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Performance and calibration of the helicoper GPR system BGR-P30

Airborne ground penetrating radar (GPR) measurements of geological structures and of temperate ice are a challenge because of absorption, internal scattering, and surface roughness. We found that at center frequencies of 30 MHz or below effects of scattering and roughness are sufficiently reduced to produce good quality radar data. We report results and penetration depths of recent helicopter measurements performed over sand and gravel in Germany and over glaciers in Patagonia with the 30 MHz airborne radar system BGR-P30. Calibration of airborne GPR instruments is accomplished by flying over a flat surface with a known reflection coefficient (e.g. a freshwater lake) at different altitudes. The determined dynamic range of the BGR-P30 system is consistent with in situ penetration depths for the different materials.