Method for determining and correcting incorrect orientations and offsets of the sensors of an inertial measurement unit in a land vehicle

摘要

An inertial measurement unit (IMU) contains three linear acceleration sensors and three rotational speed sensors. For the sensors there are desired installation directions parallel to the co-ordinate axes of a Cartesian co-ordinate system which is fixed to the vehicle. The actual installation directions of the sensors may differ from the desired installation directions owing to incorrect orientations. By comparing accelerations which are measured by the linear acceleration sensors for different attitudes of the vehicle with acceleration values which are known for these different attitudes in the Cartesian co-ordinate system which is fixed to the vehicle, the actual installation directions of the linear acceleration sensors are determined. By using a co-ordinate transformation it is then possible to convert the measured accelerations into the actual accelerations.