We proposed a novel high precision spaceborne InSAR baseline estimation approach based on interferometric fringe frequency which makes the improvements from two aspects:the baseline calculation formula and the fringe frequency estimation precision. The accurate mathematic relationship between the baseline parameters and the interferometric fringe frequency was deduced considering the earth curvature. Also the Semi-Newton iterative method was introduced to estimate the fringe frequency of each pixel in the complex interferogram. Furthermore, the frequency evaluation was processed by the linear fitting to suppress the noise and the high precision fringe frequency was obtained. With the accurate frequency and the deduced baseline calculation formula, the baseline estimation precision was improved to centimeter.Finally,the computer simulation was employed to confirm the new baseline estimation approach.%现有基于干涉复图像的基线估计方法采用平地假设并利用傅里叶变换估计条纹频率,应用于星载InSAR时基线估计误差很大.本文针对星载InSAR,从基线计算公式和条纹频率估计两个方面对现有基于干涉复图像的基线估计方法进行改进,提出了一种基于干涉条纹频率的高精度星载InSAR基线估计新方法.在考虑地球曲率的情况下,推导了星载InSAR中基线与干涉条纹频率之间的精确关系式.通过引入半牛顿迭代法,精确估计每一像素点处的干涉条纹频率;对所估计的频率值进行线性拟合,进一步抑制噪声对条纹频率估计精度的影响,获得高精度的干涉条纹频率值,用于基线计算.最后,利用星载InSAR仿真数据进行基线估计,所得到的估计精度达到了厘米量级,结果验证了所提方法的有效性.
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