The principles of radar beacons (racons) are described and their significance for navigation discussed. Developments in radars which may affect the operation of racons are considered and ways of meeting the requirement to locate and identify aids to navigation on a radar display are considered. The developments in non-radar band transponders are reviewed to determine whether they might present an alternative to racons in the future.

During recent years there has been significant development in several technologies which can contribute to the efficiency and safety of maritime traffic. The most important of these are accurate positioning systems (DGPS), digital data transmission/transponder technology, electronic chart systems (ECDIS), control of ships using electronic passage plans, and ship path prediction. With a widespread implementation of these new techniques, combined with advanced ship-shore and ship-ship data transfer, significant improvements can be achieved in traffic situation awareness both in a VTS and onboard. This paper describes the research carried out at VTT on VTS development, and especially gives an outline of new VTS functions using ship—shore and ship—ship data transfer.

Radar transponders and radar target enhancers have been in use in a variety of applications for many years. Perhaps the most widely-known applications of radar transponders are in Identification Friend or Foe (IFF) and its civilian counterpart, secondary surveillance radar for air traffic control, and as racons in marine navigation and, most recently, as Search And Rescue Transponders (SART) in the Global Marine Distress and Safety System (GMDSS).

A device has been developed to enhance the radar conspicuity of navigation buoys. It is also very effective on small craft. This paper describes the specification and testing of the device and discusses the regulatory position regarding its use.