Inventory measurements based on non-metric aerial photos from the board of unmanned aerial vehicle (UAV)

Abstract

The main task of land surveying, among others, is efficient implementation of the inventory of new objects, what sometimes require doing measurements in difficult terrain (mud, cuttings, moving earth masses, working at high altitude) and during ongoing construction works. Geodetic surveys are primarily used to update some databases essential for Polish principal national map, but they also support cadastral and control measurements related to excavation or construction works. Field surveys are usually done by total station or satellite GNSS receivers in a way that guarantees accuracies required in geodesy. It is also allowed the usage of other methods that ensure required accuracies. Photogrammetric technique is one of those methods. Despite the great precision and many other advantages (overall points collection and archiving the state of the object), it has not found a proper place among field measurement methods. Revolutionary developments in this area occurred along the development of small, unmanned flying vehicles (UAV) which can carry onboard camera or other sensor, and can reach places difficult to access by humans. Development of images obtained this way supports more and more developed computer software. This paper aims to bring the adopted method of measuring and computing images taken out from the board of hexacopter (6-rotor drone), discussion about obtained precision and presentation the results of the development of a number of selected terrain objects. As a result, the study found that the results obtained in conjunction with the ability to reach inaccessible places and non-invasive measurement allow to consider this method as a viable alternative to direct methods of inventory measurements.