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The EDA (European Defence Agency) project PoMM (Protection of Marine Mammals) is based on an agreement between the Ministries of Defence for Germany, Italy, the Netherlands, Norway, Sweden and the United Kingdom. The project, running for 3 years since August 2010, aims to protect marine mammals against the impact of active sonar and maintain the ability to operate active sonar at the same time. Within this project a comprehensive common marine mammal database, being essential for risk mitigation tools, was established. The database, built on an extensive data set collection with the focus on areas of operational interest for European Navies, consists of four parts: random and systematic sightings, annual and seasonal distribution and density maps, audio information including numerous examples of various vocalizations and an encyclopaedia providing knowledge on the characteristics of 126 marine mammal species. Special investigations on marine mammal acoustics were carried out to improve the detection and classification capabilities. Based on the available audio data an algorithm was developed, trained and tested to classify selected groups of marine mammals including beaked whales, the species mostly affected by active sonars. A follow-on EDA project PoMM2 is planned to upgrade the common marine mammal database, to improve detection, classification and localization performances and to establish a common risk assessment procedure to avoid negative impact on marine mammals by military active sonars.

Between 2002 and 2007 FWG has carried out four sea trials at different locations of the western Baltic Sea. These were BAROC 2002 near Landsort and Gotland and UCAC 2006, VOICE 2006 and UCAC 2007 east of Bornholm. Altogether quite a large number of runs with different configurations of source and receiver and different environmental conditions were analysed. Important processing outputs are transmission loss (TL) and channel impulse response as function of acoustic propagation distance. The data add to FWG's existing transmission loss data base which is largely based on experiments performed before 1990. Improvements of the experimental equipment as well as of the processing techniques allowed us to probe the acoustic channel more thoroughly than previously possible. This provides new opportunities to validate but also to pinpoint shortcomings of existing sound propagation models. In particular, our focus is on a possible improvement of the stochastic ray tracer SIPSI / MOCASSIN developed by FWG. In this paper we give an overview of the sea trials and compare measured and modelled transmission loss for a few situations

The future role of unmanned underwater vehicles (UUVs) is expected to include autonomous tasks in environmental assessmenl, route survey, mine hunting, and battlefield preparation. Depending on the mission, there will be a need for a robust communication link between the mother ship and the UUV, with a low probability of intercept by third parties. The overall goal of the joint European project "UUV Covert Acoustic Communications" with contributions from Denmark, Finland, Italy, The Netherlands, Germany, Norway and Sweden is to develop covert communication algorithms to enable such a communication link. The present paper describes intlial results of the project's first sea trials, conducted in the Baltic and North Sea environments in September 2006. The main purpose of these trials is characterization of Íhe communication channel. A variety of probe signals were transmitted with a mobile projector, and recorded on a vertical hydrophone array deployed from a moored platform. The data analysis focuses on aspects relevant to acoustic communication, such as ambient noise, multi-path propagation, Doppler effects, and their time variability. The outcome of the analysis will be used for the development of a filter model, designed to model the underwater acoustic communication channel in a realistic fashion.