The project Naval Surveillance Systems was created with the objective to make a broad study on the development of new surveillance systems for the Royal Swedish Navy, in particular for its new operational tasks. Research has been carried out at all levels, from development of individual sensors up to the system level for complete surveillance systems. The project has involved both experimental and theoretical work in the areas underwater acoustics, electromagnetics and optics. The goal has been the development of methods and techniques for bottom fixed, ship borne and rapidly deployable underwater surveillance systems. An important aspect has been the ability to carry out large field experiments with multisensor systems to be able to study methods for data fusion. Research has been carried out in sonar support, low frequency active sonar, synthetic aperture sonar (SAS), optical underwater sensors, active electromagnetic sensors, airborne MAD and multisensor systems. The results of the research has been applied to studies on how the surveillance systems of the navy can be further developed, and in support of the procurement process at FMV. A large quantity of experimental data has been acquired at the various field experiments which have been carried out as a part of the project. Much of this data has not yet been analysed and it will be a good resource for upcoming new projects in the area of underwater systems.