The invention discloses a
levelling and calibrating method used for an indoor space surveying and
positioning system. The
levelling and calibrating method comprises the following steps: rigidly connecting an
inclinometer with a base; fixing a launch
station at the top end of the base; fixing a
laser at the top end of the launch
station; supplying power by the launch
station to drive the
laser at the top end to emit
visible laser to the outside, thus forming a
scanning plane and guaranteeing that all points on the
scanning plane are positioned inside a view field of a
theodolite; reading the coordinate value in the Z-axis direction by utilizing three points which are aligned by the
theodolite and are separated by 120 degrees; calculating the differences of three average values until any two difference value is smaller than 0.1mm, otherwise, adjusting the height of a support leg corresponding to the triangular base; and setting the output angle values of the two axes of the
theodolite to be zero, and taking the output angle values as the
levelling criterion of the launch station. According to the levelling and calibrating method, the calibration process of external parameters is simplified, and the applicability of the
system is improved; a rotating shaft of the launch station is taken as the criterion of a geodetic coordinate
system, and further, the position and posture relationship with other measuring instruments is established, so that the
combined use of various instruments is convenient.