Simulation studies of new observing concepts for geodetic Very Long Baseline Interferometry

Licentiate thesis, 2017

Very Long Baseline Interferometry (VLBI) is a space-geodetic technique in which observations are carried out simultaneously by radio telescopes separated by hundreds or thousands of kilometers. The time difference of signal reception between the telescopes is the basic observable used in geodetic VLBI. This technique is capable of determining all five Earth Orientation Parameters (EOP), which provide the connection between the Earth-fixed and space-fixed reference frames. Currently, there is an ongoing effort concerning the establishment of the VLBI Global Observing System (VGOS), which will significantly improve the present measurement precision and increase the total number of observations per session. This requires the key components of the infrastructure, data handling as well as observation approaches to be upgraded and refined. Thus, the focus of this thesis is set on new observing concepts for VGOS. This includes extensive simulations regarding an improved determination of the rotation of the Earth (UT1-UTC) from one-hour VLBI sessions and investigations on the potential of lunar observations in regular geodetic VLBI sessions. The studies summarized in this work address the main topic from two different aspects, providing valuable insights concerning observations in the VGOS era and stimulating new concepts for space geodesy.