Pros and Cons in Helicopter-Borne GPR Data Acquisition on Rugged Mountainous Areas: Critical Analysis and Practical Guidelines

We critically discuss both advantages and limitations of helicopter-borne GPR surveys in rugged mountainous areas by analyzing a pseudo 3D data set acquired over the Marmolada Glacier, which constitutes the largest ice body in the Dolomites (Eastern Alps) and contains several peculiar features both in terms of the internal structures and the surrounding topography. In this paper we analyze several possible issues that can be encountered when performing airborne surveys in mountain regions, related to both the local conditions in the particular survey areas, and the general performance of the data acquisition equipment, which includes the GPR device, the GPS system, and the helicopter itself. Based on our analyses and observations, we propose a few guidelines and optimization strategies in order to address several issues, including the choice of various data acquisition parameters, interpretation problems related to curvilinear or irregular flight paths, and trace positioning errors caused by GPS malfunctioning or oscillating antennas. Such results have general validity and can be used for helicopter-borne survey planning, as well as for data analysis and interpretation.