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1
Content available Pochylnie Kanału Elbląskiego. Doskonałe rozwiązanie inżyniera Steenke
Kohutek Zdzisław B.
Budownictwo, Technologie, Architektura
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2024
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nr 2
48--52
2
Content available Test of Vibrations Influence on the Measurement Accuracy in the Precise Digital Leveller Trimble Dini 03 And Comparison of its Vibration Sensitivity with Leveller Ni 002
Kurnatowski Marek
Civil and Environmental Engineering Reports
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2020
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Vol. 30, no. 4
112--124
PL
The article presents findings from research on the effect of vibrations on the accuracy of measurement with an automatic precise digital leveller. A special research station was created to induce vibrations on a leveller and to measure vibration parameters that affect staff reading. It contains description of discovered relationship between the vibration parameters and the mean error of a single height difference measurement. The range of frequencies for which the measurement was possible was estimated. The reliability of the measured values obtained under specific vibration conditions was also analysed. The results of current research were compared with similar studies on analogue leveller Ni 002. The conclusions described in this paper can be helpful in engineering measurements under adverse conditions of ambient vibrations.
3
Content available Validation of European Gravimetric Geoid models in context of realization of EVRS system in Poland
Marjańska Dorota, Olszak Tomasz, Piętka Dominik
Geodesy and Cartography
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2019
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Vol. 68, no. 2
329--347
EN
In this study, several variants create and choose of a local quasi-geoid model in Poland have been considered. All propositions have a source in European Gravimetric Geoid models – EGG2008 and EGG2015, which are purely gravimetric models of reference surface. In the course of this work, each model has been analyzed in various ways: without any corrections, by parallel shifting of residuals, by the 7-parameter conformal transformation and by fitting residuals by 4- and 5-parameter trigonometric polynomials. Eventual corrections were based on points of national GNSS/levelling networks (EUVN, EUVN_DA, POLREF, EUREF and ASG-EUPOS eccentric points). As a final result of this study, a comparison of the accuracy of selected models has been carried out by RMSE statistics and maps showing spatial distribution of residuals and histograms. Validation has shown that the maximum achievable accuracy of the EGG models is approximately 2 cm for the ETRF2000 reference system and approximately 8 cm for ETRF89. In turn, fitting with the use of different mathematical methods results in an improvement of the standard deviation of residues to the level of 1.3–1.4 cm. The conclusions include an evaluation of considerations for and against the use of models based only on EGG realizations and, on the other hand, fitted to the points of Polish vertical network. Its usefulness is strictly connected with needs of the definition of up to date quasi-geoid model for the new realization of heights system in Poland, based on EVRF2007 frame.
4
Content available Evaluation of some levelling techniques in surveying application
Pirti Atinc, Hosbas Ramazan Gürsel
Geodesy and Cartography
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2019
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Vol. 68, no. 2
361--373
EN
Applications in geodesy and engineering surveying require the determination of the heights of the vertical control points in the national and local networks using different techniques. These techniques can be classified as geometric, trigonometric, barometric and Global Positioning System (GPS) levelling. The aim of this study is to analyse height differences obtained from these three techniques using precise digital level and digital level, total station (trigonometric levelling) and GPS which collects phase and code observations (GPS levelling). The accuracies of these methods are analysed. The results obtained show that the precise digital levelling is more stable and reliable than the other two methods. The results of the three levelling methods agree with each other within a few millimetres. The different levelling methods are compared. Geometric levelling is usually accepted as being more accurate than the other methods. The discrepancy between geometric levelling and short range trigonometric levelling is at the level of 8 millimetres. The accuracy of the short range trigonometric levelling is due the reciprocal and simultaneous observations of the zenith angles and slope distances over relative short distances of 250 m. The difference between the ellipsoidal height differences obtained from the GPS levelling used without geoid and the orthometric height differences obtained from precise geometric levelling is 4 millimetres. The geoid model which is obtained from a fifth order polynomial fit of the project area is good enough in this study. The discrepancy between the precise geometric and GPS levelling (with geoid corrections) is 4 millimetres over 5 km.
