In modern industrial geodesy, high demands are placed on the final accuracy, with expectations currently falling below 1 mm. The measurement methodology and surveying instruments used have to be adjusted to meet these stringent requirements, especially the total stations as the most often used instruments. A standard deviation of the measured distance is the accuracy parameter, commonly between 1 and 2 mm. This parameter is often discussed in conjunction with the determination of the real accuracy of measurements at very short distances (5–50 m) because it is generally known that this accuracy cannot be increased by simply repeating the measurement because a considerable part of the error is systematic. This article describes the detailed testing of electronic distance meters to determine the absolute size of their systematic errors, their stability over time, their repeatability and the real accuracy of their distance measurement. Twenty instruments (total stations) have been tested, and more than 60,000 distances in total were measured to determine the accuracy and precision parameters of the distance meters. Based on the experiments’ results, calibration procedures were designed, including a special correction function for each instrument, whose usage reduces the standard deviation of the measurement of distance by at least 50%.

. Can. J. Chem. 71, 2079Chem. 71, (1993.An apparatus for the study of the discharge patterns generated in gaseous dielectric breakdown is described. ' The discharge patterns are imaged using a fast optical imaging system (== 40 ns exposure time) and are found to be fractals. [Traduit par la redaction]

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Abstract

The paper deals with the construction and determination of coordinates of the absoluteEDMs baseline in a laboratory with 16 pillars with forced centring. Leica Absolute TrackerAT401 (standard deviation of distance measurement: 5 μ m, standard deviation of anglemeasurement: 0.15 mgon), which is designed for very accurate industrial measurements,was used for our purpose. Lengths between the baseline points were determined with astandard deviation of 0.02 mm. The baseline is used for determining systematic and randomerrors of distance meters and for accuracy of distance meters at short distances commonin engineering surveying for purposes of mechanical engineering.