在使用FFT距離多普勒算法進行ISAR成像處理時，回波相關性的減弱將加大運動補償難度，帶來較大的誤差。該文在常規相鄰相關法基礎上，提出了一種改進的運動補償方法。在距離向上，利用基準回波相關法與曲線擬合，克服了低回波相關性下包絡對齊時出現的包絡漂移、包絡跳變等缺陷；在方位向上，利用DCFT變換，對目標的運動參數進行精確估計并加以補償，減小了回波相關性降低對相位補償的影響。仿真驗證了該方法的有效性。
關 鍵 詞 離散調頻傅里葉變換; 包絡漂移; 包絡跳變; 二次曲線擬合

Abstract When the range-Doppler algorithm is used in inverse synthetic aperture radar (ISAR) imaging, the reduction of echo correlation will add more difficulties on motion compensation and bring more error. Accordingly, based on the adjacent-correlate compensate method used in FFT range-Doppler algorithm, an improved compensation method is presented in this paper. The traditional compensation method is modified to avoid the envelope drift and envelope jump in range align. In phase compensation, a new algorithm based on accurate target parameter estimation by use of discrete chirp-Fourier transform (DCFT) transform is presented. Finally the improve method is verified by simulation.
Key words discrete chirp-Fourier transform; envelope drift; envelope jump; 2 order polynomial fitting