Nowadays, new GNSS, like European Galileo or Chinese Beidou are available. Some members of the International GNSS Service (IGS) provide multi-GNSS precise satellite orbits, but no final orbit combination exists yet. We developed a new algorithm to combine satellite orbits for all GNSS constellations. Two different strategies were applied. To validate our results we compared our GPS orbits with the official IGS orbits. Our results show that the best strategy applied reached an agreement ~15 mm.

We have developed a first Germany-wide 3D data-based density and temperature model integrating geoscientific observations and physical processes. The model can serve as a reference for local detailed studies dealing with temperature, pressure, stress, subsidence and sedimentation. Our results help to improve subsurface utilization concepts, reveal current geomechanical conditions crucial for hazard assessment and gather information on viable resources such groundwater and deep geothermal energy.

In this paper we investigate the application of a solar-powered bus route to a small-scale transportation system, as such of a university campus. We investigate three different scenarios: (1) solar panels installed on the roof of bus stop shelters, (2) solar panels installed at unused open space in the university, and (3) solar roads, i.e. roads constructed by photovoltaic (PV) materials. We conclude that scenario (2) presents the lowest capital cost in relation to energy generation.

The combination of VLBI Intensive and GNSS Rapid products on the base of Normal Equations for a consistent estimation of a full set of EOPs is focused. In this context, meaningful investigations of the obtained accuracies have been carried out. The combined estimates of polar motion, UT1 and their associated rates are therefore discussed and compared with respect to the official reference series and the specific single solutions, respectively.

We study oscillations recorded at Stromboli and Campi Flegrei by different sensors. Seismicity and deformation are investigated on several time scales in order to identify the basic elements of their interaction, whose understanding should provide new insights on the predictive models. At Stromboli, a departure from the equilibrium state is marked by solid tide variations in a certain frequency band. At Campi Flegrei diurnal to annual solid tides modulate an increase of volcanic activity.

Here, three schemes have been considered for remedying the rank deficiency of the GNSS tomography problem. For this purpose, the Virtual Reference Stations (VRS) and horizontal and vertical constraints have been defined to analyze the impact of different constraints on the accuracy of the reconstructed refractivity field. The obtained results illustrate that applying VRS stations in the sparse GNSS Network can lead to a better solution compared to applying horizontal and vertical constraints.

In this article we analyze the benefit of computing a combined solution from individual orbit solutions for the low Earth orbiting satellite Sentinel-3A. The selected combination scheme for calculating the combined solution is Variance Component Estimation. It could be shown that a combination of individual solutions can be beneficial in terms of Satellite Laser Ranging validation. In our opinion the findings are well transferable to other satellite missions.