BazTech - Yadda

1

Stability of GPS and GLONASS onboard clocks on a monthly basis

Ziętala Michał

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2022

|

z. 114

193--209

EN

This paper presents the stability of the GPS and GLONASS system clocks’ stability. It describes the construction of these two systems and calculated four different Allan variances (AVAR), based on the MGEX (the Multi-GNSS Experiment) clock products. Four used variances allowed making a better analysis of each GNSS system clock. The results are shown at different averaging times from 5 s as successive multiples to 655,360 s in a monthly period. The stability of GPS and GLONASS clocks is included in the range of 10-12~10-14 s. The results showed that GLONASS clocks are stable (10-12~10-14 s) and are affected with white frequency noise (WFM). The GPS clock stability models have more fluctuations for τ > 40,960 s and the mean stability is concluded between 10-12~10-13 s. Mean frequency accuracy for GPS clocks is related with WFM and Random Walk Frequency (RWF). The differences in clock stability are caused by several factors – block type, type of clock and the time of a satellite in orbit. These factors have an influence on stability results.

2

Wkład systemu satelitarnego Galileo w rozwój geodezji

Mikoś Marcin, Nowak Adrian, Lackowski Maciej, Sośnica Krzysztof

Przegląd Geodezyjny

|

2022

|

R. 94, nr 3

21--24

PL

Wiele osób uważa, że system satelitarny Galileo będzie stanowił dodatek do istniejących systemów nawigacyjnych, takich jak amerykański GPS, czy rosyjski GLONASS. Galileo to jednak coś więcej – nie tylko z tego względu, że jest w pełni niezależny od wojska oraz budowany przez Unię Europejską i Europejską Agencję Kosmiczną, ale również dlatego, że posiada szereg nowych rozwiązań technologicznych skutkujących znaczną poprawą jakości pozycjonowania w pomiarach geodezyjnych i badaniach naukowych. Otwartość informacji dotyczących kalibracji anten nadawczych, mocy sygnału, jak i szczegółów konstrukcyjnych cywilnych satelitów Galileo, nie pozostają bez wpływu na jakość produktów pozycjonowania. Niniejszy artykuł podsumowuje najważniejsze osiągnięcia technologiczne systemu Galileo i ich znaczenie w realizacji układów odniesienia, pozycjonowaniu w czasie rzeczywistym, jak i badaniach naukowych parametrów kształtu i obrotu Ziemi oraz w kontekście różnic względem systemów GPS i GLONASS.

EN

Many people believe that the Galileo satellite system will be an addition to existing navigation systems, such as the American GPS and Russian GLONASS. However, Galileo is something more – not only because it is fully military-independent and is built by the European Union and the European Space Agency, but also because it has a number of new technological solutions resulting in a significant improvement in the quality of positioning, geodetic and surveying measurements, and scientific applications. The openness of information regarding the calibration of broadcast antennas, signal strength, as well as construction details of civil Galileo satellites, has an impact on the quality of positioning products. This article summarizes the most important technological achievements of the Galileo system and their importance in the implementation of reference systems, real-time positioning, as well as scientific studies of the shape and rotation of the Earth in the context of differences in relation to GPS and GLONASS systems.

3

Efficient cost-effective static-PPP using mixed GPS/GLONASS single-frequency observations (KSA)

