NOAA AVHRR数据的高精度导航定位

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。

High Precision Navigation of NOAA AVHRR Data

Based on the quantitative analysis ofthe major errorsources for NOAAAVHRRdata ,this paper presents a new navigation method .In this method ,correction oftime driftonboard and adjustmentofthe ephemeris datais carried out atthe criteria ofconstraint Least Mean Square Error;andthe spacecraftattitude deviationsis also estimated and cor rected .This navigation methodiscomprehensively considered with othercriticalelementsoflocation ,such asorbitcalcu lation ofsatellite,determination ofthe positioninformation ofeach pixel,and preciseimageregistration betweenreference image andslaveimage.By using high resolution 1 :1 ,000 ,000 digital map dataand LANDSATTMdatatoidentify GCPs (Ground Control Points) ,the geolocation accuracy ofselected GCPs can be improved . With these accurate GCPs,the geolocation accuracy of navigation for NOAAAVHRRdata can be improved to 1km in the whole image,and lessthan 1km at nadir.