Determining the influence on orbit prediction based on uncertainties in atmospheric models
Orbit prediction and knowing its uncertainties is a key part in planning collision avoidance maneuvers or conducting re-entry estimations. For high accuracy forecasts numerical propagators are used. These propagators use force models to estimate the perturbing elements that affect a satellite's orbit. Especially on low Earth orbits (LEO) with decreasing perigee altitude the atmosphere becomes the dominating perturbing force. The available atmospheric models are complex in nature and react very sensitive to their input data. As with any model the atmospheric models also feature uncertainties. Because they heavily depend on the solar and geomagnetic activity, further uncertainty is introduced due to insufficient forecast capabilities of the solar and geomagnetic activity. The uncertainties introduced to the orbit prediction due to the atmospheric model's input parameters are investigated. The approach is to analyze the trajectory of different satellites, which are on different altitudes and inclinations. Using a numerical propagator a baseline is established applying observed solar and geomagnetic activity data of the past and estimate the satellites' orbit. Different types of solar and geomagnetic activity forecasts are used as implemented in the Orbital Spacecraft Active Removal (OSCAR) software, a tool of ESA's Debris Risk Assessment and Mitigation Analysis (DRAMA) software suite. The orbit prediction is repeated with the different solar and geomagnetic forecasts. The uncertainties of the orbit prediction as a result of the comparison to the baseline are shown.
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