A lightweight ground penetrating radar

The detection of buried objects, particularly unexploded ordnance (UXO), has gained significant interest in the US in the late 1990s. The desire to remediate the thousands of sites worldwide has become an increasing humanitarian concern. The application of radar to this problem has received renewed attention. Bechtel Nevada, Special Technologies Laboratory (STL) has developed several frequency modulated, continuous wave (FM-CW) ground penetrating radar (GPR) units for the US Department of Energy since 1984. To meet these new technical requirements for high resolution data and UXO detection, STL is moving forward with advances to GPR technology, signal processing, and imaging with the development of an innovative system. The goal is to design and fabricate a lightweight, battery operated unit that does not require surface contact and can be operated by a novice user

Mapping surface soil water content with the ground wave of ground-penetrating radar

We investigated the accuracy of surface soil water content measurements with the ground wave of GPR. We examined the influence of SWC mapping equipment near the GPR and tested the significance of reported time differences in air and ground wave arrival time at zero antenna offset (t0). The influence of the equipment on the radar signal was tested by introducing the sleds, odometer and vehicle to pull equipment stepwise. The sleds caused a decrease in the amplitude of the ground wave and all the equipment caused disturbances in the air wave. However, the data quality remained sufficient to pick arrival times automatically. The importance of t0 was assessed with 20 WARR measurements and a sensitivity analysis based on GPR simulations. We observed a mean t0 of 0.5231 ns that could not be explained from the GPR simulations. There also was a large variation in t0, but that could be explained by considering picking error, positional error and soil water content heterogeneity in the sensitivity analysis. We conclude that a t0 correction in the calculation of soil water content would improve measurements with GPR, but it should be noted that the large variation in t0 makes it difficult to accurately estimate mean t0