An S Mode ADS-B Preamble Detection Algorithm

Abstract

Automatic Dependent Surveillance - Broadcast (ADS-B) is a significant technology in the worldwide air traffic control. The preamble detection of S-mode ADS-B signal is one of the keys to determining the performance of an ADS-B receiver. This paper presents a preamble detection algorithm for ADS-B baseband signals. A threshold is set in the algorithm to search for a series of sampling points above the threshold. The potentially valid signal sequence is extracted when the amount of points exceeding the threshold continuously meets the format requirement of ADS-B signal. Cross-correlation detection is performed in the potentially valid signal sequence, aiming at searching for the maximum value that satisfies the threshold of cross-correlation. The position of the maximum value can be the beginning of the data block. To exclude the false alarm caused by the interference of high-energy A/C mode signals, the amplitude detection is performed on the preamble which passed the correlation detection to ensure that the amplitudes of the four effective pulses all in the same range. Simulation results show that the algorithm achieves good results.