"Stray magnetic field(s)" are adverse magnetic fields that exist around the instrument. ... The former includes non-periodic magnetic fields generated by cars and trains, and geomagnetism. The latter includes periodic magnetic fields generated by power supplies, fluorescent lamps and external devices.

What does stray field mean?

[′strā ¦fēld] (electromagnetism) Leakage of magnetic flux that spreads outward from a coil and does no useful work.

How can we reduce stray magnetic field?

Homogenous stray magnetic fields can be suppressed using just a two-pole magnet for linear position detection and full 360-degree angle measurement. For 180-degree angle measurement, a four-pole magnet may be used, suppressing gradient fields.