Experiments on Long-term Geodetic Monitoring by Low-cost GNSS Receivers and GoGPS Positioning Engine

This paper describes experiments of GNSS-based monitoring by means of different models and brands of low-cost receivers. Single-frequency observations were processed by Open Source goGPS Positioning Engine, in relative positioning mode with respect to a virtual reference station and three physical permanent stations. The experiments were carried out in Osaka, Japan and the results here described cover a timespan of eight months. The daily solutions show standard deviations ranging from about 1mm to 1cm, mainly depending on the base station observations quality

Key economic drivers enabling municipal renewable energy communities’ benefits in the Italian context

Community energy is a buzzword that has historically included various type of experiences. In 2018, the Renewable Energy Directive (RED II) legally defined renewable energy communities (RECs). Based on the first pilot projects and on the Italian legal framework, a possible REC configuration of municipal initiative with a high replicability potential is one in which a photovoltaic system is installed in educational buildings and shares energy with neighbouring residential consumers. This analysis presents an economical evaluation of different possible scenarios depending on variables such as solar radiation, system capacity, fraction of self-consumption within the REC, installation costs and energy prices. All the scenarios identified and analysed show positive economic indexes, although the energy and economic results may significantly vary depending on the variables studied. In the analysed case studies, the Net Present Value (after 20 years) is between kEUR 51 and kEUR 478; the internal rate of return is between 9.5% and 88%; the payback time is between 13.6 years and 1.1 years. The results of this analysis are relevant as they allow us to better understand the critical factors that can enable REC in providing local economic and social benefits to have a real impact on energy poverty or on the provision of local social services

GNSS-based dam monitoring: The application of a statistical approach for time series analysis to a case study

Dams are one of the most important engineering works of the current human society, and it is crucial to monitor and obtain analytical data to log their conditions, predict their behavior and, eventually, receive early warnings for planning interventions and maintenance activities. In this context, GNSS-based point displacement monitoring is nowadays a consolidated technique that is able to provide daily millimeter level accuracy, even with less sophisticated and less expensive single-frequency equipment. If properly designed, daily records of such monitoring systems produce time series that, when long enough, allow for an accurate reconstruction of the geometrical deformation of the structure, thus guiding semi-automatic early warning systems. This paper focuses on the procedure for the GNSS time series processing with a statistical approach. In particular, real-world times series collected from a dam monitoring test case are processed as an example of data filtering. A remove–restore technique based on a collocation approach is applied here. Basically, it consists of an initial deterministic modeling by polynomials and periodical components through least squares adjustment and Fourier transform, respectively, followed by a stochastic modeling based on empirical covariance estimation and a collocation approach. Filtered time series are interpreted by autoregressive models based on environmental factors such as air or water temperature and reservoir water level. Spatial analysis is finally performed by computing correlations between displacements of the monitored points, as well as by visualizing the overall structure deformation in time. Results positively validate the proposed data processing workflow, providing useful hints for the implementation of automatic early warning systems in the framework of structural monitoring based on continuous displacement measurements

Monitoraggio dei prezzi del GPL nel settore residenziale, dalle serie storiche uno strumento per valutare le differenze a livello locale

A differenza dei principali combustibili utilizzati in ambito domestico (energia elettrica, gas naturale, gasolio) per il GPL distribuito sfuso o in bombole non esiste un’Autorità che raccolga periodicamente i prezzi al consumatore a livello nazionale, bensì i dati sono pubblicati dalle singole Camere di Commercio. Dal monitoraggio e dall’analisi dei database provinciali nel periodo compreso tra il 2012 e il 2017 sono emerse significative differenze locali nei prezzi di listino, che riflettono un contesto di mercato liberalizzato

Monitoring of Structures and Infrastructures by Low-Cost GNSS Receivers

This paper deals with the problem of geodetic monitoring of structures by means of permanent GNSS stations, with a focus on a specific project of monitoring a bridge by a small network of three stations. What is peculiar about this paper is that the stations used are endowed with low-cost GNSS receivers, and the data treated continuously cover a time-span of more than 4 years. The monitoring service GeoGuard, at work on the project, has proved to be reliable in terms of both hardware and software. The results display almost uniform accuracy at less than the 1 mm level for daily adjusted coordinates and at the level of ∼1–2 mm for hourly solutions. After a short review on the basics of positioning by GNSS phase observations, the error of the estimated coordinates is discussed in detail, and a procedure of warning/alarm is described. The experience in terms of hardware and software employed is then presented together with the results, which are mostly displayed in graphical form and with a few tables

