Study On Complexity Of Electromagnetic Environment Based On Information Entropy Theory

In electronic warfare,a variety of electromagnetic equipment and information guided weapon equipment work at the same time,and finally form a complex and changeable electromagnetic environment.The complexity assessment of electromagnetic environment is the most basic and important task in EW situation research,which is helpful for commanders to coordinate and deploy EW combat forces.In this paper,we use approximate entropy and information entropy methods to evaluate the complexity of simulated radar signal environment.In the complexity assessment of local electromagnetic environment,the approximate entropy method is used to analyze the static and dynamic complexity of local electromagnetic environment.First,construct the analog signal data of periodic sequence,chaotic sequence,white noise sequence and combination sequence,calculate the approximate entropy of the sequence,and the results show that the approximate entropy method can effectively identify the sequence complexity of different random degrees,and the complexity of periodic sequence,chaotic sequence,white noise sequence and white noise combination sequence is gradually increasing.Then intercept the simulated radar carrier frequency data in different directions for a period of time to analyze the complexity of the local electromagnetic environment,its static and dynamic approximate entropy consistently show that that the complexity of the simulated electromagnetic environment has spatial differences,and the approximate entropy value is increasing from north to south,the electromagnetic environment in the north direction is closer to the complexity of the chaotic system,and the south direction is closer to the complexity of white noise and white noise combination system.In the complexity assessment of global electromagnetic environment,a comprehensive evaluation method combining information entropy and analytic hierarchy process is used to analyze complexity of the simulated electromagnetic environment.First,based on the information entropy theory,the complexity evaluation indicators of frequency domain information entropy,airspace information entropy,time domain information entropy,and energy domain information entropy are constructed.Then,the judgment matrix is constructed based on conditional entropy,which effectively avoids the subjectivity of weighting according to the expert experience.Finally,the weight of each complexity evaluation index is obtained based on analytic hierarchy process,Through the calculation of the uncertainty complexity of the electromagnetic environment,the complexity value of the macro electromagnetic environment is finally obtained.The complexity assessment ofelectromagnetic environment studied in this paper is helpful for commanders to judge the situation of electromagnetic environment and provide a reference for the decision of operational strategy.