The Swiss Federal Railways and ALTAMETRIS create a 3D model of a rocky slope with sub-centimetre precision .

In the framework of the European In2Smart project, ALTAMETRIS, the drone subsidiary of SNCF Réseau, was commissioned to work on-site, at an altitude of over 1100 m, in Brienz/Brinzauls in the Swiss Alps, to validate new technological methods of detecting, modelling and preventing natural hazards, potentially affecting infrastructures. The slope, situated in the region of Albula, in the canton of Grisons, is 500 m high and almost 900 m long. It is unstable, with movements of approximately 1 to 10 mm per day and constant rock falls. The village of Brienz is permanently threatened by the risk of landslides with potentially catastrophic consequences. Because of this, the slope is closely monitored by the Swiss authorities.

Swiss Federal Railways (CFF) does not have any infrastructure in direct proximity to the rocky slope at Brienz. However, since the rate of movement at the site is so exceptional, it provides an opportunity for the CFF to rapidly evaluate new technologies, which it can then use to monitor rocky slopes that represent a potential risk to their infrastructure. The assignment, carried out at the beginning of July in the framework of the ‘Natural Hazard’ use case of the In2Smart programme, was the first in a series consisting of capturing LiDAR 3D data to make a model of the slope, roughly every three months. The eventual goal is to make a diachronic analysis of the movements of the slope by comparing different time periods. Dr. Nicolas Ackermann, Liaison Agent for CFF and Drone Development Engineer explains: "Brienz has all the characteristics of a complex mission, the rocky slope is at high altitude with aerological conditions which make data capture difficult. ALTAMETRIS, with its long experience of using the LIDAR 3D software seemed to me like a natural partner". ALTAMETRIS deployed a team composed of a senior drone pilot with 15 years of experience in the civil and military worlds, as well as a topographic geometrist specialised in 3D who was able to parameterize the LiDAR payload and then verify the quality of the acquired data in the field. They deployed the Riegl RICOPTER multi-rotor drone with a mass of 25 kg and a span of 2 metres equipped with a VUX-1 UAV Class 1 type LiDAR. This technology allowed them to build a very high density 3D model of the slope with almost 1000 points per square metre in some places. The mission was accomplished in complete safety and without deploying heavy equipment on the ground or by heliporting. Olivier Néel, Manager of the Business Unit Inspection at ALTAMETRIS describes the achievement: "The RICOPTER is a drone with a robust and reliable aeronautic design, using it follows rigorous protocols and it has to be piloted by highly qualified personnel". The results obtained are of high quality: "the first sets of analysed data have a higher point density than that specified by the customer! This validated the service and we are ready to industrialize the service for other infrastructure operators or authorities with similar needs”. The 2D model of the slope has sub-centimetre precision. This allows the maintainer to analyse the slightest movement on the slope, over time, in order to plan specific corrective actions.
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About Swiss Federal Railways (CFF): Swiss Federal Railways, (in French Les Chemins de fer fédéraux (CFF), in German, Schweizerische Bundesbahnen (SBB), in Italian Ferrovie Federali Svizzere (FFS)) is the main railway company in Switzerland, with headquarters in Berne. Created in 1902 with the nationalisation of a large part of the railway network, it was incorporated as a state-owned enterprise in 1992, its capital is 100% owned by the Swiss Federation. The CFF is an integrated railway company, simultaneously managing the infrastructure and offering transport services. It operates a network of 3,232 km, the longest in Switzerland, and offers both passenger and freight services. In 2016 it transported 1.26 million passengers and 210,000 tonnes of freight every day. The company earned profits of 399 million Swiss Francs in 2017.
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Gabriela VRECKO, Relations Presse