Modeling And Application Of Target Scattering Characteristics Based On Non-cooperative Radiation Source

Non-cooperative radiation source detection refers to the use of electromagnetic signals existing in space to irradiate the target surface to form scattering without radiating electromagnetic waves,so as to achieve target tracking and detection.Compared with the active detection system,the non-cooperative radiation source detection system can have higher sensitivity,and the transceiver is separated,which improves the survivability of the battlefield.In target detection,the scattering characteristics of the target are particularly important.The scattering characteristics of the target involve many factors such as frequency,angle and polarization.How to effectively use a small amount of information instead of complex scattering field data to obtain the electromagnetic scattering characteristics of the target has become a research hotspot of non-cooperative emitter detection.In this thesis,the scattering center is applied to target detection based on non-cooperative radiation source.The main work is as follows:1.Introduce the basic concepts related to electromagnetic scattering characteristics,including radar cross section and common electromagnetic scattering mechanism.Combined with the actual scene of non-cooperative radiation source,the method of moment,multilayer fast multipole and physical optics method based on RWG basis function are studied,and the accuracy of the algorithm is verified by an example;By comparing the monostatic scattering characteristics of a stealth fighter with the bistatic scattering characteristics,the advantages of non-cooperative radiation source detection are verified;Taking the satellite as the noncooperative radiation source,the electromagnetic scattering field of the civil aircraft in the actual scene is simulated;In addition,simple targets such as cube and cylinder and small UAV models are tested.Compared with the simulation results,the error is less than 5d B.2.The bistatic scattering center extraction algorithm based on non-cooperative radiation source is studied,and the one-dimensional and two-dimensional bistatic scattering centers of the target are extracted and analyzed;The reconstructed field of one-dimensional scattering center in frequency domain is compared with the measured results,and the error is less than 2d B;The influence of scene width and the number of scattering centers in onedimensional scene is explored;The radar imaging of the target is realized by using the twodimensional scattering center,the distribution of the scattering center of the actual aircraft model in the two-dimensional space is obtained,and the effects of different frequencies,bandwidths and polarization modes on the two-dimensional scattering center are explored.3.A wide-angle scattering field reconstruction algorithm based on point scattering center is proposed,and the wide-angle scattering field reconstruction of the target is realized.The scattering center in the frequency domain is extended to the angle domain,and the traditional Fourier method is used to reconstruct the scattering field of the flying target in the range of20°;On this basis,the orthogonal matching pursuit algorithm is introduced to greatly improve the extraction efficiency of two-dimensional scattering center,and it is applied to the reconstruction of wide-angle scattering field to realize the reconstruction of 20°scattering field;The test results of simple target and small UAV are compared with the results of angular domain scattering field reconstruction based on orthogonal matching tracking.The model error of simple target is less than 0.5d B,and the model error of small UAV is3.69 d B.This verifies the reliability of wide-angle scattering field reconstruction,and provides a theoretical basis and technical support for wide-angle data compression.