| River and Harbor Aid to Navigation System [¦riv·ǝr ǝn ¦här·bǝr `ād tǝ ´nav·ǝ`gā·shǝn ´sis·tǝm] NAVIGATION An all-weather system for precision navigation in harbors and harbor entrances, which provides sufficient accuracy for vessels to proceed as if visual aids did not exist, with a 50-foot (15-meter) position radius accuracy requirement at a 95% confidence level. Abbreviated RIHANS. |