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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.

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Performance analysis of GPS/BDS integrated precise positioning system considering visibility of satellites

Noh Jae Hee, Jo Gwang Hee, Lim Deok Won, Lee Jin Hyuk, Lee Sun Yong, Lee Sang Jeong

Annual of Navigation

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2019

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No. 26

65--75

EN

Research on precise positioning is being actively carried out to provide accurate position information for land transportation. The most significant problem when performing precise positioning in urban canyon is the degradation of performance due to the lack of visible satellites. Prior to open service of BDS, most of the studies on positioning were focused on using GPS/GLONASS integrated navigation system. Since BDS began open service, studies using GPS/BDS have been actively performed in the Asia-Pacific region as it became possible to acquire enough available BDS satellites. The average number of visible satellites in Korea is 9 for GPS and 14 for BDS. In this paper, we analyze the availability of precise positioning using BDS in urban canyon. To do this, we simulate the urban canyon environment by applying the mask to the azimuth and the elevation. We analyze the positioning accuracy using two simulation scenarios. From the results, it is shown that the accuracy of precise positioning in the case where the satellites in the east-west direction are blocked is lowered than that in the case where the satellites in the south-north direction are blocked for the same elevation mask angle. This result comes from the fact that the PDOP increases when the satellites are blocked in the east-west direction. Also, it can be confirmed that the GPS/BDS integrated positioning is available for the high mask angle while the GPS-only positioning is not possible continuously.

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Use of scanning area related multiple degradation profiles for AFM assessment of polystyrene/PC61BM nanocomposite surface deterioration

Sikora A., Moczała M., Boharewicz B.

Materials Science Poland

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2018

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Vol. 36, No. 3

397--402

EN

In this paper, we present a novel approach developed in order to increase the reliability and accuracy of AFM investigation of morphological changes in a nanocomposite due to exposure to the media causing its degradation. By precise sample positioning and repetitive determination of the roughness changes at specific spots, we were able to create space-related degradation profiles. As the multi-step experiment based on exposure/scanning cycle was performed, we were able to observe a unique response of investigated samples revealing spatial inhomogeneity of the material. In order to present the measurement methodology, we used polystyrene samples containing various quantities of PC61BM nanofiller (0 %, 5 %, 10 % and 20 % of mass proportion), which was exposed to 370 nm UV radiation. Obtained data can be recognized as specific fingerprints of investigated materials. The solution based on creation and analysis of degradation profiles can be particularly useful for diagnostics of nanomaterials and nanocomposites to test their resistance to various conditions.

4

Future of National Reference Frames – from static to kinematic?

Poutanen M., Häkli P.

Geodesy and Cartography

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2018

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Vol. 67, no. 1

117--129

EN

Technical development, new applications and requests for increased accuracy in georeferencing are setting new demands for accuracy and reliability of reference frames. Due to crustal deformations and local movements of benchmarks, a static reference network deteriorates with time, thus eventually requiring update of the whole system. Technically, renewal of a reference frame is straightforward and should be done whenever enough new data or updated information exist to get an improvement in accuracy. An example is the International Terrestrial Reference Frame, ITRF, which is renewed regularly. The situation is more complicated with national reference frames which may have been given a legal status, and parameters defined by the national legislation. Even without that, renewal and implementation of such a frame is a multi-million euro project taking years to complete. Crustal deformations and movements deteriorate static reference frames (defined by fixed/static coordinates of benchmarks) with time. Eventually, distortions in a static reference frame will become bigger than the uncertainties of GNSS measurements, thus deteriorating the obtainable accuracy of the measurement technique. Instead of a static reference frame, one can use semi-kinematic or kinematic approach where either the transformation from global to the national reference frame or the coordinates of reference frame benchmarks are time-dependent. In this paper we give a short overview of the topic, and discuss on technical issues and future aspects of the reference frames in the viewpoint of National Mapping and Cadastre Authorities (NMA) with an example on the national strategy in Finland.

5

Positioning and applications

Rogowski J. B., Wielgosz P.

