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1

Gauss-Markov model with random parameters to adjust results of surveys of geodetic control networks

Banaś Marek, Czaja Józef, Dąbrowski Janusz

Reports on Geodesy and Geoinformatics

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2021

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Vol. 111

1--6

EN

Alignment of an engineering object project in the field is always conducted at the points of the geodetic control network, the coordinates of which are determined on the basis of the results of its elements survey and with connection to the national spatial reference system. The points of the national spatial reference system determined on the basis of previous surveys have specified coordinates with adequate accuracy, which is included in their covariance matrix. The coordinates of the geodetic control network points are determined more accurately than the points of the national spatial reference system and this means that the results of surveys of the geodetic control network have to be adequately incorporated into the coordinates of the reference points. In order to perform this incorporation, it may be assumed that the coordinates of the reference points are random, that is, they have acovariance matrix, which should be used in the process of adjusting the results of the geodetic control network observation. This research paper presents the principles for the estimation of the Gauss-Markov model parameters applied in case of those geodetic control networks in which the coordinates of the reference points have random character. On the basis of the observation equations δ+AX=L for the geodetic control network and using the weighting matrix Pand the matrix of conditional covariances [wzór] for the observation vector L, the parameter vector X is estimated in the form of the derived formula [wzór]. The verification of these estimation principles has been illustrated by the example of a fragment of a levelling geodetic control network consisting of three geodetic control points and two reference points of the national spatial reference system. The novel feature of the proposed solution is the application of covariance matrices of the reference point coordinates to adjust the results of the survey of geodetic control networks and to determine limit standard deviations for the estimated coordinates ofgeodetic control network points.

2

Low aerial imagery – an assessment of georeferencing errors and the potential for use in environmental inventory

Smaczyński M., Medyńska-Gulij B.

Geodesy and Cartography

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2017

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Vol. 66, no. 1

89--104

EN

Unmanned aerial vehicles are increasingly being used in close range photogrammetry. Real-time observation of the Earth’s surface and the photogrammetric images obtained are used as material for surveying and environmental inventory. The following study was conducted on a small area (approximately 1 ha). In such cases, the classical method of topographic mapping is not accurate enough. The geodetic method of topographic surveying, on the other hand, is an overly precise measurement technique for the purpose of inventorying the natural environment components. The author of the following study has proposed using the unmanned aerial vehicle technology and tying in the obtained images to the control point network established with the aid of GNSS technology. Georeferencing the acquired images and using them to create a photogrammetric model of the studied area enabled the researcher to perform calculations, which yielded a total root mean square error below 9 cm. The performed comparison of the real lengths of the vectors connecting the control points and their lengths calculated on the basis of the photogrammetric model made it possible to fully confirm the RMSE calculated and prove the usefulness of the UAV technology in observing terrain components for the purpose of environmental inventory. Such environmental components include, among others, elements of road infrastructure, green areas, but also changes in the location of moving pedestrians and vehicles, as well as other changes in the natural environment that are not registered on classical base maps or topographic maps.

3

Verification of applicability of the Trimble RTX satellite technology with xFill function in establishing surveying control networks

Krzyżek R.

Geodesy and Cartography

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2013

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Vol. 62, no. 2

217--233

EN

The paper presents the results of real time measurements of test geodetic control network points using the RTK GPS and RTX Extended technologies. The Trimble RTX technology uses the xFill function, which enables real measurements without the need for constant connection with the ASG EUPOS system reference stations network. Comparative analyses of the results of measurements using the methods were performed and they were compared with the test control network data assumed to be error-free. Although the Trimble RTX technology is an innovative measurement method which is rarely used now, the possibilities it provides in surveying works, including building geodetic control networks, are satisfactory and it will certainly contribute to improving the organisation of surveying works.

PL

W pracy przedstawiono wyniki pomiarów w czasie rzeczywistym punktów osnowy testowej z wykorzystaniem technologii RTK GPS oraz RTX Extended. W technologii Trimble RTX wykorzystano funkcję xFill, która daje możliwości realnego wykonywania pomiaru bez konieczności stałej łączności z siecią stacji referencyjnych systemu ASG EUPOS. Wykonano analizy porównawcze wyników pomiaru między metodami oraz odniesiono je do danych osnowy testowej, przyjętych za bezbłędne. Choć technologia Trimble RTX jest innowacyjną metodą pomiaru i jeszcze rzadko stosowaną, to możliwości jakie daje w realizacjach prac geodezyjnych, w tym zakładaniu osnów pomiarowych, są bardzo zadawalające i z pewnością przyczyni się do jeszcze lepszej i bardziej ekonomicznej organizacji prac geodezyjnych.

4

Zastosowanie metod pozycjonowania GPS do modernizacji osnowy geodezyjnej oraz ewidencji gruntów i budynków

Baryła R., Bakuła M., Oszczak S.

