A method and an arrangement is provided for determining the location and/or speed of an object configured to move along a controlled trajectory, in connection with which object is fitted a measuring device measuring at least the magnetic field acting on the object in its different locations, which measuring device comprises a device configured to measure the magnetic field, from the measuring data received from which device a magnetic footprint describing the magnetic field acting on the object in its different locations is formed, which magnetic footprint is recorded in connection with a teaching run, or with self-learning, for later use. The location of the object after a teaching run is determined by measuring in essentially real-time in the direction of the three coordinates X, Y, Z of the magnetic field acting on the object moving along a controlled trajectory and by comparing the measurement results to a magnetic footprint recorded in advance and also by deducing as a result of the comparison the exact location of the object on its path of travel.