Satellite Orbit Simulation to Support Sensor Calibration/Validation

Abstract

Satellite orbit predictions are utilized to determine a spacecraft’s timing and position relative to Earth, which are necessary for identifying overpasses, coordinating observations, and supporting the calibration and validation of environmental satellites. This study examines how satellite trajectories can be predicted using Two-Line Element (TLE) data and the Simplified General Perturbations 4 (SGP4) model. It considers factors that alter satellite orbits, including Earth’s nonspherical gravity, atmospheric drag, solar radiation pressure, Earth and ocean tides, the gravitational pull of the Sun and Moon, and spacecraft maneuvers, all of which can reduce prediction accuracy over time. To do so, the study compares Systems Tool Kit (STK), a high-fidelity aerospace analysis platform, with Zerua, a more accessible web-based 3D satellite visualization tool. Zerua was used to simulate satellites from the Joint Polar Satellite System (JPSS) and the six-satellite COSMIC-2 constellation and to examine their orbits, ground tracks, and opportunities for coordinated observations. Reliable orbit prediction helps ensure that their measurements can be accurately calibrated. Overall, this study shows how satellite orbit simulation and visualization can support more reliable Earth-observing data and strengthen the environmental information scientists use to better understand changes in Earth’s systems. These applications are relevant to environmental science because these satellites collect data used for weather forecasting, climate research, and environmental monitoring.