Accuracy evaluation of digital terrain model based on different flying altitudes and conditional of terrain using UAV LiDAR technology

Unmanned Aerial Vehicle (UAV) with Light Detecting Radar (LiDAR) sensor can be used to obtained high ground resolution data and generate good quality of Digital Terrain Model (DTM) as much can decrease the cost of data acquisition and processing time. This study aims to evaluate the influences of flying altitude and terrain on DTM accuracies obtained with UAV-based LiDAR. In this study, point clouds from UAV AL3 S1000 and AL3 – 32 LiDAR were used for generating DTM on two different terrains (i.e. flat, slope and overall) with three different flying altitudes (i.e. 20m, 40m and 60m) and validate with ground control points by using 129 reference points which taken from ground survey technique (GPS, total station and optical levelling). The Root Mean Square Error (RMSE) of point clouds elevation obtained at different altitudes for the flat area are 0.015m, 0.027m and 0.105m at the altitudes of 20m, 40m and 60m, respectively. Meanwhile, RMSE values for slope area are 0.267m, 0.298m and 0.343m at the altitudes of 20m, 40m and 60m, respectively. Overall study area gives the RMSE values of 0.323m, 0.450m and 0.616m at 20m, 40m and 60m altitude, respectively. The result shows that the change of RMSE values influenced by the different of altitude and terrain, which provides accurate and faster results.