Fast algorithm for prediction of satellite passes and image opportunity

On the basis of mean orbit concept, a fast algorithm for the prediction of LEO satellite passes and image opportunity is presented. Regarding the mean orbit parameters from two line element (TLE) initial value as initial information, coarse searching is performed by comparing geocentric angle from target to subastral point with observable arc. The time of satellite passes is provided. The time prediction of satellite passes over earth stations at different latitude. It is indicated that prediction precision is up to second level at low latitude and gradually worsens with increasing latitude. The method establishes precondition for next exact search based on SGP4. and greatly reduces the onboard computational amount.