UAV-based stereo vision for photogrammetric survey in aerial terrain mapping

Recently, Unmanned Aerial Vehicle (UAV) technology is becoming useful to solve problems in many applications. The aim of this study is to investigate the use of light weight rotary-wing UAV for mapping simulation model. The objective of this study is to determine the accuracy of the photogrammetric output. This study only concentrates on one type of rotor-wing UAV. It is because rotor-wing units are more stable and able to capture images easily. It allows remote control UAV to be practiced in any environment and urban mapping. In the simulation model, ground control points (GCP) and checked point (CP) were established using total station. The GCP is used in the photogrammetric processes to produce photogrammetric output while the CP is used for accuracy assessment. A Nikon Coolpix consumer digital camera was used for images acquisition of the simulation model where two methods were used. In the first method, the camera was mounted vertically in a rotary-wing UAV and captured the images at an altitude. In the second method, the camera is mounted vertically at a fixed height. The acquired images were processed using photogrammetric software to produce orthophoto and digital elevation model of the simulation model. From this study, it was found that root mean square errors for fixed platform are ±0.002m, ±0.001m, ±0.214m for coordinate x, y and z respectively while the root mean square errors for mobile platform are ±0.002m, ±0.002m, ±0.223m for coordinate x, y and z respectively. It can be concluded that the differences between the mobile and fixed platforms are not significant. In conclusion, UAV system can be used for large scale mapping for aerial terrain mapping.