Marine Radar Interrogator-Transponder (MRIT)

This paper reports on the development of a Marine Radar Interrogator-Transponder (MRIT). Unfortunately, all vessel paints on a radar PPI look alike. As a result, when a ship master caught in a fog is trying to use his radio-telephone to work out a maneuvering plan with another vessel, it is difficult for him to identify which blip on the PPI is the source of the voice on the radio. One solution now receiving worldwide attention is to fit all vessels with active transponders. MRIT's are an advanced form that provide not only target identity and "clutter-free" target paints but also maneuvering information and such data as target's course, speed, draft, safe or dangerous cargo, etc. Mounted on a fixed navigation aid they can also function as racons. The paper describes the operational parameters and reviews the system bench tests and sea trials.