Drone-based Magnetometers: Tools and Tips

A magnetometer is an instrument used to measure magnetic fields. It consists of a sensor, also known as a magnetic sensor or magnetometer sensor, which detects the changes in the magnetic field and converts them into electrical signals. These signals are then interpreted and analyzed to provide valuable data about the magnetic field's characteristics. Magnetometers measure magnetic fields, detecting variations in the Earth's magnetic field caused by the presence of magnetic materials or anomalies.

In drone-based magnetometry, these instruments are mounted on drones to conduct aerial surveys. As the drone flies over the survey area, the magnetometer records magnetic field data, which is then processed to identify subsurface features such as metal objects, geological structures, or archaeological artifacts. Advanced magnetometers like the Geometrics MagArrow Mk2, MagNIMBUS, and SENSYS MagDrone R4 use highly sensitive sensors, onboard GPS, and data storage to provide accurate, real-time data collection and analysis, enabling precise mapping and detection even in challenging terrains.

• Select the Appropriate Magnetometer: Choose a magnetometer based on your survey objectives, the type of data needed, and the operating environment. Options include the Geometrics MagArrow Mk2, MagNIMBUS, and SENSYS MagDrone R4.

• Plan the Survey Mission: Use flight planning software like UgCS to design the survey area and establish flight paths. Define the altitude, speed, and coverage required for the survey.

• Prepare the Equipment: Mount the magnetometer on the UAV, ensuring all components are securely attached. Set up any additional equipment needed, such as GPS units or altimeters.

• Calibrate the Magnetometer: Perform any necessary calibration procedures to ensure the magnetometer is providing accurate measurements. This may include zeroing the magnetometer or adjusting settings.

• Follow-Up Actions: Based on the survey results, plan and execute any necessary follow-up actions, such as further investigations, site remediation, or archaeological excavations.

The Geometrics MagArrow Mk2 Magnetometer is designed to enhance aerial magnetic surveys with its advanced technology and lightweight design, integrating seamlessly with most drones. Weighing only 1 kg, it extends drone flight times by up to 20% and includes a self-contained system with onboard GPS, data storage, and WiFi, eliminating the need for data connections to the drone. Its high sampling rate of up to 10 m/s with measurements every 1 cm effectively filters out drone motor noise, and field QC allows for on-site data quality checks using any device with a web browser app interface. Powered by a 1800 mAh lithium polymer battery for up to 2 hours with hot-swappable batteries for extended operations, the MagArrow Mk2 is ideal for various applications, including locating abandoned wells, pipes, and storage tanks in environmental surveys, conducting magnetic field surveys for geological variations, detecting subtle anomalies indicative of archaeological features and artifacts, and identifying unexploded ordnance with precision and efficiency.

The MagNIMBUS Atomic Total-Field Magnetometer uses QuSpin Gen-2 atomic total-field magnetometer sensors, offering high precision and versatility for various applications. It features low clearance capability, allowing it to fly at incredibly low heights while safely navigating obstacles and vegetation. Its self-foldable sensor mount simplifies take-off and landing, reducing the need for extensive operator training. Available in vertical gradiometer and single sensor configurations, the system is tailored for different detection needs. The SkyHub onboard computer enhances data logging and terrain following for DJI drones, while the altimeter, either laser or radar-based, provides precise altitude measurements. 

The SENSYS MagDrone R4 Magnetometer is optimized for high-resolution mapping tasks, featuring 5 triaxial Fluxgate magnetic sensors for superior sensitivity and accuracy. Its high sensitivity allows it to excel in detecting small and compact objects buried beneath the surface. The included terrain following system in the recommended magnetometer bundle ensures optimal performance. It is easily integrated with drones capable of carrying a 2 kg payload, such as the DJI M350 RTK. The MagDrone R4 is ideal for conducting precise and efficient unexploded ordnance searches, surveying for archaeological features and artifacts, and detecting metal objects for various applications.