Dead reckoning using an attitude and heading reference system based on a free gyro with equatorial orientation

Abstract

The paper develops an earlier proposed approach to the construction of a geographically oriented horizon trihedron nonperturbed by inertial accelerations to aid navigation dead reckoning. The method developed by the author is called gyroscopic orientation with correctable pendulum. The proposed scheme is implemented using a trihedron of accelerometers and a free (uncontrolled) gyro with equatorial orientation. Special attention is given to the Schuler filter, which not only provides “absolute” nonperturbility of navigation dead reckoning but also makes it possible to formulate the problem of its autonomous error estimation to the accuracy determined by the gyro drifts in the steady state. The problem of occasional correction of “azimuth” heading during in situ observation is also considered.