基于deramp的星载聚束式SAR改进ECS算法

李 然; 李景文; 李林琳

基于deramp的星载聚束式SAR改进ECS算法

北京航空航天大学电子信息工程学院, 北京 100191

详细信息

作者简介:
李然(1984-),男,山西和顺人,博士生,lir@ee.buaa.edu.cn.

中图分类号: TN 957
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- 被引次数: 0
出版历程
- 收稿日期: 2008-09-16
- 网络出版日期: 2009-09-30

Improved ECS algorithm for spaceborne spotlight SAR based on deramp processing

School of Electronics and Information Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100191, China

摘要

摘要: 基于两步成像算法和ECS(Extended Chirp Scaling)成像算法,提出一种结合Deramp预处理的星载聚束式SAR(Synthetic Aperture Radar)改进的ECS成像算法.Deramp预处理是基于SPECAN算法的思想,将信号通过非空变的方位滤波器实现批压缩,该方法在保证成像分辨率的前提下,通过deramp处理消除了由采样率不足导致的方位频谱混叠特别是在星载SAR高分辨率聚束模式下.尽管ECS算法中的子孔径处理可以降低对系统脉冲重复频率的要求,但是脉冲重复频率依然受到单点多普勒带宽的限制.所介绍的方法可以进一步降低ECS算法中子孔径分割处理对脉冲重复频率的要求,使得ECS的算法的应用更为广泛.通过对点目标进行仿真和成像,成像指标评估验证了该算法的可行性.
- 聚束式 /
- 扩展调频变标 /
- 合成孔径雷达 /
- 成像算法
Abstract: Based on the two-step imaging algorithm and the extended chirp scaling (ECS) algorithm,an approach for spotlight mode of spaceborne synthetic aperture radar(SAR), which combines the deramp processing and ECS algorithm was proposed. The deramp processing is based on SPECAN algorithm, and passes the raw data through a space invariant azimuth matched filter. The azimuthal spectral folding caused by insufficient sampling rate especially in high resolution spaceborne spotlight SAR was overcomed through the deramp processing. Although the division into subappertures in ECS can reduce the system requirement of the pulse repetition frequency(PRF), the PRF is restricted to higher than the accumulated doppler frequency bandwidth of a single point target. The presented method further reduces the requirement of the PRF in subapperture processing without the resolution loss. Thereby the ECS algotithm can be applied easily. The simulating and imaging results of point targets demonstrate the validity of this approach.
- spotlight mode /
- extended chirp scaling /
- synthetic aperture radar /
- imaging algorithm

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参考文献(1)

[1] Riccardo Lanari, Manlio Tesauro, Eugenio Sansosti, et al. Spotlight SAR data focusing based on a two-step processing approach[J]. IEEE Transactions on Geoscience and Remote Sensing, 2001,39(9): 1993-2004 [2] 王国栋,周荫清,李春升.高分辨率星载聚束式SAR的Deramp Chirp Scaling成像算法[J].电子学报, 2003, 31(12):1784-1789 Wang Guodong, Zhou Yinqing, Li Chunsheng. A deramp chirp scaling algorithm for high-resolution spaceborne spotlight SAR imaging[J]. Acta Electronic Sinica, 2003, 31(12):1784-1789(in Chinese) [3] Ding Zegang, Long Teng, Zeng Tao, et al. Deramp range migration processing for space borne spotlight synthetic aperture radar[J]. Advances in Space Research, 2008, 41:1822-1826 [4] Moreira Alberto, Mittermayer Josef, Scheiber Rolf. Extended chirp scaling algorithm for air-and spaceborne SAR data processing in stripmap and scanSAR imaging modes[J]. IEEE Transactions on Geoscience and Remote Sensing,1996,34(9):1123-1136 [5] Mittermayer Josef, Moreira Alberto. Spotlight SAR processing using the extended chirp scaling algrithm IEEE International Conference on Geoscience and Remote Sensing. :IEEE, 1997,4:2021-2023 [6] Sun Jinping, Wang Jun, Yuan Yunneng, et al. Extended chirp scaling algorithm for spotlight SAR[J]. Chinese Journal of Aeronautics, 2002,15(2):103-108 [7] 王国栋,周荫清,李春升.高分辨率星载聚束式SAR改进的ECS成像算法[J].宇航学报, 2003, 24(1):65-70 Wang Guodong, Zhou Yinqing, Li Chunsheng. Refined ECS algorithm for high resolution spaceborne spotlight SAR imaging[J]. Journal of Astronautics, 2003, 24(1):65-70(in Chinese) [8] 黄岩,李春升,陈杰,等.高分辨率聚束SAR改进chirp scaling成像算法[J].电子学报, 2000, 28(3):35-38 Huang Yan, Li Chunsheng, Chen Jie, et al. Refined chirp scaling algorithm for high resolution spaceborne SAR imaging[J]. Acta Electronic Sinica, 2000, 28(3):35-38(in Chinese)

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