由于机载SAR多普勒参数受载机不稳定飞行和复杂地形影响明显,目前仍缺少有效的矢量估计法.本文对POS和DEM 数据及其误差对机载多普勒参数的影响进行了分析,以距离G共面方程构建的SAR几何关系为基础,在POS和DEM 数据支持下,建立了一种多普勒参数矢量估计法,并通过仿真对提出的方法进行了验证和分析.理论和仿真表明,本文方法在高山地形、不稳飞行及大斜视角等复杂条件下,亦能够为机载SAR瞬时多普勒中心提供高精度估计.
It is difficult to estimate the Doppler frequency and modulating rate for ai rborne SAR by using traditional vector method due to instable fl ight and complex terrain.In this paper,it is qual itatively analyzed that the impacts of POS,DEM and thei r errors on ai rborne SAR Doppler parameters.Then an innovative vector method is presented based on the range-coplanarity equation to estimate the Doppler centroid taking the POS and DEM as auxi l iary data.The effectiveness of the proposed method is val idated and analyzed via the simulation experiments.The theoretical analysis and experimental results show that the method can be used to estimate the Doppler centroid with high accuracy even in the cases of high rel ief,instable fl ight,and large squint SAR.