The Detection Of Radar Emitter Signals Under Conditions Of Low SNR

The detection of the Radar Emitter Signal is the key technology in electronic intelligence systems,and it is also the first step.The following estimation and extraction of parameters and other steps can be carried out after the existence of the Radar Emitter Signal is ensured.The detection of Radar Emitter Signal has always been a difficult problem,which has the difficulties that the detection of the signal of other areas do not have.On the one hand,the detection of the Radar Emitter Signal is generally non-cooperative reception,so the prior information is limited.On the other hand,the form of the Radar Emitter Signal is more varied and the detection scene is more diverse.Therefore the detection method exploits a specific signal form or a specific detection scene,and the method should be able to detect the Radar Emitter Signal with the limited prior information as much as possible.Based on this,the main contents of this paper are as follows:1.In the second chapter,the traditional second-order correlation method and matching filtering method are reviewed,and then the bispectrum detection method are studied emphatically,which uses the cross bispectrum of the transmitted signal and the received signal.The method of cross bispectrum can adapt to stronger Gaussian white noise.2.The long time accumulation could be used for the high-speed Radar Emitter Signal to increase the echo energy,therefore four methods of correcting range migration are studied in the third chapter: correcting first order only by first order Keystone transform,the method of direct accumulation by Hough transform,the method of Hough transform combining with Radon transform and the method of angle traversal,which can be used to correct the range migration caused by long time accumulation for moving Radar Emitter Signal.3.The time-frequency curve of the LFM signal is a straight line,and Hough transform can detect the straight line.Therefore the blind detection method for the LFM signal combining with Wigner-Ville distribution and Hough transform are studied in the fourth chapter.4.The dimension of the signal subspace needs to be estimated in advance in traditional blind detection method for the detection of multichannel mixed signals composed by coded signals.By using the characteristics that the signal energy will gather in the direction of main eigenvalue,a blind detection algorithm based on eigenvalue decomposition is applied in the fifth chapter,which is not necessary to estimate the dimension of the signal subspace in advance.The simulation results verify the effectiveness of the proposed Radar Emitter Signal detection algorithm in a specific signal form or a specific detection scene.