Farah Ashraf

Artificial Satellites : Journal of Planetary Geodesy

|

2022

|

Vol. 57, No. 1

1--17

EN

Precise point positioning (PPP) is a GNSS positioning technique that saves cost and has an acceptable accuracy for enormous applications. PPP proved its efficiency through two decades comparing with traditional differential positioning technique. PPP uses one receiver collecting observations at an unknown station without the need for a reference station with known coordinates. PPP-collected observations must undergo extensive mitigation of different GNSS errors. Static-PPP accuracy depends mainly on the observations type (dual or single frequency), used systems (GPS or GLONASS or mixed GPS/GLONASS), satellites geometry, and observations duration. Static-PPP using dualfrequency observations gives optimum accuracy with a high cost. Static-PPP using singlefrequency observations gives acceptable accuracy with a low cost. Since the end of 2012, PPP users are able to depend on GLONASS system as an alternative. This research investigates singe-frequency/static-PPP accuracy variation on KSA based on different factors: the system used (GPS or GLONASS or GPS/GLONASS), satellites geometry, observations duration, and ionosphere activity state. Observations from 2 days reflecting different ionospheric activity states were used for this research from three CORS stations (KSA-CORS network) operated by KSA-General Authority for Survey and Geospatial Information (KSA-GASGI). It can be concluded that precision (0.05 m lat., 0.12 m long., and 0.13 m height) under quiet ionosphere and precision (0.09 m lat., 0.20 m long., and 0.23 m height) under active ionosphere could be attained using 24 h mixed GPS/GLONASS single-frequency observations. Static-PPP using 24 h mixed GPS/GLONASS single-frequency observations’ accuracies are 0.01 m lat., 0.01 m long., and 0.03 m height (quiet ionosphere) and 0.01 m lat., 0.06 m long., and 0.06 m height (active ionosphere) compared to true station coordinates.

4

The research into the integrity parameter in air transport using GLONASS data

Krasuski Kamil, Goś Artur, Ciećko Adam

Journal of KONBiN

|

2020

|

Vol. 50, iss. 2

231--241

EN

The article presents the results of the integrity parameter of the GLONASS satellite positioning system in civil aviation. As a source material for the research the authors used observation and navigation data of the GLONASS system from the onboard GNSS receiver mounted on the Cessna 172. In the research, the authors used a model to determine the aircraft position based on the single-frequency SPP code method for GLONASS L1-C/A observations. The numerical calculations were conducted in the RTKLIB software, in the RTKPOST library. The obtained results are interesting from the point of using an application of the GLONASS system in aviation and the possible implementation of the single-frequency GLONASS code observations in the SPP model in order to determine the aircraft position. On the basis of the obtained results it was found that the GLONASS integrity performance data can be used in a procedure of non-precision approach to landing NPA GNSS.

PL

W pracy przedstawiono wyniki badań parametru wiarygodności pozycjonowania satelitarnego GLONASS w lotnictwie cywilnym. Jako materiał do badań posłużyły dane obserwacyjne i nawigacyjne GLONASS z pokładowego odbiornika GNSS zamontowanego na samolocie Cessna 172. Wykorzystano model wyznaczenia pozycji SP oparty na jednoczęstotliwościowej metodzie kodowej SPP do obserwacji GLONASS L1-C/A. Obliczenia numeryczne wykonano w oprogramowaniu RTKLIB w bibliotece RTKPOST. Uzyskane wyniki badań są interesujące z punktu zastosowania systemu GLONASS w lotnictwie oraz możliwości implementacji jednoczęstotliwościowych obserwacji kodowych GLONASS w modelu SPP wyznaczenia pozycji statku powietrznego. Na podstawie uzyskanych wyników stwierdzono, że osiągi wiarygodności GLONASS mogą zostać wykorzystane w procedurze nieprecyzyjnego podejścia do lądowania NPA GNSS.

5

The positioning of the aircraft using GPS/GLONASS data

Krasuski Kamil, Kobiałka Ewelina, Ćwiklak Janusz, Grzegorzewski Marek

Journal of KONBiN

|

2019

|

Vol. 49, iss. 3

65--96

EN

The article presents the results of aircraft positioning using GPS/GLONASS data in air navigation. In the work, the flight trajectory of the Cessna 172 aircraft was determined on the basis of GPS, GLONASS and GPS/GLONASS data. The coordinates of the Cessna 172 were determined using the least squares method in a stochastic processing compliant with the ICAO recommendations. In the air test, the Cessna 172 made a test flight over EPDE military airfield in Dęblin. The GPS, GLONASS and GPS/GLONASS measurement data from the Topcon HiperPro on-board aircraft installed on the Cessna 172 aircraft were used in the research experiment. The coordinates of the Cessna 172 in the geocentric XYZ and ellipsoidal BLh were compared with the precise flight reference trajectory determined from the differential technique RTK-OTF.

