A Comparative Study of UAV Lidar, UAV, and GNSS RTK on Infrastructure Survey

Abstract

Abstract The advancement of the latest techniques allows surveyors to have various approaches to solving survey tasks. The paper is an experimental study on collecting terrain data using different techniques including Lidar on a UAV, normal UAV, and GNSS-RTK. The study uses the point clouds extracted from Agisoft for data from Phantom 4 RTK, and Copre for data from Lidar. The lidar method uses AA450, the first lidar product line of the CHC brand in Vietnam with a Livox Avia scanner. UAV phantom4 RTK uses a 1” CMOS camera, with 20M effective pixels. Both Lidar and UAV methods use the PPK processing technique, and flight altitude is 80m and 100m respectively while GNSS-RTK uses the single-base method at around 7km distance between base and rover. The study results show the deviations in coordinates are very small, and the differences in elevation of Lidar and Phantom4 RTK compare to GNSS-RTK range from 3-5cm at open positions. The differences in elevation between Lidar - GNSS-RTK and Phantom 4RTK-GNSS RTK are 5-8cm and 10-15 cm respectively at the low vegetation and sparse density positions. The differences in elevation between Lidar and GNSS-RTK method range from 8-15cm while Phantom 4RTK cannot reach the ground point at the high and dense vegetation. However, the deviations in elevation between Lidar and GNSS-RTK are 15-25cm at the low, dense positions.