中圖分類號：TN959.3 文獻標志碼：A DOI: 10.16157/j.issn.0258-7998.257050 中文引用格式： 于春輝，徐婧，張士偉，等. 星載SAR信號處理中等效速度的計算[J]. 電子技術應用，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
隨著商業衛星的不斷發展，遙感衛星的品類日趨多元化，其中合成孔徑雷達（Synthetic Aperture Radar, SAR）衛星已逐步發展成為遙感衛星領域的核心研究方向之一[1-4]。作為典型的主動式遙感載荷，星載 SAR 衛星通過星上載荷系統發射微波信號并接收回波信號，從而實現對地觀測功能。依托其獨特的電磁物理特性，星載 SAR 衛星具備在復雜氣象條件及晝夜交替環境下穩定開展對地觀測任務的能力。SAR 遙感影像數據在諸多領域具有重要應用價值，具體涵蓋災害動態監測、農林資源精細化調查、軍事目標偵察以及高精度地形測繪等方面[5-8]。
本文以 SAR 衛星定位模型為理論基礎，結合 Chirp Scaling（CS）成像算法框架，開展不同距離單元等效速度的精確估計研究。通過對比基于最大對比度準則計算的等效速度與本文所提算法的估計結果，對星載 SAR 條帶模式下的點目標數據進行聚焦處理驗證。在此過程中，優化速度估計環節的運算流程、提升算法執行效率，最終構建起以一級速度粗估計為基礎、分數階傅里葉變換精估計為核心優化環節的全流程等效速度估計方案。該方法可使 SAR 信號處理系統更快速、高效且精準地滿足 SAR 成像處理的任務需求。