PL

W artykule dokonano przedstawienia rezultatów pozycjonowania statku powietrznego z użyciem danych GPS/GLONASS w nawigacji lotniczej. W pracy dokonano wyznaczenia trajektorii lotu statku powietrznego Cessna 172 na podstawie danych GPS, GLONASS oraz GPS/GLONASS. Współrzędne statku powietrznego Cessna 172 zostały określone z użyciem metody najmniejszych kwadratów w procesie stochastycznym zgodnym z zaleceniami ICAO. W teście lotniczym statek powietrzny Cessna 172 dokonał próbnego oblotu lotniska wojskowego EPDE w Dęblinie. W eksperymencie badawczym wykorzystano dane pomiarowe GPS, GLONASS oraz GPS/GLONASS z pokładowego odbiornika Topcon HiperPro zainstalowanego na statku powietrznym Cessna 172. Wyznaczone współrzędne statku powietrznego Cessna 172 w układzie geocentrycznym XYZ oraz elipsoidalnym BLh, zostały porównane z precyzyjną trajektorią odniesienia lotu wyznaczoną z techniki różnicowej RTK-OTF.

6

Research into the integrity of Galileo positioning at Dęblin aerodrome

Krasuski Kamil, Kobiałka Ewelina, Ćwiklak Janusz, Grzegorzewski Marek, Ciećko Adam

Journal of KONBiN

|

2019

|

Vol. 49, iss. 4

75--96

EN

The paper presents the results of the integrity of Galileo satellite positioning for the area of the military aerodrome in Dęblin. The integrity parameters of the Galileo satellite positioning have been determined for en-route navigation and the precision approach. To study the integrity parameter, Galileo satellite measurements from the GNSS reference station located in the area of the Aviation Department of the Polish Air Force University, located near EPDE military aerodrome in Dęblin, were used. In particular, in the research, to determine the integrity parameter, the mean errors of the determined coordinates of GNSS reference station in the BLh ellipsoid frame were used. The research test was carried out on 11 January,2019. The authors of the work studied the parameter of the integrity of Galileo positioning used HPL and VPL protection levels.

PL

W pracy przedstawiono rezultaty wiarygodności pozycjonowania satelitarnego Galileo dla terenu lotniska wojskowego w Dęblinie. Parametry wiarygodności pozycjonowania satelitarnego Galileo zostały określone dla nawigacji typu en-route oraz podejścia precyzyjnego PA. Do zbadania parametru wiarygodności wykorzystano pomiary satelitarne Galileo ze stacji referencyjnej GNSS umieszczonej na terenie Wydziału Lotnictwa Lotniczej Akademii Wojskowej, zlokalizowanej w pobliżu lotniska wojskowego EPDE w Dęblinie. W szczególności w badaniach do określenia parametru wiarygodności wykorzystano błędy średnie wyznaczonych współrzędnych stacji referencyjnej GNSS w układzie elipsoidalnym BLh. Test badawczy został przeprowadzony w dniu 11.01.2019 r. Autorzy prac do badania parametru wiarygodności pozycjonowania Galileo wykorzystali poziomy bezpieczeństwa HPL oraz VPL.

