No abstract

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.

In this research, Digital level (DL), Total station (TS) and GPS were used to assess accuracy and precision of the height component. Field observations were implemented in two tested areas. A reference network which consisted of 34 points on area1 and 10 control points on area2 which had been observed five times using Digital level, RTK-GPS and Total station (TS) where Digital level was considered as a base for comparison. Several known control points were used as check points to evaluate the accuracy of measurements. According to the obtained results, TS and GPS-RTK measurements were compared with the adjusted reference points measured by precise Digital level (DNA 03). Around ±15 mm standard deviation for TS and ±13.5 mm for GPS were achieved. Linear accuracy of TS, GPS, and orthophotos measurements from Vossing German Company were also investigated in regular features within the same tested areas. The actual lengths were measured with steel tape up to a millimeter accuracy and were considered as being a base for comparing. The maximum deviation 22mm accuracy has been obtained in area2 and 12 mm in area1. The study shows that the extracted features from orthophotos had less accuracy in hilly regions due to relief displacement whereas they were more accurate in gentle slopes.