基于光学测角数据的风云四号同步轨道卫星精密定轨

针对风云四号同步卫星的精密定轨和精度评估需求，首先利用地面光学测角数据对FY-4A卫星进行精密定轨，定轨后方位角和高度角的残差rms分别为0.25＂和0.45＂。与基于测距数据的轨道相比，位置精度在有测角数据的弧段内小于50m。进一步联合测角数据和测距数据对FY-4A卫星进行联合定轨，定轨后轨道重叠精度优于15m。利用联合定轨结果评估了基于测距数据的实时轨道产品精度，可以明显发现轨道精度随着测距数据的积累而逐步提高。

Precise orbit determination of FY-4 synchronous orbit satellite based on optical angle measurement data

In response to the precise orbit determination and accuracy evaluation requirements of the FY-4 synchronous orbit satellite, the ground optical angle measurement data were firstly used to perform precise orbit determination on the FY-4A satellite. The root mean square of the azimuth and altitude residuals are 0.25″ and 0.45″ respectively. Compared with the orbit determination based only on ranging data, the position accuracy is less than 50m in the arc with angle measurement data. The FY 4A satellite orbit was further jointly determined with combined angle measurement data and ranging data, and the orbit overlap accuracy was improved significantly to be better than 15m. Compared with the results of joint orbit determination, the accuracy of real-time orbit products based on only ranging data was evaluated. It is shown obviously that, with the accumulation of ranging data, the orbit accuracy can be gradually improved, e.g., the precision of orbit determination with ranging data can be gradually stabilized to about 20m in 6h.