Determination of precise Galileo orbits using combined GNSS and SLR observations
- PDF / 2,253,658 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 69 Downloads / 200 Views
ORIGINAL ARTICLE
Determination of precise Galileo orbits using combined GNSS and SLR observations Grzegorz Bury1 · Krzysztof Sośnica1 · Radosław Zajdel1 · Dariusz Strugarek1 · Urs Hugentobler2 Received: 17 April 2020 / Accepted: 9 October 2020 © The Author(s) 2020
Abstract Galileo satellites are equipped with laser retroreflector arrays for satellite laser ranging (SLR). In this study, we develop a methodology for the GNSS-SLR combination at the normal equation level with three different weighting strategies and evaluate the impact of laser observations on the determined Galileo orbits. We provide the optimum weighting scheme for precise orbit determination employing the co-location onboard Galileo. The combined GNSS-SLR solution diminishes the semimajor axis formal error by up to 62%, as well as reduces the dependency between values of formal errors and the elevation of the Sun above the orbital plane—the β angle. In the combined solution, the standard deviation of the SLR residuals decreases from 36.1 to 29.6 mm for Galileo-IOV satellites and |β|> 60°, when compared to GNSS-only solutions. Moreover, the bias of the Length-of-Day parameter is 20% lower for the combined solution when compared to the microwave one. As a result, the combination of GNSS and SLR observations provides promising results for future co-locations onboard the Galileo satellites for the orbit determination, realization of the terrestrial reference frames, and deriving geodetic parameters. Keywords Galileo · GNSS · SLR · Precise orbit determination · Co-location
Introduction Modern satellites of the global navigation satellite systems (GNSS) are commonly equipped with laser retroreflector arrays (LRA) for satellite laser ranging (SLR). As a result, two independent space techniques are co-located onboard navigation satellites. This allows investigating the orbital quality using SLR residuals as well as performing an independent GNSS orbit solution based solely on laser observations (Pavlis 1995). Moreover, GNSS orbits can be determined using the combination of two types of observations (Thaller et al. 2011; Hackel et al. 2015).
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10291-020-01045-3) contains supplementary material, which is available to authorized users. * Grzegorz Bury [email protected] 1
Institute of Geodesy and Geoinformatics, Wrocław University of Environmental and Life Sciences, Grunwaldzka 53, 50‑357 Wrocław, Poland
Institute for Astronomical and Physical Geodesy, Technical University of Munich, 80333 Munich, Germany
2
The International Laser Ranging Service (ILRS, Pearlman et al. 2019) provides recommendations for the SLR stations in the form of the priority list of targets to be tracked. Nowadays, not only the dedicated geodetic satellites are tracked, but also plenty of other scientific missions including GNSS spacecraft. In 2013, the ILRS established a special study group, called Laser Ranging to GNSS s/c Experiment (LARGE) to organize special
Data Loading...
