Abstract: Based on the characteristics of De-chirp LFM-CW SAR signals，the signal model is analyzed firstly.Then a fast raw data simulation algorithm based on FFT is presented according to the given signal model，with the same data precision，the computation burden is reduced significantly compared to the time domain direct adding algorithm.The algorithm is proved valid by the analysis of the compressed image of raw data simulated.

摘要： 将基于De-chirp LFM-CW SAR的信号特点，首先给出其信号模型；根据给定的信号模型，提出一种适合De-chirp LFM-CW SAR的基于FFT的快速回波模拟算法，与时域直接叠加算法相比，保持数据精度的同时，运算量大大降低。通过对原始数据成像处理后得到的图像进行分析，验证了算法的有效性。