SONAR (sound navigation and ranging) systems have many similarities to RADAR and electro-optical systems. Again, detection is based on the propagation of waves between the target and detector. There are active sonar systems, where the wave propagates from the transmitter to the target and back to the receiver, analogous to pulse-echo radar. There are also passive sonar systems, where the target is the source of the energy which propagates to the receiver, analogous to passive infrared detection. Therefore, a great deal of what has been discussed about these systems will also apply to sonar. Sonar, however, differs fundamentally from radar and electro-optics because the energy is transferred by acoustics waves propagating in water. So we first begin by discussing the characteristics of acoustic waves.

This discussion of sonar signal processing bridges a number of related fields, including acoustic propagation in the medium, detection and estimation theory, filter theory, digital filtering, sensor array processing, spectral analysis, fast transforms and digital signal processing. The book begins with a discussion of the topics of analogue signalling conditioning, digital filtering, and the calculation of the discrete Fourier transform. Other topics discussed include analogue filters and analogue-to-digital conversion, finite impulse and infinite impulse response digital filters, and multirate processing techniques.

Offering complete and comprehensive coverage of modern sonar spectrum system analysis, Underwater Acoustics: Analysis, Design and Performance of Sonar provides a state-of-the-art introduction to the subject and has been carefully structured to offer a much-needed update to the classic text by Urick. Expanded to included computational approaches to the topic, this book treads the line between the highly theoretical and mathematical texts and the more populist, non-mathematical books that characterize the existing literature in the field. The author compares and contrasts different techniques for sonar design, analysis and performance prediction and includes key experimental and theoretical results, pointing the reader towards further detail with extensive references. Practitioners in the field of sonar design, analysis and performance prediction as well as graduate students and researchers will appreciate this new reference as an invaluable and timely contribution to the field. Chapters include the sonar equation, radiated, self and ambient noise, active sonar sources, transmission loss, reverberation, transducers, active target strength, statistical detection theory, false alarms, contacts and targets, variability and uncertainty, modelling detections and tactical decision aids, cumulative probability of detection, tracking target motion analysis and localization, and design and evaluation of sonars

Fundamentals of sonar systems are presented in this book, prepared for both regular navy and naval reserve personnel who are seeking advancement in rating. An introductory description is first made of submarines and antisubmarine units. Determination of underwater targets is analyzed from the background of true and relative bearings, true and relative motion, and computation of target angles. Then, applications of both active and passive sonars are explained in connection with bathythermographs, fathometers, tape recorders, fire control techniques, internal and external communications systems, maintenance actions, test methods and equipment, and safety precautions. Basic principles of sound and temperature effects on wave propagation are also discussed. Illustrations for explanation use, information on training films and the sonar technician rating structure are also provided.

Sonar and Underwater Acoustics brings together all the concepts necessary for designers and users of sonar systems. Unlike other books on this subject, which are often too specialized, this book is accessible to a wider audience. The first part focuses on the acoustic environment, antenna structures, and electric acoustic interface. The latter provides knowledge required to design, as well as the development and implementation of chain processes for an active sonar from the conditioning input to output processing. The reader will find a comprehensive range of all problems encountered in underwater acoustics for a sonar application, from physical phenomena governing the environment and the corresponding constraints, through to the technical definition of transducers and antennas, and the types of signal processing involved. In one section, measures in underwater acoustics are also proposed.

Have you ever wondered how stealth planes achieve "invisibility," how sunken ships are found, or how fishermen track schools of fish in vast expanses of ocean? Radar and sonar echolocation—a simple matter of sending, receiving, and processing signals. Weaving history with simple science, Mark Denny deftly reveals the world of radar and sonar to the curious reader, technology buff, and expert alike. He begins with an early history of the Chain Home radar system used during World War II and then provides accessible and engaging explanations of the physics that make signal processing possible. Basic diagrams and formulas show how electromagnetic and sound waves are transmitted, received, and converted into images, allowing you to literally see in the dark. A section on bioacoustic echolocation, with a focus on the superior sonar systems of bats and whales and a discussion of the advanced technology of next-generation airborne signal processors, opens the imagination to fascinating possibilities for the future.