改进的Wavenumber Domain算法在实时处理中的应用和研究

The Research and Application of Modified Wavenumber Domain Algorithm to Real-time Processing

WavenumberDomain算法是一种最优SAR信号处理算法,它广泛被应用于大孔径、高斜视情况下。但它需要在二维频域精确插值,并且不能和运动补偿技术相结合,因此不适合在实时处理中应用。该文提出两种改进方法:一种通过忽略残余距离徙动而提高处理效率,它适合于低精度处理;另一种方法使用FractionalFourier变换精确校正残余距离徙动,它适合高精度处理。这两种方法都不需要插值运算,并且都可以被应用于实时处理中。该文对两种方法的相位误差进行了详细分析。最后给出了理想点目标仿真和真实X波段原始数据处理结果。仿真和实际数据处理结果表明该文所提出的两种方法都可以满足实际工程中处理精度的要求。

Wavenumber Domain Algorithm （WDA）, as a superior SAR signal processing algorithm, is widely applied to the case of wide aperture and high squint angle. However, Interpolation in the 2-dimensional frequency domain is necessary and the motion compensation can not be integrated, so it can not be implemented easily in the real-time processing. In this paper, two modified version of WDA are exploited： one is fit for low-accurate processing, in which the residual Range Cell Migration （RCM） is ignored to improve the processing efficiency; Another is fit the high-accurate processing, in which the FRactional Fourier Transform （FRFT） is employed to correct residual RCM. The two algorithms are free of interpolation and able to be implemented in the real-time processing. In addition, the phase errors of the two algorithms are analyzed particularly. Finally, the results of simulating the point targets and processing the real X-band data are given. The results show that the two algorithms can satisfy the requirements of the real engineering.