Typically ground based GPR systems for geophysical applications consist of low frequency pulse radars which operate in the MHz frequency range. As those rudimentary radar concepts have proven to be easy to use and offer enough resilience to endure in rough environments in the past, the most recent and enormous advances in radar technology have almost exclusively been made in other fields such as automotive radar or personnel security scanner systems. Innovative GPR approaches can strongly benefit from these new radar techniques e.g. by multi-functional radar systems that utilize software defined waveforms and measuring principles best adapted to the specific environment and measuring task. A holistic hardware-software design based on cutting-edge technology is needed to obtain the maximum performance for the intended field of use.
Structures in the firn and snow cover on glaciers can be caused by annual melt/freeze cycles, but also by internal water percolation or refreezing. Additionally, water channels within the glaciers are important indicators for melt water routing in geophysical and hydrological glacier models. The highest changes occur within the upper layer (first tens of meters) and are therefore of importance to be monitored. Synthetic Aperture Radar (SAR) tomography is an evolving 3D imaging technique that enables the mapping of subsurface properties of glaciers and ice sheets with high spatial resolution, taking advantage of the penetration of radar signals up to several tens of meters into dry snow, firn, and ice (Tebaldini et al., 2016, Fischer et al., 2019).
Information on ice thickness and internal structures of ice bodies (e.g. water table, isochrones, water pockets, and channels) from ground penetrating radargrams is to date often picked manually. Often only a specific target neglecting all other information is traced since existing contour-following algorithms in standard software like REFLEX do not provide consistent and reliable output. Within this doctoral project, we aim at using and modifying machine learning techniques from medical imaging as well as natural language processing (NLP) and apply those to glaciological radargrams.