LORAN

Japanese: LORAN - ロラン

Abbreviation of long range navigation. A long-distance radio navigation aid system for aircraft and ships, a representative of hyperbolic navigation systems. Usually, one master station and two slave stations are paired, and the master station transmits a radio pulse, which is received by the slave station and retransmitted by the aircraft or ship, and the time difference between the pulses of the master and slave stations is measured on a display. The locus of positions that produce the same time difference is a hyperbola, but the two sets of loci are found on a Loran chart that already has this hyperbola drawn on it, and the exact position can be easily determined from the intersection point. There are Loran A, which uses a medium wave of 2 MHz, and Loran C, which uses a long wave of 100 kHz. The latter can be used at distances of over 1,000 nautical miles, and a more accurate device is simple and can be used at distances of several hundred nautical miles, so it was the main navigation device in the Far East and on the coast of the American continent. However, when the United States switched to GPS (Satellite Positioning System), the operation of Loran C around Japan was taken over by the Japan Coast Guard. →DECCA/Radio Navigation→Related topicsNavigational instruments｜Hyperbolic navigation｜Electronic weapons｜Radio beacons

Source : Heibonsha Encyclopedia About MyPedia Information

Japanese:

long range navigationの略。航空機や船舶用の長距離電波航法援助システムで，双曲線航法システムの代表的なもの。通常一つの主局と二つの従局が１組になり，主局が発する電波パルスを，従局が受けて再発信し，これを航空機や船舶で受信，ディスプレー上で主従両局のパルス間の時間差を測定する。同一の時間差を生ずる位置の軌跡は双曲線になるが，あらかじめこの双曲線を記載したロランチャート上で，２組の軌跡を求め，その交点から簡単に正確な位置が決定される。2MHzの中波を用いるロランA，100kHzの長波を用いるロランCがあり，後者は1000カイリ以上の遠距離でも使え，精度もより高い装置が簡便で数百カイリの長距離に使えるため，極東地域や米大陸沿岸の主要航法装置だったが，米国がGPS（衛星測位システム）に切り換えたため，日本周辺のロランC運用は海上保安庁が引き継いだ。→DECCA／電波航法
→関連項目航海計器｜双曲線航法｜電子兵器｜電波標識

出典　株式会社平凡社百科事典マイペディアについて　情報

<<: Lopukhin, AA (English spelling) LopukhinAA

>>: Lord, AB (English spelling) LordAB