风云3号(FY-3)微波成像仪采用天线绕轴旋转形成圆锥形跨轨的扫描方式。该研究依据这种特殊的扫描几何, 给出了适用于FY-3微波成像仪遥感图像地理定位的方法。根据微波成像仪观测几何、仪器空间位置和指向建立了遥感图像观测像元与地面位置之间关系的模型, 其中包括根据卫星位置计算实时速度的算法模型。将此方法用于FY-3微波成像仪遥感图像地理定位, 将计算结果与实际遥感图像比较以及通过地面控制点定位精度统计分析, 使用该方法的地理定位精度达到像元级。

MWRI (MicroWave Radiation Imager) is one of the payloads on our next generation polar meteorological satellite FY-3. MWRI conically scans with a fixed incident angle on the earth surface. It is the first time for Chinese remote sensor to use this scan mode. In this work, we present a geolocation method for FY-3 MWRI’s remote sensing image based on its special scan geometry. The integrated coordinate systems and the specific relationships with these coordinate systems are defined. A spatial relationship model between the remote sensing data and the earth-based coordinate system is established. This method also includes an algorithm of satellite orbit computation, which is used to get the satellite’s instantaneous velocity vector from its position. This method has been applied to MWRI’s remote sensing image geolocation. The results show that the accuracy of this method can achieve 1 pixel. The 33 GCPs (Ground Control Points) which are in the regiones of FY-3 MWRI’s observation have been collected and used to analyze the precision of the geolocation. By statistical analysis, the error along-track is about 1.5km, and the error along-scan is about 3.0km. It is obvious that this method fulfills the requirement of precision for FY-3 MWRI whose space resolution exceeds 5km.