Elzbieta Jasinska, Edward Preweda

Effect the Accuracy of Benchmarks to Establish of the Determination of Geodetic Network

View full text in PDF format

Abstract

In classical applications of parametric method to compensate the coordinates of geodetic networks is usually assumed to establish faultless points. The object of estimation parameters, the coordinates of points are determined by observations which mediate appointment of unknowns. References points can have larger standard deviations than the accuracy of observations. This is the results of the advances in technology. If it is necessary to obtain the coordinates of the height accuracy freely alignment is often used, taking for example the coordinates of one point and the azimuth direction of the flat networks or the level of only one point from network leveling. This simplified solution is justified when it is important to get internal network precision because we get rid of the errors in this way to benchmark point. This is not the exact solution.
In the case of having the knowledge of variance-covariance matrix of benchmark points, it should be reflected in calculation. In the case of benchmarks, which amount was set many years ago, generally covariance are not known. In this case, alignment it is still possible, it can be based on the variance, which can be determined, for example, on the altitude network class. Benchmark points are considered establish in this case as the observations and unknowns simultaneously. They shall be the subject to appointment and are treated as pseudo-observations.
This article is an example of comparison between network adjustment which included level marks standard deviation and the other one freely alignment and assumptions inerrancy establish points. Convenient extension of the of parametric method was proposed, where the notion of observation equations for the point (coordinate) was interposed.

Keywords: Benchmarks; Geodetic Network; freely alignment.