the alternating direction method of multipliers algorithm is utilized to solve the nonconvex blind adaptive beamforming problem. Simulations demonstrate that the proposed algorithm is effective even if there is only one non-overlapping snapshot.