在NOAAAVHRR数据的导航定位中,一般只进行卫星轨道根数调整和卫星时间漂移校正,而未考虑卫星姿态系统偏差的影响。该文在定量分析影响导航定位精度的主要因素基础上,提出了一种新的导航算法。该导航算法不仅对卫星时间漂移、卫星轨道根数进行约束最优调整,而且通过估算卫星姿态偏差将其融入到导航定位中加以校正。同时,将导航算法和卫星轨道计算、地面扫描点地理经纬度的计算方法以及参考图像的高精度配准等结合起来考虑,利用具有足够定位精度的1∶100 万数字地图数据和高分辨率Landsat TM图像,提取地面控制点,使AVHRR数据导航定位精度在整条轨道大范围内提高到1 个像元,在星下点附近小于1 个像元。

Based on the quantitative analysis of the major errorsources for NOAA AVHRR data, this paper presents a new navigation method.In this method, correction of time-drift onboard and adjustment of the ephemeris datais carried out atthe criteria of constraint Least Mean Square Error; and the spacecraft attitude deviationsis also estimated and cor rected.This navigation method is comprehensively considered with other critical elements of location, such as orbit calculation ofsatellite, determination of the position information of each pixel, and precise image registration between reference image and slaveimage.By using high resolution 1:1,000,000 digital map dataand LANDSAT TM data toidentify GCPs (Ground Control Points), the geolocation accuracy ofselected GCPs can be improved. With these accurate GCPs, the geolocation accuracy of navigation for NOAA AVHRR data can be improved to 1km in the whole image, and lessthan 1km at nadir.