4D surface kinematics monitoring through terrestrial radar interferometry and image cross-correlation coupling

Complex gravitational phenomena can require terrestrial remote sensing solutions for monitoring their possible evolution, especially when in situ installations are not possible. This study merges terrestrial radar interferometry (TRI) and image cross-correlation (ICC) processing, which can detect complementary motion components, to obtain a 3-dimensional system able to measure the actual surface motion field of a pre-defined target. The coupling can be carried out on data acquired from different installations of the devices, and by applying specific transformations of the related coordinate systems. The data georeferencing is a critical issue that affects the correct spatial correspondence of the data and a new approach for georeferencing radar data is proposed. The result is a spatio-temporal (3 + 1-dimensional) high-resolution representation of the surface kinematics. The presented method has been tested for the measurement of the Planpicieux glacier surface kinematics (NW of Italy). The error analysis revealed a millimeter accuracy and precision of the measurement and a georeferencing uncertainty of a few metres.