The GEM-5 array is a vehicle-mounted or vehicle-towed gradiometer sensor for rapid ground coverage. It has a transmitter in the middle straddled by two identical receiver coils below and above. The difference between the two receiver coils constitutes the signal. The gradiometer configuration has the following advantages:
- Vertical directional response, not affected by targets to the side, ideal for vehicle mounting
- Immunity to noise induced by sensor motion
- Immunity to ambient environmental EM noise
- Immunities provide improved signal-to-noise ratio (SNR)
The array has the following advantages:
- Maximum possible transmitter moment for a given array size
- Broadband, up to 10 frequencies between 30Hz – 93kHz
- Multiple receiver channels operating simultaneously;
- High-speed survey with high data density
Many configurations are possible.
For an explanation of the GEM-2, GEM3 and GEM5 configurations, see the document Sensor Configurations.