Abstract: 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.

Key words: precise orbit determination, optical angle measurement, CCD drift scan, GEO satellite, FY-4