Passive GNSS-based SAR imaging with sub-apertures combination
Passive GNSS-based SAR imaging with sub-apertures combination
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DOI：
10.1007/s11760-022-02432-8
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发表时间：
2022-12-21
影响因子：
2.3
通讯作者：
Wu，Peng
中科院分区：
文献类型：
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作者：
Zheng，Yu;Zhang，Zhuxian;Wu，Peng
基于全球导航卫星系统(GNSS)的无源合成孔径雷达(简称GNSS-SAR)是近十年来发展起来的一种新型雷达传感工具。然而，如果系统在大视角下表现为非线性弹道，将对方位分辨率产生不利影响。针对这一问题，本文提出了一种基于子孔径组合的GNSS-SAR成像新方法。在该方法中，全长孔径根据轨迹长度、期望方位分辨率和每个点散射上的停留时间被划分为多个子孔径。然后，在每个子孔径内，基于第一作者的工作中的算法进行成像以提高信噪比(郑等人。见SIViP 13(8)：1549-1557,2019年)。最后，对子孔径内的成像结果进行连续组合，得到完整的GNSS-SAR图像。以北斗B3I为机会信号，通过仿真和野外实验对所提出的方法进行了验证。结果表明，对于多场景条件下的非直线弹道，该方法可以提供较高的方位分辨率。
The passive global navigation satellite system (GNSS)-based synthetic aperture radar (SAR), known as GNSS-SAR, is a newly developing radar sensing tool in recent decade. However, if the system is characterized by a nonlinear trajectory under wide viewing angles, the azimuth resolution will be negatively affected. To address the issue, this paper proposes a new GNSS-SAR imaging method based on sub-apertures combination. In the proposed method, the full-length aperture is partitioned into several sub-apertures according to the trajectory length, the expected azimuth resolution, and the dwell time on each point scatter. Then within each sub-aperture, to enhance signal-to-noise ratio, imaging is performed based on the algorithm in the first author’s work (Zheng et al. in SIViP 13(8):1549–1557, 2019). Finally, the imaging results in the sub-apertures are consecutively combined to obtain the full GNSS-SAR image. The proposed method was examined via simulation and a field experiment using BeiDou B3I as the signal of opportunity. The results revealed that the proposed method can provide a higher azimuth resolution for non-straight trajectory under multi-scene conditions.