When range-Doppler algorithm is used in bistatic Inverse Synthetic Aperture Rador (ISAR), migration through resolution cell may occur in bistatic ISAR, affecting the imaging quality. To suppress migration through resolution cell, it is necessary to estimate the equivalent rotation center of the target. Aiming at the problem in the rotation center estimation of the bistatic inverse synthetic aperture radar in the presence of time-varying bistatic angles, a rotation center estimation algorithm is proposed in this paper. Firstly, one-dimensional range image sequences after motion compensation are divided into two groups, obtaining two images separately. Secondly, assuming that a range cell is the equivalent rotation center, we correct the distortion of the two images so that only one angle difference of view exists between the two images. Based on the difference of viewing angle, we rotate one of the images and correlate it with the other image, obtaining the correlation coefficient. Then, assuming the next range cell is the position of the rotation center, we repeat the above steps until the end of the traversal, and the assumed position corresponding to the maximum correlation coefficient is the estimated equivalent rotation center. Finally, the simulations are carried out and the results show that the method in this paper can effectively estimate the rotation center of the bistatic ISAR in the presence of time-varying bistatic angles.
[1] 杨振起, 张永顺, 骆永军. 双(多)基地雷达系统[M]. 北京:国防工业出版社, 1998:14-15. YANG Z Q, ZHANG Y S, LUO Y J. Bistatic (multi-static) radar system[M]. Beijing:Defense Industry Press, 1998:14-15(in Chinese).
[2] MARTORELLA M, PALMER J, HOMER J, et al. On bistatic inverse synthetic aperture radar[J]. IEEE Transactions on Aerospace and Electronic Systems, 2007, 43(3):1125-1134.
[3] FABRICE C, ALI K, ALEXANDRE B, et al. Bistatic synthetic aperture radar imaging:Theory, simulation, and validation[J]. IEEE Transactions on Antennas and Propagation, 2006, 54(11):3529-3540.
[4] GUO B F, WANG J L, GAO M G, et al. Research on spatial-variant property of bistatic ISAR imaging plane of space target[J]. Chinese Physics B, 2015, 24(4):507-520.
[5] MA C Z, TAT S Y, GUO Q, et al. Bistatis ISAR imaging incorporating interferometric 3-D imaging technique[J]. IEEE Transactions on Geoscience and Remote Sensing, 2012, 50(10):3859-3867.
[6] BAI X R, ZHOU F, XING M D, et al. Scaling the 3-D image of spinning space debris via bistatic inverse synthetic aperture radar[J]. Transactions on Geoscience and Remote Sensing Letters, 2010, 7(3):430-434.
[7] 朱晓秀, 胡文华, 马俊涛, 等.双基地角时变下的ISAR稀疏孔径自聚焦成像[J]. 航空学报, 2018, 39(8):322059. ZHU X X, HU W H, MA J T, et al. Bistatic ISAR autofocusing imaging with time-varying bistatic angle and sparse apertures[J]. Acta Aeronautica et Astronautica Sinica, 2018, 39(8):322059.
[8] KANG B S, BAE J H, KANG M S, et al. Bistatic ISAR cross-range scaling[J]. IEEE Transactions on Aerospace & Electronic Systems, 2017, 53(4):1962-1973.
[9] KANG B S, RYU B H, KIM K T. A Study on rotational motion compensation method for bistatic ISAR imaging[J]. Journal of Korean Institute of Electromagnetic Engineering & Science, 2017, 28(8):670-677.
[10] ZHAO L Z, MARTORELLA M, DANIELE S, et al. Bistatic three-dimensional interferometric ISAR image reconstruction[J]. IEEE Transactions on Aerospace Electronics and Systems, 2015, 51(2):951-961.
[11] PAN X Y, WANG W, FENG D J, et al. On deception jamming for countering bistatic ISAR based on sub-Nyquist sampling[J]. IET Radar, Sonar and Navigation, 2014, 8(3):173-179.
[12] 黄峣, 尹春雷, 程潇. 合成孔径雷达成像RD算法仿真实验[J]. 四川兵工学报, 2014(5):109-111. HUANG Y, YIN C L, CHENG X. Simulation experimental study of synthetic aperture radar imaging based on RD[J]. Journal of Sichuan Ordnance, 2014(5):109-111(in Chinese).
[13] 保铮, 邢孟道, 王彤. 雷达成像技术[M]. 北京:电子工业出版社, 2010:24-30, 243-249. BAO Z, XING M D, WANG T. Radar imaging technology[M]. Beijing:Publishing House of Electronics Industry, 2010:24-30, 243-249(in Chinese).
[14] JIANG Z L, XING M D, BAO Z. Correction of migration through resolution cell in ISAR imaging[C]//2001 CIE International Conference on Radar Proceedings, 2001:933-937.
[15] 朱仁飞, 朱小鹏, 张群. 基于调频连续波信号的双基地ISAR成像研究[J]. 宇航学报, 2012, 33(2):222-227. ZHU R F, ZHU X P, ZHANG Q. Imaging study on bi-static ISAR based on frequency modulation continuous wave[J]. Journal of Astronautics, 2012, 33(2):222-227(in Chinese).
[16] 叶春茂, 许稼, 左渝, 等. 逆合成孔径雷达目标等效旋转中心估计[J]. 清华大学学报(自然科学版), 2009, 49(8):1205-1208. YE C M, XU J, ZUO Y, et al. Rotating center estimation for inverse synthetic aperture radar imaging[J]. Journal of Tsinghua University (Science and Technology), 2009, 49(8):1205-1208(in Chinese).
[17] 叶春茂, 许稼, 彭应宁, 等. 多视观测下雷达转台目标成像的关键参数估计[J]. 中国科学(信息科学), 2010, 40(11):1496-1507. YE C M, XU J, PENG Y N, et al. Key parameter estimation for radar turntable target imaging under multiple sight[J]. Science China (Information Science), 2010, 40(11):1496-1507(in Chinese).
[18] 董健, 尚朝轩, 高梅国, 等. 双基地ISAR成像平面研究及回波模型修正[J]. 电子与信息学报, 2010, 32(8):1855-1862. DONG J, SHANG C X, GAO M G, et al. The image plane analysis and echo model amendment of bistatic ISAR[J]. Journal of Electronics & Information Technology, 2010, 32(8):1855-1862(in Chinese).
[19] 郭宝锋, 尚朝轩, 王昕, 等. 空间目标双基地ISAR越多普勒单元徙动校正算法[J]. 通信学报, 2014, 9(9):197-206. GUO B F, SHANG C X, WANG X, et al. Correction algorithm of migration through Doppler cells for space target in bistatic ISAR[J]. Journal on Communications, 2014, 9(9):197-206(in Chinese).
[20] 郭宝锋, 尚朝轩, 王俊岭, 等. 双基地角时变下的逆合成孔径雷达越分辨单元徙动校正算法[J]. 物理学报, 2014, 63(23):238406. GUO B F, SHANG C X, WANG J L, et al. Correction of migration through resolution cell in bistatic inverse synthetic aperture radar in the presence of time-varying bistatic angle[J]. Acta Physics Sina, 2014, 63(23):238406(in Chinese).
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