Assessment of the possible contribution of space ties on-board GNSS satellites to the terrestrial reference frame

Abstract

The realization of the international terrestrial reference frame (ITRF) is currently based on the data provided by four space geodetic techniques. The accuracy of the different technique-dependent materializations of the frame physical parameters (origin and scale) varies according to the nature of the relevant observables and to the impact of technique-specific errors. A reliable computation of the ITRF requires combining the different inputs, so that the strengths of each technique can compensate for the weaknesses of the others. This combination, however, can only be performed providing some additional information which allows tying together the independent technique networks. At present, the links used for that purpose are topometric surveys (local/terrestrial ties) available at ITRF sites hosting instruments of different techniques. In principle, a possible alternative could be offered by spacecrafts accommodating the positioning payloads of multiple geodetic techniques realizing their co-location in orbit (space ties). In this paper, the GNSS-SLR space ties on-board GPS and GLONASS satellites are thoroughly examined in the framework of global reference frame computations. The investigation focuses on the quality of the realized physical frame parameters. According to the achieved results, the space ties on-board GNSS satellites cannot, at present, substitute terrestrial ties

Contribution of Multi‐GNSS Constellation to SLR‐Derived Terrestrial Reference Frame

“…SLR tracking of GNSS is typically used for the GNSS microwave‐based orbit validation (Arnold et al, ; Montenbruck et al, ; Sośnica, Thaller, et al, , ; Urschl et al, ). SLR‐to‐GNSS data can also be used for the GNSS orbit determination (Bury et al, ; Hackel et al, ; Pavlis, ), GNSS‐SLR co‐location in space that is independent from ground‐based local ties (Bruni et al, ; Thaller et al, ), time transfer and GNSS onboard clock synchronization (Sadovnikov & Shargorodskiy, ), determination of GNSS antenna offsets (Thaller et al, ), and the scale transfer from SLR to GNSS networks (Thaller et al, ).…”

Estimating global geodetic parameters using SLR observations to Galileo, GLONASS, BeiDou, GPS, and QZSS

“…We use the relative weighting of 8 mm for LAGEOS and 40 mm for GNSS, which is dictated by the quality Fig. 3 Processing scheme of the GNSS + LAGEOS combination of the GNSS data from the SLR validation (Zajdel et al 2017;Bruni et al 2018). Figure 4 shows how many 7-day solutions in % are possible to obtain for particular SLR stations when using LAGEOS-only, GNSS-only, and LAGEOS + GNSS observations.…”

Estimation of SLR station coordinates by means of SLR measurements to kinematic orbit of LEO satellites

“…The Bernese Software v5.2 is a well-tested software and is capable to process both data types, i.e., GNSS and SLR. The software is capable to perform the SLR analysis obeying the state-ofthe-art models and guidelines for SLR (Thaller et al 2011;Dach et al 2015;Bruni et al 2017;Otsubo et al 2018). The space-time curvature correction (Petit and Luzum 2010) is applied.…”

“…The assessment of the possible contribution of spacebased ties to study the possible contribution of GNSS satellites between SLR and GNSS to the ITRF can be found in Altamimi et al (2011), Thaller et al (2011), Sośnica et al (2015) and Bruni et al (2017). Thaller et al (2011) and Sośnica et al (2015) show that the combination using satellite-based colocations as connection between GNSS and SLR is feasible and allows the estimation of SLR network at the level of 1-2 cm.…”

“…At present, the SLR measurements to LEO satellites were mainly used for precision orbit determination together with other space geodetic techniques or as an independent way of orbit validation (Thaller et al 2015;Bruni et al 2017). The inter-technique combination between GNSS and SLR can be performed in a limited way.…”