Search results for "GNSS applications"
showing 10 items of 40 documents
Non-tidal loading of the Baltic Sea in Latvian GNSS time series
2021
Abstract The objective of this study is to investigate the effect of the Baltic Sea non-tidal loading in the territory of Latvia using observations of the GNSS continuously operating reference stations (CORS) of LatPos, EUPOS®-Riga, EPN and EstPos networks. The GNSS station daily coordinate time series obtained in a double-difference (DD) mode were used. For representation of the sea level dynamics, the Latvian tide gauge records were used. Performed correlation analysis is based on yearly data sets of these observations for the period from 2012 up to 2020. The approach discloses how the non-tidal loading can induce variations in the time series of the regional GNSS station network. This pa…
Use of CORS Time Series for Geodynamics Applications in Western Sicily (Italy)
2020
In the last few decades, the use of GNSS Continuously Operating Reference Station (CORS) networks allowed improving the accuracy of real-time positioning and post-processing positioning. In this way, several applications have been performed including remote sensing, agriculture, cultural heritage and geodynamics studies. The latter have been developed analysing CORS time-series and consistent data over long periods were needed to validate the results. In Italy, specifically in Sicily, two CORS networks were be used to monitor the geodynamics motions: the Istituto Nazionale di Geofisica e Vulcanologia (INGV) GNSS CORS network in the eastern part and the University of Palermo (UNIPA) GNSS COR…
Monitoring displacements of an earthen dam using GNSS and remote sensing
2014
This paper shows the results of a scientific research in which a GNSS continuous monitoring system for earth-dam deformations has been developed, then, deformations have been related with reservoir water surface and level. The experiment was conducted near Bivona (Sicily, Italy), on the Castello dam (Magazzolo Lake). On the top of the dam three control points were placed and three GNSS permanent stations were installed. The three stations continuously transmitted data to the control centre of the University of Palermo. The former has been determined using freely available satellite data (specifically Landsat 7 SLC-Off) collected during the whole study period (DOYs 101 to 348 2011). Issues r…
Monitoring Water Surface and Level of a Reservoir Using Different Remote Sensing Approaches and Comparison with Dam Displacements Evaluated via GNSS
2018
Remote sensing allowed monitoring the reservoir water level by estimating its surface extension. Surface extension has been estimated using different approaches, employing both optical (Landsat 5 TM, Landsat 7 ETM+ SLC-Off, Landsat 8 OLI-TIRS and ASTER images) and Synthetic Aperture Radar (SAR) images (Cosmo SkyMed and TerraSAR-X). Images were characterized by different acquisition modes, geometric and spectral resolutions, allowing the evaluation of alternative and/or complementary techniques. For each kind of image, two techniques have been tested: The first based on an unsupervised classification and suitable to automate the process, the second based on visual matching with contour lines…
Precipitable water vapour content from ESR/SKYNET sun-sky radiometers: validation against GNSS/GPS and AERONET over three different sites in Europe
2018
The estimation of the precipitable water vapour content (W) with high temporal and spatial resolution is of great interest to both meteorological and climatological studies. Several methodologies based on remote sensing techniques have been recently developed in order to obtain accurate and frequent measurements of this atmospheric parameter. Among them, the relative low cost and easy deployment of sun–sky radiometers, or sun photometers, operating in several international networks, allowed the development of automatic estimations of W from these instruments with high temporal resolution. However, the great problem of this methodology is the estimation of the sun-photometric calibration par…
Global Navigation Satellite Systems And Services
2008
This chapter introduces the concept of Satellite Navigation in the context of space infrastructures and technologies that can contribute for improvement of life on Earth. It includes a review of the motivations for developing a satellite navigation system, and the applications and services these systems have in daily life. Furthermore, currently existing Global Navigation Satellite Systems (GPS and GLONASS) and other GNSS systems under development (GALILEO) are described from different perspectives: from the technical and architectural aspects to the ways chosen to finance their development and operations. To round up this chapter, an analysis of the expected trends in GNSS systems is prese…
Digital zenith camera for vertical deflection determination
2012
Recent accomplishments in advancement of accurate astrometric reference star catalogues, development of digital imaging technology, high accuracy tiltmeter technology, and geocentric coordinate availability provided by GNSS, have made possible accurate, fast and automated determination of vertical deflections using astrometric methods. Zenith cameras for this kind of measurements have been developed or are being developed by several research groups. The paper describes a research project by Institute of Geodesy and Geoinformation, intended to design a portable digital zenith camera for vertical deflection determination with 0.1” expected accuracy. Camera components are described, proposed d…
DIGITAL PHOTOGRAMMETRY, TLS SURVEY and 3D MODELLING for VR and AR APPLICATIONS in CH
2020
Abstract. The world of valorization of Cultural Heritage is even more focused on the virtual representation and reconstructions of digital 3D models of monuments and archaeological sites. In this scenario the quality and the performances offered by the virtual reality (VR) and augmented reality (AR) navigation take primary importance, improving the accessibility of cultural sites where the real access is not allowed for natural conditions or human possibilities. The creation of a virtual environment useful for these purposes requires a specific workflow to follow, combining different strategies in the fields of survey, 3D modelling and virtual navigation. In this work a specific case of stu…
INTEGRATED SURVEYNG WITH MOBILE MAPPING SYSTEM, EGNOS, NTRK AND LASER TECHNOLOGIES IN THE PARK "NINNI CASSARA" IN PALERMO
2018
Abstract. This article summarizes the experience gained between 2012 and 2013 by the department of "Civil Engineering, Environmental, Aerospace and Materials" of University of Palermo on the integrated survey of Ninni Park Cassara Park in Palermo and the subsequent testing of methods, tools and techniques based on current research regarding the acquisition and processing of GNSS (Global Navigation Satellite System) data and laser-scanner. A fruitful time dedicated to the design of the survey has allowed us to become aware of the critical issues that the site presents because of its vast extent and diversity in size and number of the elements of which it is composed. The work has been addres…
Bathymetry time series using high spatial resolution satellite images
2020
The use of the new generation of remote sensors, such as echo sounders and Global Navigation Satellite System (GNSS) receivers with differential correction installed in a drone, allows the acquisition of high-precision data in areas of shallow water, as in the case of the channel of the Encañizadas in the Mar Menor lagoon. This high precision information is the first step to develop the methodology to monitor the bathymetry of the Mar Menor channels. The use of high spatial resolution satellite images is the solution for monitoring many hydrological changes and it is the basis of the three-dimensional (3D) numerical models used to study transport over time, environmental variability, and wa…