Comparison of individual and combined zenith tropospheric delay estimations during CONT08 campaign

Pollet, Arnaud; Coulot, D.; Bock, Olivier; Nahmani, S.

doi:10.1007/s00190-014-0745-5

Cited by 8 publications

(9 citation statements)

References 25 publications

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“…In general, these parameters have an excellent agreement of better than 1 cm in RMS and are consistent with numerical weather models and other meteorological measurements (Pollet et al, 2014). Teke et al (2013) showed ZTD and gradients during CONT02 to CONT11 derived from observations of GNSS, VLBI, DORIS, water vapor radiometers (WVR), and numerical weather model.…”

Section: Introductionsupporting

confidence: 81%

“…Additionally, they stated that the agreement and the accuracy of the troposphere parameters mainly depend on the humidity in the atmosphere. Pollet et al (2014) also found that the consistency of ZTD parameters depends on the humidity level and the number of observations per estimated ZTD parameter. Heinkelmann et al (2016) compared the atmospheric parameters derived by DORIS, GPS, VLBI, and numerical weather models at five colocated sites during CONT14.…”

Section: Introductionmentioning

confidence: 86%

“…A strong correlation exists between atmospheric parameters, especially zenith tropospheric delay (ZTD), and the height component (Schuh and Böhm, 2013). Therefore, an improvement in the ZTD estimation can theoretically improve the co-located station positions (Pollet et al, 2014). Thus, the atmospheric parameters at the same observing site (atmospheric ties) could improve the combination of space geodetic techniques to establish an ITRF meeting the GGOS goals.…”

Section: Introductionmentioning

confidence: 99%

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Validation of tropospheric ties at the test setup GNSS co-location site Potsdam

Kitpracha

Heinkelmann

Ramatschi

et al. 2021

Preprint

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Abstract. Atmospheric ties are theoretically affected by the height differences between antennas at the same site and the meteorological conditions. However, there is often a discrepancy between the expected zenith delay differences and those estimated from geodetic analysis, potentially degrading a combined solution employing atmospheric ties. In order to investigate the possible effects on GNSS atmospheric delay, this study set up an experiment of four co-located GNSS stations of the same type, both antenna and receiver. Specific height differences for each antenna w.r.t the reference antenna are given. One antenna was equipped with a radome at the same height and type as a antenna close to the ground. In addition, a meteorological sensor was used for meteorological data recording. The results show that tropospheric ties from the analytical equation based on meteorological data from GPT3, Numerical Weather Model, and in-situ measurements, and ray-traced tropospheric ties, reduced the bias of zenith delay roughly by 72 %. However, the in-situ tropospheric ties yield the best precision in this study. These results demonstrate, that the instrument effects on GNSS zenith delays were mitigated by using the same instrument. In contrast, the radome causes unexpected bias of GNSS zenith delays in this study. Additionally, multipath effects at low-elevation observations degraded the tropospheric east gradients.

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Section: Introductionsupporting

confidence: 81%

Section: Introductionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

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Validation of tropospheric ties at the test setup GNSS co-location site Potsdam

Kitpracha

Heinkelmann

Ramatschi

et al. 2021

Preprint

View full text Add to dashboard Cite

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“…In their geographical positions, the stations may be installed alone or co-located with other space geodetic techniques such as Very Long Baseline Interferometry (VLBI); Satellite Laser Ranging (SLR); Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS); water vapour radiometers (WVR) or tide gauge stations. In both single and multi-purpose CORS networks, ZTDs can be estimated from the tracked GNSS (Bevis et al, 1992;Alshawaf et al, 2017), VLBI (Heinkelmann et al, 2007;Balidakis et al, 2018); SLR (Pollet et al, 2014); DORIS (Teke et al, 2013), and WVR (Bock et al, 2010) observations.…”

Section: Introductionmentioning

confidence: 99%

Applying Malawi Continuously Operating Reference Stations (CORS) in GNSS Meteorology

