Research On Interference Type Recognition And Suppression Technology In Mark XIIA System

In modern warfare,how to use wireless communication to communicate and attack dexterously has always been the focus of research.In information-based operations,it's key to distinguish oneself from the other correctly,fastly,and accurately.This leads to the concept of electronic countermeasures.Interfering signals can significantly reduce the quality of the signal or even the normal reception of the signal,so interference suppression methods are usually added.However,the interference patterns are complex and changeable,and the interference suppression methods usually only work in a few interference patterns.Therefore,if you want to deal with interference correctly,you must first accurately identify and judge the type of interference.The Mark XIIA system is a new enemy identification system developed by NATO.The research of the relevant content of this article is based on this system.The main work of the thesis is as follows:First,introduce the frame structure and signal format of Mark XIIA system.Then introduced the five interference patterns of single tone interference,frequency hopping interference,narrow-band interference,frequency sweep interference and pulse interference,and established the mathematical formulas of these five types of interference.The characteristics of the domain.Then,for the above five types of interference,analyze their characteristics in different domains,and choose to sort out four characteristic parameters,namely: normalized spectral bandwidth,normalized spectral peak,normalized spectral flatness,time domain peak Flat ratio,used to identify and detect interference types.Next,for these five kinds of interference,using four kinds of characteristic parameters,according to the purpose of step-by-step division,two algorithms are designed to identify these five kinds of interference.First,the decision tree theory is designed,the CART algorithm is used to generate the decision tree,and the algorithm verifies that the algorithm can successfully distinguish 5 kinds of interference.Then introduce the theory of support vector machine,design the binary tree support vector machine recognition algorithm,and finally verify the recognition algorithm through simulation.After identifying the types of interference,the interference suppression algorithms are introduced for the five types of interference.First,the double-threshold suppression algorithm based on overlapping windowing is introduced,and the suppression effects are simulated for single-tone interference,frequency hopping interference,and narrow-band interference.For narrow-band interference,the differential interference algorithm is studied and verified by simulation.Aiming at the swept frequency interference,the interference suppression technology based on STFT is introduced and simulated in detail.Finally,an over-threshold suppression algorithm is introduced to suppress pulse interference.Because the design parameters need to be adjusted to verify interference settings and identify suppression,this article uses the APP Designer component in MATLAB to create a visual platform in which you can set various parameters about interference and simulate the Mark XIIA Mode5 Level1 query / response system in real time.After identifying the type of interference,show the recognition results.And call the corresponding interference suppression method to suppress the interference,and real-time display bit error rate,timefrequency domain and other signal characteristics.Tests have proved that the platform can achieve the target function and meet the experimental expectations.