双站前视低频超宽带(UWB)SAR兼具双站前视的复杂成像构型和低频UWB的强距离方位耦合两个特点,因此极大地增加了实现高精度成像处理的难度。针对这个问题,该文提出一种基于快速因式分解后向投影(FFBP)算法的双站前视低频UWB SAR成像处理方法。首先,基于双站前视低频UWB SAR的成像几何构型和信号模型,给出了双站前视低频UWB SAR 原始BP算法成像的原理和流程。其次,在上述基础上,推导了双站前视低频UWB SAR FFBP算法成像处理的精确相位误差形式,并分析了相位误差对成像处理的影响,据此建立了双站前视低频UWB SAR FFBP成像处理中的子孔径和子区域划分原则。接下来,给出了双站前视低频UWB SAR FFBP算法成像处理流程,并对比分析了BP算法和FFBP算法的成像效率。最后,利用仿真实验证明了文中所作理论分析的正确性和所提方法的有效性。
Bistatic forward looking low frequency Ultra Wide Band (UWB) Synthetic Aperture Radar (SAR) has both complicated imaging geometry and strong range-azimuth coupling, which increases the difficulty of high-precision imaging extremely. In order to solve this problem, this paper proposes an approach based on Fast Factorized Back Projection (FFBP) algorithm to focus the low frequency UWB Bistatic Forward-looking SAR (BFSAR) data. First, based on the imaging geometry of BFSAR, the principle and implementation of Back Projection (BP) algorithm are presented. Then, the phase error in FFBP algorithm is analyzed, and the formula of the phase error in bistatic forward looking SAR is derived. The implementation of FFBP algorithm is presented, and the computational burden of BP algorithm and FFBP algorithm are estimated and compared. Finally, the simulation experiment is progressed, and the results prove the correctness of analysis and the validity of the proposed approach.
冯东,安道祥,谢洪途,黄晓涛. 双站前视低频超宽带SAR的快速因式分解后向投影算法成像处理[J]. 电子与信息学报, 2016, 38(4): 941-949.
FENG Dong, AN Daoxiang, XIE Hongtu, HUANG Xiaotao. Fast Factorized Back Projection Algorithm for Bistatic Forward-looking Low Frequency Ultra Wide Band SAR Imaging. JEIT, 2016, 38(4): 941-949.
XIE Hongtu, AN Daoxiang, HUANG Xiaotao, et al. Fast factorised backprojection algorithm in elliptical polar coordinate for one-stationary bistatic very high frequency ultrahigh frequency ultra wideband synthetic aperture radar with arbitrary motion[J]. IET Radar Sonar & Navigation, 2014, 8(8): 946-956. doi: 10.1049/iet-rsn.2012.0350.
HUANG Lijia, QIU Xiaolan, HU Donghui, et al. A modified wK algorithm for air-borne spotlight bistatic SAR[J]. Journal of Electronics & Information Technology, 2013, 35(9): 2154-2160. doi: 10.3724/SP.J.1146.2012.01111.
[3]
WU Junjie, YANG Jianyu, HUANG Yunlin, et al. Bistatic forward-looking SAR: theory and challenges[C]. IEEE Radar Conference, Pasadena, USA, 2009: 1-4.
[4]
MA Chao, GU Hong, SU Weimin, et al. Focusing bistatic forward-looking synthetic aperture radar based on modified Loffeld’s bistatic formula and chirp scaling algorithm[J]. Journal of Applied Remote Sensing, 2014, 8(1): 083586. doi: 10.1117/1.JRS.8.083586.
AN Daoxiang, HUANG Xiaotao, and ZHOU Zhimin. A three-stage motion compensation method for small size airborne low frequency UWB SAR[J]. Acta Electronica Sinica, 2011, 39(12): 2776-2783.
WANG Guangxue, HUANG Xiaotao, and ZHOU Zhimin. UWB SAR change detection of target in foliage based on local statistic distribution change analysis[J]. Journal of Electronics & Information Technology, 2011, 33(1): 49-54. doi: 10.3724/SP.J.1146.2010.00202.
[8]
王浩丞. 双基前视合成孔径雷达成像算法研究[D]. [硕士论文], 电子科技大学, 2010.
WANG Haocheng. Study on the imaging algorithms for bistatic forward-looking synthetic aperture radar[D]. [Master dissertation], University of Electronic Science and Technology of China, 2010.
[9]
AN Daoxiang, LI Yanghuan, HUANG Xiaotao, et al. Performance evaluation of frequency-domain algorithms for chirped low frequency UWB SAR data processing[J]. IEEE Journal of Selected Topics Applied Earth Observation and Remote Sensing, 2014, 7(2): 678-690. doi: 10.1109/JSTARS. 2013.2265272.
[10]
WU Junjie, LI Zhongyu, HUANG Yulin, et al. Focusing bistatic forward-looking SAR with stationary transmitter based on keystone transform and nonlinear chirp scaling[J]. IEEE Geoscience and Remote Sensing Letters, 2014, 11(1): 148-152. doi: 10.1109/LGRS.2013.2250904.
[11]
ULANDER L M H, HELLSTEN H, and STENSTROM G. Synthetic-aperture radar processing using fast factorized back-projection[J]. IEEE Transactions on Aerospace and Electronic Systems, 2003, 39(3): 760-776. doi: 10.1109/TAES. 2003.1238734.
[12]
VU V T, SJOGREN T K, and PETTERSSON M I. Fast time-domain algorithms for UWB bistatic SAR processing[J]. IEEE Transactions on Aerospace and Electronic Systems, 2013, 49(3): 1982-1994. doi: 10.1109/TAES.2013.6558032.
[13]
ULANDER L M H, FROELIND P O, GUSTAVSSON A, et al. Fast factorized back-projection for bistatic SAR processing[C]. European Conference on Synthetic Aperture Radar, Aachen, Germany: EUSAR, 2010: 1-4.
[14]
VU V T, SJOGREN T K, and PETTERSSON M I. Phase error calculation for time domain bistatic SAR algorithms[J]. IEEE Transactions on Aerospace and Electronic Systems, 2013, 49(1): 631-639. doi: 10.1109/TAES.2013.6404127.
QIU Xiaolan, DING Chibiao, and HU Donghui. Technology of Bistatic SAR Imaging Processing[M]. Beijing: Science Press, 2010: 147-182.
[16]
刘光平. 超宽带合成孔径雷达高效成像算法[D]. [博士论文], 国防科技大学, 2003.
LIU Guangping. Efficient image generation for ultra-wide band synthetic aperture radar[D]. [Ph.D. dissertation], National University of Defense Technology, 2003.