1. Combination: Tsunami Early Warning System
The monitoring, modeling and finally predicting the Earth system behavior starts with the observations on the left-hand side: this includes the space techniques, but also a variety of satellite missions and terrestrial observation techniques. From the collected observations, time series of Earth‘s geometry (including the ocean and ice surfaces), Earth‘s rotation and Earth‘s gravity field can be derived. These three pillars of geodesy provide very important information concerning the Earth system components on the right-hand side. As better models of the Earth processes become available, the interpretation and separation of the temporal variations of the three pillars can be improved and, in view of gaps in the observation system, new innovative technologies can be developed, closing the circle. On the left-hand side the combination and integration of all sensors into a GGOS is a big challenge, on the right- hand side it is the modeling of the full interactions between the components that is very demanding. All the monitoring and modeling can, finally, only be achieved, if a high-precision, long-term stable reference frame is available and maintained. Global sea level change is a major example to illustrate the necessity of such a high-quality reference frame.
GNSS receivers