Abstract: The present invention relates to a transfer system for providing wireless data transfer, electrical power transfer and navigation between a mobile subsea vehicle and a deployed subsea station that uses acoustic and electromagnetic carrier signals for wireless communication and navigation. An inductive connector is provided for power transfer between mobile subsea vehicle and a deployed subsea station without conductive contact.

Abstract: The present invention provides a precision alignment system operable to provide alignment of a first and second apparatus. The precision alignment system makes use of inductive coupling between loop antennas in the first and second apparatus. The mechanism for alignment is the detection of a null in the signal induced in the loop antennas of the second apparatus arising from an input signal fed to a loop antenna of the first apparatus. The precision alignment system can be incorporated in a system for the wireless transfer of electrical power or may be incorporated in a system for the transfer of data. The precision alignment system of the present invention is particularly suited to applications where optical or other means for alignment of two apparatus are unreliable. In particular, the alignment system disclosed is suitable for operation underwater.

Abstract: The present invention discloses a system for digitally modulated radio communication directly between a submerged underwater station and an airborne station. Each of the underwater station and the airborne station has or is associated with a radio communications antenna. Suitable radio communications antennas include loop antennas, solenoid antennas, stacked multiple loop antennas, planar arrayed loop antennas, a multiple resonant loop antennas. In some embodiments, the communications antennas of the submerged underwater station and the airborne station are each deployed horizontally thereby improving the efficiency of the signal transfer between the submerged underwater station and the airborne station.

Abstract: An underwater system (10) comprising a transmitter (12) for broadcasting an electromagnetic synchronisation signal and at least one node (14) that has a receiver for receiving that signal, the node being adapted to use the received signal for synchronisation.

Abstract: The present invention discloses a tagging and identification device and system for tracking and monitoring sea vessels as they enter sea ports, estuaries and/or other channels. The tagging device of the present invention comprises a receiver, for receiving an underwater electromagnetic signal transmitted by an underwater beacon. An acoustic transmitter is provided for transmitting an identification signal to an acoustic receiver deployed nearby. The acoustic identification signal is transmitted after an electromagnetic trigger signal is received from the underwater beacon. The tagging and device may further comprise a memory device which can store data relating to position and time of the see vessel to which it is attached. The tagging and identification device of the present invention is covert, compact and is capable of extended active deployment without replenishment of batteries etc.

Abstract: The present invention provides an antenna for underwater radio communications. The antenna of the present invention comprises an elongate section submerged in water and a feed point for feeding electrical signals to the antenna located on the elongate section, the elongate section is attached to an underwater object at a first end thereof, and during deployment hangs downwards there from so that said elongate section is substantially vertical in orientation. A first portion of the elongate section comprises a flexible wire having an electrically conductive core, which is electrically insulated on an outer surface thereof. During operation the flexible wire radiates electromagnetic signals through the water.

Abstract: The present invention provides a buoy supported antenna for underwater radio communications. The antenna of the present invention comprises an elongate section submerged in water and a feed point for feeding electrical signals to the antenna located on the elongate section, the elongate section is attached to an underwater object at a first end thereof, and during deployment is suspended by a buoy at a second end thereof so that the elongate section is substantially self supporting and vertical in orientation. At least a first portion of the elongate section comprises a flexible wire having an electrically conductive core, which is electrically insulated on an outer surface thereof. During operation the flexible wire radiates electromagnetic signals through the water.