Optimal Levelling and Gyrocompassing of Inertial Systems

This paper develops the optimal method of levelling, gyro-drift correction and gyrocompassing a moving inertial platform when its velocity is not known precisely; this information need not be available throughout the operation. The accuracy of setting up the system depends on certain statistical parameters of the errors in velocity measurement and, between certain "break" times, on inverse powers of time. A "semiclosed loop" instrumentation of the method is put forward that corrects the platform tilt and the system velocity error as they are calculated.