Research On Radar Waveform Design For Spectrum Sharing

With the continuous development of electromagnetic spectrum equipment,RF spectrum resources have become strategic resources.Radar,as one of the main users,is now facing increasing pressure of spectrum congestion.Especially in the frequency band below C band,the problem of spectrum overlap between radar and communication is becoming more and more serious.In this paper,several problems to be solved in the process of optimizing the design of waveforms to realize shared spectrum are studied.the main work and innovations are as follows:1,A fast cyclic iterative algorithm has been improved,and the problem of fast design of the constant envelope waveform with stopband is solved.The algorithm avoids the semi-positive definite relaxation process and the step-by-step optimization steps in the cyclic iteration process,and the computational complexity is lower and the convergence speed is faster.2,The method of obtaining the optimization signal by using the known matrix element approximation is proposed.This method aims at solving the problem of designing arbitrary amplitude waveform in multi-interference environment,and establishes a nonconvex model to relax and solve it.This method is not limited by constraint conditions,has wider applicability and lower computational complexity.3 The problem of designing constant amplitude signal in a variety of interference environments is effectively solved.In the process of solving the model,the randomization method and the known matrix element approximation method are proposed to obtain the signal,and the discrete phase iterative algorithm is combined to further reduce the spectrum energy in a specific frequency band.The spectrum compatibility and autocorrelation characteristics of the signals obtained by this method are good.4,Considering the clutter environment and multiple interference,the problem of designing constant envelope transmission waveform in the design of joint receiving filter is solved.The non-convex problem model of fractional programming is established,and the optimization waveform is obtained by using randomization method when the filter parameters are fixed.The spectrum coexistence is realized and the detection performance is guaranteed in the clutter environment.