Density Model Corrections Derived from Orbit Data to Characterize Upper Atmospheric Density Variations

Abstract

One goal of this research is to estimate density model corrections using readily available Satellite Laser Ranging (SLR) data, and to demonstrate this approach's validity for additional satellites with similar data sets in the future. The research also aims to utilize previously unused or little used sources of orbit state data to generate corrections to existing density models. These corrections yield estimated density corrections which lead to better drag estimates, improved orbit determination and prediction, as well as an enhanced understanding of density variations in the thermosphere and exosphere. This research primarily focuses on using SLR data. This examination will give a better idea of obtainable improvements in atmospheric density. Consideration will also be given to the effects of varying levels of geomagnetic and solar activity. This work established the validity of using SLR data to estimate atmospheric densities by comparing results for the ANDE Castor satellite to results for the CHAMP and GRACE satellites for the same time periods. The density correction factors and standard deviations comparing the baseline model densities to the derived atmospheric densities are also examined for the ANDE Castor satellite. For the entire family of ANDE satellites, the uncertainty in atmospheric density is established for each arc. The uncertainties are significantly higher at the beginning of the arc for each of the satellites, and the uncertainties also increase as the satellites drop in altitude. Preliminary density values for the Special Purpose Inexpensive Satellite (SPINSat) are also derived.