a device designed for the three - dimensional geometrical detection of an environment includes at least one inertial measurement system for provisionally calculating a trajectory of the detection device . the device is calibrated by steps of : positioning and / or orienting the detection device in a position and / or orientation with respect to at least one reference point characterized by at least one predefined relative coordinate , or determining at least one relative coordinate which characterizes the position and / or the orientation of the detection device relative to at least one reference point ; determining at least one error variable which characterizes the deviation of the relative coordinate in accordance with step from the relative coordinate provisionally calculated by the inertial measurement system ; and if the error variable fulfills a predefined correction criterion , correcting the provisional trajectory .