Abstract:
The systems and methods of the invention provide for improved underwater communication systems. In particular, the systems and methods of the invention provide for improved underwater optical modems including optical transmitters and optical receivers that allow omni-directional transmission and reception of optical signals underwater and having a range of about 100 m and allowing data rates greater than 1 Mbit/s. The systems and methods of the invention also provide for underwater communication networks having a plurality of optical modems communicating with each other.
Abstract:
Common wave and sideband mitigation communication systems and methods are provided that can be used with both wireless and wired communication links. The systems and methods provided can enable faster data rates, greater immunity to noise, increased bandwidth/spectrum efficiency and/or other benefits. Applications include but are not limited to: cell phones, smartphones (e.g., iPhone, BlackBerry, etc.), wireless Internet, local area networks (e.g., WiFi type applications), wide area networks (e.g., WiMAX type applications), personal digital assistants, computers, Internet service providers and communications satellites.
Abstract:
Advantageous underwater acoustic (UWA) apparatus, systems and methods are provided according to the present disclosure. The apparatus, systems and methods employ nonbinary low density parity check (LDPC) codes that achieve excellent performance and match well with the underlying modulation. The nonbinary LDPC codes of the proposed apparatus, systems and methods are formed, at least in part, from a generator matrix that has a high density to reduce the peak-to-average-power ratio (PAPR) with minimal overhead. The disclosed apparatus, systems and methods employ nonbinary regular LDPC cycle codes if the constellation is large and nonbinary irregular LDPC codes if the constellation is small or moderate. The nonbinary irregular and regular LDPC codes enable: i) parallel processing in linear-time encoding; ii) parallel processing in sequential belief propagation decoding; and iii) considerable resource reduction on the code storage for encoding and decoding.
Abstract:
An underwater inspection system comprising an underwater mobile inspection station (52) having an electromagnetic antenna (53), the mobile station (52) being adapted to capture inspection data and use the electromagnetic antenna (53) to send information relating to the inspection data to a underwater electromagnetic receiver that has a fixed electromagnetic antenna (55).
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.
Abstract:
An underwater communications system is provided that transmits electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically insulated, magnetic coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically insulated, magnetic coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor de-compresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form. Similarly, the transmit system comprises appropriate audio/visual/text entry mechanisms.
Abstract:
An underwater navigation system comprising a transmitter having an electrically insulted magnetic coupled antenna for transmitting an electromagnetic and/or magneto-inductive signal, a receiver having an electrically insulated magnetic coupled antenna for receiving an electromagnetic and/or magneto-inductive signal from the transmitter, and determining means for determining the position of the receiver relative to the transmitter using the received electromagnetic and/or magneto-inductive signal.
Abstract:
An underwater remote sensing system comprising a transmitter for transmitting an electromagnetic signal, a receiver for receiving an electromagnetic signal reflected from an object and determining means for determining the location of the object, wherein at least one of the transmitter and receiver is underwater. The determining means may be operable to determine the location of the object using signals received at three or more receiver positions. To do this, three or more receiver antennas may be provided. Alternatively, a single receiver antenna may be provided and moved between three or more different measurement locations.
Abstract:
A payload delivery unit for protecting and delivering a payload submerged in a submersion medium comprises a container including a pressure resistant shell and a resilient seal device. The shell defines a containment chamber and includes first and second shell members having opposed first and second sealing faces, respectively. The seal device engages and is interposed between the first and second sealing faces. The container is configured and constructed such that: when the submersion medium applies an exterior pressure to the first and second shell members such that a shell pressure differential, defined as the exterior pressure less an interior pressure of the containment chamber, exceeds a prescribed pressure, the first and second shell members compressively load and deform the seal device to effect a seal between the first and second shell members that prevents ingress of the submersion medium into the containment chamber; and when the shell pressure differential is less than the prescribed pressure, the seal device elastically rebounds to separate the first and second shell members to permit ingress of the submersion medium into the containment chamber.
Abstract:
A system for secure communication of collected data is provided. The system comprises a data dissemination subsystem, the data dissemination subsystem operable to store and disseminate collected data. The system also comprises a transmitter subsystem coupled to said data dissemination subsystem, said transmitter subsystem operable to encrypt said disseminated collected data, encode said encrypted data to form a plurality of ultra wideband signals, spectrum spread said plurality of ultra wideband signals with a direct sequence spectrum spreading code, and transmit said spread plurality of ultra wideband signals.