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1

Geometric aspects of ground augmentation of satellite networks for the needs of deformation monitoring

Protaziuk E.

Artificial Satellites : Journal of Planetary Geodesy

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2016

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Vol. 51, No. 2

75--88

EN

Satellite measurements become competitive in many tasks of engineering surveys, however, in many requiring applications possibilities to apply such solutions are still limited. The possibility to widely apply satellite technologies for displacements measurements is related with new challenges; the most important of them relate to increasing requirements concerning the accuracy, reliability and continuity of results of position determination. One of the solutions is a ground augmentation of satellite network, which intention is to improve precision of positioning, ensure comparable accuracy of coordinates and reduce precision fluctuations over time. The need for augmentation of GNSS is particularly significant in situations: where the visibility of satellites is poor because of terrain obstacles, when the determined position is not precise enough or a satellites constellation does not allow for reliable positioning. Ground based source/sources of satellite signal placed at a ground, called pseudosatellites, or pseudolites were intensively investigated during the last two decades and finally were developed into groundbased, time-synchronized transceivers, that can transmit and receive a proprietary positioning signal. The paper presents geometric aspects of the ground based augmentation of the satellite networks using various quality measures of positioning geometry, which depends on access to the constellation of satellites and the conditions of the observation environment. The issue of minimizing these measures is the key problem that allows to obtain the position with high accuracy. For this purpose, the use of an error ellipsoid is proposed and compared with an error ellipse. The paper also describes the results of preliminary accuracy analysis obtained at test area and a comparison of various measures of the quality of positioning geometry.

2

Możliwości wykorzystania naziemnych nadajników sygnału GNSS w zastosowaniach automotive

Rapiński J., Cellmer S., Śmieja M., Caban J.

Logistyka

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2015

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nr 3

4118--4122, CD 1

PL

Artykuł przedstawia sposób modyfikacji depeszy nawigacyjnej systemu GNSS w celu dołączenia do sygnału informacji o położeniu naziemnego nadajnika wspomagającego konstelację satelitów. Do tego celu wykorzystane są nieużywane słowa w depeszy nawigacyjnej. Przedstawiono również schemat przepływu i przetwarzania danych efemerydalnych w nadajniku PL.

EN

The article presents method of modifying GNSS navigation message in order to include in the signal the information about the location of the terrestrial transmitter. The main role of this transmitter is to support a constellation of satellites. For this purpose unused words in the navigation message are modified. The paper also presents a flow diagram of the ephemeris data processing, in a terrestrial transmitter.

3

Some considerations in designing a GPS pseudolite

Rapiński J., Koziar M., Rzepecka Z., Cellmer S., Chrzanowski A.

Artificial Satellites : Journal of Planetary Geodesy

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2012

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Vol. 47, No. 1

1--11

EN

Pseudolites are transmitters of GPS-like signals placed on the ground. Though pseudolites are well known devices and have already been used in the project where visibility to the GNSS satellites is limited, there are still many issues that need enhancement. A prototype of a low-cost pseudolite is being designed and assembled at the University of Warmia and Mazury. This will allow for conducting tests with various codes, signals and software. The goal of the project is to apply the pseudolite as an augmentation to GNSS positioning tasks in geodetic engineering projects. Some practical considerations crucial for the design are discussed in this paper.

4

Pseudolite signal tests

Rapinski J., Cellmer S., Rzepecka Z.

Artificial Satellites : Journal of Planetary Geodesy

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2012

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Vol. 47, No. 4

147--153

EN

Pseudolites are ground based GNSS signal transmitters that have already been used in the project where visibility to the GNSS satellites is limited, however there are still many issues that need enhancement. A prototype of a low-cost pseudolite is being designed and assembled at the University of Warmia and Mazury. The goal of the project is to apply the pseudolite as an augmentation to GNSS positioning tasks in geodetic engineering projects. This paper presents the results of first prototype testing in the area of code generation, carrier frequency and signal power.

5

Pseudolite augmented navigation for automotive application

Rapiński J., Śmieja M.

Journal of KONES

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2011

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Vol. 18, No. 4

405-411

EN

This paper presents the idea of the Local Area Navigation Systems (LANS) for automotive application in combination with standard GNSS navigation systems. The navigation system is based on four components: the widely available GPS, pseudolites located in areas where GPS signal is obstructed (tunnels, parking lots, city canyons), GPRS communication and supervisory informatics system. In this kind of system, reliable positioning is crucial. This article covers basic aspects of GPS single point positioning commonly used in navigation applications. Some information about differential positioning (DGPS/RTK) is also provided. A strong pressure is put on the application of pseudolite, its design and possible usability. This article presents authors own pseudolite design and the idea of pseudolite application to increase road safety in areas where standard GNSS signals are not available. The pseudolite presented in this paper is in the stage of development and testing. It is a device designed at the University of Warmia and Mazury in Olsztyn in cooperation with Canadian Center for Geodetic Engineering, University of New Brunswick, Canada. Different approach to the navigation in harsh environment is to move the source of the navigation outside of the vehicle and place it inside of the obstructions. It is much more efficient way to use in vehicles standard GPS receivers augmented with signals from the pseudolites, when the satellite signals are unavailable.

