Project Details
Projekt
Novel clock technologies for combination on ground and in space: real data and simulation
Subject Area
Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
Term
since 2023
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 490990195
The Project evaluates the impact of novel clock technologies, based on a common target (CT) and a common clock, on the ground- and space-based combination of space-geodetic techniques using real observational data and simulations. This is done with respect to a global terrestrial reference frame (TRF) that meets the requirements of the Global Geodetic Observing System (GGOS). First, we will analyze CT calibration data at the Geodetic Observatory Wettzell (GOW) together with space-geodetic observations and geophysical data to identify and explain remaining residuals and to relate the space-born observation data to the CT with high accuracy. Observations of all four space geodetic techniques, all referenced to the CT and the common clock at GOW, will be performed simultaneously. Strategies will be developed for combining the space-geodetic techniques, taking advantage of the new clock technologies, beyond what has previously been possible with local ties. We will focus first on intra- and then on inter-technology combinations. The parameters considered in the combination will initially include the usual station coordinates, station velocities, and Earth orientation parameters, plus the clock parameters. Later, the combination of tropospheric parameters and orbital parameters will also be investigated for a fully consistent solution. Through simulations, it will be shown how additional globally distributed stations with a clock technology analogous to that at GOW, can improve the accuracy and stability of the TRF. In addition to a common clock on the ground, simulations of a common clock at a co-location satellite and the addition of other features such as inter-satellite links will also be investigated. By comparing TRFs from real and simulated data and with previous realizations, results will be evaluated to draw conclusions about the utility of novel clock technologies. In the first funding phase, time coherence in GOW will be investigated using real data and supported and extended by simulations. The second funding phase will focus on time transfer and time coherence between stations (GOW and Potsdam, and possibly others) and within a global network (based on simulations). This will result in a further significant improvement of the accuracy and stability of the TRF. Finally, we want to answer the following question: How can novel clock technologies, based on a common target and clock, be exploited to improve combined solutions with the goal of computing reference frames that meet GGOS requirements?
DFG Programme
Research Units
