engleski

Development of Geodetic Linear Scales Calibration Method – Initial Works and Tests

Comparator for calibration of geodetic linear scales such as levelling staffs or measuring tapes is a device that compares nominal (reference) graduation values with measured distances of graduations from zero point. Calibration is conducted to determine the actual behavior model of tested linear scale graduation. Comparators are not mass-produced and therefore are not commercially available. They must be individually designed according to the requirements of individual calibration, test, or research laboratory. Such comparator was constructed in 2002 as a part of the doctoral dissertation of prof. Đuro Barković, PhD, at the Laboratory for Measurements and Measuring Technique of the Faculty of Geodesy, University of Zagreb. Constructed comparator calibration works on the principle of distance measurement by using a linear encoder, and individual graduation lines on a geodetic linear scale are observed manually by aiming each edge of each graduation using an optical microscope. Aim of this doctoral thesis is to develop fully automated geodetic linear scales calibration method that will have uncertainty lower than 5 μm/m. It will be accomplished by updating existing comparator with a CCD camera on a servomotor driven cart. The whole calibration process will be supervised by a software developed in an open-source environment. In this paper performed works on hardware update and software development will be presented, also with initial testing and results.

geodetic linear scales ; levelling staff ; calibration ; CCD camera ; linear encoder

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