基于干涉Cartwheel编队构形的系统参数定标

System parameter calibration based on interferometric Cartwheel configuration

干涉Cartwheel是实现星载合成孔径雷达干涉测量(InSAR)的一种编队卫星构形。它能利用相对稳定的星间基线进行干涉测高,并通过系统参数定标获得高精度的地面数字高程模型(DEM)。首先利用干涉Cart-wheel的几何构形,建立了多基线干涉平台待定标参数之间的关系。然后在精确的星间测距基础上,将待定标参数关系引入到各干涉平台定标方程中,提出了多干涉平台联合定标算法。该算法利用干涉Cartwheel构形的冗余信息,不仅能一次联合修正多个干涉平台的系统参数,而且降低了地面定标控制点的实现要求。仿真表明该算法能给出较好的参数定标结果,并重建出精确的地形高程。

Interferometric Cartwheel is an important satellite configuration for spaceborne InSAR system. The baselines between multi-satellites can be used for interferometric height measurement, and then high-precision DEM can be generated through parameter calibration. In this paper, the parameter relations between dif- ferent interferometric platforms are firstly given from the geometric configuration of Cartwheel. Then, based on accurate inter-satellite distance measurement, the relations of system parameters are introduced to the calibration equations of all interferometric platforms, and the united multi-platform calibration algorithm is proposed. Using the redundant information of Cartwheel configuration, this algorithm can not only fix all system parameters within one scaling procedure, but also reduce the realization requirements of ground control points. The simulation results indicate that this algorithm can provide better parameter calibration with accurate topographic elevation.