Suya¹,

Kapachika²,

Soko³

et al. 2022

SA J of Geomatics

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Global Navigation Satellite System (GNSS) signals in the L-band are affected by the non-dispersive neutral atmosphere. Regardless of their center frequency, the L-band code and phase observations are affected by the same measure of delay. GNSS receivers play a significant role in quantifying the zenith tropospheric delay (ZTD) from satellite signals. Malawi has a Continuously Operating Reference Stations (CORS) network which was established to support research in geophysical geodesy and geodynamics. However, the quality of the observations tracked by the CORS has never been tested in terms of its meteorological application. In this paper, the ZTD estimation approach and the evaluation of results from the Global Positioning System (GPS) measurements are presented. The optimal approach of precise point positioning (PPP) was used to estimate ZTD from one-week datasets which were collected from six CORS monuments distributed in the northern and southern regions of Malawi. In addition, the zenith wet delay (ZWD) and zenith hydrostatic delay (ZHD) were also estimated to determine their respective contributions to the total delay in all the stations. Alongside the meteorological parameters, the positioning repeatabilities were also established for all stations. Results indicate that the averaged ZTD, ZWD and ZHD can reach as high as 247mm, 47 mm, and 199 mm, respectively. The minimum ZTD, ZWD, and ZHD for the stations can drop to as low as 220 mm, 24 mm, and 181 mm, respectively. This indicates that the ZHD contributes to more than 90% of the total delay at the stations. For the positioning performance, there was no obvious disparity in the latitude (less than 0.5 cm), longitude (less than 1 cm), and ellipsoidal height repeatabilities (less than 1.5 cm). Thus, the results clearly demonstrate that the Malawi CORS network may be used for GNSS-based meteorological applications using the available geodetic receivers. However, for high precision meteorological applications, Malawi may consider densifying the available network with geodetic grade receivers.

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“…A strong correlation exists between atmospheric parameters, especially Zenith Tropospheric Delays (ZTD), and the height component (Schuh and Behrend, 2012). Therefore, an improvement in the ZTD estimation can theoretically improve the co-located station positions (Pollet et al, 2014). Thus, the atmospheric parameters at the same observing site (atmospheric ties) could improve the combination of space geodetic techniques to establish an ITRF meeting the GGOS goals (Plag et al, 2009;Männel et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Validation of tropospheric ties at the test setup GNSS co-location site in Potsdam

Kitpracha

Heinkelmann

Ramatschi

et al. 2022

Preprint

View full text Add to dashboard Cite

Abstract. Atmospheric ties are the differences of atmospheric parameters between antennas or stations at the same site and meteorological conditions. However, there is often a discrepancy between the expected zenith delay differences and those estimated from geodetic analysis, potentially degrading a combined solution employing atmospheric ties to constrain atmospheric delay differences. To investigate the possible effects on GNSS atmospheric delay, this study set up an experiment with four co-located GNSS stations of the same type, both antenna and receiver. Specific height differences for each antenna w.r.t. one reference antenna have been measured. One antenna was equipped with a radome of the same height and type as an antenna close to the ground. Additionally, a meteorological sensor was used for meteorological data recording. The results show that tropospheric ties from the analytical equation based on meteorological data from Global Pressure and Temperature 3 (GPT3) model, Numerical Weather Models, in-situ measurements, and ray-traced tropospheric ties, reduced the bias of zenith delay roughly by 72 %. However, the in-situ tropospheric ties yielded the best precision in this study. These results demonstrate that the instrument effects on GNSS zenith delays were mitigated using the same instrument. In contrast, although the effects of the radome on atmospheric delays are well known, the magnitude of the effects determined in this study is unexpectedly large. Additionally, multipath effects at low-elevation observations degraded the tropospheric gradients. To extract the instrument effect, we set up another experiment with three GNSS stations and four different antennas. The height differences between the three stations were on one centimeter level. One of the three stations could be adjusted in height to control the height displacement after changing antenna. We succeeded in keeping the shift in the GNSS zenith delays within 2 mm level. The bias on GNSS zenith delays and tropospheric gradients agrees with the result of the previous experiment in this study. Moreover, we successfully detected the antenna-dependent effect on both the GNSS zenith delays and gradients from this experiment.

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Comparison of individual and combined zenith tropospheric delay estimations during CONT08 campaign

Cited by 8 publications

References 25 publications

Validation of tropospheric ties at the test setup GNSS co-location site Potsdam

Validation of tropospheric ties at the test setup GNSS co-location site Potsdam

Applying Malawi Continuously Operating Reference Stations (CORS) in GNSS Meteorology

Validation of tropospheric ties at the test setup GNSS co-location site in Potsdam

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