Gestão ambiental e o meio urbano do município de Franca: uma abordagem a partir da Política Nacional de Resíduos Sólidos

Pós-graduação em Planejamento e Análise de Políticas Públicas - FCHS

Montagem e avaliação de um sistema de varredura a LASER embarcado em VANT

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Gestão ambiental e o meio urbano do município de Franca: uma abordagem a partir da Política Nacional de Resíduos Sólidos

Pós-graduação em Planejamento e Análise de Políticas Públicas - FCHS

Use of a Single L1 GPS Receiver for Monitoring Structures: First Results of the Detection of Millimetric Dynamic Oscillations

This paper presents preliminary results to determine small displacements of a global positioning system (GPS) antenna fastened to a structure using only one L1 GPS receiver. Vibrations, periodic or not, are common in large structures, such as bridges, footbridges, tall buildings, and towers under dynamic loads. The behavior in time and frequency leads to structural analysis studies. The hypothesis of this article is that any large structure that presents vibrations in the centimeter-to-millimeter range can be monitored by phase measurements of a single L1 receiver with a high data rate, as long as the direction of the displacement is pointing to a particular satellite. Within this scenario, the carrier phase will be modulated by antenna displacement. During a period of a few dozen seconds, the relative displacement to the satellite, the satellite clock, and the atmospheric phase delays can be assumed as a polynomial time function. The residuals from a polynomial adjustment contain the phase modulation owing to small displacements, random noise, receiver clock short time instabilities, and multipath. The results showed that it is possible to detect displacements of centimeters in the phase data of a single satellite and millimeters in the difference between the phases of two satellites. After applying a periodic nonsinusoidal displacement of 10 m to the antenna, it is clearly recovered in the difference of the residuals. The time domain spectrum obtained by the fast Fourier transform (FFT) exhibited a defined peak of the third harmonic much more than the random noise using the proposed third-degree polynomial model. DOI: 10.1061/(ASCE)SU.1943-5428.0000070. (C) 2012 American Society of Civil Engineers.

A new method for calculating the convergent point of a moving group

Context. Convergent point (CP) search methods are important tools for studying the kinematic properties of open clusters and young associations whose members share the same spatial motion. Aims. We present a new CP search strategy based on proper motion data. We test the new algorithm on synthetic data and compare it with previous versions of the CP search method. As an illustration and validation of the new method we also present an application to the Hyades open cluster and a comparison with independent results. Methods. The new algorithm rests on the idea of representing the stellar proper motions by great circles over the celestial sphere and visualizing their intersections as the CP of the moving group. The new strategy combines a maximum-likelihood analysis for simultaneously determining the CP and selecting the most likely group members and a minimization procedure that returns a refined CP position and its uncertainties. The method allows one to correct for internal motions within the group and takes into account that the stars in the group lie at different distances. Results. Based on Monte Carlo simulations, we find that the new CP search method in many cases returns a more precise solution than its previous versions. The new method is able to find and eliminate more field stars in the sample and is not biased towards distant stars. The CP solution for the Hyades open cluster is in excellent agreement with previous determinations.

Troposphere Calibration Techniques for Deep Space Probe Tracking

Ground-based Earth troposphere calibration systems play an important role in planetary exploration, especially to carry out radio science experiments aimed at the estimation of planetary gravity fields. In these experiments, the main observable is the spacecraft (S/C) range rate, measured from the Doppler shift of an electromagnetic wave transmitted from ground, received by the spacecraft and coherently retransmitted back to ground. If the solar corona and interplanetary plasma noise is already removed from Doppler data, the Earth troposphere remains one of the main error sources in tracking observables. Current Earth media calibration systems at NASA’s Deep Space Network (DSN) stations are based upon a combination of weather data and multidirectional, dual frequency GPS measurements acquired at each station complex. In order to support Cassini’s cruise radio science experiments, a new generation of media calibration systems were developed, driven by the need to achieve the goal of an end-to-end Allan deviation of the radio link in the order of 3×〖10〗^(-15) at 1000 s integration time. The future ESA’s Bepi Colombo mission to Mercury carries scientific instrumentation for radio science experiments (a Ka-band transponder and a three-axis accelerometer) which, in combination with the S/C telecommunication system (a X/X/Ka transponder) will provide the most advanced tracking system ever flown on an interplanetary probe. Current error budget for MORE (Mercury Orbiter Radioscience Experiment) allows the residual uncalibrated troposphere to contribute with a value of 8×〖10〗^(-15) to the two-way Allan deviation at 1000 s integration time. The current standard ESA/ESTRACK calibration system is based on a combination of surface meteorological measurements and mathematical algorithms, capable to reconstruct the Earth troposphere path delay, leaving an uncalibrated component of about 1-2% of the total delay. In order to satisfy the stringent MORE requirements, the short time-scale variations of the Earth troposphere water vapor content must be calibrated at ESA deep space antennas (DSA) with more precise and stable instruments (microwave radiometers). In parallel to this high performance instruments, ESA ground stations should be upgraded to media calibration systems at least capable to calibrate both troposphere path delay components (dry and wet) at sub-centimetre level, in order to reduce S/C navigation uncertainties. The natural choice is to provide a continuous troposphere calibration by processing GNSS data acquired at each complex by dual frequency receivers already installed for station location purposes. The work presented here outlines the troposphere calibration technique to support both Deep Space probe navigation and radio science experiments. After an introduction to deep space tracking techniques, observables and error sources, in Chapter 2 the troposphere path delay is widely investigated, reporting the estimation techniques and the state of the art of the ESA and NASA troposphere calibrations. Chapter 3 deals with an analysis of the status and the performances of the NASA Advanced Media Calibration (AMC) system referred to the Cassini data analysis. Chapter 4 describes the current release of a developed GNSS software (S/W) to estimate the troposphere calibration to be used for ESA S/C navigation purposes. During the development phase of the S/W a test campaign has been undertaken in order to evaluate the S/W performances. A description of the campaign and the main results are reported in Chapter 5. Chapter 6 presents a preliminary analysis of microwave radiometers to be used to support radio science experiments. The analysis has been carried out considering radiometric measurements of the ESA/ESTEC instruments installed in Cabauw (NL) and compared with the requirements of MORE. Finally, Chapter 7 summarizes the results obtained and defines some key technical aspects to be evaluated and taken into account for the development phase of future instrumentation.

