Magnetic Observatories (IMOs)

An INTERMAGNET Magnetic Observatory (IMO) is a magnetic observatory, having full absolute control, that provides one minute magnetic field values measured by a vector magnetometer, and an optional scalar magnetometer, all with a resolution of 0.1 nT. Vector measurements performed by a magnetometer must include the best available baseline.

An IMO must try to meet the following minimum requirements:

Vector Magnetometer

Vector Magnetometer requirements
Resolution 0.1nT
Dynamic Range 8000 nT Auroral and Equatorial
6000 nT Mid Latitude
Band Pass DC to 0.1 Hz
Sampling Rate 1 Hz (1 sec)
Thermal Stability 0.25 nT/°C
Long Term stability 5 nT/year

Scalar Magnetometer

Scalar Magnetometer requirements
Resolution 0.1nT
Sampling Rate 0.033 Hz (30 sec)
Accuracy 1 nT

Further details on IMO requirements are described in the INTERMAGNET Technical Reference Manual.