MGS-6 Gravity Meter
(Marine Gravity System)

Features and Specifications
MGS-6 Brochure


Micro-g LaCoste is proud to announce the next generation of marine based dynamic gravity meters: The Marine Gravity System-6 (MGS-6). It represents the next generation in a long line of LaCoste-based dynamic gravity systems, stretching back to the first successful dynamic gravity meter tests on ships more than 50 years ago. Note though, that the MGS-6 is more than a simple upgrade to the Air-Sea System II (AS-2). The MGS-6 is based on the smaller, lighter, more power-efficient TAGS-6 (airborne) platform, and employs the same full-force feedback sensor. In both systems, the platform control and data acquisition system have been overhauled, resulting in unparalleled data quality.

Sensor Improvements

As mentioned above, the MGS-6 employs the same, full-force feedback sensor that is used in the TAGS-6 system. This system insures that the floating beam is always held in the center of the sensor range. The electrical force necessary to keep the beam centered is proportional to gravity. This system functions not only over the entire worldwide gravity range, but also in highly dynamic environments. Indeed, the MGS-6/TAGS-6 can endure accelerations of ± 500,000 milliGals without saturating.

The true advantage of the new sensor however, is the increased accuracy over its entire (expanded) range. The older AS-2 system had a much smaller region in which it could measure accurately. So not only did it saturate at smaller local accelerations, but a spring tensioning system had to be employed to keep the beam "in range" as local gravity changed. Further, because the beam was actually moving, its velocity had to be calibrated to gravity. The imperfect mechanical properites of the screw and the behavior of the beam "off-center" meant that the system was nevery perfectly linear, and these errors showed up in the data as system noise.

Finally, the data acquisition system has been improved by going from a 16-bit to 24-bit A2D (effectively 25-bit; the raw sensor samples at 100Hz, and the data are recorded at 1Hz). The result is the quietest, most precise, and most accurate dynamic gravity meter ever made. The figure below shows actual earth tides measured over a rougly two day period. Note that these are not data from a static sensor - this sensor is mounted in the active, level-controlled platform (gimbal).

Comparison with Original AS-2

  • Smaller sensor/gimbal (60%)
  • Lighter sensor/gimbal (30%)
  • New slip ring technology on the gimbal makes for a more robust and reliable stable platform
  • Larger Pitch (25° vs. 22°) and larger Roll (35° vs. 25°) ranges
  • Full feedback: ± 500,000 mGal range on beam
  • 100 times the dynamic acceleration range
  • Double oven temperature control
  • Temperature controlled electronics
  • Separate, rack-mountable electronic unit and computer allow for more flexibility in configuration
  • Lockable gimbal
  • System ships with gimbal installed in frame
  • Static Repeatability improved (0.02 vs. 0.05 millGals)
  • Reduced Power requirements (75 vs. 240W)
  • Greatly reduced size: 48% smaller (59 x 53 x 56cm vs. 71 x 56 x 84cm, frame size)
  • Greatly reduced weight (101kg vs. 121kg, including UPS and electronics)

Shown above is the original AS-2 next to the frame of the MGS-6. Note the size difference.

Upgrade path to TAGS-6

Because the MGS-6 is based on the same platform and sensor as the TAGS-6, Micro-g LaCoste is pleased to announce that an upgrade path is available! Please contact Micro-g LaCoste for pricing and options.

Applications include

  • Geoid Mapping
  • Petroleum Exploration
  • Regional Geophysics
  • Mineral Exploration

For a complete list of applications, specifications, and example data, please download a pdf version of the MGS-6 brochure here.