THE USE OF SLAM AND UAV TECHNOLOGY IN GEOLOGICAL FIELD FOR MONITORING: THE CASE STUDY OF THE BOSSEA CAVE

The geomatics survey in the speleological field is one of the main activities that allows adding a scientific and informative value to the exploration of caves and is of fundamental importance to have a detailed knowledge of the hypogean cavity: only thanks to the reconstruction of the three-dimensional environment through range-based techniques, are possible orientation, inland navigation, lithological understanding, as well as a better organization of the exploration of the cave itself. This work describes the surveys made in the Bossea Cave, in the province of Cuneo (NW, Italy), considered among the most suggestive and geologically interesting in Europe because they also have an underground karst laboratory managed by the Scientific Station of Bossea (CAI of Cuneo) and the Department of Environment, Land, and Infrastructure Engineering (DIATI) of the Politecnico di Torino, with the collaboration of the department of Cuneo of ARPA Piemonte and the Radiation Section of ARPA Valle d'Aosta. The survey activities described below have been concentrated both on the internal environment and the mountainside above the cave. The work presents the analytical measuring principle of the portable rapid mapping system, and it is dedicated to analysing the performances of this instrument in terms of the accuracy and completeness of 3D point clouds generated. The proposed validation method follows the assessment of point cloud deviation between data based on SLAM technology and 3D point clouds obtained from a terrestrial LiDAR system. The trajectory covered about 1km, with a height difference of about 120m, reaching differences between SLAM and LiDAR sensors of about 15 cm in the plan and 22 cm on the vertical component.