Research of error reading reference to geometric leveling short beam digital levels

One of the modern methods of observation for unique buildings’ precipitation (basements of nuclear power stations, high-level dams of hydroelectric power stations, charged particles accelerators, radio telescopes) is a high-precision geometric levelling by means of short beam with the use of digital level. The basis for the levelling method development is the AQE (average quadratic error) of taking a reading.  The researches have been performed to define the dependence of value mreading on the length of the beam D (ranging from 5 to 30 m), the number of taking the readings n and the rail E illumination. With the help of the electronic level, the study aimed at measuring the standard exceedings is known to have an accuracy which is much higher than the accuracy of taking the readings by the level. Standard exceedings were given by the lifting mechanism, which had been tested before. This mechanism was used to change the height of the rail relatively to the sighting level beam as the starting point, and it ensured the accurate identification of the rail height changes m = ± 0.003 mm. According to the results, the error of the rail inclination is absent. Based on the results of experimental measurements it has been found out that the illumination in the range from 80 to 360 lx (lux) does not affect the precision of the automatic taking the reading. At the same time there is a clear linear dependence mreading on D and n, which is approximated for the high-precision level TOPCON DL- 501 by the equation. For precise electronic level Sprinter 150M this dependence is approximated by the equation . The analysis shows that mreading for the precise one to a great extent depends on the number of sensing the readings. Obtained dependences allow to develop optimum methodologies of conducting geometry levelling and can be applied in working out normative documents.