Initial Alignment of the Attitude and Heading Reference System

Vadym V. Avrutov, Dmytro V. Buhaiov, Vladislav V. Meleshko


Background. At the alignment of strapdown inertial navigation system (INS) the main problems are the accuracy and the alignment time. The article discusses the alignment accuracy of the portable gimballess attitude and heading reference system, namely the accuracy of the gyrocompassing mode.

Objective. The aim of the paper is to develop a mathematical model for the gyrocompassing mode error.

Methods. To develop a mathematical model for the gyrocompassing mode error, based on the output signals of the accelerometers and gyroscopes, a cosine matrix is obtained. Using the elements of cosine matrix, the full mathematical model of the gyrocompassing error is obtained by the variation method, which depends on the gyros’ drifts, the errors of the accelerometers and the error in determining the latitude of the place.

Results. The main result of the study is the derivation of the full formula for the gyrocompassing error.

Conclusions. The greatest influence on the gyrocompassing error is the drift of gyroscopes. Therefore, it is necessary to use more precise gyroscopes to increase the alignment accuracy.


Gyroscope; Accelerometer; Level axis alignment; Attitude and heading reference system; Inertial measurement unit


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