The Very Low-Frequency (VLF) Electromagnetic Method (EM) survey technique is a passive method that utilizes distant, globally positioned transmitters that are broadcasting at frequencies in the range of 15.0 – 30.0kHz. In a VLF investigation the primary fields (generated by the radio transmitters) are horizontal, vertical deviations are measured (which are effected by local ground conditions).
• Exploration for mineralized bodies
• Resistivity imaging for bedrock mapping
• Delineate contrasts in conductivity at depth • Map geological contacts (i.e. faults)
• Water exploration
• Detection of underground pipelines
Revolutionary, Unmanned Aerial Vehicles (UAVs) can be used to perform airborne geophysical surveys. Acquiring data via drone offers many advantages such as time efficiency, being cost effective, as well as the opportunity to survey in areas that are not easily accessible (i.e. swamps) when compared to traditional manned-aircraft or ground surveys. In addition, UAV-borne VLF surveys can deliver better data quality in environments where topography and safety standards prohibit manned aircrafts from acquiring data at optimum terrain clearances.
GEM Systems GSM-90AVU UAV VLF system provides true measurements of the Vertical in- phase & Out-of-phase components as % of total field within the VLF frequency range of 15.0 – 30.0kHz. Many older systems only measure the total field and quadrature components of the field. This VLF system features two separate sensors with three light weight orthogonal air coils in each to provide reduced noise and allow true in-phase and quadrature data to be gathered rapidly from two VLF transmitting stations simultaneously, regardless of sensor orientation. Data includes in-phase, out-of-phase, horizontal components in x and y and field strength in picoTesla (pT).