Abstract
Measuring level deviation in an automated storage and retrieval system, the system having a rail system, container handling vehicle, and central control unit. The rail system includes first parallel rails to guide movement of a container handling vehicle in a first direction across the top of a frame structure, and second parallel rails perpendicular to the first rails to guide movement of the vehicle in a second direction perpendicular to the first. The first and second parallel rails divide the rail system into grid cells. The vehicle operates on the rail system. The vehicle has at least one orientation sensor to measure at least one orientation parameter in a 3D Cartesian reference system. The control unit can process data signals of the vehicle and the sensor. Method includes arranging the vehicle in a position on the grid, transmitting a signal from the control unit to the vehicle to move a distance in one direction, measuring at intervals, using the sensor, a parameter to produce orientation measurements of the vehicle's orientation within the reference system, transmitting and processing data concerning the orientation to the control unit to identify deviating rail system portions.