Geodesy and Cartography

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2015

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Vol. 64, no. 2

243--259

EN

The paper presents national report of Poland for IAG on positioning and applications. The selected research presented was carried out at leading Polish research institutions and concern precise multi-GNSS satellite positioning - relative and absolute - and also GNSS-based ionosphere and troposphere modelling and studies. The research resulted in noticeable advancements in these subjects confirmed by the development of new algorithms and methods. New and improved methods of precise GNSS positioning were developed, and also GNSS metrology was studied. New advanced troposphere models were presented and tested. In particular, these models allowed testing IPW variability on regional and global scales. Also, new regional ionosphere monitoring web-based services were developed and launched.

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Recent Advances in Wide Area Real -Time Precise Positioning

Lapucha D., Jong K., Liu X., Oerpen O., Vigen E.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2011

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Vol. 5, no. 1

87--92

EN

This paper describes briefly new high precision wide area real time positioning systems, dis-cusses their evolution, implementation and presents recent results. In the latter part the paper is primarily fo-cused on discussing the benefits of GLONASS augmented high precision positioning.

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Reliable Technique of GNSS/RTK Positioning under severe observational conditions

Bakuła M., Pelc-Mieczkowska R.

Reports on Geodesy

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2011

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z. 2/91

67-73

EN

Nowadays GNSS/RTK positioning is a very efficient technique for determination of coordinates especially when it is based on permanent reference stations. It allows every land surveyor to do his work easily and efficiently. However there are some situations when the use of RTK technique makes some difficulties, especially if the GNSS receiver has no full availability for satellites. It is well know that obstructions caused by tress, buildings, power lines etc., limit satellites availability. In those situations gross errors can appear. In order to avoid misleading coordinates occurring we can use more than one receiver has no full availability for satellites. It is well known that obstructions caused by tress, buildings, power lines etc. limit satellite availability. In Those situations gross errors can appear. In Order to avoid misleading coordinates occurring we can use more than one receiver. The paper presents practical tests and description of the GNSS/RTK technology based on the simultaneous use of three different GNSS receivers for the specific control points. Three different GNSS/RTK receivers can be placed on a special mounting beam and additionally RTK positions are send in real-time to a computer. The software on the computer analyses not only the precision but also the accuracy of determined RTK positions. In effects that solution can allow obtaining reliable coordinates even if observational GNSS conditions are very severe.

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"ASG+": Project for improving Polish Multifunctional Precise Satellite Positioning System

Figurski M., Bogusz J., Bosy J., Kontny B., Krankowski A., Wielgosz P.

Reports on Geodesy

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2011

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z. 2/91

51-57

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Application of predictive regional ionosphere model to medium range RTK positioning

Wielgosz P., Krankowski A., Sieradzki R., Grejner-Brzezińska D.

Acta Geophysica

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2008

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Vol. 56, no. 4

1147-1161

EN

Real Time Kinematic (RTK) GPS positioning over longer distances requires a support of atmospheric (ionospheric and tropospheric) corrections, since the atmospheric errors decorrelate with the growing distances and cannot be completely eliminated by double differencing of the satellite observations. Currently, the most commonly used approach is to derive the atmospheric corrections at the reference station network and provide them in real time to the roving receiver. Another solution, proposed here, is to use predictive atmospheric models in order to derive the atmospheric corrections. This paper presents the test results of the performance assessment of the predictive ionosphere model (UWM-IPM) application to medium-range RTK positioning. The rover data collected within 25 to 67 km from the closest reference station were processed in the kinematic mode with the support of the ionospheric corrections derived from the UWM-IPM model. The RTK solution was derived in both single-and multi-baseline modes, and compared to the two reference solutions obtained without the ionospheric corrections. All numerical tests were carried out using the MPGPS software developed in cooperation with The Ohio State University; a recent extension to the software, developed at the University of Warmia and Mazury in Olsztyn, introduces the predictive ionosphere model to the RTK solution. The test results are very promising, and indicate that predicted ionosphere corrections can effectively support medium-range RTK positioning, and allow for fast ambiguity resolution over distances of several tens of kilometers under moderate ionospheric conditions.