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GEO EMAP-1 120-Channel Multifunction Array Electromagnetic System | AMT+ERT
PRODUCT PARAMETERS
Description
Abstract
The GEO EMAP-1 120-channel multifunction array electromagnetic system is the flagship configuration of GEOTECH’s independent R&D product line. It innovatively integrates Array Audio-frequency Magnetotellurics (RAMT, 10 Hz–20 kHz) and High-Density Electrical Resistivity Tomography (ERT), enabling simultaneous acquisition of two geophysical datasets with a single electrode deployment, maximizing survey efficiency for large-scale and deep exploration projects.
This 120-channel full configuration is designed for ultra-long profiles and large-area 3D survey projects, delivering maximum detection depth and coverage range, and is the preferred solution for regional geological survey, energy exploration and large-scale geohazard assessment. The system supports multi-mode wireless communication via Bluetooth, WiFi and 4G/5G, simplifying large-scale array layout in complex terrain. GNSS pulse-per-second synchronization keeps clock error below 50 nanoseconds, ensuring phase coherence across the 120-channel distributed array. Combined local magnetic sensing with distributed multi-point measurement effectively suppresses cultural noise and improves deep sounding accuracy, while the distributed cascaded architecture supports multi-unit networking for larger-scale survey demands.
Features
Full-channel dual-method efficiency
Array AMT and ERT share one 120-channel electrode array; a single deployment returns two complete datasets, delivering the highest efficiency for ultra-long profile and 3D surveys.
GNSS sub-nanosecond sync
GNSS pulse sync with clock error under 50 ns ensures strict phase consistency across all 120 channels, supporting high-precision joint inversion of large-array dual-method data.
Full-depth observation coverage
Supports 2D/3D ERT & IP surveys (Wenner, Schlumberger and other arrays) plus array AMT sounding, realizing continuous high-precision detection from shallow surface to kilometer-deep geological structures.
Full-scene wireless interconnection
Bluetooth, WiFi and 4G/5G multi-mode links cover all complex field conditions; paired with an Android industrial panel for distributed control of the 120-channel array.
High SNR magnetic system
1 Hz–100 kHz wide-band AMT magnetic sensor; host unit supports 1 extra magnetic coil to maximize noise suppression and improve deep data quality.
Maximum-scale cascaded architecture
Distributed cascade cabling design with 120-channel full configuration; supports multi-unit GNSS synchronous networking for super-large 3D survey and ultra-long profile requirements.
Specifications
System Info
| Parameter | Specification |
| Frequency Range | 10 Hz ~ 20 kHz |
| Clock Sync | GNSS pulse sync; error < 50 ns |
| Communication | Bluetooth, WiFi and 4G/5G |
| Magnetic Sensor | 1 Hz ~ 100 kHz AMT mag Sensor; host supports 1 extra Mag coil |
Observe and Expand
| Parameter | Specification |
| Measure Array | 2D/3D ERT and IP; Array AMT |
| Electrode Spacing | 10 m standard; adjustable for AMT survey |
| Channel Configuration | 120 channels (10 × Switch-12 units); supports multi-instrument GNSS sync networking |
Power & Environment
| Parameter | Specification |
| Power | Built-in instrument battery; high-voltage input via DC480 power module |
| Operating Temp. | -20℃ ~ 60℃ |
System Components
This 96-channel professional package includes full hardware, software and service as follows:
GEO EMAP-1 Main Unit
Packaged in a portable waterproof case with built-in lithium battery; supports ERT & IP functions and 1 extra magnetic coil; 4G/5G + Bluetooth dual-mode communication.
| Item | Spec | Quantity |
| Communication | 4G/5G + Bluetooth dual-mode | 1 unit |
| Core Function | ERT / IP / Array AMT | 1 unit |
DC-480 Adjustable DC Lithium Battery Power Supply
10-level adjustable output, maximum 480 V / 2.0 A, providing high-voltage DC for transmission; IP67 rated for field use.
| Item | Spec | Quantity |
| Output voltage | Up to 480 V (10 steps) | 1 unit |
| Max. current | 2.0 A | 1 unit |
Cascade Converter
12-tap non-directional electrode switcher; 1000 V / 4 A rating; lightweight for easy field deployment.
| Item | Spec | Quantity |
| Channels per unit | 12 electrode channels | 10 units (total 120 channels) |
| Rating | 1000 V / 4 A | – |
Android Control Panel
Industrial-grade Android tablet for wireless acquisition control, real-time data monitoring and parameter setting.
