Satellite gravimetry missions like GRACE and GRACE Follow-On (GRACE-FO) have mapped the Earth’s time-variable gravity field for over two decades. Both missions consist of two near-polar satellites in an inline formation, with an inter-satellite link (ISL) for ranging. This mainly along-track ISL geometry is understood to cause the characteristic north-south striping artefact in GRACE(-FO) data. In contrast, emerging mega-constellations have hundreds to thousands of satellites spread across various orbital planes, inclinations, and altitude bands. This can provide much more diverse ISL directions than a conventional along-track formation. This motivates us to investigate whether a more diverse set of ISL directions could yield more isotropic error behaviour of the recovered gravity field and to explore the potential of mega-constellations for gravity field mapping as a satellites-of-opportunity concept.
Additionally, the VLEO regime unlocks increased sensitivity to Earth's gravity field along with new challenges of operating satellites in VLEO.
Caption: / SFB 1667/1 (ATLAS - Advancing Technologies of Very Low-Altitude Satellites)
Simulation Approach
The study involves conducting several simulations for various mission scenarios to evaluate their gravity recovery potential. We adopt a reduced-scale closed-loop simulation approach to test all possible design and recovery parameters. We implement the approach as a Julia package. The package is currently a work in progress and is being continually updated.
Caption: / SFB 1667/1 (ATLAS - Advancing Technologies of Very Low-Altitude Satellites)
funding acknowledgement
This work is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Project-ID 516238647 – SFB 1667/1 (ATLAS - Advancing Technologies of Very Low-Altitude Satellites)
Abhishek Mhamane
M.Sc.Scientific Employee