IN-THE-FIELD LEVELING CALIBRATION OF A SURVEYING INSTRUMENT

The invention relates to a surveying instrument (1), comprising at least one rotational movement axis (2a) such as a azimuth axis, which is for providing a positioning of the measurement direction (4) of the surveying instrument (1), a rotational position encoder (5a) configured for deriving a rotational direction value (31) around the movement axis (2a) and an acceleration sensor (9) such as a MEMS-accelerometer for deriving a leveling for the surveying instrument (1) and being rotatable around the rotational movement axis (2a) in different rotational positions. The instrument (1) further comprises a mechanism (10) designed to move the accelerometer (9) from a first orientation (O1) in at least a second orientation (02), the second orientation (02) being different to the first orientation (O1), wherein the mechanism (10) is designed and arranged in such a way that the targeting direction (4) is uninfluenced by a movement of the accelerometer (9) by the mechanism (10), and an evaluation unit (7) configured to derive a calibrated leveling for the instrument (1) based on position encoder readings in at least a first and a different, second rotational position of the accelerometer (9) around the movement axis (2a) and accelerometer readings in the first orientation (O1) and in the second orientation (02).