PURPOSE: To increase a position-detection range by laying a rail as a guide, arranging transponders on the rail as reference points for position detection at constant intervals, and measuring distance from and the angle of each transponder by an ultrasonic position measuring means fitted to the body of a ship.
CONSTITUTION: This describes a long base line system. To a rail laid on the bottom of the sea previously, transponders 21, 22 and 23 (three units in the figure) are fitted and fixed, and a couple of transmitter and a receiver 31 and 32 are provided to the bottom of the ship. The transmitter 31 transmits an answer signal and the receiver 32 receives answer signals from the transponders 21W23; those times are counted to calculate distance to each transponder, thereby finding the position of the ship by trigonometrical measurement. In this case, the transponders 21W23 are installed at distance which is nearly once W ten times as long as the depth of water.
KOYANAGI YASUO
SHIMADA KATSUHIKO
YAMADA TAKEO
HORIGOME HIDEKAZU
