Method
Introduction
Measurements are made along lines using a total-field magnetometer suspended from an Unmanned Aerial Vehicle (Drone).
All pilots are FAA Part 107 certified, and operations are carried out in compliance with Zonge’s UAV SMS program.
Drone magnetics strikes a balance between helicopter-borne surveys and ground surveys. There may be slightly less detail than ground surveys, but draping with an RTK-based drone is generally better, so there can be more detail than helicopter surveys.
Applications
- Mapping mafic and ultramafic rock units and other magnetic lithologic contrasts
- Detecting magnetite-destructive alteration in porphyry, epithermal, and geothermal settings
- Mapping structure where magnetic units are offset across faults or contacts
- Mapping steel casing in abandoned wells and other magnetic anthropogenic features.
Survey Design
| Parameter | Description |
|---|---|
| Depth | Depth of investigation depends on body size, magnetic contrast, sensor height, and the noise environment. |
| Line Spacing | Typical line spacing ranges from 25-100 m depending on target size and the required level of detail. |
| Scale | Programs can range from small detailed surveys to broad line-kilometer campaigns where drone acquisition remains practical. |
| Production | Drone magnetics can significantly outpace ground magnetic programs in suitable terrain. |
| Processing | Data are processed and gridded in Oasis Montaj with filtering workflows that may include RTP and first vertical derivative products. |
Instrumentation
- Airborne Magnetometers: Geometrics MagArrow
- Base Station: GEM GSM-19 Overhauser magnetometer
Deliverables
- Contoured total magnetic intensity products, including reduced-to-pole grids where appropriate
- First vertical derivative and related filtered products
- Optional magnetic inversion products when survey objectives support modeling
Case Studies and Resources
- Contact Zonge for UAV magnetic survey examples, terrain-specific planning guidance, and representative deliverables.