Investigation of GPS positioning accuracy during the seasonal variation

For this purpose, we selected three days of each month in 2009 from the GPS observations made in the Marmara Continuous GPS Network (MAGNET). The GPS observations were processed in the ITRF 2005 reference frame using the Bernese 5.0 GPS software. The baseline length varies between 6 km and 237 km, session duration varies between 4 h and 24 h. Seasonal variation effects on the accuracy of coordinate components were analyzed. Our results showed that seasonal variation is a significant factor for determining the accuracy of GPS measurements. Also, increasing the observation period hardly improves the horizontal positioning accuracy while improving the vertical positioning accuracy.