existing R&D efforts be maintained and focused on coastal applications. A healthy R&D foundation must be sustained so that attempts to “reconstitute” that capability will be successful.

The discussion session began with a presentation by a representative from the Naval Underwater System Center's Surface ASW Directorate who discussed the most pressing issues in shallow-water ASW. The three primary issues are:

• Variable performance owing to environment and season. - The performance of ASW techniques depends on the season and the unique environment of the coastal site. Seasonal water column conditions (particularly summer versus winter) are inherently more variable in shallow water than in deep water. Further, bottom conditions vary in different operating areas as a function of grazing angle and frequency. Because system detection performance is highly sensitive to these variabilities, system design must account for them.

• Boundary interactions. The effects of the seafloor and the sea surface on acoustic systems in shallow water are highly complex, making range predictions difficult. Multi-path degradation affects overall figure of merit and active classification. As a result, false target identifications are frequent.

• Practical limitations. Another key issue is the range dependence of shallow water propagation and reverberation. For example, shallow water limits the depth of towed sound detection arrays, thus increasing the possibility of the system's detecting its own noise. In addition, closer ship spacing increases the potential for mutual interference effects.

A recent workshop on the role of ASW in regional conflicts identified two general S&T areas that could support shallow-water ASW:

1. Developing affordable detection systems that work against quiet submarines moving through turbid and complex environments and

2. Understanding the technical limits of acoustic methods, for example, how many data are needed to predict both sound and light-based performance and whether the necessary data can be collected quickly enough?

Front Matter (R1-R5)

Table of Contents (R6-R6)

Executive Summary (1-1)

Introduction (2-3)

Warfare Summaries (4-16)

Science and Technology Summaries (17-31)

Appendix I Symposium Program (32-40)

Appendix II Symposium Attendees (41-44)