A novel map-matching procedure for low-sampling GPS data with applications to traffic flow analysis

An extensive sample (2%) of private vehicles in Italy are equipped with a GPS device that periodically measures their position and dynamical state for insurance purposes. Having access to this type of data allows to develop theoretical and practical applications of great interest: the real-time reconstruction of traffic state in a certain region, the development of accurate models of vehicle dynamics, the study of the cognitive dynamics of drivers. In order for these applications to be possible, we first need to develop the ability to reconstruct the paths taken by vehicles on the road network from the raw GPS data. In fact, these data are affected by positioning errors and they are often very distanced from each other (~2 Km). For these reasons, the task of path identification is not straightforward. This thesis describes the approach we followed to reliably identify vehicle paths from this kind of low-sampling data. The problem of matching data with roads is solved with a bayesian approach of maximum likelihood. While the identification of the path taken between two consecutive GPS measures is performed with a specifically developed optimal routing algorithm, based on A* algorithm. The procedure was applied on an off-line urban data sample and proved to be robust and accurate. Future developments will extend the procedure to real-time execution and nation-wide coverage.

Design and implementation of a novel multi-constellation FPGA-based dual frequency GNSS receiver for space applications

The PhD activity described in the document is part of the Microsatellite and Microsystem Laboratory of the II Faculty of Engineering, University of Bologna. The main objective is the design and development of a GNSS receiver for the orbit determination of microsatellites in low earth orbit. The development starts from the electronic design and goes up to the implementation of the navigation algorithms, covering all the aspects that are involved in this type of applications. The use of GPS receivers for orbit determination is a consolidated application used in many space missions, but the development of the new GNSS system within few years, such as the European Galileo, the Chinese COMPASS and the Russian modernized GLONASS, proposes new challenges and offers new opportunities to increase the orbit determination performances. The evaluation of improvements coming from the new systems together with the implementation of a receiver that is compatible with at least one of the new systems, are the main activities of the PhD. The activities can be divided in three section: receiver requirements definition and prototype implementation, design and analysis of the GNSS signal tracking algorithms, and design and analysis of the navigation algorithms. The receiver prototype is based on a Virtex FPGA by Xilinx, and includes a PowerPC processor. The architecture follows the software defined radio paradigm, so most of signal processing is performed in software while only what is strictly necessary is done in hardware. The tracking algorithms are implemented as a combination of Phase Locked Loop and Frequency Locked Loop for the carrier, and Delay Locked Loop with variable bandwidth for the code. The navigation algorithm is based on the extended Kalman filter and includes an accurate LEO orbit model.

Uso del gnss per applicazioni di monitoraggio glaciologico in Antartide

Studio relativo alle correlazioni tra sisma e icestream nella zona antartica della terra Vittoria. Si presentano inoltre due studi approfonditi relativi a due reti gps presenti nei pressi di Talos Dome e Dome Concordia. Inoltre è presente anche una descrizione completa del sistema gps e di tutti gli strumenti utilizzati in campagna

La deflessione della verticale ed il coefficiente di rifrazione atmosferico nel monitoraggio in alta precisione

La tesi è suddivisa in due parti. La prima è dedicata alla determinazione della Deflessione della Verticale (DdV) in Medicina (BO). Vengono presentati tre metodi per la determinazione delle componenti della DdV. Il primo utilizza la livellazione geometrica ed il sistema GNSS, il secondo, eseguito dal dott. Serantoni, utilizza il sistema QDaedalus, messo a punto all' ETH di Zurigo ed il terzo approccio utilizza il programma ConvER, messo a disposizione dalla regione Emilia-Romagna. Nella seconda parte viene presentato un metodo per la determinazione del Coefficiente di Rifrazione Atmosferico (CRA). La procedura di calcolo è di tipo iterativo ed utilizza, oltre agli angoli zenitali, anche le distanze misurate. Il metodo è stato testato in due aree di studio. La prima nella città di Limassol (Cipro) in ambiente urbano nell' autunno 2013. La seconda in Venezia nella laguna durante l'estate 2014.

