Ricerc@Sapienza

In the past, the possibility to access to dual frequency GNSS was achievable only with expensive and high quality receivers, in environment and conditions that are different from the everyday lifestyle. The use of dual-frequency is relevant because it allows increasing the accuracy and the reliability on the user’s position estimation. The technological evolution has brought today the possibility to extend the advantages of the high accuracy positioning to a larger number of users and applications.

A new low-cost L1/L2c receiver board is presented in this short letter, along with its first tests. The main strength of the board is its low price tag (around 200 EUR, in quantities of hundreds) as an effective dual-frequency receiver. The effectiveness of the receiver was at first proven by a pedestrian walk experiment on a closed loop, allowing the evaluation of closure errors. Raw measurements were collected and processed in a real-time scenario through a variometric approach implemented in VADASE software.

In recent years, significant advances have been made in the field of global navigation satellite systems (GNSS) algorithms and new applications.

Caves have been used by humans and animals for several thousand years until present but, at these time scales, their structures can rapidly change due to erosion and concretion processes. For this reason, the availability of precise 3D models improves the data quality and quantity allowing the reconstruction of their ancient appearance, structure and origin. However, caves are usually characterised by lack of light, high percentage of relative humidity, narrow spaces and complex morphology. Thus, quite often the traditional topographic instruments cannot be employed.

Climate-induced stresses, more than in the past, expose trees to hazards possibly compromising their stability, with serious risk for people, objects, structures and infrastructures. In order to prevent trees falling phenomena, a constant improvement of the knowledge of relations between trees and meteorological events (trees-wind in particular) is crucial.

In recent years, the measurement of dam displacements has benefited from a great improvement of existing technology, which has allowed a higher degree of automation. This has led to data collection with an improved temporal and spatial resolution. Robotic total stations and GNSS (Global Navigation Satellite System) techniques, often in an integrated manner, may provide efficient solutions for measuring 3D displacements on precise locations on the outer surfaces of dams.