GEM Systems’ autonomous magnetic gradiometer in Survey mode. Ground portable magnetometer surveys can’t match the rapid data acquisition of a UAV borne survey, as this video demonstrates .
It is a simple matter to re-launch your autonomous gradiometer, after a stop for fresh batteries as this video illustrates.
Unmanned Airborne Vehicles are pilot-less aircraft that are flown on military, commercial, and police missions for a variety of applications. They are gaining in popularity as they are inexpensive, collect good quality data from a stable platform, and they can be equipped with many kinds of sensors, ranging from simple cameras to infrared cameras to magnetometers.
Driven initially by military applications, platforms, such as helicopter and fixed wing, have evolved significantly in the last ten years with new technology improvements, efficiency, range, size, and payload of UAVs. While these developments have been outside the commercial sector, this trend is changing as more and more commercial applications are uncovered.
In commercial applications, UAVs are well-suited for mapping mineral deposits, mapping pipelines and other buried infrastructure, potentially surveying hydro lines for breaks, and police missions involving detection of small buried arms or buried “fresh” graves.
The primary commercial use to date has been in mineral exploration but the other fields are developing. Mineral exploration is a natural fit for a UAV for a number of reasons. Manned flights in remote areas are dangerous and cost significant resources to support, including mechanics, fuel dumps and more. UAVs are easier to launch, mobilize, set up and refuel. Moreover, UAVs can fly in all weather and at night – giving significant productivity gains over conventional airborne surveys.
In the bottom line, these systems require few materials to build, use less fuel to fly, emit less pollution, and are easier to dispose of at the end of their useful lifetime.
GEM’s airborne technology has been proven on Fixed Wing, Helicopter and UAV platforms. Part of its success is due to its components – specially designed for high resolution and noise-free data:
All components are backed by GEM’s three-year warranty – the strongest in the industry.
An effective UAV system is defined as one that is capable of acquring ultra-sensitive magnetic data on either a helicopter or fixed wing platform.
In order to be effective, UAV magnetometer systems must acquire data close to the target. Responses of a dipolar target fall off as the inverse cube of distance so the farther from the source – the smaller the signal. This can be compensated for by using an ultra-sensitive magnetometer such as the Potassium optically pumped version.
UAV systems must also record position effectively. With GEM, this is done with accurate GPS positioning – giving reliable positioning information to 0.6 m. Depending on the application, lesser accuracy is also an option.
Lastly, it is essential to collect low-noise magnetic data. With GEM, this is done by conducting a gradiometer survey around the craft initially to determine magnetic hot spots. These areas are then addressed, typically by magntically cleaning the craft. Attention is also paid to rotor noise and propeller noise in UAV’s – ensuring that the platform is as magnetically quiet as possible.
There are two main confgurations possible for UAVs – helicopters and fixed wing.
On helicopters, a nose boom is attached to the platform and the magnetometer is set up on the boom with electrical connections in the airframe.
On fixed wing platforms, one or more sensors is/are housed in wingtip pods. Fixed wing surveys take advantage of the lack of microphony of the sensor, resolution and minimal heading error.
High quality data are only obtained after reliable, accurate application of base station corrections. With GEM, you have the choice of working with two versions – the Overhauser or Potassium base stations. Both offer excellent value and a range of sensitivities that accommodates typical to highest resolution specifications.
These implementations share a number of advanced features, including precise time synchronization of field and base station units using a built-in GPS option; flexible scheduling (up to 30 on/off periods); or manual.
Partial specifications are below:
Sensitivity: 0.0003 nT @ 1 nT
Heading Error: + / – 0.05 nT 360 degrees full rotation about axis
Resolution: 0.0001 nT
Absolute Accuracy: +/- 0.05 nT
Dynamic Range: 15,000 to 120,000 nT
Gradient Tolerance: 50,000 nT/m
Sampling Rate: 1, 2, 5, 10, 20 Hz (higher optional)
Sensor Orientation: optimum angle 35 degrees between sensor head axis and field vector
To learn more about GEM’s UAV solutions or to obtain a complete list of specifications, contact GEM. Our World is Magnetic!BACK
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