针对逆合成孔径雷达(ISAR)非平稳目标成像,提出基于两特显点相位联合估计成像时间和转速的方法,并得到了转速与相位斜率差(PSD)的解析表达式。首先,基于两个特显点距离单元估计目标转动相位,根据不同时间段转动相位线性度(PLD)选择成像时间。其次,在适合成像的时间段,将成像时间等分成两段,分别提取两段时间内转动相位的斜率。最后,基于两段观测数据PSD估计目标的转速,从而实现目标距离-多普勒(RD)图像的横向定标。仿真和实测数据均验证了本文方法的有效性。
In this paper, a method of joint estimation of imaging time and rotation velocity is proposed for inverse synthetic aperture radar (ISAR) maneuvering targets, and the closed expression form of rotation velocity with phase slope difference (PSD) is derived in detail. First, the target rotation phase is retrieved based on two prominent scatterers, and the suitable imaging times are selected as the intervals with high phase linearity degree (PLD). Second, the rotation phase during the suitable imaging time is divided into two half segments, and the PSD between the two half segments is estimated by their difference. Accordingly, the rotation velocity can be obtained based on the PSD, and the range-Doppler(RD) image cross range scaling can be realized by using the estimated rotation velocity. Finally, the effectiveness of the proposed method is verified by using simulated as well as real data.
[1] 王勇, 许小剑. 海上舰船目标的宽带雷达散射特征信号仿真[J]. 航空学报, 2009, 30(2):337-342. Wang Yong, Xu Xiaojian. On wideband radar signature simulation of ships over sea surface[J]. Acta Aeronautica et Astronautica Sinica, 2009, 30(2): 337-342. (in Chinese)
[2] Munoz-Ferreras J M, Perez-Martinez F. Uniform rotational motion compensation for inverse synthetic aperture radar with non-cooperative targets[J]. IET Radar Sonar Navigation, 2008, 2(1): 25-34.
[3] Gao Z Z, Li Y C, Xing M D, et al. ISAR imaging of manoeuvring targets with the range instantaneous chirp rate technique[J]. IET Radar Sonar Navigation, 2009, 3(5): 449-460.
[4] 汪玲, 朱兆达, 朱岱寅. 机载ISAR舰船侧视和俯视成像时间段选择[J]. 电子与信息学报, 2008, 30(12): 2835-2839. Wang Ling, Zhu Zhaoda, Zhu Daiyin. Interval selections for side-view or top-view imaging of ship targets with airborne ISAR[J]. Journal of Electronics & Information Technology, 2008, 30(12): 2835-2839. (in Chinese)
[5] Pastina D, Spina C. Slope-based frame selection and scaling technique for ship ISAR imaging[J]. IET Signal Processing, 2008, 2(3): 265-276.
[6] Martorella M, Berizzi F. Time windowing for highly focused ISAR image reconstruction[J]. IEEE Transactions on Aerospace and Electronic Systems, 2005, 41(3): 992-1007.
[7] 韩兴斌, 胡卫东, 郁文贤. 基于散射点信号特性的ISAR成像时间选择算法[J]. 信号处理, 2007, 23 (5): 705-709. Han Xingbin, Hu Weidong, Yu Wenxian. An algorithm for selecting ISAR imaging intervals based on the scatter-signal property[J]. Signal Processing, 2007, 23(5): 705-709. (in Chinese)
[8] Martorella M. A novel approach for isar image cross-range scaling[J]. IEEE Transactions on Aerospace and Electronic Systems, 2008, 44 (1): 281-294.
[9] 李玺,顾红,刘国岁. ISAR成像中转角估计的新方法[J]. 电子学报, 2000, 28(6):44-47. Li Xi, Gu Hong, Liu Guosui. A method for estimating the rotation angle of the ISAR image[J]. Acta Electronica Sinica, 2000, 28(6): 44-47. (in Chinese)
[10] Wang Y, Jiang Y C. A novel algorithm for estimating the rotation angle in ISAR imaging[J]. IEEE Geoscience and Remote Sensing Letters, 2008, 5(4): 608-609.
[11] Yeh C M, Xu J, Peng Y N, et al. Cross-range scaling for ISAR based on image rotation correlation[J]. IEEE Geoscience and Remote Sensing Letters, 2009, 6(3): 597-601.
[12] 彭石宝, 许稼, 向家彬, 等. 基于相位线性度的ISAR非平稳目标成像时间选择新算法[J]. 电子与信息学报, 2010,32(12):2637-2640. Peng Shibao, Xu Jia, Xiang Jiabin, et al. A novel ISAR imaging time selection method for maneuvering target based on phase linear degree[J]. Journal of Electronics & Information Technology, 2010,32(12): 2637-2640. (in Chinese)
[13] Djuric P M, Kay S M. Parameter estimation of chirp signals[J]. IEEE Transactions on Acoustics, Speech and Signal Processing, 1990, 38(12): 2118-2162.
[14] Wang Y X, Ling H, Chen V C. ISAR motion compensation via adaptive joint time-frequency technique[J]. IEEE Transactions on Aerospace and Electronic Systems, 1998, 34(2): 670-676.
[15] Li J F, Ling H, Chen V C. An algorithm to detect the presence of 3D target motion from ISAR data[J]. Multidimensional Systems and Signal Processing, 2003, 14(1/2/3): 223-240.
CJA