GGOS-SIM-2: Simulation of the Global Geodetic Observing System

• Applicants: Dr.-Ing. Rolf König; Professor Dr.-Ing. Harald Schuh
• Subject Area: Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
• Term: from 2014 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 255986470

The overall objective of GGOS-SIM-2 is to assess the potential of co-location in space of the four main space geodetic techniques (Doppler Orbitography and Radiopositioning Integrated by Satellite, Global Navigation Satellite Systems, Satellite Laser Ranging, Very Long Baseline Interferometry), i.e. on board of one or more satellites, to realize a global terrestrial reference system (TRS) with an accuracy and stability meeting the science-driven requirements specified by the Global Geodetic Observing System (GGOS) of the IAG (International Association of Geodesy). Currently, these quality requirements are not achieved but are strongly required to reliably interpret global processes, such as the global sea level rise. Within the first phase of project GGOS-SIM, the achieved results have demonstrated the suitability of simulations of the four main space geodetic techniques for investigating the accuracy and stability of global terrestrial reference frames (TRF). In the second phase (GGOS-SIM-2) we plan extending these simulations by considering co-locations of the four techniques in space and quantifying the effects on the TRF determination. Using space ties instead of or additionally to ground local ties that are customarily interconnecting the individual techniques will allow validating these local ties, which are currently applied without any external control in the TRS realization approaches.Within GGOS-SIM-2 the following questions will be addressed:• Which level of accuracy of the TRF and the related products like Earth orientation parameters can be obtained, applying co-location in space through a GRASP-like satellite?• What is the added value for TRS realization of a space tie on one (or more) satellite(s) complementing the local ties on ground?• Which criteria have to be fulfilled in order to get a TRF meeting the GGOS requirements depending on optimal orbit selection, number of ground stations, observation time, and number of satellites? • What is the impact of technique-specific systematics within the common POD on the TRF?• What can be concluded for the local ties at the ground?• What are the prospects for the static and time-variable gravity field?

• DFG Programme: Research Grants