EVALUATION OF PHOTOGRAMMETRIC TOTAL STATION

Abstract: Photogrammetry is a science which obtains reliable measurements by a means of pho-tographs, and it can be aerial or terrestrial. This study is done in KTH main Campus on L building located at Drottning Kristinas väg 30. It assessed the precision of Trim-ble total station S8 for photogrammetric point measurement relative to the coordi-nates measured with a total station. The steps performed in the study were: planning the measurements (selection of the study area, selection of the instruments, selection of the station points, selection of the software and putting the target points over the facade), data acquisition and finally data processing in TBC software. In the work, sys-tematic error tests were carried out, and the tests results show that there are systematic errors in easting and northing of the measurement result, however it was difficult to say there is or there is no systematic error in the elevation. The most likely source of these errors might be an incorrect orientation of the camera. It was seen that there were some factors influenced the precision of photogrammetric point measurements, such as image redundancy and parallax angle between images. The precision assess-ment was done by calculating photogrammetric points; from different parallax angles between images and from different numbers of images which were taken from differ-ent station points. The better results or smaller differences between the total station and photogrammetric coordinates were detected from five station points relative to four and three station points and from parallax angle in range 60-105 degree relative to parallax angles in range 30-60 and 0-30 degrees. In general, precise photogrammet-ric coordinates were obtained from parallax angle in range 60-105 degree and from five station points.Keywords: Photogrammetry; precision; station points, checkpoints, Trimble total sta-tion, Trible Business Center.