Abstract: A container 11, carries a component 12 of the telemetry system. The container mounted unit 12 transmits via its antenna 34, a signal 41 containing data indicating the status of the container. This signal is received by shipboard transponder 32 including an antenna 33, a first transceiver 35 for communication with shipboard devices such as the container module 12, control unit 36 which monitors and buffers signals for re-transmission and routes incoming signals, and a second transceiver 37 which transmits and receives signals 39, to and from the satellite 15 via its antenna 38. Thus signals from the container mounted module 12 may be relayed via the shipboard relay 32, the satellite 17 and the communications network 19, 20, 21 to the receiver station 22.

Abstract: A synchronisation system for synchronisation of multiple markers (12,13,14) in a geographical location or waterway (16). Synchronisation is achieved by periodically re-synchronising each marker (12,13,14) to a common reference signal. A wireless communications system is used to distribute the reference signal to isolated markers. The markers (12,13,14) are also remotely monitored to indicate the status of multiple markers which is communicated to a central control centre. The status can indicate the number of spare light bulbs left. the status of the spare bulbs, the correct or incorrect flashing of the light, unauthorised entry to or tampering with the marker or lighthouse. the condition of the battery and/or the correct function of a solar panel or other remote power source. The status of multiple markers is then communicated to a central control centre or to another location.