强地杂波背景给微动目标检测带来很大困难,为此在详细分析距离向压缩数据域自旋目标回波特性基础上,提出了基于双通道合成孔径雷达相位中心偏置天线(SAR/DPCA)和沿航迹干涉(ATI)杂波抑制的两类自旋目标检测方法,并作比较分析。在DPCA模式下,微多普勒频率沿频率(m-D)轴有一整体平移量,其与目标自旋中心的方位向坐标成正比,由此可在估计目标微动参数的同时对其定位;在ATI模式下,不能直接由干涉信号虚部作时频变换来获取微多普勒特征,为此提出了一种基于干涉信号虚部重建自旋目标复信号的微多普勒提取方法。从避免微多普勒模糊的角度,指出在较小基线长度的情况下,ATI模式较DPCA模式对雷达脉冲重复频率(PRF)的要求更宽松,更适宜于大旋翼类目标检测。不同模式下的仿真数据验证了理论分析和所述方法的正确性。
It is very difficult to detect micro-motion targets against a strong ground clutter background. In order to solve this problem, this paper proposes respectively the methods of dual-channel synthetic aperture radar/displaced phase center antenna (SAR/DPCA) and along-track interferometry (ATI) based on a detailed study of the echo features of rotating targets in the range-compressed data domain. Under the mode of SAR/DPCA, the entire micro-Doppler (m-D) signature undergoes a shift along the frequency axis which is proportional to the azimuth position of the revolving center. Therefore, the target can be located while the micro-motion parameters are estimated. Under the mode of SAR/ATI, the m-D signature cannot be directly obtained from the imaginary part of the interferometric signal by time-frequency transform, so a method is proposed of reconstructing the complex signal of a rotating target based on the imaginary part. In order to avoid m-D ambiguity, the paper points out that when the length of baseline is comparatively short, the method of SAR/ATI is more suitable for detecting targets with big rotating blades than the method of SAR/DPCA, because it requires lower pulse repetition frequency (PRF), The results of simulation tests for these modes testify the validity of the theoretical analysis and the proposed methods.
[1] Gabele M, Brautigam B, Schulze D, et al. Fore and aft channel reconstruction in the TerraSAR-X dual receive antenna mode[J]. IEEE Transactions on Geoscience and Remote Sensing, 2010, 48(2): 795-806.
[2] 钱江, 吕孝雷, 刑孟道, 等. 机载三通道SAR/GMTI快速目标运动参数估计[J]. 西安电子科技大学学报, 2010, 37(2): 235-241. Qian Jiang, Lü Xiaolei, Xing Mengdao, et al. Parameter estimation of the fast moving target based on tri-channel airborne SAR-GMTI[J]. Journal of Xidian University, 2010, 37(2): 235-241. (in Chinese)
[3] Chen V C, Li F, Ho S -S, et al. Micro-Doppler effect in radar: phenomenon, model, and simulation study[J]. IEEE Transactions on Aerospace and Electronic Systems, 2006, 42(1): 2-21.
[4] 庄钊文, 刘永祥, 黎湘. 目标微动特性研究进展[J]. 电子学报, 2007, 35(3): 520-525. Zhuang Zhaowen, Liu Yongxiang, Li Xiang. The achievements of target characteristic with micro-motion[J]. Acta Electronica Sinica, 2007, 35(3): 520-525. (in Chinese)
[5] Zhang Q, Yeo T S, Tan H S, et al. Imaging of a moving target with rotating parts based on the Hough transform[J]. IEEE Transactions on Geoscience and Remote Sensing, 2008, 46(1): 291-299.
[6] 白雪茹, 周峰, 邢孟道, 等. 空中微动旋转目标的二维ISAR成像算法[J]. 电子学报, 2009, 37(9): 1937-1943. Bai Xueru, Zhou Feng, Xing Mengdao, et al. 2D ISAR imaging algorithm for air micro-motion targets[J]. Acta Electronica Sinica, 2009, 37(9): 1937-1943. (in Chinese)
[7] 黄小红, 贺夏, 辛玉林, 等. 基于时频特征的低分辨雷达微动多目标分辨方法[J]. 电子与信息学报, 2010, 32(10): 2342-2347. Huang Xiaohong, He Xia, Xin Yulin, et al. Resolving multiple targets with micro-motions based on time-frequency feature with low-resolution radar[J]. Journal of Electronics & Information Technology, 2010, 32(10): 2342-2347. (in Chinese)
[8] 刘进, 王雪松, 马梁, 等. 空间进动目标动态散射特性的实验研究[J]. 航空学报, 2010, 31(5): 1014-1023. Liu Jin, Wang Xuesong, Ma Liang, et al. Experimental study on dynamic scattering properties of space precession target[J]. Acta Aeronautica et Astronautica Sinica, 2010, 31(5): 1014-1023. (in Chinese)
[9] Sparr T, Krane B. Micro-Doppler analysis of vibrating targets in SAR[J]. IEE Proceeding Radar Sonar Navigation, 2003, 150(4): 277-283.
[10] Rüegg M, Meier E, Nuesch D. Vibration and rotation in millimeter-wave SAR[J]. IEEE Transactions on Geoscience and Remote Sensing, 2007, 45(2): 293-304.
[11] 吴晓芳, 刘阳, 王雪松, 等. 旋转微动目标的SAR成像特性分析[J]. 宇航学报, 2010, 31(4): 1181-1189. Wu Xiaofang, Liu Yang, Wang Xuesong, et al. Analysis of SAR imaging characteristics of targets with rotational micro-motion[J]. Journal of Astronautics, 2010, 31(4): 1181-1189. (in Chinese)
[12] Muehe C E, Labitt M. Displaced-phase-center antenna technique[J]. Lincoln Laboratory Journal, 2000, 12(2): 281-296.
[13] Suchandt S, Runge H, Breit H, et al. Automatic extraction of traffic flows using TerraSAR-X along-track interferometry[J]. IEEE Transactions on Geoscience and Remote Sensing, 2010, 48(2): 807-819.
[14] 郑明洁, 杨汝良. 双通道沿迹干涉SAR地面动目标检测[J]. 电子与信息学报, 2005, 27(10): 1561-1563. Zheng Mingjie, Yang Ruliang. Dual channels along-track interferometry SAR ground moving target detection[J]. Journal of Electronics & Information Technology, 2005, 27(10): 1561-1563. (in Chinese)
[15] 高红卫, 谢良贵, 文树梁, 等. 摆动锥体目标微多普勒分析和提取[J]. 电子学报, 2008, 36(12): 2497-2502. Gao Hongwei, Xie Lianggui, Wen Shuliang, et al. Analysis and extraction of micro-Doppler induced by cone-shaped target's wobbling[J]. Acta Electronica Sinica, 2008, 36(12): 2497-2502. (in Chinese)
[16] 彭海良, 王彦平. 地形测绘用三天线机载干涉合成孔径雷达[J]. 现代雷达, 2006, 28(10): 70-74. Peng Hailiang, Wang Yanping. A tri-antenna airborne interferometric synthetic aperture radar for topographic mapping[J]. Modern Radar, 2006, 28(10): 70-74. (in Chinese)
CJA