A Method of Calibrating Thermosphere Density Based on Temperature Parameters

Thermosphere atmospheric drag is the significant factor affecting most space operations of low Earth orbiter, especially, an inherent 15% formal error of empirical models has become the cumber to improve orbit calculations accuracy. Among the empirical models used in aerospace engineering, JACCHIA71 model, which has relative explicit physical bac kground and less parameters, is selected as a basic model. The temperature T_c and T_x, namely nighttime minimum of the global exospheric temperature and inflection point temperature, are chosen as the estimated parameters during the differential correction. The condition equation of density with respect to these two temperatures is established, and the least square solutions are given as well. The model accuracy improvement is almost enhanced by over an order of magnitude after calibration using CHAMP data. Orbit prediction accuracy of TG01 with the position bias of 2 km is also improved to 1.3 km through temperature corrections using in-site detecting data. All of these case studies validates the effectiveness of the calibration algorithm.