Concerning smallrotationangle alignment of locked azimuthgimbal
Abstract
The daytoday drift of a gyroscope is greater than its random drift by as much as an order of magnitude. Therefore, if the daytoday drift of a gyroscope can be measured and compensated automatically during the time of initial alignment of an inertial navigation system (INS), the accuracy of INS will be greatly improved. Techniques are examined for providing the necessary data and compensation. Several conclusions are reprinted. The method of smallrotationangle alignment of locked azimuthgimbal can measure and compensate for the gyro drift in three coordinate directions of the platform (two horizontal gyros and one azimuth gyro) within the short time that can be expected for initial alignment. The effect of the introduced local latitude error on the measurement accuracy of the azimuth gyro drift is proportional to the cosine of local latitude, but the effect of the gyro scale factor error is proportional to the sine of local latitude. The selection of the optimal azimuth small angle of rotation depends on the maximum permissible precession angular rate and the scale factor error of the azimuth gyro. THe accuracy in determining the azimuth angle of a platform depends on the azimuth.
 Publication:

Northwestern Polytechnical University Journal
 Pub Date:
 October 1986
 Bibcode:
 1986NPUJ....4..449R
 Keywords:

 Alignment;
 Azimuth;
 Drift (Instrumentation);
 Gimbals;
 Gyroscopic Stability;
 Inertial Navigation;
 Instrumentation and Photography