A means is provided for defending a target from attack by a torpedo with high probability. When a controller detects a torpedo based on an image generated by a sonar, it specifies a path of movement of the torpedo. If there is a water craft or the like within the path of movement, the controller instructs a launcher to launch a torpedo capture device and instructs mines to switch to detonation-off mode. Moveable devices of the torpedo capture device launched by the launcher in accordance with the instruction of the controller move in the water to spread a net. The controller then specifies a location of each of a first moveable device and second moveable devices based on an image generated by the sonar, and instructs the first moveable Device and the second moveable devices to move such that the center of the net is within the path of movement of the torpedo. The first moveable device and the second moveable devices move in accordance with the instruction of the controller. When the torpedo reaches the net, the net captures the torpedo and the mines, which are in the detonation-on mode, explode the torpedo before it reaches the water craft or the like.

A means is provided for defending a target from attack by a torpedo with high probability. When a controller detects a torpedo based on an image generated by a sonar, it specifies a path of movement of the torpedo. If there is a water craft or the like within the path of movement, the controller instructs a launcher to launch a torpedo capture device and instructs mines to switch to detonation-off mode. Moveable devices of the torpedo capture device launched by the launcher in accordance with the instruction of the controller move in the water to spread a net. The controller then specifies a location of each of a first moveable device and second moveable devices based on an image generated by the sonar, and instructs the first moveable Device and the second moveable devices to move such that the center of the net is within the path of movement of the torpedo. The first moveable device and the second moveable devices move in accordance with the instruction of the controller. When the torpedo reaches the net, the net captures the torpedo and the mines, which are in the detonation-on mode, explode the torpedo before it reaches the water craft or the like.

A method and apparatus for underwater acoustic communication are disclosed. A data packet frame structure in the communication transmission includes a preamble, a synchronization code, and a data code. A guard interval is disposed between the preamble and the synchronization code. This method utilizes the different impact response environments of linear frequency modulation signals in different frequency bands to obtain the mapping relationships corresponding to the characteristics of the impulse responses in the frequency band, and adopts the quadrature phase shift keying (QPSK) modulation method to convert four groups of LMF signals with different center frequencies and the same modulation frequency, representing different symbols for signal transmission, where the LFM carrier signal of each center frequency can represent two bits of binary information to improve transmission efficiency. The apparatus for underwater acoustic communication also has the above-mentioned technical effects.

A method and apparatus for underwater acoustic communication are disclosed. A data packet frame structure in the communication transmission includes a preamble, a synchronization code, and a data code. A guard interval is disposed between the preamble and the synchronization code. This method utilizes the different impact response environments of linear frequency modulation signals in different frequency bands to obtain the mapping relationships corresponding to the characteristics of the impulse responses in the frequency band, and adopts the quadrature phase shift keying (QPSK) modulation method to convert four groups of LMF signals with different center frequencies and the same modulation frequency, representing different symbols for signal transmission, where the LFM carrier signal of each center frequency can represent two bits of binary information to improve transmission efficiency. The apparatus for underwater acoustic communication also has the above-mentioned technical effects.

Techniques of present disclosure are directed to methods of providing acoustic communication networks. For example, methods are provided for that include obtaining, at a first transceiver of a plurality of transceivers arranged within an installation pattern, a first acoustic signal provided by a second transceiver of the plurality of transceivers. A location of the first transceiver within a message distribution pattern is determined from the acoustic signal. A delay based upon the location of the first transceiver within the message distribution pattern is determined. Finally, a second acoustic signal corresponding to the first acoustic signal is provided from the first transceiver after the delay.

Techniques of present disclosure are directed to methods of providing acoustic communication networks. For example, methods are provided for that include obtaining, at a first transceiver of a plurality of transceivers arranged within an installation pattern, a first acoustic signal provided by a second transceiver of the plurality of transceivers. A location of the first transceiver within a message distribution pattern is determined from the acoustic signal. A delay based upon the location of the first transceiver within the message distribution pattern is determined. Finally, a second acoustic signal corresponding to the first acoustic signal is provided from the first transceiver after the delay.

A wireless audio streaming system for swimmers and underwater applications uses directional transmission antennas, one or more reception antennas worn on a user, and a combination of radio frequency and near-field magnetic induction communication, for streaming audio to a swimmer, buffering the streamed audio, and allowing the user to play the audio on a wireless, waterproof headset.

A wireless audio streaming system for swimmers and underwater applications uses directional transmission antennas, one or more reception antennas worn on a user, and a combination of radio frequency and near-field magnetic induction communication, for streaming audio to a swimmer, buffering the streamed audio, and allowing the user to play the audio on a wireless, waterproof headset.

A method for transmitting information across a water-air interface with a ultraviolet (UV) beam, the method including emitting the UV beam in a first medium, with a first optical wireless communication device; measuring a scintillation index of the UV beam in a second medium, different from the first medium, at a second optical wireless communication device; selecting, based on a value of the scintillation index, a modulation scheme for the UV beam; and modulating the UV beam with the selected modulation scheme. The UV beam has a wavelength in a range of 100 to 400 nm.

A method for transmitting information across a water-air interface with a ultraviolet (UV) beam, the method including emitting the UV beam in a first medium, with a first optical wireless communication device; measuring a scintillation index of the UV beam in a second medium, different from the first medium, at a second optical wireless communication device; selecting, based on a value of the scintillation index, a modulation scheme for the UV beam; and modulating the UV beam with the selected modulation scheme. The UV beam has a wavelength in a range of 100 to 400 nm.