Journal: Journal of surveying engineering

Abbreviation

J. surv. eng.

Publisher

American Society of Civil Engineers

Journal Volumes

ISSN

0733-9453
1943-5428

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2010 - 201932020 - 20231
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Publications 1 - 4 of 4
  • Movement Detection Based on High-Precision Estimates of Instantaneous GNSS Station Velocity
    Item type: Journal Article
    Hohensinn, Roland; Geiger, Alain; Willi, Daniel; et al. (2019)
    Journal of surveying engineering
  • Results from the Third QDaedalus Astrogeodetic System Observation Campaign in the Mountainous Terrain of the Surses Region in Switzerland
    Item type: Journal Article
    Albayrak, Muge; Guillaume, Sébastien; Willi, Daniel; et al. (2023)
    Journal of surveying engineering
    This study presents the results of an astrogeodetic survey campaign conducted in the mountainous terrain of the Surses region in Switzerland. In our third astrogeodetic campaign using the QDaedalus system, we observed new deflections of the vertical (DoV) using three astrogeodetic systems. These observations were used to validate DoV data derived from the Global Gravity Model GGMplus and the Swiss Geoid model CHGeo2004. Astrogeodetic observations were conducted at 15 benchmarks (BMs) along the astrogeodetic profile over five nights in June 2021 at elevations ranging from 1,185 to 1,800 m and a station spacing of about 1 km. This is the first time two TS60 total station-based QDaedalus systems and one zenith telescope-based COmpact DIgital Astrometric Camera (CODIAC) system were used together for an astrogeodetic observation campaign. The standard deviations (SDs) of the QDaedalus system data for each session were 0.04″-0.22″ and 0.01″-0.20″ for the N-S and E-W components, respectively, while the SDs of the CODIAC system for each session were 0.02″ for both components. These high quality data were compared to DoV data derived from GGMplus and CHGeo2004. The N-S components from GGMplus exhibited large residuals ranging from -2.31″ to 1.75″, while the E-W component residuals are from -0.27″ to 1.80″. The residuals from CHGeo2004 range from -0.60 to 1.21 for the N-S components and -1.01 to 0.32 for the E-W components. These results show that the derived DoV data from CHGeo2004 are closer to the observed DoV and more accurate than the global GGMplus model that does not incorporate local gravity field data. The first and second astrogeodetic observation campaigns were conducted in the coastal terrain of Istanbul, Turkey and in the flat terrain in the Munich region, Germany, respectively. In this study, we provide an overall comparison of these previous results to the GGMplus residuals. Our latest results show that the GGMplus model is of higher quality in the Surses mountainous terrain than in the coastal terrain of Istanbul, while it is of lower quality than in the flat terrain of the Munich region.
  • Calibration of a Six-Axis Robot for GNSS Antenna Phase Center Estimation
    Item type: Journal Article
    Willi, Daniel; Guillaume, Sebastien (2019)
    Journal of surveying engineering
  • Modern Determination of Vertical Deflections Using Digital Zenith Cameras
    Item type: Journal Article
    Hirt, Christian; Bürki, Beat; Somieski, Anna; et al. (2010)
    Journal of surveying engineering
    At the beginning of the 21st century, a significant technological change took place in geodetic astronomy. In Zurich and Hannover, digital zenith camera systems were developed based on digital imaging sensors (charge-coupled device) that strongly improved the degree of automation, efficiency, and accuracy of the observation of the direction of the plumb line and its vertical deflection. This paper describes the instrumental design of the new digital zenith camera systems and gives an overview of the data processing with focus on the models used for astrometric data reduction and tilt correction. Results of frequently repeated observations of vertical deflections and comparison measurements show an accuracy of vertical deflection measurements of better than 0.1 arc sec. Application examples for vertical deflection data from zenith camera observations, such as the high-precision local gravity field determination in engineering projects and gravity field validation are summarized.
Publications 1 - 4 of 4