Evaluation of a Wild NA3000 Digital Level

Final Year Thesis, School of Geomatic Engineering, UNSW
by Edward Sheil, November 1997
Supervisor and Editor: Associate Professor J. M. Rüeger

The Wild NA3000 precise digital level with serial number 91053 was evaluated for temperature dependent errors and the instrument's precision in double-run line levelling.

A computer-instrument interface program (NA3K) was developed to remotely operate the Wild NA3000 digital level from a personal computer.

The instrument tested was found to have a standard deviation of 1 km double-run line levelling (after DIN 18723 Part 2) of 0.34 mm per square-root kilometre.  This value certainly classes the Wild NA3000 as a precise levelling instrument.

The change of the collimation error with temperature was investigated.  A value of -0.392"/°C was determined for the temperature range from 21.6°C to 45.3°C.  This value is smaller than, and of opposite sign to, the values found by other researchers conducting similar experiments. The collimation error changed by +0.248"/°C in the temperature range from -11.5°C to 21.2°C. Previously published results are of the same sign but of larger value.

Vertical shifts in the line of sight of the instrument of about +0.003 mm/°C were also detected. These vertical shifts are at least partly due to the expansion of the body of the instrument and its footscrews with temperature.
 
 


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Last modified: 10/15/2001 by EGM