Calibration Method of the IGSO Satellites Ascending Node Longitude

As the ascending node longitude of IGSO satellites should be maintained in a relatively large range with long control period and high precision, it is necessary to predict the long-term variation of the ascending node longitude accurately in order to obtain the accurate ascending node longitude and drift rate. A calibration model is established by using several orbit measurement results, the drift rate and drift acceleration of the ascending node longitude is calibrated by using the least squares method, and the ascending node longitude of long-term forecast is calculated according to the calibration results. The practical results show that the forecasting accuracy of the method is quite similar with that of orbit prediction. This method can accurately calculate the drift rate of the satellites ascending node longitude and avoid the orbit prediction error due to the effect of measurement data.