In a system for sensing a relative position between vehicles, each vehicle (1) has an emitting device (2) of a position sensing ray to the other vehicle, and a ray receiving device (3) of the position sensing ray from the other vehicle. Each vehicle (1) calculates the relative position of the other vehicle to itself by triangulation based on the received position sensing ray, to determine the relative position in both lateral and longitudinal directions, using a planar coordinate detector in the receiver. <IMAGE>
