PRECISION LOW EARTH ORBIT DETERMINATION USING ATMOSPHERIC DENSITY CALIBRATION

Atmospheric drag is the largest uncertainty in determining orbits of low altitude satellites. Deficiencies in operational satellite drag models persist due to empirical model limitations as well as inadequacies of proxy indices used as model drivers. Satellite drag errors result in degraded accuracy, requirements for frequent updates and inadequate predictions of true positions for accurate catalog maintenance, collision avoidance and re-entry operations. Time-dependent global corrections to operational drag models have been derived based on assimilation of satellite tracking data. These corrected drag values circumvent the persisting deficiencies of current drag models and provide significant improvements in precision orbit determination and prediction for low-earth orbit satellites.