遥感数据的地理定位精度是影响其定量化应用的重要因素,为了提高FY-3B中分辨率光谱成像仪(MERSI)L1级数据的定位精度,分析了地理定位算法模型中安装矩阵与实际定位偏差之间的关系,通过修正风云三号卫星地面应用系统预处理模块中参数——安装矩阵,提高了地理定位精度。当仪器坐标系分别绕X轴、Y轴和Z轴旋转一个小角度后,遥感图像的定位结果会分别产生左右平移、前后平移和旋转变形。分析并建立旋转角度与变形之间的数量关系,根据海陆掩码与遥感图像的偏差程度估算安装矩阵的误差。修正安装矩阵后,计算出的定位结果准确性得到明显提高,精度达到1个像元左右。通过一段时间的业务系统测试,地理定位结果的质量稳定可靠。

Geolocation accuracy is an important factor for remote sensing applications. In order to improve the geolocation accuracy of FY-3B/MERSI (medium resolution spectrum imager) data, we analyze how the installation matrix impacts the accuracy of the geolocation results. When the instrument coordinate system rotates around the X-axis, Y-axis and Z-axis, the remote sensing images will shift left or right, up or down, and they will rotate. According to the relationship of ground control points and land-sea mask to estimate the error of the installation matrix, the accuracy of the image geolocation results can be about one pixel. The geolocation results from the operate system updated the installation matrix are stable and reliable. The new matrix includes not only the relationship between the installation of the instrument and the satellite platform, but also the systematic bias of the internal device due to vibration, environmental changes and measurement errors of the satellite’s position, velocity, and attitude.