In-the-field leveling calibration of a surveying instrument

A surveying instrument, in particular a Theodolite, Total-Station, Rotating Laser, Layout-Tool, Laser-Tracker or Laser-Scanner, comprising:

• at least one rotational movement axis, in particular an azimuth axis, which is for providing a positioning of a targeting direction of the surveying instrument,
• a rotational position encoder configured for deriving a rotational direction value around the rotational movement axis and
• an acceleration sensor, in particular a MEMS-accelerometer, for deriving a leveling for the surveying instrument and being rotatable around the rotational movement axis in different rotational positions,
• a mechanism designed to move the acceleration sensor from a first orientation to at least a second orientation, the second orientation being different from the first orientation, wherein the mechanism is designed and arranged in such a way that the targeting direction is uninfluenced by a movement of the acceleration sensor by the mechanism and
• an evaluation unit configured to derive a calibrated leveling for the surveying instrument from position encoder readings in at least a first and a different, second rotational position of the acceleration sensor around the rotational movement axis and acceleration sensor readings in the first orientation and in the second orientation.