AVHRR 1B定位数据经验插值模型的误差分析

Precision Evaluation of Empiricism Interpolation Model for AVHRR 1B Locating Data

确定像元地理坐标是几何纠正及卫星数据应用的基础。经验插值方法常用于计算高分辨率辐射计AVHRR1B定位数据,研究插值模型的定位误差具有重要意义。该文分析了AVHRR像元空间位置和像元大小,利用AVHRR扫描线的圆心角θ表示像元的位置,建立了像元位置θ和像元大小Δθ的表达模型;根据分段线性插值模型,计算插值后的像元位置θafter和像元大小Δθafter,获得分段线性插值模型的像元位置和大小的误差模型。

For NOAA/AVHRR Level 1B data, because there is not enough location data for each pixel, empiricism interpolation model is usually exploited to acquire coordinates of pixels. Obviously, it is important to know the error of the model. This paper analyses the pixel location and pixel size of AVHRR data along the scan line,and use angle θ and angle △θ to represent pixel location and pixel size respectively. Then, θ and △θ are separately modeled. According to the empirical method of linear interpolation for subsection, plxel location after interpolation θafter and pixel size after interpolation △θafter are calculated respectively. And then, the error condition analysis is implemented from two sides, change of pixel location and change of pixel size. The result equations are given for change of plxel size and change of plxel location along the scan line.