April 2000
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145 Reads
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28 Citations
In this paper, a new measurement procedure is presented for the system calibration of digital levels using a vertical comparator. The proposed routine system calibration yields information about the scale of the coded invar staff, the accuracy and the errors of the instrument-staff measuring system, with the staff in its vertical working position. The calibration is carried out at 3 m distance and, additionally, at a typical sighting distance. The proposal is based on a thorough review of the development of the system calibration and the type testing of digital levels. The error sources of digital levels and staffs are discussed and the technical data of the current digital levels are tabled.