Mehdi Rezaei - Master of RS & GIS from Azad university, Science and Research Faculty, Branch of Yazd
Amir Hosein Shokri - Associate Degree in Surveying from Kermanshah Technical and Vocational Institute
Babak Miri Jazari - Associate Degree in Surveying from Kermanshah Technical and Vocational Institute

In this study, the effect not being in the same orientation of the antennas error in a triangular network with approximate dimensions of 19,12 and15 meters has been tested. Satellite observations of the three sides traverse were tested in fourconsecutive days and every 6 hour. Four times of traverse have been done during 0,6,12 and 18 hours of day. In allObservations on the first and second day, the antennas direction has been to the West, in the third day observations, thedirection of antennas to the outside of each Baseline and on the fourth day observations, antenna direction has beenlocated inside the Baseline. Thus, a total of 16 times of the traverse, has been carried at a rate of 1 in the metropolitanarea with excellent viewing angles and free of annoying GPS signals. The observations of each Baseline have beenlasted for twenty minutes. In all processing times of Baseline absolutely identical name satellites and completely identical time interval have been used. Finally, the effect of antennas direction in positioning as well as DOP satelliteimpact on different days and other possible errors on satellite traverse have been evaluated.

Antenna Phase Center, GPS, DOP, Baseline, Satellite travers