A method and device produce an optical link with laser pulses between an emitter of the pulses and a receiver of the pulses. The optical link is used by a locating device for locating a body moving at constant speed away from the locating device. The locating device delays the start of emission of the laser pulses with respect to the departure of the moving body and varies the energy of the successive laser pulses in proportion to the square of the time elapsed since the start of emission of the pulses.