Summary:

Analysing the results of determining x, y coordinates of a single point posi-tion by GPS hand held receiver leads to find out a systematic component. It exists for different types of receivers, in different provinces, in different reference
systems. Elimination of this bias from the set of observations makes it possible to diminish true values of errors of determination of point location.
There are some other different sources of errors in determination of point location: number of satellites in view, quality of their geometry (PDOP), using EGNOS system, multipath errors and also observation time at the station.
Researching the latter error it was found out, that reliable results are opta-inable after 2 minutes since the observation started.