7

KinematiC PPP using mixed GPS/GLONASS single-frequency observations

Hamed Mostafa, Abdallah Ashraf, Farah Ashraf

Artificial Satellites : Journal of Planetary Geodesy

|

2019

|

Vol. 54, No. 3

97--112

EN

Nowadays, Precise Point Positioning (PPP) is a very popular technique for Global Navigation Satellite System (GNSS) positioning. The advantage of PPP is its low cost as well as no distance limitation when compared with the differential technique. Singlefrequency receivers have the advantage of cost effectiveness when compared with the expensive dual-frequency receivers, but the ionosphere error makes a difficulty to be completely mitigated. This research aims to assess the effect of using observations from both GPS and GLONASS constellations in comparison with GPS only for kinematic purposes using single-frequency observations. Six days of the year 2018 with single-frequency data for the Ethiopian IGS station named “ADIS” were processed epoch by epoch for 24 hours once with GPS-only observations and another with GPS/GLONASS observations. In addition to “ADIS” station, a kinematic track in the New Aswan City, Aswan, Egypt, has been observed using Leica GS15, geodetic type, dual-frequency, GPS/GLONASS GNSS receiver and singlefrequency data have been processed. Net_Diff software was used for processing all the data. The results have been compared with a reference solution. Adding GLONASS satellites significantly improved the satellite number and Position Dilution Of Precision (PDOP) value and accordingly improved the accuracy of positioning. In the case of “ADIS” data, the 3D Root Mean Square Error (RMSE) ranged between 0.273 and 0.816 m for GPS only and improved to a range from 0.256 to 0.550 m for GPS/GLONASS for the 6 processed days. An average improvement ratio of 24%, 29%, 30%, and 29% in the east, north, height, and 3D position components, respectively, was achieved. For the kinematic trajectory, the 3D position RMSE improved from 0.733 m for GPS only to 0.638 m for GPS/GLONASS. The improvement ratios were 7%, 5%, 28%, and 13% in the east, north, height, and 3D position components, respectively, for the kinematic trajectory data. This opens the way to add observations from the other two constellations (Galileo and BeiDou) for more accuracy in future research.

8

Advantages of combined GNSS processing involving a limited number of visible satellites

Maciuk K.

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2018

|

z. 98

89--99

EN

Millimetre-precise GNSS measurements may only be achieved by static relative (differential) positioning using a double-frequency receiver. This accuracy level is needed to address certain surveying and civil engineering issues. Relative measurements are performed using a single- or multi-network reference station, whose accuracy depends on a number of factors, such as the distance to the reference station, the session duration, the number of visible satellites, or ephemeris and clock errors. In this work, the author analyses the accuracy of static GNSS measurements according to the number of visible satellites, based on different minimal elevation cut-off angles. Each session was divided into three modes: GPS, GLONASS and hybrid GNSS (GPS+GLONASS). The final results were compared with the corresponding daily EPN solution at the observational epoch in order to determine their accuracy.

9

Availability of the GNSS geodetic networks position during the hydrographic surveys in the ports

Specht C., Makar A., Specht M.

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

|

2018

|

Vol. 12, no. 4

657--661

EN

Geodetic network GNSS receivers are more commonly associated with positioning systems used in maritime hydrography. In terms of positioning accuracy when no terrain obstacles are present, they meet international hydrographic surveys standards (S‐44) fully. Those standards are defined as 1m (0.95) for Exclusive Order and 2m (0.95) for Special Order. It is equally as important to ensure access to position which error is not higher than above mentioned maximum values. This is most often determined by the density of port infrastructure. This article presents the results of analysis of availability of hydrographic system that operates based on geodetic GNSS networks. Hydrographic surveys in question were undertaken in inner basins with diverse infrastructure. Three representative types of ports were selected for this reason: fishing type (Hel), medium sized, modern commercial type (Gdynia) and highly congested, narrow canal type (Gdansk – Motlawa). A nonpublic, geodetic GNSS network was used for all surveys. It is worth mentioning that the above network is at the moment the only available network that provides both GPS and GLONASS corrections. The surveys provided evidence that geodetic GNSS networks can be successfully utilised to determine position of hydrographic vessel in low and moderately developed ports as well as in Exclusive and Special Orders. In highly congested ports however, the availability of the above mentioned method of measurement can be insufficient to realise a survey.

10

Determination of reliability parameters of HPL and VPL technical safety in the procedure of a non-precision landing approach NPA GNSS with using GPS and GLONASS navigation systems in air transport

Krasuski K., Wierzbicki D.

Scientific Journal of the Military University of Land Forces

|

2018

|

Vol. 50, No. 2(188)

176--186

EN

The paper presents the results of determining the HPL and VPL safety parameters used to evaluate the reliability of aircraft positioning in air transport. The HPL and VPL security level parameters were determined using GPS and GLONASS systems for the NPA GNSS non-precision landing approach. The work also compares the HPL and VPL values with the technical standards published by ICAO.

