Rapid mapping using UAV and RTK-GNSS | |
| Author | Kanth, Dasari Ravi |
| Call Number | AIT Thesis no.RS-16-25 |
| Subject(s) | Geographic information system Mapping |
| Note | thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Remote Sensing and Geographic Information Systems |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. RS-16-25 |
| Abstract | In recent years, the utilization of unmanned manned aerial vehicles (UAVs) and real time kinematic global navigation satellite systems (RTK - GNSS) ha s become more feasible for applications like risk mapping and prevention, hazard mitigation and for several rapid mapping activities because of its flexible, efficient and weather independent rapid collection of very high resolution data in a cost effective manner. This accurate high resolution data has been critical for quick decision making and emergency response. But the use of non - metric cameras, consumer grade GPS sensor, geographic location of area and the local environment (trees, buildings and electrical lines) affect this geo spatial data. The contribution of this study is to evaluate the accuracy of different UAV products (orthophoto and digital surface model (DSM)) with the use different ground control points (7,9 and 11) obtained from smart phone and rapid static positioning and also with processing softwares (Agisoft and Pix4D) and to evaluate the accuracy of RTK - GNSS positioning measurements with the consideration of interferences like trees, buildings and electric lines at different timings of day (morning, afternoon and night).In this study, first we evaluated the geometric accuracy of data products obtained from UAV; found that best possible geometric accuracy of orthophoto is obtained from the use of ground control points from rapid static positioning in UAV i.e. geometric accuracy of 0.33 m for rapid11 orthophoto for Pix4D software and it is followed by Automatic orthophoto with a geometric accuracy of 3.24 m and phone9 orthophoto with geometric accuracy of 4.07 m. According to NSSDA and UNDP with these geometric accuracies, the obtained map scales are 1:1000, 1:10000 and 1:12000. The orthophoto’s with these map scales can be used for detailed and city level rapid mapping activities. The associated map scales of computed Orthoimagery pixel sizes (5.6cm) is 1:500 and it should have associated horizontal accuracy of less than 30 cm (i.e. less than 6 pixels). But the rapid 7, 9 and 11 Orthoimagery only had satisfied this condition. For digital surface model, the highest geometric accuracy is f rom rapd11 DSM with an accuracy of 1 m from Pix4D software and there is also an effect of trees and buildings shadows on DSM which is giving false height variations. The impact of environment or surroundings (trees, building and electrical lines) on RTK - G NSS at various session of a day is evaluated, we found that effect of trees is more on RTK - GNSS at amid morning time i.e. we got the positioning error of 1.9 7 m and the effect of buildings on position measurements of RTK - GNSS is 1.669 m it happened at afternoon time . The effect of electric wires on position measurements of RTK - GNSS is 1.2497 m it happened on both evening and night time. We also found that distribution of satellites had effect on positioning measurements and the calculated double difference residual errors tells us the RTK - GNSS positioning measurements is highly influenced by trees with a residual error of 2.69 m and the second is buildings with a residual errors of 1.669m and electric lines with a residual error of 1.27m. We also evaluated the positioning measurements of smart phone with RTK and found that horizontal positioning error is about 4.79 m and it is equivalent to map scale of 1:15000 of class 1 according to ASPRS standards. Key words : UAV, RTK - GNSS , Agisoft , Pix4D, Orthophoto, DS M, Smart phone (HTC Desire), Local environment, Double difference residual errors, ASPRS, NSSDA, UNDP |
| Year | 2016 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. RS-16-25 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Remote Sensing (RS) |
| Chairperson(s) | Nitin Kumar Tripathi |
| Examination Committee(s) | Sarawut Ninsawut;Durairaju Kumaran Raju |
| Scholarship Donor(s) | AIT Fellowship |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2016 |