Motorized measurement devices

Motorized measurement devices for magnetometer and GPR prospection are developed, tested and optimized. The target for magnetic surveying has been defined by a mean area-coverage of 10 to 20 hectares per day of fieldwork with 10 cm in-line and at maximum 50 cm cross-line sample spacing. In order to achieve this goal multichannel Fluxgate (FG) magnetometer systems supporting up to 12 gradiometer probes for parallel operation with cross-line sample spacing of 25 cm, as well as a Caesium (CS) magnetometer system consisting of up to 12 total-field sensors are developed and tested for large-scale applications. The FG magnetometer systems permit surveys with 0.2-0.3 nT accuracy, while the CS magnetometer system allows measurement sensitivities of 0.005 nT in combination with variable gradiometer configurations and total-field surveys. Directional dependence of the magnetometer systems is investigated by test measurements in order to minimize any disturbing effects. Gradiometer measurements using various sensor arrays are studied.

Novel motorized GPR systems based on GPR antennae arrays enabling measurements at several different spatial resolutions are developed, applied and improved within the case studies. Antennae arrays permitting very dense GPR trace spacing (as small as 8 cm cross-line) covering various frequency ranges as well as step-frequency antenna systems have been evaluated.