The Experts below are selected from a list of 333 Experts worldwide ranked by ideXlab platform

Oliver Montenbruck - One of the best experts on this subject based on the ideXlab platform.

  • springer handbook of global Navigation Satellite Systems
    2017
    Co-Authors: P J G Teunissen, Oliver Montenbruck
    Abstract:

    This Handbook presents a complete and rigorous overview of the fundamentals, methods and applications of the multidisciplinary field of Global Navigation Satellite Systems (GNSS), providing an exhaustive, one-stop reference work and a state-of-the-art description of GNSS as a key technology for science and society at large. All global and regional Satellite Navigation Systems, both those currently in operation and those under development (GPS, GLONASS, Galileo, BeiDou, QZSS, IRNSS/NAVIC, SBAS), are examined in detail. The functional principles of receivers and antennas, as well as the advanced algorithms and models for GNSS parameter estimation, are rigorously discussed. The book covers the broad and diverse range of land, marine, air and space applications, from everyday GNSS to high-precision scientific applications and provides detailed descriptions of the most widely used GNSS format standards, covering receiver formats as well as IGS product and meta-data formats. The full coverage of the field of GNSS is presented in seven parts, from its fundamentals, through the treatment of global and regional Navigation Satellite Systems, of receivers and antennas, and of algorithms and models, up to the broad and diverse range of applications in the areas of positioning and Navigation, surveying, geodesy and geodynamics, and remote sensing and timing. Each chapter is written by international experts and amply illustrated with figures and photographs, making the book an invaluable resource for scientists, engineers, students and institutions alike.

  • Broadcast versus precise ephemerides: a multi-GNSS perspective
    GPS Solutions, 2015
    Co-Authors: Oliver Montenbruck, Peter Steigenberger, André Hauschild
    Abstract:

    A consistent analysis of signal-in-space ranging errors (SISREs) is presented for all current Satellite Navigation Systems, considering both global average values and worst-user-location statistics. The analysis is based on 102year of broadcast ephemeris messages of the Global Positioning System (GPS) , GLONASS, Galileo, BeiDou and QZSS collected with a near-global receiver network. Position and clock values derived from the Navigation data are compared against precise orbit and clock products provided by the International GNSS Service and its multi-GNSS experiment. Satellite laser ranging measurements are used for a complementary and independent assessment of the orbit-only SISRE contribution. The need for proper consideration of antenna offsets is highlighted and block-/constellation-specific radial antenna offset values for the center-of-mass correction of broadcast orbits are derived. Likewise, the need for application of differential code biases in the comparison of broadcast and precise clock products is emphasized. For GPS, the analysis of the legacy Navigation message is complemented by a discussion of the CNAV message performance based on the first CNAV test campaign in June 2013. Global average SISRE values for the individual constellations amount to 0.702±020.0202m (GPS), 1.502±020.102m (BeiDou), 1.602±020.302m (Galileo), 1.902±020.102m (GLONASS), and 0.602±020.202m (QZSS) over a 12-month period in 2013/2014.

  • galileo orbit and clock quality of the igs multi gnss experiment
    Advances in Space Research, 2015
    Co-Authors: Peter Steigenberger, Urs Hugentobler, Sylvain Loyer, Felix Perosanz, Lars Prange, Rolf Dach, Maik Uhlemann, Gerd Gendt, Oliver Montenbruck
    Abstract:

    The Multi-GNSS Experiment (MGEX) of the International GNSS Service (IGS) aims at the data collection and analysis of all available Satellite Navigation Systems. In particular the new global and regional Satellite Navigation Systems are of interest, i.e., the European Galileo, the Chinese BeiDou, the Japanese QZSS as well as Satellite based augmentation Systems. This article analyzes the orbit and clock quality of the Galileo products of four MGEX analysis centers for a common time period of 20 weeks. Orbit comparisons of the individual analysis centers have a consistency at the 5–30 cm level. Day boundary discontinuities range from 4 to 28 cm whereas 2-day orbit fit RMS values vary between 1 and 7 cm. The accuracy evaluated by Satellite laser ranging residuals is on the one decimeter level with a systematic bias of about −5 cm for all analysis centers. In addition, systematic errors on the decimeter level related to solar radiation pressure mismodeling are present in all orbit products. Due to the correlation of radial orbit errors with the clock parameters, these errors are also visible as a bump in the Allan deviation of the Galileo Satellite clocks at the orbital frequency.

Jacek Szmaglinski - One of the best experts on this subject based on the ideXlab platform.

  • testing the positioning accuracy of gnss solutions during the tramway track mobile Satellite measurements in diverse urban signal reception conditions
    Energies, 2020
    Co-Authors: Mariusz Specht, Cezary Specht, Andrzej Wilk, Leszek Smolarek, Krzysztof Czaplewski, Krzysztof Karwowski, Pawel Dąbrowski, Jacek Skibicki, Piotr Chrostowski, Jacek Szmaglinski
    Abstract:

