MagNIMBUS vs MagDrone R4: Which Drone Magnetometer Should You Choose?

Short answer: Choose MagNIMBUS if you want very low, safe flights for small UXO and buried metal, an atomic total-field sensor, and no base station (in its gradiometer form). Choose the SENSYS MagDrone R4 if you want five fluxgate sensors covering a 2.5 m swath per line from one compact kit strapped to a DJI M300/M350. Both are magnetometers, so both find ferrous (iron) metal, not aluminium, copper or gold.

Last updated: 24 October 2026.

Key takeaways

• MagNIMBUS (SPH Engineering): QuSpin QTFM Gen-2 atomic total-field sensors, as a single sensor or a gradiometer, logged by SkyHub.
• MagDrone R4 (SENSYS): 5 triaxial FGM3D/75 fluxgates on a 2.07 m tube, 2.5 m swath, own datalogger, 1,400 g.
• MagNIMBUS flies from a couple of dozen centimetres above the surface, and ground contact does not crash the drone.
• R4 data runs through the free MagDrone DataTool and SENSYS MAGNETO; SPH recommends Geosoft Oasis montaj for MagNIMBUS.
• Both suit a DJI M350 or M300 RTK. Neither should be used to declare an area free of landmines.

Drone magnetometers are used in India for UXO clearance on old ranges, locating buried pipes and cables, mineral prospecting and archaeology. HobiTech supplies both of these systems. This comparison uses the figures SPH Engineering and SENSYS publish; where a figure is not published, we say so.

Side by side

Figures from SPH Engineering and SENSYS, as listed on our MagNIMBUS and MagDrone R4 pages.

Where MagNIMBUS stands out

• Low and safe. The self-folding mount lets the sensor fly from a couple of dozen centimetres above the surface, and SPH says a sensor touching the ground or vegetation will not bring the drone down. That matters when searching fields for small items.
• No suspension cord. Because the mount folds for take-off and landing, the crew does not need the extra skill of flying a sensor on a hanging cord.
• Gradiometer option. With the gradiometer add-on, SPH says processing is simpler, no base station is needed, and you can survey near power lines and other EM sources.
• Published detection figures. SPH gives an estimated sensor-to-target distance of 1.0 m for an F1 hand grenade, and a few metres for aerial bombs.
• Survey time you can plan. SPH works through the numbers: 1 ha at 0.5 m line spacing and 2 m/s takes about 168 minutes of flight (about 4.5 hours with battery breaks on a DJI M350 RTK, which flies 30 minutes with the system). At 1 m spacing and 6 m/s, it takes 30 minutes.

Where the MagDrone R4 stands out

• Five sensors, one pass. The 2.5 m swath covers more ground per line than a single sensor, which helps on larger areas.
• Simple to fit. SENSYS describes strapping the R4 to the landing gear with four cable ties, and running it with a single button or over WLAN.
• Noise handling. Sampling at 200 Hz or more lets the R4 filter out noise from motors, power lines and infrastructure, which is why it can sit right on the airframe. SENSYS advises not to fly a camera gimbal with it.
• Self-contained. Its own datalogger and the free DataTool mean it does not depend on an onboard computer.

Which one to choose

• Small UXO on vegetated fields, or work near power lines: MagNIMBUS, ideally as a gradiometer.
• Larger areas where swath width saves flight time: MagDrone R4.
• Buried pipes and live power cables: both detect them. SPH lists metallic pipes and cables under load for MagNIMBUS.
• Mineral prospecting and geology: both are used. Tell us the survey scale and target.

Either way, plan the lines in UgCS (SPH pairs MagNIMBUS with UgCS EXPERT), and consider a MagBase reference station for single-sensor work. Our drone magnetometer guide also covers the Geometrics MagArrow and the MagDrone R1 and R3.

A note on landmines

SPH Engineering is clear that MagNIMBUS can detect only some landmine types with a lot of ferrous metal, such as TM-62M and OZM-72, and must never be used to confirm that an area is free of landmines or small UXO. The same caution applies to any drone magnetometer: it supports non-technical and technical surveys, it does not replace clearance.

Sources: product data published by SPH Engineering and SENSYS, as listed on each HobiTech product page.

Frequently asked questions

What is the difference between a fluxgate and an atomic magnetometer?

A fluxgate, like the R4's FGM3D/75, measures the magnetic field along three axes. An atomic total-field sensor, like MagNIMBUS's QuSpin QTFM Gen-2, measures the strength of the total field. Both detect the anomalies that buried ferrous objects create.

Can a drone magnetometer find gold or aluminium?

No. Magnetometers respond to ferrous (iron) metal. SENSYS notes the R4 does not detect aluminium or gold, as they are only conductive. For those, look at a metal detector such as the Ebinger VEMOS AIR.

Do I need a base station?

Not for MagNIMBUS in the gradiometer configuration. With a single MagNIMBUS sensor, SPH recommends one in some cases; the R4's DataTool supports MagBase or GPS referencing.

Which drone do these magnetometers need?

Both suit a DJI M350 or M300 RTK. SPH supplies MagNIMBUS mounting sets for other drones, including Pixhawk-based drones, on request. SENSYS lists the R4 at 1,400 g and advises checking your drone's payload against 1.5 kg or more.

How low should a drone magnetometer fly?

As low as is safe for compact targets: SENSYS suggests 50 cm for the R4, and MagNIMBUS can fly from a couple of dozen centimetres. True Terrain Following with a radar altimeter keeps that height over uneven ground.

How do I buy a drone magnetometer in India?

Both are quoted per configuration with a GST invoice. Send us your survey details and drone, and we will recommend the system and mounts.

Still deciding? Tell us what you need to find and the drone you fly.