Underwater Acoustic Channel

✍ Scribed by Junying Hui, Xueli Sheng

• Publisher: Springer
• Year: 2022
• Tongue: English
• Leaves: 243
• Category: Library

✦ Synopsis

This book introduces sonar system and acoustic channel model, average energy channel, coherent multipath channel, the theoretical basis for the stochastic time-varying space-variant channel, slowly time-varying coherent multipath channel, and reverberation channel. Based on the basic theory of underwater acoustic channels and the various characteristics of the marine acoustic environment factor, this textbook aims to help students understand the impact of the marine acoustic channel on the sonar system. It helps students to grasp underwater acoustic signal processing principles and obtain the ability to solve practical problems in underwater acoustic channel engineering. Finally, it aims at laying a foundation for the further sonar system design. This textbook is recommended for graduate or undergraduate students in the field of sonar signal processing, underwater acoustic engineering, as well as some related subjects of marine technology.

✦ Table of Contents

Preface
Content Brief Introduction
Contents
1 Introduction
1.1 Introduction
1.2 Mechanical Vibration
1.3 Basic Concepts of Sound Wave
1.4 Ohm’s Law of Acoustics
1.5 Basic Concepts of Vector Acoustics
1.6 Sonar System and Acoustic Channel Model
1.7 Sonar Equation
2 Average Energy Channel
2.1 Sound Velocity in Seawater
2.2 Sound Absorption in Seawater
2.3 Marine Environmental Noise
2.4 Seabed Reflection Loss
2.5 Ray Acoustic in Layered Media
2.6 Sound Lines and Fields in Constant Gradient Water Layer
2.7 Deep Sea Sound Transmission Mode and Spreading Loss
2.8 Pekeries Model in Shallow Water
References
3 Coherent Multipath Channel
3.1 System Functions of Coherent Multipath Channel
3.2 Correlator and Matched Filter
3.3 Signal Ambiguity Function
3.4 Response of Copy Correlator in Coherent Multipath Channel
3.5 Adaptive Correlator
3.6 Response of Adaptive Correlator in Coherent Multipath Channel
3.7 Cross Correlation in Coherent Multipath Channel
3.8 Normal Wave Vertical Filtering for Near Field Interference Suppression [4]
3.9 Interference Structure of Low Frequency Short Range Sound Field
3.10 Sound Pressure Time Reversal Mirror
3.11 Vector Time Reversal Mirror
References
4 Theoretical Basis of Random Time-Varying Space-Varying Channel
4.1 General Concept and Description of Random Sound Field
4.2 Acoustic Signal Fluctuation
4.3 System Function of Time Varying Channel
4.4 System Function of Random Time-Varying Channel
4.5 Generalized Stationary Channel (WSS Channel), Uncorrelated Scattering Channel (US Channel) [4]
4.6 Generalized Stationary Uncorrelated Scattering Channel (WSSUS Channel)
4.7 Scattering Function
4.8 Coherence Function
4.9 Directivity Function of Array
4.10 Random Space Variant Channel
4.11 Physical Model of Passive Sonar
4.12 Response of Linear Array in Random Space-Varying Channel
References
5 Slow Time-Varying Coherent Multipath Channel
5.1 Experimental Results of Scattering Function
5.2 Measurement Method of Channel Coherence—Inter Pulse Correlation Method
5.3 Modified Matching of Shallow Water Coherent Multipath Channel with Slow Time Variation
5.4 Modified Correlation Matching for Deep Sea Coherent Channel
5.5 Response of Adaptive Correlator in Slow Time-Varying Coherent Multipath Channel
5.6 System Function of Moving Sound Source in Coherent Channel
5.7 Loss of Cross-Correlation During Target Motion
References
6 Reverberation Channel
6.1 Average Characteristics of Reverberation
6.2 Scattering Function of Reverberation
6.3 Doppler Spread of Reverberation Spectrum
6.4 Other Statistical Characteristics of Reverberation
6.5 Anti-reverberation
References
7 Active Sonar Target Channel
7.1 Point Targets
7.2 Coherent Point Target Channel
7.3 Multiple Highlight Target Model
7.4 General Characteristics of Submarine Target Strength
8 Coherent Structure of Shallow Acoustic Field
8.1 Coherent Structure of Short-Range Sound Field in Shallow Water [1]
8.2 The Interference Structure of Normal Wave Sound Field in Shallow Water Waveguide
8.2.1 The Sound Pressure Field of Pekeris Waveguide
8.2.2 The Normal Wave Sound Intensity Flow
8.2.3 Low Frequency Normal Wave Sound Intensity Flow Characteristics [10]
8.2.4 The Cross Spectrum Processor
8.3 Waveguide Invariants β
References
9 Examples in Application
9.1 The Optimum Operating Frequency of Interrogation Transponder
9.2 Passive Sonar Range Estimation
9.3 Fundamentals of Three Element Array Passive Ranging Sonar
9.4 Passive Detection Principle of Single Vector Sensor
9.5 Moving Target Detector
References