Analyses of results of the National Geodetic Survey's leveling refraction tests indicate that the standard deviation about the mean (sigma) for high-scale minus low-scale rod readings closely correlates with measured refraction error. Use of this relation in conjunction with values for sigma obtained from routinely constrainted surveys provides a basis for estimating the refraction error associated with levelings of stipulated order and class. -Authors
Additional publication details
Empirical estimates of cumulative refraction errors associated with procedurally constrained levelings based on the Gaithersburg- Tucson refraction tests of the National Geodetic Survey.