The thesis is dedicated to the study of the UNDERWATER VEHICLE – SURFACE SHIP search engine`s information hydroacoustic channel formation specialties provided the information message is propagated through the underwater sound waveguide represented by the shallow sea.
The practical significance of the work lies in the further development of applied aspects of shallow sea physics, introduction of research results into the theory and practice of designing robotic telemetry and sound supplysystems, as well as highlighting the acoustic field formation specialtiesin the course of creating newpresentation andoperation models of information channels while conducting applied search, cartographic, exploratoryandother underwater works.
The main content of thethesis is set out in five sections and four annexes.
The introduction substantiates the relevance of the thesis, formulates the purpose and defines the range of the research tasks, describes the research methods, and provides information about the scientific novelty and practical significance of the results achieved. The purpose of the work is to improve existing and develop perspective acoustic field formation model constructions and problem solution algorithms in information hydroacoustic channels to ensure communication among the UNDERWATER VEHICLE – SURFACE SHIP systemsubscribers.
The first section of the work is dedicated to the review of the latest publicationson the development of underwater robotics, existing modern underwater vehicles, organization ofinformation channels for subscribers of different classes, and modern approachesto the formation of acoustic fieldsin the waveguidesbeing disturbedby pulsesignals.The section also describes the main performance characteristics of the UNDERWATER VEHICLE and the ascertained organization principles of information exchange processesas for operating and checking information as well ascontrol, communication and telemetry information. In addition, the section rendersa general characteristics of the information hydroacoustic channel.
Thus, as a result of processing a wide range of information sources, it has been determined that the information hydroacoustic channel formationresearch methodology within the framework of autonomous telemetry and code communicationsystem ofthe UNDERWATER VEHICLE – SURFACE SHIPsystemin the shallow seamust be subjected to consideration and development.
At the same time, the acoustic field formation specialties in the shallow sea mustbe considered onthe subject of specific distributions ofacoustic field scalar and vector characteristics provided theUNDERWATER VEHICLE – SURFACE SHIP channel environment is disturbed by various frequency signals.
The main output ratiosfor the problemof acoustic pressure field formation in the information channel has been determinedin the second section.
A compound message signal has been selected and the speed of communication messages has been determined. The wave packet deformation effects have been described. The "group velocity problem" has been considered and the signal propagation rate frequency dependences have been calculated in case ofdual-frequency wave excitation.
The third section is dedicated to the issue of intensity vector field formation in the waveguide channelin regard tothe mathematical and physical prerequisites for the emergence of "curl" and "saddle" structures with defining their coordinate dependences.
The fourth section contains research results of the waveguide impedance characteristics. In addition, it clarifies the spatial and frequency dependences of the workspace specific impedancefor combinational and acoustically soft boundaries in case ofdual-frequency wave excitation.
The fifth section is dedicated to experimental researches that have taken place by means of a full-scale maritime experiment. At the same time, themaneuvering modes have been carried out by the subscribers whose performance characteristics correspond to the data having been set out in section 1 and served as the basis for the information hydroacoustic channel operation energy range calculation.
Keywords: information hydroacousticchannel, underwater, wave packet, scalar/ vector characteristics, acoustic field,impedance, frequency characteristics.
