Abstract: 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.

Abstract: 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.

Abstract: The present invention provides a multi-mode dispersion energy imaging device and method for a four-component marine interface wave of an ocean bottom seismometer, belonging to the technical field of marine seismic exploration. The method includes the following steps: designing an marine interface wave artificial seismic observation system, designing a reasonable observation system according to the geological condition of the operation area to ensure the resolution of the imaging to perform the marine artificial source seismic operation carrying out the data preprocessing of the seafloor surface wave, and then carrying out the three-component seismometer Scholte wave and the acoustic guided wave dispersion energy imaging, and the one-component hydrophone acoustic guided wave dispersion energy imaging; superposing and normalizing the three-component Scholte wave dispersion energy spectrum and the one-component acoustic guided wave dispersion energy spectrum. The device is implemented based on the method above.

Abstract: Provided is a wireless time servicing method, device and system. The wireless time servicing method includes: obtaining absolute time information sent by an external clock source; correcting a system time of a master station according to the absolute time information; broadcasting path information to a slave station; receiving feedback from the slave station in response to the path information, calculating a transmission path delay between the master station and the slave station, and storing the transmission path delay in the time information; and sending the time information to the slave station.

Abstract: The present invention provides a multi-mode dispersion energy imaging device and method for a four-component marine interface wave of an ocean bottom seismometer, belonging to the technical field of marine seismic exploration. The method includes the following steps: designing an marine interface wave artificial seismic observation system, designing a reasonable observation system according to the geological condition of the operation area to ensure the resolution of the imaging to perform the marine artificial source seismic operation; carrying out the data preprocessing of the seafloor surface wave, and then carrying out the three-component seismometer Scholte wave and the acoustic guided wave dispersion energy imaging, and the one-component hydrophone acoustic guided wave dispersion energy imaging; superposing and normalizing the three-component Scholte wave dispersion energy spectrum and the one-component acoustic guided wave dispersion energy spectrum. The device is implemented based on the method above.