Recognition And Intercept Method Of Unmanned Aerial Vehicle (UAV) TT&C Signals

In the field of modern military,the electronic warfare supported by unmanned aerial vehicles become an important form of modern military war,because of the unique ability of gathering interligence,reconnaissance and surveillance,electronic interference,effective attack enemy.the key technology of signal recognition and interceptthe of UAV Spread Spectrum TT&C Has significant practical significance.Unified Spread Spectrum TT&C system is a new and effective TT&C System with some advantages of good anti-jamming capability,good concealment capability,low probability to be intercepted.UAV Spread Spectrum TT&C includes Direct Sequence Spread Spectrum(DS-SS)and hybrid Direct Sequence/Frequency-Hopped(DS/FH).Main research results include the detection and identification of the type of UAV Spread Spectrum TT&C and the estimates of parameters.there are three ways include WVD + BP neural network,improved delay multiplication method,cyclic spectrum correlation technology to detect and identificate the type of Spread spectrum.The parameter estimation mainly includes blind estimation of carrier frequency,spreading code rate,spreading code period and so on.Firstly,the model and characteristics of DS signals and DS/FH signals are analyzed.For the low signal-to-noise ratio(SNR)of UAV Spread spectrum tt&c signals,based on the traditional theory of the combination of inger Ville distribution and BP artificial neural network,Delay multiplication method and Cyclical stationary theory,the performance of these algorithms are simulated and analyzed int this paper.And on the basis of which the algorithm can be improved so that it can not only detect the UAV Spread Spectrum TT&C signals but also can identify the spread spectrum type of the signal,and can extract and characterize some characteristic parameters.Secondly,based on the identification of spread spectrum types,some parameters of direct spread spectrum TT&C signals which are very important to the automatic reception,non-cooperative signal interference and information-capture of the partners are estimated.First,Carrier frequency are estimation,the algorithms include frequency doubling method and its improved method,cyclic spectrum method,time-frequency method.Secondly,the improved delay multiplication method combined with the spread spectrum recognition algorithm is used to estimate the symbol rate of signal.Finally,the pseudo-code period is estimated based on the time domain autocorrelation method.Meanwhile,the influence of modulations and the length of signals are simulated and analysised.Finally,based on the method of Direct Spread Spectrum TT&C signals parameter estimation,DS/FH mixed spread spectrum TT&C signal's parameters are analyzed and estimated.By comparing with the DS signals,it is proposed to convert the DS/FH signal into a direct spread signal by Frequency resolution and splicing technology to improve the parameter estimation performance of the signal.what we done provides some reference for DS/FH signal blind processing.With the identification of Spread spectrum type and parameter estimation of UAV,the basis of unmanned aerial vehicle information interpretation is established,which not only solveed the problem of low SNR signal detection and identification and parameter blind estimation,but also provides new ideas of the interception of complex emitter signals.