142 research outputs found
BeiDou-3 orbit and clock quality of the IGS Multi-GNSS Pilot Project
Within the Multi-GNSS Pilot Project (MGEX) of the International GNSS Service
(IGS), precise orbit and clock products for the BeiDou-3 global navigation
satellite system (BDS-3) are routinely generated by a total of five analysis
centers. The processing standards and specific properties of the individual
products are reviewed and the BDS-3 orbit and clock product performance is
assessed through direct inter-comparison, satellite laser ranging (SLR)
residuals, clock stability analysis, and precise point positioning solutions.
The orbit consistency evaluated by the signal-in-space range error is on the
level of 4-8 cm for the medium Earth orbit satellites whereas SLR residuals
have RMS values between 3 and 9 cm. The clock analysis reveals sytematic
effects related to the elevation of the Sun above the orbital plane for all ACs
pointing to deficiencies in solar radiation pressure modeling. Nevertheless,
precise point positioning with the BDS-3 MGEX orbit and clock products results
in 3D RMS values between 7 and 8 mm.Comment: 13 pages, 5 figure
Compatibility between the preliminary ITRF2020 solution and GNSS antenna phase center offsets
Influence of Innovative Rehabilitation Technology on Intensity of Training:Preliminary Results
GNSS processing at CODE: status report
Since May 2003, the Center for Orbit Determination in Europe (CODE), one of the analysis centers of the International GNSS Service, has generated GPS and GLONASS products in a rigorous combined multi-system processing scheme, which promises the best possible consistency of the orbits of both systems. The resulting products, in particular the satellite orbits and clocks, are easily accessible by the user community. In the first part of this article, we focus on the generation of the combined global products at CODE, where we put emphasis not only on accuracy, but also on completeness. We study the impact of GLONASS on the CODE products, and the benefit of using them. Last, but not least, we introduce AGNES (Automated GNSS Network for Switzerland), a regional tracking network of small extensions (roughly 400km East-West, 200km North-South), which consequently tracks all GNSS satellites and analyzes their measurements using the CODE product
Validation of Galileo orbits using SLR with a focus on satellites launched into incorrect orbital planes
The space segment of the European Global Navigation Satellite System (GNSS) Galileo consists of In-Orbit Validation (IOV) and Full Operational Capability (FOC) spacecraft. The first pair of FOC satellites was launched into an incorrect, highly eccentric orbital plane with a lower than nominal inclination angle. All Galileo satellites are equipped with satellite laser ranging (SLR) retroreflectors which allow, for example, for the assessment of the orbit quality or for the SLRâGNSS co-location in space. The number of SLR observations to Galileo satellites has been continuously increasing thanks to a series of intensive campaigns devoted to SLR tracking of GNSS satellites initiated by the International Laser Ranging Service. This paper assesses systematic effects and quality of Galileo orbits using SLR data with a main focus on Galileo satellites launched into incorrect orbits. We compare the SLR observations with respect to microwave-based Galileo orbits generated by the Center for Orbit Determination in Europe (CODE) in the framework of the International GNSS Service Multi-GNSS Experiment for the period 2014.0â2016.5. We analyze the SLR signature effect, which is characterized by the dependency of SLR residuals with respect to various incidence angles of laser beams for stations equipped with single-photon and multi-photon detectors. Surprisingly, the CODE orbit quality of satellites in the incorrect orbital planes is not worse than that of nominal FOC and IOV orbits. The RMS of SLR residuals is even lower by 5.0 and 1.5 mm for satellites in the incorrect orbital planes than for FOC and IOV satellites, respectively. The mean SLR offsets equal â44.9,â35.0, and â22.4 mm for IOV, FOC, and satellites in the incorrect orbital plane. Finally, we found that the empirical orbit models, which were originally designed for precise orbit determination of GNSS satellites in circular orbits, provide fully appropriate results also for highly eccentric orbits with variable linear and angular velocities
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