A Statistical Analysis of the A-6A Inertial Navigation System.

Abstract : The report describes a statistical analysis of the gyro-compass mode of the A-6A inertial navigation system. The inertial system is assumed to have various stochastic perturbations caused by gyroscope drifts, accelerometer drift, and a white measurement noise from the ship inertial navigation system (SINS). The result of the analysis is the variance in the estimate of the gyroscopic drift due to the assumed stochastic processes. The analysis of the system as provided by the ground support department showed that the system was unstable as it stood. A change in one of the feedback gains was made so as to stabilize the gyro-compass loop. Then, an analysis of the resulting loop showed a maximum error (1 sigma) of 9.9 degrees/hr due to all of the assumed noises. (Author)