Coarse leveling of gyro-free INS

Abstract

For a stationary system, coarse alignment is used to initially determine the orientation of the INS by utilizing the Earth gravity and rotation vectors. Yet, a gyro-free INS has only accelerometers and hence cannot measure the Earth rotation vector and thus cannot deduce its yaw angle. In this paper, we formulate the coarse-alignment procedure and derive error characteristics for a gyro-free system. In addition, a comparison between different configurations of accelerometers is being conducted.