In this research, RTK GPS (Real time Kinematic GPS) was used to compare with precise Digital Level for estimating earthwork volumes. Any volume calculation process has to pass through two stages. Firstly, data collection using surveying instrument, for instance, level instrument, total station, Global Positioning System (GPS), or laser scanning. In the second stage, carrying out measurement of figuring volumes using either manual or computerized method. In this paper, the field test was conducted to gather data for estimating earthworks using two technologies; Digital Level (DNA 03) and RTK GPS. Two sites have been chosen; open to the sky and partially obstructed to satellites in order to evaluate RTK GPS technique. The main aim is to compare the RTK manufacturer claimed accuracy (height component only) with trusted data. The comparison has been carried out using two different categories; first, through using the volume calculation and second via statistical testing through the cloud to cloud comparison. Finding revealed that the mean differences for the test01 and test02 are about -20mm and 16mm, respectively. The Root Mean Square (RMS) and maximum error were found to be about ±63mm, 45cm and ±56 mm, 25cm for test01 and test02, respectively.

The progress in modern technologies such as precise lightweight cameras mounted on unmanned aerial vehicles (UAV) and the more user-friendly software in the photogrammetric field, allows for 3-D model construction of any structure or shape. Software now achieves in sequence the processes of matching, generating tie points, block bundle adjustment, and generating digital elevation models.The aim of this study is to make a virtual 3-D model of the college of engineering /University of Duhok. Kurdistan Region, Iraq. The data input is vertical and oblique imagery acquired by UAV, ground control points distributed on the surrounded ground, facades, and roof. Ground control points were measured by the GPS RTK system in addition to the reflectorless total station instrument. The data is processed mainly using Agisoft PhotoScan software as well as the Global Mapper and the ReCap software. The output is a 3-D model, digital elevation model, and orthomosaic.Geometric and visual inspections were carried out. Some imperfections appeared on the sharp edges and parapets of the building. In the geometric accuracy of selected points on the building, the maximum standard deviation in the coordinates was ±4cm. The relative accuracy in distance measurements were in the range of 0.72% to 4.92 %

The Unmanned aerial vehicles (UAV) have become convenient for many applications such as the production of 3D ground models, orthophotos, road maintenance and dam monitoring, etc. The aim of this paper is to investigate the accuracy of the orthophoto obtained from UAV images compared to the existing orthophoto generated from aerial survey conducted by Vossing German Company in Duhok city, 2011 using GPS ground control point as a reference base. A digital elevation model (DEM) of the university campus was created with the UAV vertical images. Low flight height of 80m was used with the rate of 70% forward overlap and 40% side lap. An orthophoto is produced based on this DEM. To assess the accuracy of UAV orthophotos and the existing orthophotos produced from aerial survey, 7 ground control points (GCPs) were distributed and used for processing the orthophoto mosaic and DEM, 12 GCPs were used as check points. The 19 GCPs were accurately measured using GPS-RTK. Discrepancy in horizontal position of the GCPs measured on both orthophotos was obtained relative to the reference GPS base control points.The UAV data were processed and analyzed using two softwares pix4D and Agisoft Photoscan. The RMS errors obtained from both orthophotos is presented relative to the GPS base. Sub-centimetre accuracy for horizontal position was achieved from the UAV orthophoto at low flight altitude.