摘要
在弹载曲线轨迹双基SAR成像中,三轴速度与加速度降低了传统的双基等效斜距模型精度,也使得基于匀速直线平飞轨迹模型的极坐标格式算法(PFA)不再适用。受双平台加速度引入的空变运动误差影响,传统的分子块补偿方法会造成图像子块间地物景象不连续问题,影响后续的图像匹配应用。针对这些问题,该文提出一种新的双基SAR成像算法——反向滤波PFA算法(BFPFA),该算法是基于改进的通用化双基等效斜距模型(IGBERM),利用PFA插值将频谱投影到地距平面,通过构建空变相位误差与图像畸变联合补偿滤波器,并采用反向映射插值,实现在斜地转换过程中对运动误差、波前弯曲与图像畸变进行局部联合补偿,获得的无畸变双基SAR地距图更有利于后续的图像匹配应用。最后,仿真实验验证了所提算法的有效性。
The traditional bistatic equivalent range model has low accuracy and make the traditional Polar Format Algorithm (PFA) are inapplicable in missile-borne bistatic Synthetic Aperture Radar (SAR) imaging with curved track due to the existing of three-axis velocity and acceleration. In addition, due to the existing of space-variant motion error introduced by acceleration, the traditional 2-D sub-block compensation method will cause the discontinuities between the image sub-blocks, thus affecting the subsequent image matching application. In view of these problems, this paper proposes a Back-Filtering PFA algorithm (BFPFA) which is based on the Improved Generalized Bistatic Equivalent Range Model (IGBERM). Constructing the combined compensating filter of space-variant phase error and geometric distortion, as well as reverse mapping interpolation, can realize the combined compensation of motion error, wavefront bending and geometric distortion in the process of oblique conversion, and obtain the SAR distance map without distortion, which is more conducive to the subsequent image matching applications. Finally, the simulations validate the effectiveness of the proposed algorithm.
作者
邓欢
李亚超
梅海文
全英汇
邢孟道
DENG Huan, LI Yachao, MEI Haiwen, QUAN Yinghui ,XING Mengdao(National Key Laboratory of Radar Signal Processing, Xidian University, Xi'an 710071, China)
出处
《电子与信息学报》
EI
CSCD
北大核心
2018年第11期2638-2644,共7页
Journal of Electronics & Information Technology
基金
国家自然科学基金(61001211
61303035
61471283)~~
关键词
弹载双基SAR
等效斜距模型
双基极坐标格式算法
空变运动误差
畸变校正
Missile-borne bistatic SAR
Equivalent slanting distance model
Bistatic Polar Format Algorithm (PFA)
Space-variant motion error
Distortion correction