Confronto tra stime GPS e SAR di deformazioni del suolo e di ritardi troposferici

Il Global Positioning System (GPS) e l’Interferometric Synthetic Aperture Radar (InSAR) sono due tecniche osservative di grande importanza che utilizzano segnali nel campo delle microonde. Questa tesi intende contribuire a sviluppare una base di confronto tra i risultati derivati da queste due tecniche osservative. Una parte del lavoro riguarda uno studio delle deformazioni del suolo, in particolare, la stima dei movimenti verticali e di quelli che riguardano la componente Est della posizione delle stazioni. Un secondo ambito di ricerca è invece focalizzato alla determinazione del ritardo introdotto, nella propagazione dei segnali GPS e SAR, dal loro passaggio in atmosfera. In particolare, si è studiato l’effetto della componente umida della troposfera.

Modernizzazione dei sistemi satellitari di posizionamento globale (GNSS)

In questa tesi, sono esposti i sistemi di navigazione che si sono evoluti, parimenti con il progresso scientifico e tecnologico, dalle prime misurazioni della Terra, per opera della civiltà ellenica, circa 2.500 anni fa, sino ai moderni sistemi satellitari e ai mai tramontati sistemi di radionavigazione. I sistemi di navigazione devono rispondere alla sempre maggiore richiesta di precisione, affidabilità, continuità e globalità del servizio, della società moderna. È sufficiente pensare che, attualmente, il solo traffico aereo civile fa volare 5 miliardi di passeggeri ogni anno, in oltre 60 milioni di voli e con un trasporto cargo di 85 milioni di tonnellate (ACI - World Airports Council International, 2012). La quota di traffico marittimo mondiale delle merci, è stata pari a circa 650 milioni di TEU (twenty-foot equivalent unit - misura standard di volume nel trasporto dei container ISO, corrisponde a circa 40 metri cubi totali), nel solo anno 2013 (IAPH - International Association of Ports and Harbors, 2013). Questi pochi, quanto significativi numeri, indicano una evidente necessità di “guidare” questo enorme flusso di aerei e navi in giro per il mondo, sempre in crescita, nella maniera più opportuna, tracciando le rotte adeguate e garantendo la sicurezza necessaria anche nelle fasi più delicate (decollo e atterraggio per gli aeroplani e manovre in porto per le grandi navi). Nello sviluppo della tesi si proverà a capire quali e quanto i sistemi di navigazione possono assolvere al ruolo di “guida” del trasporto aereo e marittimo.

Analisi delle prestazioni di un codice di calcolo open-source per l'elaborazione dati GNSS in modalità cinematica finalizzata al monitoraggio di strutture e applicazione di filtri sequenziali

Il presente lavoro di tesi si pone come obbiettivo l’elaborazione di dati GNSS in modalità cinematica post-processing per il monitoraggio strutturale e, in una seconda fase, lo studio delle precisioni raggiungibili delle soluzioni ottenute utilizzando algoritmi di post-elaborazione del dato. L’oggetto di studio è la torre Garisenda, situata in piazza Ravegnana, accanto alla torre Asinelli, nel centro storico di Bologna, da tempo oggetto di studi e monitoraggi per via della sua inclinazione particolarmente critica. Per lo studio è stato utilizzato un data set di quindici giorni, dal 15/12/2013 al 29/12/2013 compresi. Per l’elaborazione dei dati è stato utilizzato un software open source realizzato da ricercatori del Politecnico di Milano, goGPS. Quest'ultimo, essendo un codice nuovo, è stato necessario testarlo al fine di poter ottenere dei risultati validi. Nella prima fase della tesi si è quindi affrontato l’aspetto della calibrazione dei parametri che forniscono le soluzioni più precise per le finalità di monitoraggio considerando le possibili scelte offerte dal codice goGPS. In particolare sono stati imposti dei movimenti calibrati e si è osservata la soluzione al variare dei parametri selezionati scegliendo poi quella migliore, ossia il miglior compromesso tra la capacità di individuare i movimenti e il rumore della serie. Nella seconda fase, allo scopo di poter migliorare le precisioni delle soluzioni si sono valutati metodi di correzione delle soluzioni basati sull'uso di filtri sequenziali e sono state condotte analisi sull'incremento di precisione derivante dall'applicazione di tali correzioni.

Percutaneous radiofrequency ablation of virtual tumours in canine kidney using Global Positioning System-like technology

What's known on the subject? And what does the study add? We have previously shown that percutaneous radiofrequency ablation guided by image-fusion technology allows for precise needle placement with real time ultrasound superimposed with pre-loaded imaging, removing the need for real-time CT or MR guidance. Emerging technology also allows real-time tracking of a treatment needle within an organ in a virtually created 3D format. To our knowledge, this is the first study utilising a sophisticated ultrasound-based navigation system that uses both image-fusion and real-time probe-tracking technologies for in-vivo renal ablative intervention.