摘要
星载合成孔径雷达(Synthetic Aperture Radar,简称SAR)距离-多普勒定位算法(R-D算法)模型基于严格的成像几何构建,不需在视场中设置任何位置确知的特征点。但对具有一定高程的目标,以往的研究将目标高程直接加在平均赤道半径上对地球模型进行修正。由于地球体的椭球特征,这种修正并不能完全消除高程对定位误差的影响,会产生随纬度和目标高程变化的定位误差。本文介绍R-D定位算法的原理,推导将目标大地高归算至地球赤道半径的公式,给出地球模型合理的修正公式。最后根据实例和仿真分析,表明在低纬度的定位研究中,以往的修正方式仍然可以达到很高的精度;而在高纬度和高海拔地区,则会产生较大的定位误差,应使用更为合理的地球模型。
The Range-Doppler location algorithm of SAR is used wildly in geometric rectification, point location and imaging simulation. Its merit is to do location without the known points. However its precision is influenced by the height of target, so the earth model in this algorithm should be corrected, In previous research, the earth was regarded as sphere, and the height of point was added to the equator directly. But this correction can＇t remove the effect of height completely and will cause error. In this paper, the formula of reducing the geodetic height of point to the equator is derived and the more reasonable model is introduced. Finally, from example and the simulation of ENVISAT imaging, the error of using the previous correction in different latitude and height area was analyzed. The result indicates that the error will be remarkable and the correct correction method should be used.
出处
《测绘学报》
EI
CSCD
北大核心
2008年第1期59-63,共5页
Acta Geodaetica et Cartographica Sinica
基金
地质调查局项目(1212010560705)
关键词
合成孔径雷达
距离-多普勒定位算法
地球椭球体
大地高
synthetic aperture radar
Range-Doppler location algorithm
earth ellipsoid
geodetic height
