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Triaxial Fluxgate Magnetometer

NSSDCA ID: 1977-029A-09

Mission Name: ESA-GEOS 1
Principal Investigator:Prof. Franco Mariani


A triaxial fluxgate magnetometer was employed for simultaneous measurements of the three components of the magnetic field. The frequency range covered by the instrument extended from dc up to 5 Hz. In the normal orientation of the satellite, the main component of the field coincided with the Z axis of the instrument, which was aligned with the spin axis of the satellite. The experiment was designed with two sensitivity ranges for the X and Y components for which the magnetic field component was only a fraction of the total field and was modulated by the rotation of the spacecraft. This last feature made the range switch technique preferable to a bias offset technique. The two selected sensitivity ranges were plus or minus 60 nT and plus or minus 180 nT respectively. Along the Z axis, where the field was higher and not modulated by the satellite rotation, a single sensitivity range of plus or minus 60 nT was used. The signal was kept within range by superimposing positive and negative bias levels of 60 nT each, such that a range of plus or minus 480 nT with a constant quantization error of plus or minus 0.125 nT using a 9-bit digitization was obtained. The noise level of the sensors was comparable to this quantization error. This instrument became saturated at geocentric distances less than about 4.5 earth radii.

Alternate Names

  • ESA-GEOS1/TriaxialFluxgateMagnetometer
  • S331

Funding Agency

  • European Space Agency (International)


  • Space Physics: Magnetospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Dr. Donald H. FairfieldOther InvestigatorNASA Goddard Space Flight
Dr. Maurizio CandidiOther InvestigatorCNR, Space Plasma
Dr. Ermanno AmataOther InvestigatorCNR, Space Plasma
Prof. Franco MarianiPrincipal InvestigatorUniversita degli Studi di
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