SkyTEM is a dual-moment Time-Domain Electromagnetic System (TDEM) designed specifically to collect data comparable to the finely detailed data previously only possible with ground geophysical techniques.
The system collects the cleanest and highest quality data available on the market due to the capability to produce data that is free of drift and the need for high altitude corrections.
This unique ability reduces data manipulation and SkyTEM’s geophysicists are able to plot highly detailed maps soon after the helicopter lands. As the only airborne system capable of operating in dual transmitter modes SkyTEM can discriminate between weak geological contrasts in the top layers concurrently with those at depth. Innovative and patented receiver coil technology eliminates signal drift and an extremely rigid platform ensures the delivery of high quality high resolution data.
SkyTEM is currently the only airborne geophysical contractor able to offer this state-of-the-art technology.
Stakeholders with a need for high resolution maps of the top 400m take advantage of SkyTEM’s unique ability to operate with simultaneously in:
- Low moment (LM) mode with low current with a high base frequency and fast turn off for early-time data and high spatial sampling for shallow imaging, and
- High moment (HM) mode with high current with low base frequency for high quality late-time data for deep imaging.
The frequency range is selectable, depending on the known characteristics of the target being pursued and operate between approximately 222 Hz and 25 Hz. Dual mode transmitters configured to optimize the conductivity mapping range dramatically increases the accuracy and resolution of horizontally layered geology.
The transmitter loop is mounted around the perimeter of the lightweight lattice frame, while the receivers of the vertical Z- and the horizontal X-component are rigidly mounted at one end of the elongated hexagonal frame. This construction ensures a well defined geometry at all times and additionally allows for a low, effective terrain clearance of the system.
Testing Results
Extensive testing documented that the level of instrument noise and bias is nil compared to the measured earth response.
Data measured with ground-based systems can be fully reproduced with the SkyTEM system.
Noise Levels
Measurements performed at high altitude, where the Earth’s response is within the system background noise, demonstrates that the recorded signal at production flight heights (10-30 m) is 2-3 orders of magnitude above the noise.
There is effectively no drift in the system and no interference from the helicopter; therefore the measured data are ready for processing and inversion.
Repeatability
Repeating measurements for each flight at a local reference site within the survey area insures that the SkyTEM equipment is working properly during the entire survey. The repeatability is better than 5%.
Reproducibility tests of ground-based measurements are performed at a regular basis. Reproducibility is better than 5-10%, substantiating excellent performance during production.