 For this reason, coils like Helmholtz coils is commonly used either in a single axis or a three axis configuration.For demanding applications high homogeneity magnetic field is mandatory, in such cases magnetic field calibration can be performed using Maxwell coil, cosine coils, or calibration in the highly homogenous Earth's magnetic field.Magnetometers have a very diverse range of applications, including locating objects such as submarines, sunken ships, hazards for tunnel boring machines, hazards in coal mines, unexploded ordnance, toxic waste drums, as well as a wide range of mineral deposits and geological structures.