针对多子阵合成孔径声呐的非理想运动导致后向投影（Back Projection, BP）成像结果散焦的问题，提出一种结合自聚焦的后向投影成像方法。该方法首先对各脉冲回波数据进行粗栅格BP成像，然后根据图像对比度最优化准则估计出后向投影子图的相位误差，同时计算得到运动误差。最后，对相位补偿及包络搬移后的原始回波数据进行细栅格后向投影自聚焦成像，得到精聚焦图像。仿真结果表明，与传统的BP算法相比，该方法能有效改善运动误差下的多子阵SAS成像效果中显著提高点目标图像的分辨率、峰值旁瓣比及积分旁瓣比指标。
Aimed at the problem of multi-receiver synthetic aperture sonar (SAS) back projection (BP) image defocusing caused by the imperfect motion of the platform, an improved BP imaging method combined with autofocus algorithm is proposed in this paper. Firstly, image with coarser grid for raw data of each receiver is reconstructed by BP algorithm. Secondly, the phase error of each tomographic image is estimated according to the contrast optimization criterion, and the corresponding motion error is calculated. Finally, the range-compressed echo data can be corrected by phase compensation and range profile shifts, subsequent another BP combined with autofocus is applied to get a well-focused fine grid image, which is devoid of the previously observable degradation. The simulation results show that, compared with the conventional BP algorithm, the proposed method can correct the image degradation, and significantly improve the resolution, peak sidelobe ratio and integral sidelobe ratio of the point target image.
2023,45(20): 176-181 收稿日期：2022-9-26
DOI：10.3404/j.issn.1672-7649.2023.20.033
分类号：TB566
作者简介：姚永红(1984-),男,硕士,高级工程师,研究方向为声呐信号处理
参考文献：
[1] 刘纪元. 合成孔径声呐技术研究进展[J]. 中国科学院院刊, 2019, 34(3): 283–288
[2] 刘昊, 刘维, 刘纪元. 合成孔径成像中掩埋目标的深度误差分析[J]. 声学技术, 2015, 34(3): 214–218
[3] 徐江, 唐劲松, 张春华, 等. 多子阵合成孔径声纳逐点成像算法[J]. 信号处理, 2003, 19(2): 157–160
[4] 吕金华, 唐扶光, 赵煦, 等. 一种小斜视多接收阵合成孔径声呐距离多普勒成像算法[J]. 舰船科学技术, 2019, 41(7): 124–129
[5] ZHANG X B, DAI X T, YANG B. Fast imaging algorithm for the multiple receiver synthetic aperture sonars[J]. IET Radar, Sonar & Navigation, 2018, 12(11): 1276–1284
[6] ZHANG X B, YANG B, et al. BP algorithm for the multi-receiver SAS[J]. IET Radar, Sonar & Navigation, 2019, 13(5): 830–838
[7] 许炎义, 钟何平, 唐劲松. 多接收阵合成孔径声呐后向投影成像快速算法[J]. 武汉大学学报, 2015, 40(10): 1409–1413
[8] 张羽, 王朋, 刘纪元, 等. 合成孔径声呐重叠相位中心与惯性导航系统联合估计运动误差算法[J]. 兵工学报, 2021, 42(3): 588–597
[9] 马梦博, 唐劲松, 田振, 等. 基于惯导系统的多子阵SAS运动补偿[J]. 华中科技大学学报, 2020, 48(8): 73–78
[10] 陈家瑞, 张劲东, 班阳阳, 等. 基于对比度最优准则的反投影自聚焦方法[J]. 雷达科学与技术, 2015, 13(1): 21–26
[11] 段江涛, 黄勇, 刘纪元. PGA算法在条带式SAS场景目标成像中的应用[J]. 应用声学, 2017, 36(2): 175–181
