Abstract: To calculate the distance and angle of a measuring platform with respect to reference marks, fans of light are emitted from the measuring platform by light emitters. The light emitters are therefore arranged on a circular path about the central axis to rotate in such a manner that the fans of light are emitted tangentially to the circular path. The distance and the angle can be calculated on the basis of the angle of the reflected fans of light received on the measuring platform by the trigonometric method. This arrangement according to the invention results in precise measurements of the distance and the angle in one circular passage of the light emitter, even when the measuring platform is moving.

Abstract: At a machine for the establishing of a design--track position with a machine frame which runs on chassis and with a working unit coupled thereto, a measuring unit is in accordance with the invention directly placed on the machine frame for the working unit, resp. The measuring unit is, thereby, connected to a control device which controls the working unit in accordance with at least one parameter height position, lateral position and transverse inclination via a adjusting drive. The measuring unit includes an absolute measuring system for a registering of geodetically surveyed fixed points.

Abstract: The process for measuring relative angles between a measuring platform and measuring points provides at least one light ray (f.sub.1, f.sub.2) fanned into a flat band. This light fan is swivelled around an axis of the measuring points light is reflected back to the measuring platform, as soon as the light fan impinges on these reflecting means. The measuring platform has counters, which count continuously until the arrival of a reflecting signal at the measuring platform. The respective next reflecting signal stops at the next provided counter. A counter is provided to count with the same counting pulse, during the entire, predefined angular range, in which the measuring points are to be acquired. From the ratios of the counts stopped by the reflecting signals, to the count of the counter that is still counting, the angle of the corresponding measuring point is calculated. Preferably two light fans (f.sub.1, f.sub.2) that are preferably at right angles to each other are provided.

Abstract: A process and apparatus for surveying a railway track includes a light-receiving and emitting head capable of swivelling about vertical and pitch axes mounted on a measuring platform moveable along the track, as constantly aligned with a reference mark such as by stepping motors controlled by electronic control elements that evaluate the signals detected by the head. These control signals represent at the same time the value of the relative angular displacement of the head with respect to the reference mark while travelling along the track. A space-stabillized gyroplatform on the measurement platform detects the absolute change in position of the measurement platform which is used to correct the angular displacement values of the displacement head. The distance covered is detected by a separate distance measuring device or by the gyroplatform.