解多普勒中心模糊的一种新方法

在合成孔径雷达(SAR)成像的斜视模式下，多普勒中心频率估计往往会出现重频(PRF)模糊。本文提出的能量重心法可以有效地解决多普勒中心模糊问题。这种算法主要利用距离一多普勒城的距离徙动与多普勒中心的惟一对应关系来确定PRF模糊数。Chirp Scaling算法也是从方位傅里叶变换开始的，所以能量重心法可以与它有机地结合起来，从而大大减少运算量。能量重心法同样适用于经过Dechirp压缩处理后的数据，但此时波长差异法不再适用，因为线性调频信号经过Dechirp脉压后将变成单频脉冲信号。此外，能量重心法对大斜视角情况也是有效的。

A New Method for Resolving the Doppler Centroid Ambiguity

In squint mode of SAR imaging,doppler centroid estimation always suffers from the PRF ambiguity.A new method for resolving the doppler centroid ambiguity,that is energy center method,is proposed in this paper.Based on the unique relationship between the range migration in the range doppler domain and the doppler centroid,the PRF ambiguity number can be determined. Since the Chirp Scaling algorithm also begins with the azimuth FFT, the energy center method can be integrated with it, which will greatly reduce the amount of operation. In addition,the energy center method can be applied to the data compressed by Dechirp. The wavelength diversity method will be invalid for this case because of the fact that LFM signal will be transferred into single frequency pulse signal after Dechirp compression. Further more,the energy center method is also effective for large squint angle case.