Simulation of the SLR space segment evolution to improve the realization of terrestrial reference frames and determination of low-degree gravity field parameters
摘要
The development of the satellite laser ranging (SLR) technique is essential not only to meet the objectives set by the Global Geodetic Observing System (GGOS) but also to address growing challenges of understanding increasingly frequent processes occurring at the Earth’s surface and to realize the terrestrial reference frames (TRFs). In this study, we search for optimum orbit parameters for future geodetic satellites tracked by SLR stations. We simulate satellites at various inclination angles, ranging from 0 to 180 degrees with a 1-degree interval, across five different altitudes from 1500 to 10,300 km, with 1200 km intervals, in two solution scenarios: (1) optimized for the realization of TRFs and (2) optimized for the recovery of the Earth’s gravitational potential. We found that an optimal satellite altitude for TRF realization is at the height of 3700 km and an inclination between 0–20° or 160–180°, which minimizes the formal errors in the determination of geocenter coordinates and Earth Rotation Parameters (ERPs). On the other hand, a geodetic satellite primarily intended for recovery of the low-degree Earth’s gravitational potential parameters should orbit at an altitude of 1500 km, with inclinations between 30–40° or 135–145°. In the current SLR constellation, none of the existing satellites has optimum orbital parameters for the low-degree gravity field recovery because the lowest inclination angle of Starlette equals 49°. Adding a single satellite with the appropriate inclination to the current constellation of ten geodetic satellites reduces error in determining the Earth’s oblateness term, C20, by one order of magnitude.