Time series prediction for satellite ballistic coefficients

ABSTRACT: The leading errors in computing future positions of satellites in Low Earth Orbit are generally due to inaccuracies in the thermospheric density and the prediction thereof. The use of Dynamic Calibration Atmosphere has reduced these traditional sources of error and variations seen in ballistic coefficients can now be attributed to unmodeled satellite frontal area changes. When the orbit of a satellite needs to be predicted, a value is assumed. The assumed value of the ballistic coefficient will cause the predicted orbit to be in error. Hence, considerable improvement in the quality of orbit prediction can be achieved by reducing that error. The ballistic coefficient for prediction is usually obtained from the estimated value prior to the prediction. Instead of assuming the previous estimated value, an analysis of the time series of a history of the estimated values may reveal some characteristics which then can be used to minimize prediction error. BENEFIT: The Phase II effort will result in a software toolset that will improve ballistic coefficient modeling resulting in enhanced orbit prediction. This is of particular benefit to the conjunction assessment mission, improving warning and risk mitigation timelines and accuracy. The toolset will be made available to satellite owner/operators, commercial foreign entities and the defense community. Additionally, the toolset may be provided as a plug-in for commercial software applications such as STK and FreeFlyer.