Abstract：A new combination method based on the frequency spectrum analysis and the grey model is proposed to forecast the ionosphere TEC. First, the grey model is established based on the residuals calculated by the frequency spectrum analysis and then to calculate the next epochs’ residuals and add them to the forecast results from the frequency spectrum analysis. The results indicate that the forecast accuracy is about 0.53 TECU and the RMS error of forecast values is about 0.65 TECU. Forecast accuracy is related to longitude and latitude rather than the length of the used historical data. Compared with existing methods, this method is of higher accuracy with fewer data and has simplicity for promising application in ionosphere TEC short-term forecast.
