Abstract:

The error characteristics of the indirect analytic alignment (IAA) algorithm based on gravity acceleration vector integration are analyzed, which is mainly with respect to inertial measurement unit (IMU) sensor errors and linear vibrations, and corresponding error formulas are deduced. Analysis indicates that the IAA algorithm is easier disturbed by linear vibrations while the traditional analytic algorithm mainly by angular movement, thus the IAA algorithm can accomplish initial-alignment in swing environment and further estimate gyros drift through the changing slope of estimated initial attitude. Finally, by comparing each’s influence on azimuth estimation precision, a selection criterion is designed to decide whether use the IAA algorithm or the traditional one. The simulation results show the rationality of the above conclusions.