Geomagnetic Observatory
The geomagnetic observatory, in operation since 1953 and following on the previous century-old tradition of magnetic observations in the Brussels area, consists of variometers for measuring the variations of the field components about the baseline and magnetometers for the absolute measurements needed to establish the baseline values (Verhulst et al., 2014). The current data acquisition cadence is 1 second for time, with a precision of 0.1 nT for the induction and 0.001°) for both, the declination and the inclination. Real-time measurements from the observatory are used for estimation of the local magnetic activity (Stankov et al., 2011).
References:
Verhulst, T., Stankov, S., Rasson, J. (2014): The geomagnetic field—an actively changing global phenomenon. KBVE Review E Tijdschrift—Journal of the Royal Belgian Association of Electrical Engineers (KBVE), 130 (2), 1–6.
Stankov, S.M., Stegen, K., Warnant, R. (2011): K-type geomagnetic index nowcast with data quality control. Annals of Geophysics, 54 (3), 285–295, (doi:10.4401/ag-4655).