摘要
由于工作在UHF/VHF波段的超宽带合成孔径雷达(SAR)具有大波束角,载机运动误差将导致回波相位误差的空变效应,传统窄带的运动补偿方法已不再适应这种情况。基于宽带大波束角的特点,并考虑大测绘带的情况,对回波相位误差的空变效应进行了定量分析,并在此基础上提出一种方位向和距离向相结合的二阶补偿方法。其主要思想是:对距离压缩数据在方位向和距离向分别进行分块,在子块内根据目标回波多普勒频率与目标相对载机位置的一一对应关系,并利用视线误差随距离变化的特性,获取准确的相位补偿因子,以补偿空变相位误差。仿真实验证明该方法具有良好的补偿效果,成像质量显著改善。
Ultra wide-band SAR operating on UHF/VHF band often has a wide beam. Motion errors of the radar platform produce space-variant echo phase errors. Conventional compensation algorithms are not applicable under the new conditions. Considering the wide azimuth angle and wide width in UWB SAR, the space-variant phase errors are analyzed quantitatively. Then, a new method called second order compensation is presented, which is applied in azimuth direction and in range direction. In this method, the compressed data range are divided into sub blocks in azimuth direction and in range direction respectively. Accurate Compensation factors are calculated and Space-variant phase errors are compensated in every sub block according to the corresponding relation between Doppler frequency of one target and it’s position relative to the platform,and by utilizing the property that LOS motion errors vary along with the range. Simulation experiments show that this method is efficient and imaging quality is improved.
出处
《现代雷达》
CSCD
北大核心
2005年第6期20-23,共4页
Modern Radar
