Terra Exploration Group MGM4000

Magnetic Gradient Mapper

Professional Magnetic Field Mapping and Subsurface Detection

The MGM4000 is a professional-grade Earth's Magnetic Field survey instrument engineered to reveal underground what traditional tools miss. Using Low-SWaP dual tri-axial magneto-inductive sensors and precision gradient measurement, it maps changes in the Earth's Magnetic Field to reveal buried structures, voids, metals, pipelines, water, and mineral targets with exceptional clarity up to 20 Meters — all in real time.

Accuracy that matters:

With sub-nanotesla sensitivity and a precise 0.5m baseline gradient configuration, the MGM4000 captures subtle magnetic field variations with survey-grade stability. Advanced onboard filtering and full tilt compensation preserve data integrity even in challenging terrain and variable motion.

Lightweight. Field-proven. Designed for explorers, archaeologists, geologists, miners, utility locators, and geophysical professionals who demand reliable imaging — anywhere.

Terra Exploration Group MGM4000

The MGM4000 is a portable, ground-based magnetic gradiometer designed for high-resolution mapping of subsurface magnetic gradients associated with geological structure, lithological contrast, and mineralization-related alteration.

The system employs paired low-SWaP magneto-inductive vector magnetic sensors operating in a fixed-baseline configuration to measure first-order magnetic field gradients, enabling discrimination of localized geological features while suppressing regional magnetic background.

The MGM4000 is engineered to operate in the resolution gap between metal detectors and regional geophysical surveys, providing structurally meaningful magnetic data at exploration-relevant depths.

The collected data can be displayed during the survey, allowing the operator to observe magnetic anomalies and their spatial distribution in real time.

This approach makes the MGM4000 particularly useful when the objective is not simply to locate a single target, but to map an underground anomaly and understand its shape, extent and position.

Real-Time Magnetic Mapping

One of the key features of the MGM4000 is its ability to provide live magnetic gradient data and instant field imaging during a survey.

The system can display magnetic measurements as the operator moves across the survey area. This allows potential anomalies to be identified while fieldwork is still in progress rather than waiting until the entire survey has been completed.

The Terra Exploration Group system also supports post-processing functions through the Terra X Mapper App, including interactive data visualization, data editing, 3D graphing, GPS and gradient data display, KMZ export and satellite-image overlays.

Post Image Processing with the Terra X Mapper App

High-Sensitivity Magnetic Gradient Measurement

The MGM4000 is designed to detect relatively small variations in the Earth's magnetic field. Terra Exploration Group specifies sub-nanotesla sensitivity and a 0.5-meter gradient baseline for the system.

Advanced onboard filtering and tilt compensation are incorporated to help maintain data quality when surveying over uneven terrain or during operator movement.

These characteristics are particularly important in magnetic surveying because small variations in sensor orientation, movement and environmental interference can influence the measured magnetic field.

3D Interactive Data Graphs

What Can the MGM4000 Detect?

Magnetic surveying cannot directly identify every type of underground target. Its effectiveness depends on the magnetic properties of the target and surrounding ground.

However, magnetic anomalies can be associated with a wide range of underground features, including:

Buried ferrous objects
Buried metallic structures
Underground pipelines
Archaeological structures
Geological formations
Mineralized zones
Iron-rich geological formations
Underground cavities and void-related anomalies
Other subsurface magnetic anomalies

Terra Exploration Group states that the MGM4000 can be used to investigate buried structures, voids, metals, pipelines, water and mineral targets, with an advertised detection depth of up to 20 meters depending on target and ground conditions.

3D Interactive Data Graphs

Applications of the MGM4000

Archaeological Surveys
Geological and Mineral Exploration
Underground Void and Cavern Investigation
Pipeline and Utility Surveys
Buried Object Detection

Magnetic Mapping

One of the main advantages of the MGM4000 is its emphasis on mapping.

A point-based detection system may indicate that a target is present at a particular location. A magnetic mapping system can provide a broader picture of how magnetic values change across an area.

This makes the MGM4000 useful for applications where understanding the shape, continuity and spatial distribution of an anomaly is important.

The resulting data can be examined as profiles, 2D magnetic maps and 3D visualizations, providing additional information for interpretation.

GPS and Geospatial Data

The MGM4000 integrates magnetic gradient measurements with positioning information, allowing survey data to be associated with geographic coordinates.

The Terra X Mapper App provides GPS and gradient data visualization and supports KMZ export and satellite imagery overlays. This allows survey results to be viewed in a geographic context and compared with satellite imagery or other mapping information.