Study On Detection And Denoising Method Of Weak Signal In Sea Clutter

Small target detection in the sea clutter background has not only high value in civil research,but also can improve the safety factor of merchant ship to the sea,and also can enhance the maritime surveillance capability of maritime police ship,and enhance the national defense forces.Therefore,to remove peak false alarm and enhance the detection and extraction ability of weak target signals in sea clutter background is the research hotspot of signal processing,and has been paid great attention by scholars at home and abroad.In this paper,the weak signal detection model of sea clutter wave background is studied,in order to enhance the model's overall detection ability and prediction accuracy,proposes the prediction method of support vector machine based on bee colony algorithm;in order to remove the dopant noise in sea clutter,a method of sea clutter denoising based on improved ensemble average empirical mode decomposition(MEEMD)is proposed.Specific research contents are as follows:In view of the problem that the traditional detection method has insufficient ability to detect weak signal in chaotic background,the paper uses the time delay and embedding dimension of chaotic signal to realize phase space reconstruction,and uses the swarm algorithm to optimize the penalty coefficient and the kernel function parameter of support vector machine,a weak signal detection method based on Artificial Bee Colony algorithm optimized support vector machines is proposed.Combined with support vector machine,single-step prediction model of the chaotic sequence is set up,so we can detect the weak signal in chaos from the prediction error(including the transient signal and periodic signal).Lorenz attractor and the data from the radar sea clutter database will be used in the simulation.The simulation result shows that the method can effectively detect the weak target from chaotic signal and suppress the effect of noise on chaotic background signal.Compared with the traditional method,the performance of the prediction accuracy and detection threshold is improved significantly.Aiming at the problem that sea clutter is difficult to extract effectively because of mixed noise,this paper improves the complementary integrated empirical mode decomposition CEEMD algorithm,and proposes a sea clutter denoising method based on MEEMD algorithm.The algorithm uses the permutation entropy and Savitzky-Golay(SG)filter to process the intrinsic mode function(IMF)after the decomposition of CEEMD.Finally,the data signal after the noise reduction is obtained after the reconfiguration of the empirical mode decomposition(EMD)decomposition.In order to get the IPIX radar sea clutter data simulation experiment,combined with least squares support vector machine(LSSVM)to establish single chaotic sequence prediction model,and the weak signal detection is realized,and the denoising effect is judged by comparing the root mean square error of the prediction results before and after denoising.The simulation results show that the proposed MEEMD has good inhibition effect on mode confusion,the root mean square error after denoising(RMSE)was 0.000847,0.0122 more than the root mean square error of denoising before two orders of magnitude lower.