Study On Radar Forward-looking Imaging Method

Radar imaging plays an important role in the development of national economy and the modernization of national defense.The existing common imaging methods cannot meet the requirements of radar forward-looking high-resolution imaging,which greatly limits the application range of radar imaging technology.In view of this,a method of scanning monopulse forward-looking imaging is proposed on the basis of the original monopulse forward-looking imaging method,which improves the performance of the monopulse forward-looking imaging.At the same time,the quantum correlated imaging technology in optical imaging system is extended to microwaves.A forward-looking correlated imaging method based on random radiation field is proposed in microwave field,and this method is introduced into the 3D radar imaging field to achieve forward-looking 3D super-resolution imaging.Based on the existing monopulse forward-looking imaging method,a scanning monopulse forward-looking imaging method is proposed,which solves the problem that existing monopulse forward-looking imaging can only obtain the outline information of the target and cannot obtain the detailed information of the target.In order to solve the problem that the scene target part of each distance unit in monopulse forward-looking imaging is only equivalent to a scattering point,an equivalent scattering center is obtained,and the positions of multiple equivalent scattering centers cannot be obtained to obtain more detailed image information,a scanning monopulse forward-looking imaging method is proposed based on the existing monopulse forward-looking imaging method in this paper,which adds beam scanning function.The scanning monopulse forward-looking imaging technology uses the pulse compression to obtain the distance information and use the monopulse angle measurement technology to obtain the angle information of equivalent scattering point in each distance unit for each echo,and finally obtains many equivalent scattering points in the same distance unit.The equivalent scattering points obtained from each echo are used to get the radar images of the scene targets according to the direction of the beam scanning.Then,the quantum correlated imaging technology is extended to the microwave field,and the microwave correlated forward-looking imaging technology based on the random radiation field is realized.The microwave correlated forward-looking imaging method extracts information of scene information contained in the echoes by sending two-dimensional spatio-temporal random radiation field,and obtains forward-looking super-resolution image that does not depend on the azimuth Doppler bandwidth and the radar antenna aperture area.In view of the important role of two-dimensional spatio-temporal random radiation field in this imaging system,a method of generating random radiation field by adding random phase to the subarray of phased array antenna is proposed.With the increase of the echoes,the scene information in the echoes is also increasing.When the information is accumulated to a certain number,the azimuth and pitch information of scattering points in the scene is obtained by associating the received echoes with the known random radiation field,and the radar image of the scene target is obtained.In the processing of associating the received echoes with the known random radiation field,the method of compressed sensing based on target sparse information is used to achieve super resolution imaging.Finally,the microwave correlated forward-looking imaging method is extended to radar forward-looking 3D imaging,and radar forward-looking 3D imaging is realized.The basic principle of microwave correlated 3D imaging is that high-resolution range image is obtained by the pulse compression technology of the linear frequency modulation signal,and the information in the azimuth and pitch dimensions of the scene scattering points is obtained by associating the received echoes with corresponding transmitting signals in the same distance slice.The information of the scattering points in each distance slice are fused to obtain the radar forward-looking 3D super-resolution imaging.