基于方位波数域聚束模式PFA的运动补偿新方法研究

该文在对聚束模式SAR数据进行极坐标算法(PFA)形式成像的过程中,通过研究载机运动误差对散射点方位向波数表达式的影响,给出了一种基于方位波数域进行运动误差估计及相关补偿的新方法。该方法首先应用距离匹配滤波和方位dechirp实现对原始数据的2维调频率去斜处理,同时经过距离FFT和极坐标算法的操作将原来极坐标下的数据重采样到直角坐标系下的2维波数域,最后对数据进行距离和方位的分块误差估计及补偿。这种方法能很好地针对运动误差造成的方位二次及高次误差相位项进行精确补偿,同时也能处理误差相位的空变性问题,因此可以获得相对传统时域补偿方法更好的图像聚焦效果。实测数据的处理和分析,验证了该文所述方法的有效性,证明了与传统时域运动补偿方法相比的优越性。

Study on Azimuth Wavenumber Domain Spotlight Mode Motion Compensation Based on PFA

In this paper, the motion compensation of spotlight mode SAR data processing is studied with Polar Format Algorithm (PFA). A new approach for motion error estimation and compensation in azimuth wavenumber domain is proposed. The framework applies range matched filtering and azimuth dechirp processing to obtain the two dimensional wavenumber data support. First, range compression via fast Fourier transform and PFA interpolation to transform the polar coordinate support to rectangular one is performed. Then the error phase is estimated and compensated in sub-apertures respectively. This framework can both compensate the second or high order motion error accurately, and solve the spatial-variant errors. Compared with the traditional time domain motion compensation, the proposal can achieve better performance for focusing synthetic aperture radar imagery. Experiment?with real data is done to verify the effectiveness and advantage of the proposal.