Abstract
Abstract. This paper considers Leica backpack and photogrammetric surveys of a mediaeval bastion in Padua, Italy. Furhtermore, terrestrial laser scanning (TLS) survey is considered in order to provide a state of the art reconstruction of the bastion. Despite control points are typically used to avoid deformations in photogrammetric surveys and ensure correct scaling of the reconstruction, in this paper a different approach is considered: this work is part of a project aiming at the development of a system exploiting ultra-wide band (UWB) devices to provide correct scaling of the reconstruction. In particular, low cost Pozyx UWB devices are used to estimate camera positions during image acquisitions. Then, in order to obtain a metric reconstruction, scale factor in the photogrammetric survey is estimated by comparing camera positions obtained from UWB measurements with those obtained from photogrammetric reconstruction. Compared with the TLS survey, the considered photogrammetric model of the bastion results in a RMSE of 21.9cm, average error 13.4cm, and standard deviation 13.5cm. Excluding the final part of the bastion left wing, where the presence of several poles make reconstruction more difficult, (RMSE) fitting error is 17.3cm, average error 11.5cm, and standard deviation 9.5cm. Instead, comparison of Leica backpack and TLS surveys leads to an average error of 4.7cm and standard deviation 0.6cm (4.2cm and 0.3cm, respectively, by excluding the final part of the left wing).
Highlights
Current generation of mobile mapping systems is mostly based on the use of GNSS positioning method and either laser scanning or photogrammetric reconstruction
When GNSS positioning is not available/reliable, Leica Pegasus backpack allows positioning by integrating IMU and laser scanning measurements. This paper considers another method for positioning in environments challenging for GNSS: positioning based on the use of
Pegasus backpack is a terrestrial mobile mapping system recently developed by Leica: it features 2 laser profilers, 5 cameras, GNSS receiver and 200Hz Inertial Navigation System (INS)
Summary
Current generation of mobile mapping systems is mostly based on the use of GNSS positioning method and either laser scanning or photogrammetric reconstruction. Given the high request for accurate metric reconstructions, positioning in such working conditions is typically obtained by integrating information provided by different sensors (e,g, inertial measurements provided by the Inertial Measurement Unit (IMU), acceleration, gyroscope and magnetometer measurements, vision, and WiFi, if available (Saeedi et al, 2014, Widyawan et al, 2012)). A recent example of mobile mapping system allowing accurate surveying in indoor environments is the Leica Pegasus backpack. When GNSS positioning is not available/reliable, Leica Pegasus backpack allows positioning by integrating IMU and laser scanning measurements (acquired at different time instants)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