6

Integration of GPS and pseudolites - effect on the positioning accuracy

Rzepecka Z., Wasilewski A., Cellmer S.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2005

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nr 8

49-64

EN

It is well known that for monitoring of engineering structures it is desirable and recommended, that the measuring system used could provide equal precision in all 3D coordinates, all the time. In many cases the spaceborn position should be augmented by other additional means, especially when the configuration of satellites is not very good (signal shadowing, small number of satellites). There are many possibilities, one of them is to use additional ranging signals transmitted from ground-based devices simulating satellites. The devices are called pseudosatellites or, more often in abbreviated form, pseudolites (PLs). Most often, they are used to strengthen geometry of positioning. In this paper background theory of pseudolites as well as Dilution of Precision (DOP) is presented. Results of accuracy pre-analysis performed are also given.

PL

Wiadomo, że do monitorowania obiektów inżynierskich jest wymagane, aby wykorzystywany system pomiarowy mógł zapewnić równą dokładność wszystkim trzem współrzędnym przez cały czas trwania pomiaru. Przy wykorzystaniu pozycjonowania satelitarnego GPS często się zdarza, szczególnie w warunkach występujących zasłon sfery niebieskiej, że warunek ten nie jest spełniony. Wtedy system satelitarny powinien być zintegrowany z jakimś innym, niezależnym systemem pomiarowym. Jedną z możliwości jest zastosowanie urządzeń naziemnych, symulujących satelity GPS. Urządzenia takie są zwane pseudosatelitami lub w skrócie pseudolitami (PL). Najczęściej wykorzystuje się je do wzmocnienia geometrii pozycjonowania. W prezentowanej pracy podano podstawy teorii pseudolitów oraz wykonywania analizy geometrii pozycjonowania (Dilution of Precision). Podano także wyniki przeprowadzonej wstępnej analizy dokładności pozycjonowania przy użyciu systemu GPS wspomaganego pseudolitami.

7

Ustalenie optymalnej konfiguracji geometrycznej satelitów GPS oraz lokalizacji pseudolitów

Cellmer S.

Technical Sciences. Supplement / University of Warmia and Mazury in Olsztyn

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2005

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suppl. 2

17--26

PL

Przedstawiono wyniki wyznaczenia teoretycznych, minimalnych wartości PDOP oraz odpowiadające tym minimalnym wartościom PDOP konfiguracje geometryczne satelitów GPS lub pseudolitów. Do obliczeń zastosowano metodę Sympleksu Neldera-Meada. Rozpatrzono różne przypadki dla wartości kąta obcięcia horyzontu oraz liczby widocznych satelitów (lub pseudolitów).

EN

In this paper the results of the theoretical, minimum value of PDOP determination and parallel geometric configurations of satellites or pseudolites are presented. The Nelder--Mead Simplex Method was used to calculate the minimum values of PDOP. Various cases for values of the elevation mask and number of visible satelites (or pseudolites) were considered.

8

Analiza wyznaczeń statycznych z obserwacji GPS i pseudolitów

Rzepecka Z., Wasilewski A., Cellmer S.

Technical Sciences. Supplement / University of Warmia and Mazury in Olsztyn

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2005

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suppl. 2

7--16

PL

W Instytucie Geodezji UWM w Olsztynie przystąpiono do realizacji nowego tematu badawczego (grant KBN nr 4T12E 00426 nt. Koncepcja zintegrowanego systemu monitoringu obiektów mostowych z wykorzystaniem techniki GPS i pseudolitów). Celem badań jest wyznaczenie dokładności określenia wysokości punktów kontrolowanych umieszczonych na badanym obiekcie z obserwacji GPSD wspomaganych pseudolitami. Przy realizacji grantu pomiary będą wykonywane wypożyczonymi pseudolitami. Aktualnie trwają przygotowania do realizacji projektu - przeprowadzono wstępne analizy dokładności (współczynniki DOP), nawiązano współpracę z zespołem naukowym z University of New Brunswick, przystosowywane są programy obliczeniowe do opracowywania zintegrowanych obserwacji. W pracy przedstawiono wyniki uzyskane z zintegrowanych pomiarów GPS i pseudolitów. Badania przeprowadzono na podstawie surowych danych obserwacyjnych uzyskanych od Zespołu Naukowego prof. Adama Chrzanowskiego - University of New Brunswick w Kanadzie. Celem było wstępne zbadanie wpływu zastosowania pseudolitów na dokładność wyznaczeń w warunkach złej geometrii satelitów.

EN

A new research project has been launched at the Institute of Geodesy, University of Warmia and Mazury in Olsztyn entitled "Concept of integrated system for bridge monitoring with application of GPS technique and pseudolites". The main goal of the study is to determine accuracy of the height obtained from GPS integrated with pseudolites. For the project purposes the measurements will be carried out using borrowed devices. Accuracy pre-analyses (DOP factors) were performed, cooperation between our Institute and the University of New Brunswick was established, the works on own software has been started in the frame of preparations.In the paper the results obtained on the basis of raw data containing observations to GPS satellites as well as to a pseudolite are given and analysed. The data were obtained from Professor Adam Chrzanowski, University of New Brunswick in Canada.