Axis axial position measurement system uses the electric signal generated by one or more sensors at the passage of teeth of a cogwheel fixed on the axis. The cogwheel is cut with at least one group of teeth, including at least three types of teeth of different height: a first type of teeth (1) of constant maximum height, a second type of teeth (2) of constant minimum height, and a third type of teeth (3) of variable height in the axial direction of the axis between the maximum and minimum heights of the teeth of the first and second type of teeth.