Applying Energy Dissipation Rate GNSS Accelerometry to a Non-Circular Orbiting Satellite

Abstract

The increase in the number of objects in Low-Earth Orbit has heightened the demand for high-accuracy orbital prediction models driven by dependable measurements of thermospheric mass density (TMD). Given the added cost and complexity burden of equipping satellites with high precision accelerometers, recent attention has focused on alternative techniques for observing TMD such as “GNSS accelerometry,” which involves harnessing spacecraft as instruments themselves to quantify thermospheric density vis-à-vis orbital decay. This work demonstrates how the Energy Dissipation Rate (EDR) technique utilizes the change in spacecraft orbital energy to recover density measurements at cadences ranging from a single orbital period down to as small as a quarter of such periods. After presenting a framework for applying the EDR method to the elliptical orbit of the Communications/Navigation Outage Forecasting System (C/NOFS) satellite, “effective” TMD measurements integrated over a continuous “orbit arc” are recovered for C/NOFS during January 2011. The merits of the EDR method, especially in its heightened sensitivity to solar/geomagnetic activity, are underscored by investigating a minor geomagnetic storm on 7 January 2011 and contrasting the results with those obtained from processing Two-Line Element sets (TLEs) or the output from NRLMSISE-00 and HASDM. Furthermore, this study introduces the novel application of fractional-orbit average EDR integration tailored for satellites with eccentric orbits, demonstrating its efficacy in offering nuanced insights into thermospheric conditions. The results demonstrate the ability of physics-based techniques and readily accessible data sets to estimate thermospheric density and provide insight into aeronomy and space weather science.