中图分类号：TN959.3 文献标志码：A DOI: 10.16157/j.issn.0258-7998.257050 中文引用格式： 于春辉，徐婧，张士伟，等. 星载SAR信号处理中等效速度的计算[J]. 电子技术应用，2026，52(5)：103-109. 英文引用格式： Yu Chunhui，Xu Jing，Zhang Shiwei，et al. Calculation of equivalent velocity in spaceborne SAR signal processing[J]. Application of Electronic Technique，2026，52(5)：103-109.
Calculation of equivalent velocity in spaceborne SAR signal processing
Yu Chunhui，Xu Jing，Zhang Shiwei，Deng Junwu
Chang Guang Satellite Technology Co.， Ltd.
Abstract： To improve the imaging quality of spaceborne SAR, this study focuses on addressing the velocity spatial variation characteristics among different range cells during imaging processing. It investigates high-precision equivalent velocity calculation methods to achieve accurate focusing of targets in each range cell and optimizes the equivalent velocity calculation workflow. Firstly, based on the range equation, Doppler equation, and Earth ellipsoid model equation of spaceborne SAR, geometric positioning of targets at different range gate sampling positions at the imaging center time is performed. The traditional hyperbolic model is adopted to calculate the slant range history of targets positioned by different range gates, and a first-level rough estimation of equivalent velocity is completed according to imaging time and slant range variations. Subsequently, secondary estimation research is conducted on two types of equivalent velocity estimation strategies: one based on image statistical features (maximum contrast method) and the other on echo signal features (fractional Fourier transform method). After completing the accurate estimation of equivalent velocity, the coupling relationship between processing efficiency and estimation accuracy in different calculation methods is optimized, and a full-process framework integrating secondary rough estimation and precise estimation of equivalent velocity is finally constructed and completed. Finally, by comparing the processing results of point target echo simulation data in strip modes generated based on spaceborne imaging parameters, quantitative analysis is carried out focusing on key indicators such as point target resolution, integrated sidelobe ratio, peak sidelobe ratio, and algorithm time consumption, thereby completin
随着商业卫星的不断发展，遥感卫星的品类日趋多元化，其中合成孔径雷达（Synthetic Aperture Radar, SAR）卫星已逐步发展成为遥感卫星领域的核心研究方向之一[1-4]。作为典型的主动式遥感载荷，星载 SAR 卫星通过星上载荷系统发射微波信号并接收回波信号，从而实现对地观测功能。依托其独特的电磁物理特性，星载 SAR 卫星具备在复杂气象条件及昼夜交替环境下稳定开展对地观测任务的能力。SAR 遥感影像数据在诸多领域具有重要应用价值，具体涵盖灾害动态监测、农林资源精细化调查、军事目标侦察以及高精度地形测绘等方面[5-8]。
本文以 SAR 卫星定位模型为理论基础，结合 Chirp Scaling（CS）成像算法框架，开展不同距离单元等效速度的精确估计研究。通过对比基于最大对比度准则计算的等效速度与本文所提算法的估计结果，对星载 SAR 条带模式下的点目标数据进行聚焦处理验证。在此过程中，优化速度估计环节的运算流程、提升算法执行效率，最终构建起以一级速度粗估计为基础、分数阶傅里叶变换精估计为核心优化环节的全流程等效速度估计方案。该方法可使 SAR 信号处理系统更快速、高效且精准地满足 SAR 成像处理的任务需求。
