摘要
本文提出一种适用于低频超宽带(LrWB)合成孔径雷达(SAR)去调频接收信号的改进频率尺度(Frequency Scaling以后均简写为FS)算法。与原始的FS算法相比,该算法作了两大改进:第一步,该算法消除了信号在距离多普勒 域中所作的泰勒展开近似,实现了对参考距离目标的精确二次距离压缩(SRC)和距离迁徙校正(RCMC);第二步,该 算法减小了SRC因式没有随距离更新所造成的剩余相位误差,改善了测绘带边缘目标的聚焦性能,极大的提高了有效测 绘带宽;并且这种改进的FS算法与原始的FS算法相比并不增加运算量。仿真数据表明:这种改进FS算法的第一步改进 实现了小测绘带宽的精确聚焦,第二步改进将第一步的有效测绘带宽提高约20倍。
This paper presents a modified Frequency Scaling （FS） algorithm for low frequency Ultra-Wideband （UWB） airborne SARs with dechirped receivers. Compared with the original FS algorithm, two modifications are made. One is that the modified FS algorithm gets rid of the Taylor-approximation of the echoes in the range Doppler domain, and this operation leads to a precision Secondary Range Compression（SRC） and Range Cell Migration Correction （RCMC） at the reference range. The other one is that the modified FS algorithm introduces a phase correction function before the azimuth compression in the two-dimensional frequency domain. As a result, the residual phase error caused by the SRC factor without range updating is reduced, so the focusing performance is dramatically improved and the effective swath width is enlarged. Moreover the modified FS Algorithm doesn＇t require additional computations. Simulations demonstrate that the first modification realizes precision focus of small swath UWB SAR data and that an improvement of effective swath width 20 times of the former is achieved by the second modification.
出处
《信号处理》
CSCD
北大核心
2005年第6期605-610,共6页
Journal of Signal Processing
