To provide a desired impulse value while making emission gas pulse period adjustable and minimizing a number of valve open and close operation times of each thruster.
Data relating to a ship position are collected and the ship is located in a field of the force tending to direct the ship attitude toward a first position different from a desired attitude. Attitude data are evaluated to judge a pattern of ship attitude values according to a gas pulse and the field of the force. This device and method maintains the attitude within a predetermined range of position values including the desired position. A calculation circuit establishes an optimized continuation period of each gas pulse based on a pattern of position values and an optimized continuation period to provide a minimum number of valve open and close operation times. A thruster operates to provide gas pulses of the optimized continuation period.
STEVENS HOMER D
CARROU STEPHANE
