Song Yufan, Bi Hui, Cai Fuxuan, Li Guoxu, Zhang Jingjing, Hong Wen
College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China.
Key Laboratory of Radar Imaging and Microwave Photonics, Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China.
Sensors (Basel). 2025 Jun 22;25(13):3888. doi: 10.3390/s25133888.
To satisfy the requirement of the modern spaceborne synthetic aperture radar (SAR) system, SAR imaging mode design makes a trade-off between resolution and swath coverage by controlling radar antenna sweeping. Existing spaceborne SAR systems can perform earth observation missions well in various modes, but they still face challenges in data acquisition, storage, and transmission, especially for high-resolution wide-swath imaging. In the past few years, sparse signal processing technology has been introduced into SAR to try to solve these problems. In addition, sparse SAR imaging shows huge potential to improve system performance, such as offering wider swath coverage and higher recovered image quality. In this paper, the design scheme of spaceborne sparse SAR imaging modes is systematically introduced. In the mode design, we first design the beam positions of the sparse mode based on the corresponding traditional mode. Then, the essential parameters are calculated for system performance analysis based on radar equations. Finally, a sparse SAR imaging method based on mixed-norm regularization is introduced to obtain a high-quality image of the considered scene from the data collected by the designed sparse modes. Compared with the traditional mode, the designed sparse mode only requires us to obtain a wider swath coverage by reducing the pulse repetition rate (PRF), without changing the existing on-board system hardware. At the same time, the reduction in PRF can significantly reduce the system data rate. The problem of the azimuth ambiguity signal ratio (AASR) increasing from antenna beam scanning can be effectively solved by using the mixed-norm regularization-based sparse SAR imaging method.
为满足现代星载合成孔径雷达（SAR）系统的要求，SAR成像模式设计通过控制雷达天线扫描在分辨率和测绘带覆盖范围之间进行权衡。现有的星载SAR系统能够在各种模式下很好地执行对地观测任务，但在数据采集、存储和传输方面仍面临挑战，特别是对于高分辨率宽测绘带成像。在过去几年中，稀疏信号处理技术已被引入SAR以试图解决这些问题。此外，稀疏SAR成像在提高系统性能方面显示出巨大潜力，例如提供更宽的测绘带覆盖范围和更高的恢复图像质量。本文系统地介绍了星载稀疏SAR成像模式的设计方案。在模式设计中，我们首先基于相应的传统模式设计稀疏模式的波束位置。然后，根据雷达方程计算用于系统性能分析的基本参数。最后，引入一种基于混合范数正则化的稀疏SAR成像方法，从设计的稀疏模式采集的数据中获得所考虑场景的高质量图像。与传统模式相比，所设计的稀疏模式只需要我们通过降低脉冲重复频率（PRF）来获得更宽的测绘带覆盖范围，而无需改变现有的机载系统硬件。同时，PRF的降低可以显著降低系统数据速率。通过使用基于混合范数正则化的稀疏SAR成像方法，可以有效解决天线波束扫描导致的方位模糊信号比（AASR）增加的问题。
