High precision trajectory and speed sensor and measuring method

A method for contactlessly determining an exact passage of an athlete at points placed along a track in sports, wherein the method comprises gearing the athlete with a wearable magnetometer sensor unit, whereby the magnetometer sensor unit is equipped with at least a magnetic sensor, a processing unit, and a storage medium; placing at each point at least a permanent magnet in proximity of a track surface of the track. When the athlete moves along the track, the method further comprises recording at the magnetic sensor a signal; detecting for each permanent magnet a disturbance of a local magnetic field generated by the permanent magnet in the recorded signal and measuring the disturbance; mapping of the measured disturbance to a movement speed of the athlete and a distance of the athlete to the magnet corresponding to the local magnetic field; and correcting the movement speed and the distance for a time offset between the magnet passage of an athlete's center of mass and the magnetometer sensor unit.