Groundtech GR-3 PLUS 3D Ground Scanner

The Groundtech GR-3 PLUS is a handheld 3D ground scanner for treasure hunters and relic hunters who want the deepest scanning in the GR-3 series in a light wand. It weighs 600 grams (1.3 pounds), has no cables or external battery, and sends its scan to the Groundtech GR-3 app on an Android or iOS phone or tablet in real time. Groundtech gives a scanning depth of up to 15 meters (49 feet), depending on the target's size and the soil structure.

What is in the box with the Groundtech GR-3 PLUS

Groundtech's standard contents for the GR-3 PLUS

• Groundtech GR-3 PLUS main unit
• 5 V charging adapter and cable
• Carrying case
• User manual
• Warranty certificate

How the Groundtech GR-3 PLUS scans

Groundtech describes the GR-3 as a single sensor system and the GR-3 PLUS as a dual sensor system; both work with a 240 MHz processor and a 12-bit A/D converter. The scan data appears in real time on your phone or tablet over Bluetooth 4.2 BLE, and Groundtech says the software graphically displays magnetic metals (iron or steel) and non-magnetic metals (gold, silver or copper), as well as cavities such as graves, rooms and tunnels. Groundtech gives up to 15 meters (49 feet) for the GR-3 PLUS and says it can be used on sandy, rocky or clay soil. We would treat every anomaly on a scan as a place worth investigating rather than proof of what is buried. Groundtech's maximum depth figure depends on the target's size and the soil structure, so we would expect small objects to read at much shallower depths than the headline figure.

Four scanning modes

• Auto: automatic 3D ground scanning.
• Manual: manual 3D ground scanning.
• Live Scan: quick graphical scanning without a fixed search pattern.
• Pinpointer: helps locate the exact position of an object before you dig.

We would start a new site in Live Scan, then run an Auto scan over the area that interests you and save it, so you can compare it with a second scan before you dig.

App, battery and size

Scans save to your mobile device so you can review them after the survey. The 3.7 V rechargeable lithium-ion battery is internal and runs approximately 8 hours, according to Groundtech, with a 5 V, 2 A charging input. The GR-3 PLUS measures 810 x 70 x 70 mm (31.9 x 2.8 x 2.8 inches). Groundtech gives an operating temperature range of 0 to 70 °C (32 to 158 °F).

For a single sensor version with up to 7 meters (23 feet) of scanning depth, Groundtech makes the Groundtech GR-3; for a scanner with its own screen, see the Groundtech GR-4.

Permission and protected sites

We would get the landowner's permission before any survey and check the laws that protect historic sites, archaeological sites and burials where you plan to scan. A Groundtech scanner can show where something is different underground; it does not tell you whether you may dig there.

Groundtech GR-3 PLUS specifications

Groundtech covers the GR-3 PLUS with a 2-year warranty.

Both GR-3 models are in our Groundtech GR-3 collection, and our Groundtech buyer's guide compares the full Groundtech range.