Indoor positioning via magnetic field measurement: This method of positioning makes use of the magnetic field of the earth. It takes advantage of the fact that modern buildings have a specific magnetic fingerprint, which results from the interaction of the earth’s magnetic field with the building materials used and the architectural features. The more steel used in the building, the better for this positioning solution. So what proves to be disturbing when positioning via radio signals is what makes positioning possible in this case. The steel is responsible for the characteristic interference of the earth’s magnetic field. Positioning with an accuracy of one to two meters should be possible with the help of the compass integrated in modern smartphones.