    Mobile Global Navigation Satellite System (GNSS) measurements carried out on the railway consist of using Satellite Navigation Systems to determine the track geometry of a moving railway vehicle on a given route. Their purposes include diagnostics, stocktaking, and design work in railways. The greatest advantage of this method is the ability to perform measurements in a unified and coherent spatial reference system, which effectively enables the combining of design and construction works, as well as their implementation by engineering teams of diverse specialties. In the article, we attempted to assess the impact of using three types of work mode for a GNSS geodetic network [Global Positioning System (GPS), GPS/Global Navigation Satellite System (GLONASS) and GPS/GLONASS/Galileo] on positioning availability at three accuracy levels: 1 cm, 3 cm and 10 cm. This paper presents a mathematical model that enables the calculation of positioning availability at these levels. This model was also applied to the results of the measurement campaign performed by five GNSS geodetic receivers, made by a leading company in the field. Measurements with simultaneous position recording and accuracy assessment were taken separately on the same route for three types of receiver settings: GPS, GPS/GLONASS and GPS/GLONASS/Galileo in an urban area typical of a medium-sized city. The study has shown that applying a two-system solution (GPS/GLONASS) considerably increases the availability of high-precision coordinates compared to a single-system solution (GPS), whereas the measurements with three Systems (GPS/GLONASS/Galileo) negligibly increase the availability compared to a two-system solution (GPS/GLONASS).

Norbert Jakowski - One of the best experts on this subject based on the ideXlab platform.

  • An alternative ionospheric correction model for global Navigation Satellite Systems
    Journal of Geodesy, 2015
    Co-Authors: M M Hoque, Norbert Jakowski
    Abstract:

    The ionosphere is recognized as a major error source for single-frequency operations of global Navigation Satellite Systems (GNSS). To enhance single-frequency operations the global positioning system (GPS) uses an ionospheric correction algorithm (ICA) driven by 8 coefficients broadcasted in the Navigation message every 24 h. Similarly, the global Navigation Satellite system Galileo uses the electron density NeQuick model for ionospheric correction. The Galileo Satellite vehicles (SVs) transmit 3 ionospheric correction coefficients as driver parameters of the NeQuick model. In the present work, we propose an alternative ionospheric correction algorithm called Neustrelitz TEC broadcast model NTCM-BC that is also applicable for global Satellite Navigation Systems. Like the GPS ICA or Galileo NeQuick, the NTCM-BC can be optimized on a daily basis by utilizing GNSS data obtained at the previous day at monitor stations. To drive the NTCM-BC, 9 ionospheric correction coefficients need to be uploaded to the SVs for broadcasting in the Navigation message. Our investigation using GPS data of about 200 worldwide ground stations shows that the 24-h-ahead prediction performance of the NTCM-BC is better than the GPS ICA and comparable to the Galileo NeQuick model. We have found that the 95 percentiles of the prediction error are about 16.1, 16.1 and 13.4 TECU for the GPS ICA, Galileo NeQuick and NTCM-BC, respectively, during a selected quiet ionospheric period, whereas the corresponding numbers are found about 40.5, 28.2 and 26.5 TECU during a selected geomagnetic perturbed period. However, in terms of complexity the NTCM-BC is easier to handle than the Galileo NeQuick and in this respect comparable to the GPS ICA.

André Hauschild - One of the best experts on this subject based on the ideXlab platform.

  • Broadcast versus precise ephemerides: a multi-GNSS perspective
    GPS Solutions, 2015
    Co-Authors: Oliver Montenbruck, Peter Steigenberger, André Hauschild
    Abstract:

    A consistent analysis of signal-in-space ranging errors (SISREs) is presented for all current Satellite Navigation Systems, considering both global average values and worst-user-location statistics. The analysis is based on 102year of broadcast ephemeris messages of the Global Positioning System (GPS) , GLONASS, Galileo, BeiDou and QZSS collected with a near-global receiver network. Position and clock values derived from the Navigation data are compared against precise orbit and clock products provided by the International GNSS Service and its multi-GNSS experiment. Satellite laser ranging measurements are used for a complementary and independent assessment of the orbit-only SISRE contribution. The need for proper consideration of antenna offsets is highlighted and block-/constellation-specific radial antenna offset values for the center-of-mass correction of broadcast orbits are derived. Likewise, the need for application of differential code biases in the comparison of broadcast and precise clock products is emphasized. For GPS, the analysis of the legacy Navigation message is complemented by a discussion of the CNAV message performance based on the first CNAV test campaign in June 2013. Global average SISRE values for the individual constellations amount to 0.702±020.0202m (GPS), 1.502±020.102m (BeiDou), 1.602±020.302m (Galileo), 1.902±020.102m (GLONASS), and 0.602±020.202m (QZSS) over a 12-month period in 2013/2014.

Ediz Cetin - One of the best experts on this subject based on the ideXlab platform.

  • interference localization for Satellite Navigation Systems
    Proceedings of the IEEE, 2016
    Co-Authors: Andrew G Dempster, Ediz Cetin
    Abstract:

    Global Navigation Satellite Systems (GNSS) and, in particular, the global positioning system (GPS) have become ubiquitous in safety critical infrastructure. Vulnerability of GNSS to radio frequency interference (RFI) from either intentional (jamming) or unintentional sources is an ever growing concern. Hence, GNSS itself has become critical infrastructure which must be protected and its vulnerability to interference alleviated. As the RFI source is unknown a priori , passive localization Systems are required; this adds an order of difficulty when compared with transmitter location Systems with known and cooperative sources. The need for rapidly localizing the RFI leads to sensor network techniques which consist of spatially distributed sensor nodes (SNs). The localization Systems typically use the received signal strength (RSS), source angle of arrival (AOA)/ direction of arrival (DOA), time difference of arrival (TDOA) or a combination of AOA(DOA)/TDOA or frequency difference of arrival (FDOA) measurements to estimate the RFI position. This paper provides an overview of existing Systems from the literature and a comparison of these different interference geo-localization techniques.