| Item | Spec | Quantity |
| System | Android OS | 1 unit |
AMT Magnetic Sensor
Wide-frequency magnetic sensor for audio-frequency magnetotelluric signal acquisition.
| Item | Spec | Quantity |
| Frequency range | 1 Hz ~ 100 kHz | 1 piece |
Cascade Electrode Cable
12-tap cable with 10 m tap spacing, matched with Switch-12 units.
| Item | Spec | Quantity |
| Tap configuration | 12 taps per string | 10 strings |
| Tap spacing | 10 m | – |
Non-polarizing Electrode
30 cm non-polarizing electrodes for stable contact resistance, compatible with cascade cable strings.
| Item | Spec | Quantity |
| Type | Non-polarizing electrode | 96 pieces |
| Length | 30 cm | – |
Survey & Processing Software
Dedicated acquisition control and post-processing software, supporting data quality control and joint inversion visualization.
| Item | Spec | Quantity |
| Function | Acquisition + processing + inversion | 1 license |
System Connection
2D EMAP + RAMT Survey
The 120-channel full array supports 2D high-density ERT and array AMT survey for ultra-long profiles, with GNSS synchronization for large-depth and high-precision detection.
3D Survey Capability
Supports simultaneous 2D and 3D resistivity & AMT acquisition, and can be combined with more units for large-area 3D geological survey and regional exploration.
Applications
- Regional geological survey and deep mineral prospecting
- Large-scale engineering geological investigation
- Deep geohazard investigation and risk assessment
- Deep groundwater and environmental geological survey
- Deep archaeological and municipal engineering survey
- Oil, gas and geothermal energy exploration
- Long-distance transportation engineering geological survey
- Large hydraulic engineering deep geological detection
Case Studies
GEO EMAP-1 Joint Array AMT + ERT Observation Test (Shibei No.1 profile)
A single electrode layout acquired array AMT and ERT data simultaneously: ERT provides shallow high resolution while AMT reveals deep resistivity structure, cross-validating each other to form a complete electrical section from shallow to deep.
- The 120-channel full configuration adapts to long survey profiles, realizing high-efficiency joint detection from shallow fine strata to deep geological structure with one deployment.
- The joint inversion section clearly delineates overburden thickness, bedrock relief, deep fault and geological anomaly distribution.
FAQ
In gravity exploration (SI), what is the unit of gravity? How to convert gravity units between SI and CGS?
① In SI, it is m·s-2, and one percent of it is the international unit abbreviation g.u.;
② Conversion between SI and CGS: 1g.u.=10-1 mGal
What are gravitational field and gravitational potential?
Gravitational field: The space around the earth with gravity is called the gravitational field.
Gravitational potential: The gravitational potential W in the gravitational field is equal to the work done by a particle of unit mass moving from infinity to that point.
What is the normal gravity field of the earth? What are the rules for the change of the normal gravity field with latitude and altitude?
① The normal gravity field of the earth: Assuming that the earth is a rotating ellipsoid (reference plane), the surface is glossy, the internal density is uniform, or it is distributed in concentric layers, the density of each layer is uniform, and the deviation of the shape of the ellipsoid from the geoid is very small, then the gravity field generated by the earth is the normal gravity field.
② The normal gravity value is only related to the latitude, the smallest at the equator and the largest at the poles, with a difference of about 50,000 g.u.; the rate of change of the normal gravity value with latitude is the largest at 45° latitude, and zero at the equator and the poles; the normal gravity value decreases with increasing altitude, and its rate of change is -3.086 g.u.. The main feature of the long-term change is the "westward drift" of the geomagnetic elements, both the dipole field and the non-dipole field drift westward, and have a global nature.
What is the relationship between gravitational field strength and gravitational acceleration?
The gravitational field strength is equal to the gravitational acceleration in both numerical and dimensional terms, and the two are in the same direction. In gravity exploration, all references to gravity refer to gravitational acceleration. The gravitational field strength at a point in space is equal to the gravitational acceleration at that point.
What is gravity exploration?
Gravity exploration is an exploration method that is based on the density difference of rocks and ores. Since density difference will cause local changes in the normal gravity field of the earth (i.e. gravity anomaly), it is used to solve geological problems by observing and studying gravity anomalies.
