A method of tracking at least one mobile unit utilizing a radio and light based 3-D positioning system comprising a stationary self-positioning radio transceiver, a stationary laser transmitter positioned in a location with known coordinates, a wireless link, and a display. A read command requesting data is received from a requesting master device. In addition, in this polarization maintaining optical fiber coupler, in the fused and extended portion, the stress applying portions are enveloped by the cladding. The rotor is mounted on a rotary shaft extending in the transverse direction of the beach cleaner. Thus, only one mapping and encapsulation of data is required to directly enable through a physical layer the transparent transport of the Ethernet traffic to the OTN, and due to the rate-matching implemented upon the mapping, the traffic transport can be enabled in a standard-compliant way with guaranteed efficiency and quality.