Steel rail space three-dimensional geometrical shape construction method and device

The invention relates to a steel rail space three-dimensional geometrical shape construction method and device. The method comprises the steps that motion state information of steel rail measurement equipment and steel rail laser scanning data are acquired; establishing a steel rail three-dimensional point cloud model according to the laser scanning data; steel rail design linear change points are judged based on the motion state information of the steel rail measurement equipment; extracting the midpoint of the top end of a steel rail section in the model, performing rail top midline parameter fitting according to a curvilinear equation corresponding to a rail line shape, generating a rail top midline, and optimizing the spatial position of the rail top midline by utilizing the combination of the angular velocity and the linear velocity information; and calculating geodetic coordinates of track section key points and a course angle, a pitch angle and a roll angle at a target mileage by combining steel rail s