DATA FUSION FOR CONSTRUCTION MONITORING: HOW LEICA INFINITY MANAGES IMAGES, GNSS DATA, TERRESTRIAL SCANS AND BIM DATA TO EFFICIENTLY TRACK COMPLEX CONSTRUCTION SITES

This work explores the importance of properly handling the big variety and amount of measurements data that nowadays can be more and more easily acquired. In fact, in the last decades a new challenge took hold: the academic and industrial focus, in the most different fields, extended from developing new technologies to acquire data and more accurate ways to process it, to also developing software environments to properly handle and process the big amount and large variety of available data. In surveying, when the size and the complexity of the site requires the acquisition of diverse data and the usage of different kind of devices, working in different coordinate systems and operated by multiple people, data process and interpretation is much more error prone. When surveying a complex construction site, early identification of deviations from the design during the construction phase is crucial and has as well a big impact on the project's economic budget. Building Information Modelling (BIM) is the accepted standard for managing information for an asset, and for the construction phase it provides working from a common visualisation of the as-planned model in a 3D environment. The as-built model is generated from a large variety of acquired data, especially when site complexity requires a high level of data integration. Data are usually acquired using GNSS receivers, Terrestrial Laser Scanners (TLS), Total Stations (TS), Digital Levels, and Aerial and Terrestrial photogrammetric devices. Specifically, over the last decade Unmanned Aerial Vehicles (UAV) have been proving their importance also in construction progress and quality monitoring, thanks to their relative easiness of use and the overview they can provide over the construction site. In this work, the value of merging and processing in a single software environment different data sources to reduce errors and get geodetically relevant data is analysed. Specifically, Leica Infinity, a specialised software able to bring various data sources together for working in a common reference frame, is investigated and its effectiveness and efficiency proved for monitoring a complex construction site. The advantages of an integrated data acquisition and process, and in particular the contribution of UAV data in construction site monitoring, both from an accuracy and completeness standpoint, are also assessed.