In 1948, the port of Liverpool was probably the pioneer of European VTS, when they set up a radar station, in order to facilitate the boarding of pilots from the cutter. In 1951, Long Beach in California established a radar and VHF to facilitate port operations. Le Havre established another system and so, gradually, other ports followed. At this time commercial radar was comparatively new, and made it possible for the first time, under almost all weather conditions, to observe vessel traffic from the shore. In combination with VHF radio, a traffic surveillance system was achieved and real- time information exchange between the shore and ships became possible. Nevertheless, it was not until 1985 that the role of VTS in connection with navigation safety, traffic efficiency and environmental protection gained international recognition. This recognition is contained in an IMO resolution, which constitutes the VTS guidelines.

In this paper, we shall outline the reasons why the installation of shipborne equipment, which enables vessels to be positively identified from the shore and from other vessels, is so important and necessary. We shall also describe the latest innovations in this field and propose minimum standards for a transponder system.