Energy demand for space heating through a statistical approach: application to residential buildings

This study deals with the statistical analysis of a data set of residential buildings to find simplified correlations for the assessment of the energy demand for space heating. The analyzed data come from a sample of 50 multi-family residential buildings of the local social housing company, built in different periods between the end of the 19th century and the end of the last century. Relationships are searched between the age of the building and its main geometric and thermophysical properties: the shape ratio, the volume, the opaque and glazed surfaces, their transmittances, the external and internal temperatures. These properties are suitably combined to find out statistical relations. Moreover, starting from standard deterministic equations, this study revises them and simplifies the most involved terms. This simplification is carried out making a statistical analysis of the energy quantities that affect the performance of a building. In such a way the solution of the energy balance is simplified, making the calculation easier and faster. Results are compared with those calculated using the rigorous Standard procedure, showing a good agreement. Moreover, the assessed energy demand is compared with the actual metered energy consumption. The present statistical model estimates in a simple and prompt way the energy demand for space heating of residential buildings, in particular the existing ones. It may represent a useful tool for their energy certificatio

Energy demand for space heating through a statistical approach: application to residential buildings

This study deals with the statistical analysis of a data set of residential buildings to find simplified correlations for the assessment of the energy demand for space heating. The analyzed data come from a sample of 50 multi-family residential buildings of the local social housing company, built in different periods between the end of the 19th century and the end of the last century. Relationships are searched between the age of the building and its main geometric and thermophysical properties: the shape ratio, the volume, the opaque and glazed surfaces, their transmittances, the external and internal temperatures. These properties are suitably combined to find out statistical relations. Moreover, starting from standard deterministic equations, this study revises them and simplifies the most involved terms. This simplification is carried out making a statistical analysis of the energy quantities that affect the performance of a building. In such a way the solution of the energy balance is simplified, making the calculation easier and faster. Results are compared with those calculated using the rigorous Standard procedure, showing a good agreement. Moreover, the assessed energy demand is compared with the actual metered energy consumption. The present statistical model estimates in a simple and prompt way the energy demand for space heating of residential buildings, in particular the existing ones. It may represent a useful tool for their energy certification

Indagine sul teleriscaldamento attivo nel contesto europeo

Lo studio si propone di fare il punto della situazione sulle reti di teleriscaldamento attivo attualmente operanti nel contesto europeo, prendendo in considerazione aspetti tecnici, economici e regolatori intercorrenti tra l’utility e l’utente produttore/consumatore di calore (prosumer). Lo studio ha evidenziato come nei vari Paesi siano state adottate soluzioni tecnologiche e gestionali differenti. Nonostante la diffusione del teleriscaldamento attivo sia tuttora limitata ad un numero piuttosto esiguo di casi nel Nord Europa, alla luce della presente indagine emerge come questa soluzione tecnologica possa giocare un ruolo da protagonista nelle future politiche di efficientamento dei sistemi di produzione e di distribuzione efficiente del calore orientate alla decarbonizzazione

Precise GNSS Positioning Using Smart Devices

The recent access to GNSS (Global Navigation Satellite System) phase observations on smart devices, enabled by Google through its Android operating system, opens the possibility to apply precise positioning techniques using off-the-shelf, mass-market devices. The target of this work is to evaluate whether this is feasible, and which positioning accuracy can be achieved by relative positioning of the smart device with respect to a base station. Positioning of a Google/HTC Nexus 9 tablet was performed by means of batch least-squares adjustment of L1 phase double-differenced observations, using the open source goGPS software, over baselines ranging from approximately 10 m to 8 km, with respect to both physical (geodetic or low-cost) and virtual base stations. The same positioning procedure was applied also to a co-located u-blox low-cost receiver, to compare the performance between the receiver and antenna embedded in the Nexus 9 and a standard low-cost single-frequency receiver with external patch antenna. The results demonstrate that with a smart device providing raw GNSS phase observations, like the Nexus 9, it is possible to reach decimeter-level accuracy through rapid-static surveys, without phase ambiguity resolution. It is expected that sub-centimeter accuracy could be achieved, as demonstrated for the u-blox case, if integer phase ambiguities were correctly resolved