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Assessment of global ionosphere maps in view of ionospheric correction for coastal and inland altimetry: the case for average total electron content

Jarmołowski Wojciech, Wielgosz Paweł, Krypiak-Gregorczyk Anna, Ren Xiaodong

Meteorology Hydrology and Water Management. Research and Operational Applications

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2023

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Vol. 11, Iss. 1

76--92

EN

Several low-Earth orbit (LEO) satellites are equipped with dual-frequency altimeters, theoretically scanning the entire ionosphere in the nadir direction. These two frequencies enable the determination of ionospheric delay and, thus, total electron content (TEC) below the satellite orbit. This information helps in altimetric range determination but is limited to sea and ocean areas. Therefore, global and local ionospheric models are needed for ionospheric corrections over coastal regions and lands. At the same time, altimetry-derived TEC is an important source of validation data for global navigation satellite system (GNSS)-TEC models over the oceans, where the number of GNSS stations is limited. This study compares the application of a high-resolution regional GNSS-TEC model determined from Precise Point Positioning and modeled by least-squares collocation (PPPLSC), and global ionosphere maps (GIMs), in the determination of ionospheric corrections along coastal altimetry tracks. The ionospheric delay values from 5 models are then compared with altimetry-derived TEC from 3 satellites, in the region of southeastern Asia, during a time of moderate TEC values and solar conditions. The reason for the choice of area is that altimetric observations from coastal zones meet difficulties related to atmospheric corrections, e.g., ionospheric correction, which can be affected by the land in the altimeter footprint. For this reason, along with the rapid progress of inland satellite hydrology, we are encouraged to study the consistency of ionospheric delays in coastal regions. The study shows overall discrepancies of 30% of the entire ionospheric delay, which is 2-3 cm even in the case of 35 TEC unit (TECU = 1016 el/m2) values. For this reason, in the case of increased solar activity, the GIMs can have even less TEC consistency with the altimetry-derived TEC, resulting from different orbital altitudes, data gaps, and modeling techniques. The GIMs, modeled by low-order spherical harmonics, have particularly low resolution and do not represent well the equatorial ionization anomaly (EIA).

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Research on GNSS positioning and applications in Poland in 2019–2022

Paziewski Jacek, Hadas Tomasz, Rohm Witold, Wielgosz Paweł

Advances in Geodesy and Geoinformation

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2023

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Vol. 72, no. 2

art. no. e43, 2023

EN

This paper reviews the key studies concerning GNSS positioning and applications conducted at leading Polish research institutions from 2019 until 2022. The review also constitutes a contribution to the national report of Poland for the International Union of Geodesy and Geodynamics (IUGG) presented at the 28th General Assembly of IUGG held in 2023 in Berlin, Germany. In particular, we discuss the advances in theory and applications of relative and absolute positioning, troposphere and ionosphere sounding, smartphone and low-cost GNSS data processing, and other specific studies such as those on satellite antenna calibration and clock stability. In light of these recent advances by the Polish scientific community, continuous progress in GNSS theory and processing algorithms is thought to be maintained in the future, and GNSS applications are expected to continue to proliferate.

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Mrozoodporność nawierzchni betonowych – wymagania i metody badań

Szaj Paweł, Wielgosz Paweł

Budownictwo, Technologie, Architektura

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2020

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nr 2

68--73

PL

W artykule zestawiono wymagania w zakresie mrozoodporności nawierzchni wykonywanych z mieszanek betonowych, wbudowywanych bezpośrednio na budowie, jak również z dostarczanych na budowę elementów prefabrykowanych. Przeanalizowano najczęściej stosowane krajowe specyfikacje techniczne i normy, przedstawiając podobieństwa, jak również różnice w wymaganiach dla surowców oraz właściwości użytkowych, w kontekście odporności na działanie zamrażania i rozmrażania. Przybliżono powołane w analizowanych dokumentach bezpośrednie i pośrednie metody badania mrozoodporności (metodą zwykłą wg PN-B-06250:1988, powierzchniowego złuszczenia wg PKN-CEN/TS 12390-9, oznaczenia charakterystyki porów wg PN-EN 480-11) oraz przedstawiono klasyfikację i kryteria oceny zgodności.

EN

The article summarizes the requirements for frost resistance of concrete pavements, built-in directly at the construction site, as well as prefabricated elements delivered for construction. The most commonly used national technical specifications and standards were analyzed, showing similarities as well as differences in requirements for raw materials and performance in the context of resistance to freezing and thawing. The direct and indirect methods of testing frost resistance (standard method according to PN-B-06250:1988, surface exfoliation according to PKN-CEN/TS 12390-9, determination of pore characteristics according to PN-EN 480-11) as well as the classification and conformity assessment criteria were presented.

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Research on GNSS positioning and applications in Poland in 2015–2018

Wielgosz Paweł, Hadaś Tomasz, Kłos Anna, Paziewski Jacek

Geodesy and Cartography

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2019

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Vol. 68, no. 1

87--119

EN

This review paper presents research results on geodetic positioning and applications carried out in Poland, and related to the activities of the International Association of Geodesy (IAG) Commission 4 “Positioning and Applications” and its working groups. It also constitutes the chapter 4 of the national report of Poland for the International Union of Geodesy and Geodynamics (IUGG) covering the period of 2015-2018. The paper presents selected research, reviewed and summarized here, that were carried out at leading Polish research institutions, and is concerned with the precise multi-GNSS (Global Navigation Satellite Systems) satellite positioning and also GNSS-based ionosphere and troposphere modelling and studies. The research, primarily carried out within working groups of the IAG Commission 4, resulted in important advancements that were published in leading scientific journals. During the review period, Polish research groups carried out studies on multi-GNSS functional positioning models for both relative and absolute solutions, stochastic positioning models, new carrier phase integer ambiguity resolution methods, inter system bias calibration, high-rate GNSS applications, monitoring terrestrial reference frames with GNSS, assessment of the real-time precise satellite orbits and clocks, advances in troposphere and ionosphere GNSS remote sensing methods and models, and also their applications to weather, space weather and climate studies.