A Method of Overlapped ADS-B Signal Processing Based on Accumulation and Classification

As a major surveillance technique in the future recommended by ICAO, Automatic Dependent SurveillanceBroadcast (ADS-B) is being paid much more attention in the world, it is incorporated to the growing number of aircraft. As the broadcast property and the increasing of the aircraft, there will be overlapping among the different ADS-B signal, which will lead to a serious problem for the decoding of ADS-B signals. If the ADS-B signal cannot be properly decoded, the information of target will be lost or error recorded. In this paper, the method of overlapped signal processing is presented for singleantenna ADS-B receiver. Firstly, this paper estimate the start time of the signal by the detection of valid pulse position and lead edge, the overlapping position is detected by Hilbert transform, then the time delay between the overlapped signals is obtained; secondly, divide the sample points into intervals based on the estimated time delay and the pulse width, and the signal power on each interval can be obtained by adopting step by step integration. Finally, the data of different signal can be determined by the classification results of integral values. The method is compared with those of the presented approaches, the result of the simulation shows that if there is a certain power difference between the overlapping signals, then the separation is effective.