| It is well known that maximizing the protection of one’s own communications and jamming enemy communications is an essential problem throughout the information warfare communication confrontation.And the tactical data link,as a crucial part of modern electronic information warfare,is a hot spot for research in various countries,among which the leading Link16 data link has been studied without interruption due to its wide application.Therefore,the identification of specific features and the research and analysis of jamming techniques for data link communication countermeasures are of great national defense significance.In this thesis,based on the data link ground-air communication environment in electronic information warfare,the key technologies of identification and interference in data link communication countermeasures are studied specifically for Link16.First,this thesis analyzes and studies the Link16 data link system with modeling and simulation.Specifically,for the Link16 signal with a double-pulse package structure in fixed message format,this thesis studies the CRC coding,RS coding,interleaving and deinterleaving,CCSK coding,MSK modulation and frequency hopping modules used in its waveform generation.And then perform modeling and simulation of each module independently.Based on the model and simulation,the anti-interference capability under Gaussian channel is studied for more targeted interference.Finally,the entire Link16 data link is simulated and analyzed in conjunction with each module.Next,this thesis studies the signal identification and interference techniques in Link16 data link communication countermeasures.In the first step,this thesis takes the MSK modulation method in Link16 signal as the research point,proposes specific feature parameters for the unique amplitude spectrum characteristics after the square of MSK modulated signal.And then,Integrating the feature extraction and research of higher-order cumulants,differential higher-order cumulants,squared spectra,and quadratic spectra,an algorithm for MSK modulation identification is proposed for several common signal modulation methods in the common U.S.military active air data link,and the identification success rate of the algorithm is analyzed.Based on this,the relationship between the highest peak and the second highest peak in the squared spectrum of MSK modulated signal and the carrier frequency and code rate is used as the entry point to estimate the carrier frequency and code-rate parameters of the Link16 signal after frequency hopping,and the estimation performance is analyzed.In the second step,this thesis explores the interference techniques in Link16 ground-air communication.Through the analysis and study of specific interference signals,the feasibility of FM and multi-tone interference signals is derived.Through the analysis and study of several interference styles,it is concluded that partial band blocking interference and comb spectrum interference are applicable to Link16 data link,while forwarding interference is not considered due to the high requirements of the jammer.Finally,this thesis presents a simulation analysis of the above study.Firstly,the MSK modulation identification algorithm and parameter estimation algorithm are simulated and analyzed.The recognition rate is used as an index to analyze the success rate during the frequency hopping MSK modulation recognition and parameter estimation.Next,For the built Link16 data link,several feasible interference methods and interference signals are injected into the Link16 data link system,and the interference effect of these interferences on the Link16 system is analyzed with the BER as the index.A BER of10-2 is considered valid for interference.Several different interference methods are summarized,and it is concluded that the combination of comb-spectrum blocking interference and multi-tone interference signal is the best style of interference suitable for Link16 link system,which has certain reference significance and value. |
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