基于相位增量法的合成孔径雷达多普勒中心频率估计

Doppler center frequency estimation of synthetic aperture radar based on phase increment method

合成孔径雷达(SAR)系统中,多普勒中心频率的精度直接影响着成像的质量。针对合成孔径雷达多普勒中心频率估计问题,提出了基于相位增量的估计方法,并在MATLAB仿真软件环境下进行数据仿真。该算法利用合成孔径雷达回波在方位向上线性调频信号的相频曲线的分布特性,运用反正切定律非线性估计回波相位信息,并利用函数拟合的方法对频率中心进行了有效的估计。该算法降低了运算复杂度,对噪声的干扰具有鲁棒性,并且与已有的符号估计算法具有相当的估计性能。该算法的估计结果可以用于补偿载机运动误差引入的相位误差,从而实现高分辨率成像。

In synthetic aperture radar（ SAR） system,the accuracy of Doppler center frequency affects the quality of imaging directly. As to the estimation of Doppler center frequency of synthetic aperture radar,an estimation method based on phase increment is proposed. And the MATLAB software is used for data simulation. In this algorithm,azimuth phase frequency curve of LFM signal of synthetic aperture radar echo is used to estimate the center frequency. The nonlinear estimation of the echo phase information is carried out by using the method of arctangent law,and the frequency center is effectively estimated by the method of function fitting. The algorithm reduces the computational complexity,and the algorithm is robust to noise. And the estimated performance is comparable with that of the existing symbol estimation algorithm. The estimation results can be used to compensate the phase error introduced by the motion error of the carrier,so as to achieve high resolution imaging.