1. Biological and Enviromental Noise - This two-hour presentation will review the Wenz open ocean noise curves. It will then make a clear distinction between ambient and localised noise sources. A graphical representation detailing the relative strengths of ambient noise caused by waves, shipping and so on, and localised natural sources ranging from earthquakes, subsea volcanoes and lighting strike through to whales and dolphins will be discussed. Also included in this representation will be a wide range of man-made sources, including seismic arrays, various kinds of shipping and different sorts of conventional sonar, all of which may contaminate receiving equipment.

The second hour will present an extensive repertoire of sound recordings accompanied by movie sonograms clearly illustrating the frequency content and relative intensity of ships, shipping activities, sonars of various kinds, seismic detonations, numbers of species of vocalising fish, vocalising seals, walruses and manatees, dolphins and whales.

2. System Noise - Sonar performance is determined by the relative strength of the received signal and various ocean noise sources. However, poor choice of hydrophone and poor receiver design can lead to a situation where receiver electronic noise exceeds ocean noise and is, unnecessarily, the dominant cause of signal corruption. This section discusses noise in electronic systems, introduces a widely used hydrophone type and determines its noise performance in conjunction with a high-quality commercial front-end amplifier.

3. Sonar Detection Theory - Having thus covered all aspects of noise corruption of the sonar, we turn in this section to determining the impact that noise has on sonar detection performance and, in particular, probability of detection and probability of false alarm. This investigation leads us to the "Receiver Operating Characteristics" which allow the designer to determine the signal to noise ratio needed to obtain given probabilities of false alarm and detection.

4. Active and Passive Naval Sonar - Commissioning is a major problem for both contractor and client. Project over-runs caused by - amongst other things - overambitious "Specifications to Tender" have become commonplace. The client defines the tactical and strategic requirements. The contractor is constrained both by the laws of physics and by an economic environment which ensures that there is always competition "around the corner". To ameliorate this problem, an engineering "route map", commencing with tactical and strategic requirements and ending with a viable specification for the sonar hardware, is presented. The route map highlights the complex interweaving of links between specification, choice of system, signal processing, mathematical modelling, receiver operating characteristics and, ultimately, the hardware design of the sonar. This section concludes with an in-depth investigation of the nature and performance of active and passive military sonars.

5. Transducer Physics - Here, we examine the various technologies which may be employed to form motors for electroacoustic transducers. We investigate the way in which the piezoelectric and elastic constants of a material are defined and conclude by developing a "functional visualisation" of the piezoelectric mechanism.

6. Transducer Analysis - Static and dynamic stress and strain within the passive bar provide the starting point for a brief investigation of the wave equation as it applies to bars in longitudinal vibration. The analysis is developed to include piezoelectricity and equations are developed which provide an analysis of the thin piezoelectric disc or ring, such as is used commonly as a driver element in acoustic transducers. Also considered is the analysis of the tube element, frequently employed in hydrophone construction.

7. Modelling the Transducer - Lumped Mass models form the starting point for this section. We then investigate the structure of Transmission Line models. Finally we turn to Finite Element and Boundary Element modelling, viewed from the standpoint of commercially available modelling software.

8. Array Beamforming - Arrays of acoustic transducers offer the possibility of focussing sound, determining direction and providing beam-steering and null-steering. Advanced graphics and elementary Fourier methods will be used to provide a clear pictorial link between the mathematical description of 2 and 3-D array aperture and beam pattern.

9. Normal Mode Modelling - A limited mathematical formalisation of the Wave Equation will be studied. It will then be possible to shed light on the nature of a range of propagation modelling software. Normal Mode methods will be considered in some detail.

10. Advanced Propagation Models - Advanced modern techniques such as the Parabolic Equation and Fast Field Program will be described and their significance discussed. The BAeSEMA "INSIGHT" computer modelling software suite will be used to illustrate how modelling may reveal real ocean phenomena in underwater acoustics.

11. Surface and Volume Reverberation: Theory and Application - This section commences with a formal derivation of the surface and volume backscattering results. It concludes with a detailed worked example of the design of a minehunting sonar wherein both the reverberation and noise performance of the system are investigated and compared.

12. Mathematical Modelling for Sonar - The development of the Receiver Operating Characteristics for a sonar may, in the case of simple, memoryless demodulators and linear processing, be handled theoretically. However, treatment of more complex situations, including fading channels and channel nonlinearity, usually calls for Monte Carlo modelling techniques. Here the implementation of uniform, portable random number generators is considered. The formulae allowing computation random numbers with any of a number of important probability density distributions are presented. The technique of importance sampling to speed up the modelling process is introduced, as are extensions of the method to cater for multi-input systems and systems with memory.

13. Sound Speed and Its Measurement - The Wave Equation will be explained with the aid of computer-generated movies and the nature of travelling waves will be described. Preferred approximation equations for the prediction of sound speed in particular environmental conditions will be presented and their use discussed. Practical methods of measuring sound speed in the laboratory and in the field will be described.

14. Underwater Acoustic Communications - This section commences with the development of a formal procedure for establishing maximum achievable range, required transmission power levels, signal bandwidth and symbol rate for a communication system. The limitations to bit rate are discussed and preferred signalling schemes are determined. The section concludes with a description of numbers of communication links designed to operate in a wide variety of channel conditions and over a wide range of frequencies.

15. Modelling Communication Systems and Channels - Here we commence with developing an appreciation of the use of complex baseband equivalent models for bandpass communication, positioning, ranging and navigation systems. Such models not only provide significant speed enhancements when employed in communication system simulation, they are also of value in DSP implementations of modulator and demodulator structures for actual communication links. The section concludes with model structures and computed results for numbers of typical communication channels.

16. Underwater Distance Measurement, Navigation and Positioning - In this final section we consider factors affecting the accuracy of pulse ranging systems using transponders. The various methods of short and long baseline positioning and navigation are discussed. Doppler measurement techniques for measuring flow, velocity and penetrator implant depth are covered. Finally, we consider the requirements of dynamic positioning systems.