Abstract: An identification unit including a memory unit operable to store an identification that distinguishes the identification unit from other identically constructed identification units, an ultrasonic receiver, a radiation transmitter, a radiation receiver and a control unit operable to carry out an ultrasound propagation time measurement depending on a synchronization signal received by the radiation receiver and operable to transmit a result with the aid of the radiation transmitter. At least one of a luminous unit and an optical signaling unit is driven via the radiation unit.

Abstract: A locating arrangement has ultrasonic transmitters strung along a straight section. The use of the ultrasonic transmitters for determining a location along the section is possible with a high spatial resolution and for a multiplicity of identification units.