Noggrannhet vid låghöjdsfotografering från obemannad heliumzeppelinare

Sammanfattning: The development in photogrammetry has created possibilities for new methods in aerial images acquisition. Remotely-controlled imaging from an unmanned helium zeppelin is a new and relatively unexplored acquisition. The purpose with this degree project is to evaluate the accuracy of this kind of low-height photographing system, a task given from the consultant company WSP, in Sweden. Landbadet in Uddevalla municipality was chosen as a test field for the zeppelin. Seventeen images distributed over three strips were acquired from the flying height of 80 m. The ground control points for the purpose of block adjustment and control points for the purpose of accuracy evaluation were measured with Network RTK. Block adjustment were performed in the software Photomodeler Scanner. Afterwards the control points could be measured photogrammetrically and compared with the reference measurement. The evaluation of the photogrammetric point accuracy was based on the differences between the photogrammetric and the GPS-measured coordinates of the control points in plane and height. The RMS-value of the differences was 0,040 m in plane and 0,056 m in height for the whole block. The difference in the point accuracy was partially affected by the base-height ratio and by the number of images used to determine the point`s coordinates. The conclusion in general is that the system has the possibility to be used for rationalizing the mapping work compared to measurements done with conventional aerial images acquisition methods. However a satisfactorily result is dependent on a well working video link, good base-height ratio and calm wind conditions.