CAJ | 학술논문

基于Fourier基的压缩感知(Compressed Sensing，CS)算法已被成功应用于平稳运动目标的逆合成孔径雷达(Inversed Synthetic Aperture Radar，ISAR)成像。但由于建模时对ISAR回波方位相位高次项的忽略，Fourier基矩阵对机动目标回波数据方位信息的稀疏表示失效，导致对机动目标的成像在方位向模糊。鉴于时频分析技术良好的时频局部化特性，将其引入到雷达回波方位向分析中，以改进用于表示雷达回波数据的稀疏基，实现对选定时间切片内回波数据多普勒频率的稀疏表示。改进后的基矩阵在通过CS技术解析回波在时间切片内方位信息的同时，又保证了利用有限数据成像的分辨率。与基于Fourier基CS成像等现有方法相比较，新方法在方位向的成像质量上有较大改进。仿真实验验证了算法的有效性。
기우Fourier기적압축감지(Compressed Sensing，CS)산법이피성공응용우평은운동목표적역합성공경뢰체(Inversed Synthetic Aperture Radar，ISAR)성상。단유우건모시대ISAR회파방위상위고차항적홀략，Fourier기구진대궤동목표회파수거방위신식적희소표시실효，도치대궤동목표적성상재방위향모호。감우시빈분석기술량호적시빈국부화특성，장기인입도뢰체회파방위향분석중，이개진용우표시뢰체회파수거적희소기，실현대선정시간절편내회파수거다보륵빈솔적희소표시。개진후적기구진재통과CS기술해석회파재시간절편내방위신식적동시，우보증료이용유한수거성상적분변솔。여기우Fourier기CS성상등현유방법상비교，신방법재방위향적성상질량상유교대개진。방진실험험증료산법적유효성。
The Fourier basis compressed sensing(CS) algorithm was applied in inversed synthetic aperture radar (ISAR) imaging of smoothly moving target successfully. But it ignored the higher order terms of ISAR echo in azimuth when constructing the ISAR echo model, the sparse representation based on Fourier basis for azimuth information of ISAR echo whose target is maneuvering was invalid, which leaded to the lack of information of Doppler frequency in the local range of time domain. As a result, the imaging results of maneuvering target were blurred in azimuth. The time-frequency analysis technology, because of its good time-frequency characteristics in local, was introduced into the analysis of ISAR echo in azimuth: A Gauss window was used to improve the sparse basis which represented the Doppler frequency of ISAR echo data in a selected short time slice while the size of sparse basis matrix remained constant. Then CS technology which includes time-frequency analysis based sparse basis to represent the echo data, Gauss random observation matrix to reduce the sampling rate and Orthogonal Matching Pursuit (OMP) algorithm to solve the coefficients of the sparse representation was used to analyze the azimuth information in that time slice. As a result of CS's advantage in improving resolution,the resolution of image supported by limited data was high at the same time. The target models of uniformly accelerated motion and varying accelerated motion were both designed to simulate the ISAR echo data of maneuvering target. Compared with the existing imaging methods such as Fourier basis CS algorithm, Range Doppler(RD) algorithm and the Range instantaneous Doppler(RID) algorithm based on Gabor transform, the new one achieves significant improvement in terms of imaging results in azimuth. The corresponding imaging results show the effectiveness of the algorithm from both subjective observation results and objective evaluation indicators including Peak Side Lobe Ratio(PSLR) and azimuth resolution.