Abstract: The present invention relates to a system for calibrating translation equons of a gyro navigator of a submarine. A value of velocity and a value of position of the submarine are produced by using values of acceleration sensed by accelerometers in the navigation gyro. The value of velocity and position are produced with the aid of the translation equations. This value of velocity and value of position are compared with a value of velocity and a value position as produced by a more accurate and independent source. A comparison is made with the aid of Kalman filter. Any difference obtained during a comparison is used in order to calibrate the translation equations of the gyro navigator.