Abstract: In a geodesic measuring instrument with a fixing device for positioning the measuring instrument and with a measuring component having an optical beam path for surveying a target, whereby the measuring components are mounted in an aligning component that can be moved relative to the fixing device, and can be moved relative to the aligning component, an optical beam path is modified by at least one piezoelectric micromotor.

Abstract: The invention relates to a device for adjusting the angle of a sighting unit towards a target, in particular for a geodesic-measuring instrument. The inventive device comprises a reference base, at least one bearing for mounting the sighting unit thereon in such a way that it is pivotable with respect to said reference base around an axis, a gear for accurately adjusting an angle of rotation around said axis between the sighting unit and the reference base and a coupling unit for limiting or interrupting a torque flux around the axis. The gear and the coupling unit are in series arranged in the torque flux between the sighting unit and the reference base. The torque flux is carried out around the axis between the sighting unit and the reference base by means of the gear and the coupling unit when it is non-interrupted thereby.

Abstract: A drive device for aligning a theodolite with a target, in which the theodolite is mounted rotatably in the horizontal direction on a theodolite foot. Provision is made of a control knob and an encoder connected thereto, the encoder emitting control signals in accordance with the rotary movement at the control knob to a downstream control circuit. The circuit drives a positioning motor. The rotary table is arranged at the theodolite foot and carries the control knob. Provided between the theodolite and the rotary table is an electric contact which ensures the electrical connection between the encoder and the positioning motor.