24-Bit Geophysical EM Measurement System As in seismics, technological advances in electromagnetic recording systems have emphasised the requirement for simultaneous multi-channel data acquisition.
The Multi-Method Network Geophysical Measurement System GMS‑07 is the result of over 30 years of metronix´s experience in the design and manufacture of electromagnetic geophysical instruments.
The electric and/or magnetic field sensors are connected directly to the ADU‑07e (Analog/Digital Signal Conditioning Unit), which is the core unit of this system. Multiple ADU‑07e units can be connected to a network using simple, light-weight and inexpensive network cable or Wireless LAN. Each ADU‑07e can be operated as a stand alone system, in a network or as part of an array in which each unit is synchronized by its in-built GPS clock.
Metronix builds data logger and induction coils for more than 30 years.
The ADU‑07e electronics are housed in a small waterproof box only 7kg in weight. It comprises the complete circuitry for analog signal conditioning, 24 Bit A/D conversion and data storage. A very precise GPS-controlled time base guarantees synchronous recordings even under difficult GPS reception conditions.
The ADU‑07e can be tailored according to the user´s requirements. So the ADU contains 10 slots which can be equipped with 2 different types of A/D converter boards. A/D converter Type L is optimized for lower frequency recordings in a range from DC up to 500Hz whilst the second type H is optimized for high frequency recordings in a signal range from 1Hz up to 250kHz. For instance a broadband standard ADU‑07e is equipped with 5 low-frequency and 5 high-frequency A/D converter modules. It is possible to obtain high-frequency soundings during running low-frequency recording. Different types of sensors can be connected to the ADU and can even be operated in parallel. Example: A fluxgate sensor is connected for low-frequency sounding and induction coils cover the higher frequency range simultaneously.
The ADU‑07e has a built-in web server. All necessary setups to run a measurement are controlled by the web interface and can be accessed by any web browser; no software needs to be installed on your laptop or PDA. The software MAPROS (free) performs standard and remote reference processing of the time series data using robust algorithms. Online processing inside the ADU‑07e with unattended data publishing on the ADU's web server is under construction. Using an external GPS controlled transmitter the ADU‑07e provides CSAMT/CSEMM recordings with real-time stacking.
Single Site Configuration In this configuration a single ADU‑07e runs either in a stand alone mode and records the data according to a time schedule pre-programmed on its internal flashdisk. For highest performance an external computer can control the ADU via the USB 2.0 interface; in the latter case incoming data is processed and displayed in real time.
Multiple Site Configuration In this configuration several ADU‑07e systems are synchronized by their built-in GPS clocks, and they record the data synchronously. A typical application for this configuration is the Remote Reference method or Array Mapping. This arrangement is used for a grid with wide-spaced recording sites where cabling is impractical or cannot be handled economically.
Multiple ADUs are connected to a network by cable or WLAN. A typical example for this configuration is E‑MAP or field setups, where a close-spaced station grid is required.
DC to 250 kHz
|Number of channels|
1 up to 10 per ADU 07e
3 Bands (LF DC-1 kHz; MF DC-16kHz; HF 1 Hz-250kHz)
Sub-bands are created by digital filtering
Both bands can be recorded simultaneously
24 Bit (max. data rate max. 4096 samples/sec) LF Board
24 Bit (max. data rate max. 65536 samples/sec) MF Board
24 Bit (max. data rate 524,288 samples/sec) HF Board
> 130 dB
32 bit embedded controller, Linux
Internal SD cardup to 32GB or more, USB devices
Automatic power up self test of all important system functions including sensors and display of result on the instrument. Automatic creation of logfile
input resistance > 10 Mohm, ODU G32KON-T06QP00-000 (ADU E socket)
ODU S22KON-T06MPL0-4000 (E-Field cable plug)
input resistance 20 kOhm, socket ODU G32KON-T10QJ00-000 (ADU socket)
ODU S22KON-T10MJG0-7000 (H-Field cable plug)
|Multipurpose connector (E/H)|
input resistance > 10 Mohm (E), 20 kOhm (H); ODU G33KON-T30QF00-000 (ADU socket)
ODU S23KOC-T30MFG0-7000 (cable plug)
standard 100 Mbit Twisted Pair, WLAN
GPS clock +/- 30ns rms to satellite reference.
Station position is also determined and stored
network, magnetometers, E-field lines 2 battery inputs, GPS antenna, USB, wireless, Bluetooth
ruggedized, waterproof polycarbonate case
appr. 7.1 kg
400 x 330 x 170 mm
appr. 3-10 W (LF); 12 -20 W HF @ 64kHz up to 524 kHz sample rate
|Operating temperature range|
-40°C to + 60°C (with flash disk)