HIGH-ACCURACY GEOMETRICAL LEVELLING METHOD

摘要

FIELD: instrumentation.SUBSTANCE: method consists in use of a ?digital levelling unit + two bar-code rods? measuring system. A digital levelling unit has ?invers? function. Lengths between toe ends on each rod are known from calibration of rods under normal conditions. Measurements involve counts as to rear and front rods. Rods are turned over and measurements are repeated. By counting from upper toe ends and having switched on ?INVERS? function on the levelling unit, lengths of each rod are calculated as sums of counts obtained from two positions of the rod, and they are compared to the lengths obtained at calibration. Differences of lengths obtained at calibration and under actual conditions are corrections for temperature deviation, with a consideration of which excess values obtained at two positions of the rods are calculated. Equality to zero of calculated excess values serves as control of measurement accuracy.EFFECT: improving accuracy of geometrical levelling.