An evaluation of Jacchia and MSIS 90 atmospheric models with CBERS data

“CBERS” (China Brazil Earth Resources Satellite) was put into orbit on 14^th of October 1999. The atmospheric drag is the major non-gravitational perturbation affecting the control of ground track. As accuracy requirements increase, greater reliance is placed on the empirical techniques. During the initial operational phase of CBERS, the solar activity is almost at its peak. This phenomenon has provided an opportunity to carry out an evaluation of the atmospheric density models. The study puts emphasis on two commonly used atmospheric density models viz. Jacchia and Mass Spectrometer Incoherent Scatter (MSIS). The analysis is based on the decay histories of CBERS to choose the accurate density model. Density models used for orbit propagation are usually derived empirically from actual flight data. Brief synopsis of some of the models is presented along with some of the density tables and orbit solutions of CBERS. Typical plots of density are presented. The study indicated that the drag estimation is relatively precise using MSIS based models. Among them MSIS-90 density model is observed to be a better compromise in terms of accuracy, flexibility and computational aspects. The analysis would be useful in mitigating the impact of solar activity on orbit prediction and maintenance.