MONITORING OF LANDSLIDES WITH MASS MARKET GPS: AN ALTERNATIVE LOW COST SOLUTION

The territory of Italy is seriously afflicted by hydrological risk, with 82% of its area affected by this phenomenon. In recent years, technologies and advanced research have played an important role in realizing complex automatic systems devoted to landslide monitoring and to alerting the population. Sometimes, the cost of these systems (communications network, sensors, software, technologies) prevents their use, and in particular the cost of sensors has a large impact on the final investment. For example, geodetic GNSS receivers are usually employed to conduct landslide monitoring, but they are costly. Nowadays, new technologies make it possible to use small and efficient low cost single frequency GPS receivers, which are able to achieve a centimetrical or better level of accuracy, in static positioning. The rapid development and diffusion of the GNSS network to provide a positioning service has made it possible to use single frequency receivers, thanks to the use of virtual RINEX. This product is generated by a network of permanent stations. In this research, the actual performance of a mass market GPS receiver was tested, with the purpose of verifying if these sensors can be used for landslide monitoring. A special slide was realized, in order to conduct a dedicated test of the detection of displacements. Tests were carried out considering two factors: acquisition time and distance from the Virtual Station. The accuracy and precision of movement determination were evaluated and compared, for each test, considering the different factors. The tests and results are described in this contributio

Improving GNSS Landslide Monitoring with the Use of Low-Cost MEMS Accelerometers

Observation and monitoring of landslides and infrastructure is a very important basis for land planning, human activities, and safety. Geomatic techniques for deformation monitoring have usually involved GNSS and total station measurements or, more generally, expensive geodetic instruments, but other techniques, such as SAR (Synthetic Aperture Radar), can be efficiently applied. Using low-cost sensors could be an interesting alternative solution if the accuracy requirements can be satisfied. This paper shows the results obtained for tilt measurements using MEMS accelerometers, which were combined with mass-market GNSS sensors for monitoring five sites located on landslides. The use of a MEMS-like inclinometer requires an important calibration process to remove bias and improve the solution’s accuracy. In this paper, we explain the MEMS calibration procedure employed, with a simple and cheap solution. The results indicate that with a simple calibration, it is possible to improve measurement accuracy by one order of magnitude, reaching an angular accuracy of a few hundredths of a degree, verified by an independent technique

New tecnologies for mobile mapping

This paper deals with the development of a low cost UAV (Unmanned Aerial Vehicle) devoted to early impact phase in case of environmental disasters, based on geomatics techniques. "Pelican" is a low-cost UAV prototype equipped with a photogrammetric payload that will allows reconnaissance operations in remote areas and rapid mapping production. Different digital sensors installed in the payload allow to acquire high resolution frame images. Furthermore a GPS/INS unit will enable an automated navigation (except take-off and landing). The project is supported by ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action), an association founded by Politecnico di Torino and SiTI (Istituto Superiore sui Sistemi Territoriali per l'Innovazione) in cooperation with WFP (World Food Programme) and some private and public organisms, with the main goal to carry on operational and research activities in the field of geomatics for analysis, evaluation and mitigation of natural and manmade hazards. The main technical features of the UAV and the on-board payload are detailed described in the first part of the paper. Furthermore first results of stereopairs orientation, case studies and further developments are presented

Il monitoraggio dei movimenti e delle deformazioni con tecniche geomatiche di basso costo

L’osservazione dell’evoluzione di fenomeni di dissesto ha una importanza strategica sul nostro territorio. Un importante precursore di fenomeni franosi è il movimento o la deformazione degli stessi: tali parametri possono essere osservati con tecniche geomatiche. Le misure topografiche o GNSS con ricevitori geodetici (multi-frequenza e multi-costellazione) sono ormai ben consolidate nel trattamento e nella precisione. La realizzazione di sistemi basati su questi sensori non è tuttavia a basso costo, specie se consideriamo tecniche GNSS applicate su molti punti di controllo per una descrizione dettagliata del fenomeno, o installazioni soggette a pericoli oggettivi e dunque da considerarsi praticamente “a perdere”. Ricevitori GNSS singola frequenza sono oggi reperibili a costi minori di cento euro e possono, sotto opportune ipotesi e ingegnerizzazioni, costituire alternative ai ricevitori geodetici. Nell’ambito di un progetto di ricerca finanziato da CSI Piemonte per lo studio di tecnologie di monitoraggio a basso costo, sono stati sviluppati sistemi di acquisizione, trasmissione ed elaborazione dati basati su sensori GNSS singola frequenza di minuscole dimensioni. Il sistema costituisce una sorta di piccola stazione permanente GNSS, integrata con accelerometri per la stima di inclinazione e vibrazioni e con sensori meteorologici. È corredata di micro PC con processore ARM e interfacce di comunicazione wireless a lungo raggio per la trasmissione in tempo reale delle misure. Il sistema risulta caratterizzato da consumi elettrici molto contenuti ed è di rapida installazione in siti anche complessi dal punto di vista dell’accesso, dell’alimentazione e comunicazione. Vengono esposti nella nota i risultati delle prove di accuratezza dei sensori GNSS eseguite in laboratorio, le procedure di calibrazione dei sensori e la loro ingegnerizzazione, oltre ai primi risultati sulle installazioni situate nel nord del Piemonte su alcune zone di dissesto

Availability Performances of Ground-Coupled Heat Pump Systems

The paper presents aspects regarding the reliability and availability of ground-coupled heat pump systems (GCHP). Basic concepts of predictive reliability are introduced and the two modes of reliability analyses (quantitative and qualitative) are shown specifically for PCSS. In order to be able to model the availability of GCHP systems, global reliability indicators must be determined. Furthermore, failure manners and their effects on system reliability, as well as the graphical-analytical methods that could be applied to GCHP systems are analyzed. Finally, a case study for the experimental system installed in Thermodynamics Laboratory belonging to Energy Engineering Faculty is shown

Energy Performance Analysis of the first Research-only Ground Coupled Heat Pump in Romania

One laboratory belonging to Energy Engineering Faculty is heated with a ground-coupled heat pump (GCHP) system having two types of ground heat exchangers: a vertical one and a horizontal one. This paper presents, at first, several coefficients of performance that can be defined for heat pumps together with their usability. Then, an energy efficiency model is set specially for CGHP systems. In this paper the simulation of energy performances is done only for the vertical heat exchanger (borehole heat exchanger) having two configurations: single-U and double-U. All simulation results range between normal values and can be considered realistic

Energy Performance Analysis of a Heat Supply System of a University Campus

The energy efficiency of a system and the performance level of its equipment and installations are the two key elements based on which the investment decision in its modernization is made. They are also very important for setting up optimal operation strategies. The energy audit is a well-known and worldwide recognized tool for calculating energy performance indicators and developing improvement measures. This paper is a synthesis of the energy audit results performed for a district heating network that uses geothermal energy as its primary source of energy. The location of the heating system is inside a university campus. The first part explains the necessity of a comprehensive study on district heating networks and introduces the defining elements that characterize the analyzed equipment and installations. The complex energy balance methodology that has been developed and applied to this district heating system is presented in the second part of the paper. Next, the methodology for collecting the input data for the energy and mass balance is explained. In the final part, the numerical values of the performance indicators and the technical measures that must be applied to improve energy efficiency are shown, and conclusions are drawn