The paper presents methods of measurements and post-processing of GPS observations for engineering applications used for construction of highways. The measurements of geodetic control points on the distance of 13 km of the ring road of Wyszkow were done with the use of seven GPS receivers as Ashtech Z-XII, Ashtech Z-Surveyor and Ashtech Z-Xtreme. The control points of network were situated close to wooden area what makes more difficult accurate coordinates determination. In such situation it is extremely important to choose a proper methodology of GPS measurements and post-processing strategy in order to obtain high and reliable accuracy. The methodology of measurement and post-processing of GPS data presented in this paper allowed to obtain 2-3 mm accuracy after network adjustment having 1.5 – 3 hours GPS sessions.

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