Compact fluxgate magnetic full-tensor gradiometer with spherical feedback coil.

Area of Science:

• Geophysics
• Instrumentation
• Magnetic field measurement

Background:

• Magnetic tensor gradiometers are crucial for characterizing magnetic fields.
• Existing designs can suffer from crosstalk and orientation errors.

Purpose of the Study:

• To describe the construction of a novel magnetic full-tensor gradiometer.
• To enhance accuracy, stability, and reduce errors in magnetic field measurements.

Main Methods:

• Utilized four fluxgates on a planar cross structure with a single triaxial spherical feedback coil.
• Employed a reference fluxgate to control feedback coil currents.
• Operated fluxgates in a near-zero magnetic field environment.

Main Results:

• Achieved a measured gradient tensor magnitude of 0.52 nT/m/Hz(1/2) @ 1 Hz in unshielded conditions.
• Demonstrated improved stability, accuracy, and reduced crosstalk and orientation errors.
• Successfully verified functionality by locating a small dipole magnet.

Conclusions:

• The developed magnetic full-tensor gradiometer offers high performance and stability.
• Its compact, global feedback design makes it suitable for space-constrained moving platforms.
• This instrument advances magnetic field characterization capabilities.