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iOSG™ Superconducting Gravity Sensors

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Observatory Gravity Meters
Observatory Gravity Meters
iOSG Meters
iOSG™ Meters

The iOSG™ Observatory Superconducting Gravity Meter is the latest, lowest-noise observatory-quality SG. It builds on the industry-leading OSG that has formed the core of the Global Geodynamics Project (GGP) network of observatory gravimeters.1,2

Like the OSG, the iOSG™ uses a superconducting shield, sphere, and coils3. Supercurrents flowing in the coils produce a magnetic field which levitates the sphere. The levitating sphere and magnetic field replace the function of the mass and mechanical spring found in other relative gravity meters. The perfect stability of the supercurrents produces a completely stable, non-mechanical, zero-mass, zero-length, non-degrading spring.


PDF iOSG™ Brochure (PDF - 859KB)


  • Sub µGal precision
  • Lowest noise below 1 mHz
  • Calibration better than 0.1%
  • Continuous time series
  • No gaps and no steps
  • Stable, flat transfer function
  • Ultra-low linear drift (~µGal/year)
  • Insensitive to local environment
  • Tilt stabilized

iOSG™ Gravity Sensor Specifications

< 1 (nm/s2) 2/(Hz)
Frequency domain
0.1 nanoGal (< 10-3 nm/s2) signals observed
Time domain
< 0.3 nm/s2 signals observed, 1-minute filtering
Scale factor
Stable to better than 1 part in 104 for decades
Linear to 1 part in 107
Cryogenic environment insensitive to temperature, pressure and humidity

System Electronics

Gravity control electronics
Sphere position controlled to < ±1 Å
Cryogenic temperature control
Sensor body controlled to < ±2 µK
Setra Model 270
Data acquisition
24-bit △∑ ADC; gravity oversampled 8x/sec
GPS timing
SEL-2401 Satellite Synchronized Clock

System Software

Remote system access and control
Via Internet or other TCP/IP connection
Operating system
Windows 7
iGrav® Monitor
Data acquisition, FTP data transfer
Sensor control panel and data plotting
Email alarm and warning messages
Data compression and storage
User-selected variables
Easy concatenation into continuous time series
Lossless data compression
Data saved in TSoft-compatible format

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