Geomatics and Environmental Engineering

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2007

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Vol. 1, no. 1/1

61-70

PL

W artykule zaprezentowano technologię modernizacji ewidencji gruntów i budynków z zastosowaniem satelitarnej technologii GPS. Przeprowadzenie modernizacji ewidencji odbywa się na podstawie materiałów archiwalnych oraz nowych współrzędnych punktów wówczas założonej osnowy geodezyjnej, które uzyskuje się w wyniku wzmocnienia starej sieci osnowy geodezyjnej pomiarami GPS. Efektem końcowym przeprowadzonej modernizacji jest numeryczna mapa ewidencji gruntów i budynków oraz wykaz powierzchni działek obliczonych automatycznie na podstawie danych tworzących mapę numeryczną. W dalszej części artykułu opisano metodę RTK umożliwiającą wyznaczenie współrzędnych punktów z centymetrową dokładnością w dowolnie zdefiniowanym układzie współrzędnych oraz możliwość wykorzystania tej metody w pracach związanych z modernizacją ewidencji gruntów i budynków.

EN

In his paper, a new technology for land and buildings registration modernization supported by GPS (Global Positioning System) technique is presented. The modernization is based on archival materials and new coordinates of the reference network. The new coordinates are provided through strengthening an existing reference network with new points derived from GPS survey. As the result of the modernization, a numeric map of parcel and building cadastre together with the list of parcel areas calculated from numeric map data is provided. The authors provide also insight into RTK (Real-Time Kinematic) GPS technique that allows for centimeter-level point surveying in any user-defined reference frame. The feasibility of using RTK GPS technique for works related to cadastre modernization is also discussed.

5

Kompleksowa ocena dokładności wielkoskalowych opracowań cyfrowych miasta Zielona Góra

Dąbrowski W., Doskocz A.

Roczniki Geomatyki

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2006

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T. 4, z. 3

81-93

EN

The paper presents the results of a project carried out over the last seven years by the Department of Geodesy and Property Management, Municipal Office of the City of Zielona Góra, in cooperation with the Faculty of Geodesy and Land Management, University of Warmia and Mazury in Olsztyn. The main goal of the project was to modernize the system of national geodetic and cartographic resources of the city of Zielona Góra, and to ensure its adequate quality. A restorable control network of the 3rd class was established in Zielona Góra during the years 1998 to 1999. Points of the existing horizontal geodetic control network of class I and II were incorporated into the newly-established geodetic network by classical surveys and GPS satellite technique. A total of 480 points of the existing horizontal control network of the 3rd class were adapted for this purpose. The modernization of the horizontal geodetic control network provided an accurate and reliable basis for conducting geodetic surveys and for performing cartographic work. The maximum error of position of a point within the restorable control network of the 3rd class, established in the city of Zielona Góra, is mp = 0,027 m. The accuracy of a large-scale digital map of the city of Zielona Góra, compiled based on the results of planimetric surveys conducted during the years 1974 to 1999, was estimated in 1999. The study was performed on seven control objects, using a total of 1619 control points of the following type: corner points of building contours (denoted by the letter B), boundary points of parcels (denoted by the letter G) and points of technical utilities (denoted by the letter U). The model coordinates of control points were determined based on new field surveys (with the use of an electronic tachometer - total station survey), including redundant data, which permitted to adjust the results of control measurements and to estimate their accuracy. It was found that the adaptation of the results of previous direct measurements based on an accurate geodetic control network enabled to compile a large-scale digital map with an accuracy of 0.10 to 0.20 m (i.e. at the accuracy level of previous planimetric surveys). The accuracy of a digital orthophotomap of the city of Zielona Góra, on a scale of 1:2000, was estimated during the years 2005 to 2006. The analysis was made based on 33 orthophotomap sheets in raster form (.tif files) with reference files (.tfw). A set of plane coordinates of 501 control points, determined by direct field measurements with an electronic tachometer, was used in the study. Detail control points, most of them belonging to the 1st accuracy group (i.e. the so-called .well defined points.), were considered. The points were easy to identify on the raster image of the orthophotomap, and available for precise positioning by manual vectorization. The error of position of the control points obtained by vectorization (on the raster image of the orthophotomap) was. This indicated the possibility to perform point planimetric surveys, using the raster image of the orthophotomap, with a high accuracy. With respect to considered detail points, a scale of 1:1000 can be used for the purpose of graphic representation of vector map data produced by manual vectorization. The results show that a digital orthophotomap of the city of Zielona Góra became a valuable supplement of a large-scale digital map as for the content of a cadastral map and a basis map. Both as an autonomous source of information or combined with the content of other digital maps, the orthophotomap on a scale of 1:2000 can provide the basis for studies and projects carried out within the framework of municipal GIS.