PRELAUNCH ALIGNMENT AND CALIBRATION OF A HYBRID INERTIAL MEASUREMENT SYSTEM: ROTATION OF A STRAPDOWN UNIT ABOUT A HORIZONTAL AXIS

摘要

A technique for initial alignment and calibration of a hybrid inertial measurement system, designed as a roll-isolated inertial measurement system (RIMS), is proposed. It is intended for horizontal prelaunch orientation of a RIMS rotation axis. The initial preparation of the system involves calibration of some accuracy parameters of the accelerometers and, for certain positions of the RIMS rotation axis relative to the North direction, biases of the angular rate sensors as well. This allows considerable increase in accuracy of azimuth alignment. The potential accuracy of the technique is estimated with the help of mathematical simulation. The simulation methodology and results are discussed.