Research On Single Antenna ADS-B Overlapped Separation Algorithm Based On EMD

In recent years,Automatic Dependent Surveillance-Broadcast(ADS-B)has attracted wide attention due to its high monitoring accuracy.More and more aircraft are equipped with ADS-B systems.The ADS-B signal is sent by broadcasting,and all users using this frequency can receive it.At the same time,as the number of aircraft equipped with ADS-B systems is increasing,overlapping problems will inevitably arise.The overlapping phenomenon will cause receiver decoding errors,which will reduce the monitoring performance of the ADS-B system,resulting in inability to accurately monitor the current aircraft position and other information.This paper studies the overlapping problem of ADS-B signal in the process of antenna reception,and provides a theoretical solution based on the number of overlapping sources and processing the overlapped signal based on a single antenna.Since the ADS-B signal received by a single antenna can be directly used for processing less information,in this paper,an empirical mode decomposition(EMD)algorithm is used to convert single-antenna data into multi-antenna data,and then process the overlapped signal.The content of the thesis is mainly divided into the following aspects:Firstly,the technique of detecting the number of overlapped signal sources is studied.Based on the traditional MDL source number estimation algorithm,an EMD-MDL algorithm based on diagonal loading technology is presented.The algorithm can detect the number of sources when the number of sampling points is small,without setting a threshold.In view of the relative complexity of the above algorithm,an energy threshold estimation algorithm is provided,that is,the energy of the Intrinsic Mode Function(IMF)decomposed is calculated,a threshold is set,and all IMF energy values are detected in turn.Simulation and actual data verify the effectiveness of the algorithm.Secondly,the ADS-B overlapping signal processing technology is studied.After estimating the number of ADS-B sources,the EMD algorithm is used to construct a multidimensional data matrix,and the Fast Independent Component Analysis(Fast Independent Component Analysis,FastICA)algorithm is used to solve the overlapping problem.Before processing overlapping signals,this paper constructs a dynamic embedding matrix for eliminating mixing to reduce or even eliminate the effects of modal mixing.Simulation experiments and actual data show that the algorithm can effectively separate ADS-B signals and is insensitive to the relative delay between overlapped ADS-B signals.