Using Satellite Constellations for Improved Determination of Earth's Time-Variable Gravity

The spatiotemporal resolution of the time-variable gravity field models derived from current dedicated gravity field missions is inherently limited by their ground-track coverage. Furthermore, the results are subject to aliasing effects caused by submonthly mass transport signals, such as those caused by atmospheric and ocean processes. To address these issues, this study explores the feasibility of using nondedicated satellite constellations, such as those from commercial communication networks or a low-cost array of custom-built microsatellites, as a complementary data source. The positioning receivers onboard the constellation's satellites would ideally provide a high density of observations in the form of derived accelerations that, while much less accurate than those obtained from dedicated gravity missions, are still sufficient to observe the longest wavelength gravity signals at even subdaily intervals. Using a series of simulated mission scenarios, as well as a limited amount of real-data analysis, it is shown that such constellations, acting either independently or when combined with dedicated gravity field missions, may offer a noticeable improvement in the recovery of the large-scale (greater than 1000 km) high-frequency (less than 1 month) components of the global gravity field.