Magnetic background noise cancellation in real-world environments

Measurements of the magnetic field noise and the spatial correlation of the noise were made in a typical laboratory environment using two three-axis fluxgate magnetometers. The magnitude of the magnetic field noise was found to be approximately 100pT/√Hz at 10 Hz with a correlation of 90% at a separation of 1 m between the two sensors. The correlation was significantly reduced from noise induced eddy currents near large metallic surfaces. © 2000 American Institute of Physics.