Potential Improvements to Low Degree Gravity Fields from Satellite Laser Ranging through Additions to the Tracking Network and Satellite Constellation

For over fifty years, satellite laser ranging (SLR) has served as a fundamental technique for satellite ephemeris estimation, geocenter computation, and reference frame determination. As an independent geodetic technique, SLR can accurately measure the long-wavelength components of Earths gravity field. These measurements capture a large part of Earths time-variable gravity field, which is driven by redistribution of the hydrosphere and cryosphere. Recovery of SLR-derived spherical harmonic coefficients has additionally supported other dedicated gravity missions, namely the Gravity Recovery and Climate Experiment (GRACE) mission. SLR has been crucial in this respect because GRACE does not accurately recover certain low-degree gravity coefficients. SLR has also helped bridge a year-long data gap between GRACE and its recently launched successor GRACE Follow-On, which is complicated by the suboptimal performance of one accelerometer. To support GRACE and the continuity of gravity measurements, we should seek to improve the quality and accuracy of SLR-derived gravity estimates. A single addition to the SLR network, such as the LARES satellite that launched in 2012, can significantly improve gravity recovery. We present results from a simulation study that quantify potential improvements to estimated gravity fields from ground-based and space-based additions to the SLR network. Both a new tracking station and new satellite are simulated along with the current SLR network. Estimated gravity fields are compared to the simulated truth to determine improvements.