5
Content available Determination of correlation coefficient between geoid-to-quasigeoid separation calculated by the satellite data in Sjöberg’s equation and GPS/Levelling method
Eshaghzadeh A., Kalantari R. A., Hekmat Z. M.
Geodesy and Cartography
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2018
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Vol. 67, no. 2
179--192
EN
In this paper, two techniques for calculating the geoid-to-quasigeoid separation are employed. One of them is GPS/Levelling customary method as a criterion where the geoid undulation and height anomaly are computed by subtracting the ellipsoid height attained via GPS from the orthometric height and normal height, respectively. Another approach is Sjöberg’s equation. We have used of the ICGEM website for definition of the variables of the Sjöberg’s equation, as the applied reference model is the EGM2008 global geopotential model and WGS84 reference ellipsoid. The investigations are performed over the stations of the GPS/Leveling network related to three selected areas in desert, mountain and flatland namely the Lout, Zagros and Khuzestan in Iran and afterward the correlation coefficient between the geoid-to-quasigeoid separation calculated using the satellite data in Sjöberg’s equation and GPS/Levelling method is estimated. The results indicate a straight correlation between the estimated separations from the two methods as its value for the Lout is 0.754, for the Zagros is 0.497 and for the Khuzestan is 0.659. consequently, using the satellite data in Sjöberg’s equation for the regions where there are not the GPS/Levelling and land gravity data, specially for the even areas, yield a satisfactory response of the geoidto-quasigeoid separation.
6
Content available remote Geometrical selectivity of current sensors
Ripka P., Kaspar P., Saneistr J.
Przegląd Elektrotechniczny
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2012
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R. 88, nr 5a
38-39
EN
We analyze the influence of external "unclamped" currents on contactless current sensors, especially the gradient sensor arrays and the current clamps. Best suppression of close currents can be achieved by using magnetic yoke with optimized shielding. DC/AC fluxgate current clamps of our design have low perming error and suppress external current by the factor of 20 000.
PL
Analizujemy wpływ zewnętrznych prądów niezrównoważenia na bezstykowe czujniki prądowe w szczególności na matryce gradientowe czujników i układy poziomowania prądu. Najlepsze tłumienie prądów bliskich można osiągnąć poprzez użycie jarzma magnetycznego, w którym zoptymalizowano ekranowanie. Układy poziomujące zaprojektowane przez nas wykazują niski błąd przewodności i tłumią zewnętrzne prądy ponad 20 000 razy.
7
Content available Projekt elektrycznego wózka inwalidzkiego o zmiennej geometrii ramy
Tejszerska D, Warszawa P, Jureczko P
Aktualne Problemy Biomechaniki
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2010
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z. 4
269--274
PL
W pracy został przedstawiony projekt geometrii elektrycznego wózka inwalidzkiego ze zmienną geometrią ramy, umożliwiającą pionizację oraz uzyskanie pozycji leżącej. Wykonana została analiza numeryczna konstrukcji.
EN
The project of multi-positional electric wheelchair for handicapped people. The geometric model have been designed and analyzed with use of Autodesk Inventor environment.
8
Automatyzacja poziomowania pojazdów i pomostów roboczych : stan, tendencje rozwojowe
Sobczykiewicz W., Tkaczyk W.
Przegląd Mechaniczny
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1999
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nr 19
15-17
9
Content available remote Kombajny zbożowe do pracy na terenach pochyłych
Dreszer K., Gieroba J., Ukalski J.
Problemy Inżynierii Rolniczej
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1998
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R. 6, nr 1
57-78
PL
Omówiono budowę "kombajnów górskich" oraz systemy poziomowania poszczególnych zespołów roboczych tych maszyn. Ponadto przedstawiono wyniki badań kombajnów oraz próbę oceny celowości produkcji tego typu maszyn dla polskiego rolnictwa.
EN
A number of manufactures of long tradition in combine harvester production (such as Class, John Deere, Laverda, New Holland), along with developing construction and introducing progressive technique and technology, undertook the desi
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