Crook, C.N.; Williams, R.O. 1988 Analysis of Wild D120 data acquired by NZ Geological Survey, 1983-1987. Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey report EDS 121 11 p.
Abstract: Wild D120 distance measuring instruments have been used by NZ Geological Survey since October 1983, in which time over 900 lines have been measured (some 200 being instrument calibration measurements) with two instruments (serial numbers 41298 and 31599). The standard error of these observations is estimated as 1.9mm +/- 1.6ppm, though centring errors may be underestimated. Baselines measurements indicate an additive correction of -0.0012m is required for measurements with 31599 and Sokkisha CR3 reflectors. For 41298 the additive correction is 0.0045m. The most significant systematic error observed in the data depends on the time of day at which the observations were made; lines measured near midday are up to 3ppm longer than those measured near dawn or dusk. This is interpreted as the error in estimating the mean atmospheric temperature and pressure along the measured line from observations at each end of the line. The same effect has been observed in Mekometer data, and is consistent with systematic errors predicted by a turbulent transfer model of the atmosphere.