11

Dokładność pomiaru RTN-GNSS w różnych warunkach pomiarowych

Oleniacz G., Świętoń T.

Przegląd Geodezyjny

|

2018

|

R. 90, nr 1

20--22

PL

Przeprowadzono serię testowych pomiarów RTN, wykonanych dwoma odbiornikami GNSS (Septentrio Altus NR2 oraz Trimble R8). Wielokrotnie powtarzane obserwacje pozwoliły na oszacowanie realnie uzyskiwanej dokładności w zależności od wykorzystanego systemu nawigacji satelitarnej, czasu pomiaru na stanowisku oraz warunków panujących na stanowisku związanych z przesłonięciem horyzontu przez przeszkody terenowe. Rezultaty badań wskazują na brak istotnej zależności pomiędzy zastosowaną technologią pomiaru, a także czasem jego trwania w stosunku do uzyskiwanych dokładności oraz znaczący wpływ warunków panujących na stanowisku na wyniki pomiarów.

EN

A series of RTN measurements were made with two GNSS receivers (Septentrio Altus NR2 and Trimble R8). Repeated observations have allowed us to estimate the real accuracy, depending on the satellite navigation system being used, the time spent on site and terrain obstacles over the horizon. The results of the research indicate that there is no significant relationship between the applied measurement technology and its duration compared to the obtained accuracy and the significant influence of the conditions prevailing on the measurement results.

12

Implementation the GLONASS system in aeronautical application

Ćwiklak J., Krasuski K.

Journal of KONES

|

2018

|

Vol. 25, No. 3

121--128

EN

The article determines the accuracy of positioning of the aircraft with the use of a satellite system GLONASS. In addition, the SPP (Single Point Positioning) absolute positioning method was utilized in research test in article. Research test was carried out in the new software APS (Aircraft Positioning Software), used for precise GPS/GLONASS satellite positioning in air navigation. The article describes the research method and presents mathematical formulas of the SPP positioning method. In the research test, the positioning accuracy of the Cessna 172 aircraft was obtained based on comparison of results between APS and RTKLIB software. The difference of Cessna 172 aircraft coordinates in the XYZ geocentric frame between the APS and RTKLIB solution is between -7 m to +6 m. The research material developed in the article comes from an aeronautical experiment carried out with the Cessna 172 aircraft for the EPDE military airport in Deblin.

13

Accuracy assessment of aircraft positioning by using the DGLONASS method in the GBAS system

Krasuski K., Ćwiklak J., Grzesik N.

Journal of KONBiN

|

2018

|

No. 45

97--124

EN

The paper presents the accuracy results of aircraft positioning using the DGLONASS method in the GBAS augmentation system in air transport. In the research test, the coordinates of Cessna 172 aircraft were recovered on the basis of the DGLONASS technique. The calculations were executed in RTKLIB software in RTKPOST library in module "DGPS/DGNSS". The raw GLONASS data from the onboard Topcon HiperPro receiver and also from the REF1 physical reference station were utilized in the research test. In the paper, the standard deviations of aircraft coordinates and integrity HPL and VPL parameters were presented and described. In the paper, the obtained aircraft coordinates from the DGLONASS method were compared and verified with the DGPS solution. For this purpose, the RMS-3D term and difference of ellipsoidal height of aircraft were estimated in the paper. The average value of RMS-3D equals to 1.71 m, however the difference of ellipsoidal height amounts to 1.46 m, respectively.

PL

Artykuł przedstawia rezultaty dokładności pozycjonowania samolotu z użyciem metody DGLONASS w systemie wspomagania GBAS w transporcie lotniczym. W teście badawczym odtworzono współrzędne samolotu Cessna 172 na podstawie rozwiązania DGLONASS. Obliczenia wykonano w programie RTKLIB w bibliotece RTKPOST w module „DGPS/DGNSS”. Surowe dane GLONASS z pokładowego odbiornika Topcon HiperPro i fizycznej stacji referencyjnej REF1 zostały wykorzystane w teście badawczym. W pracy przedstawiono i opisano odchylenia standardowe współrzędnych samolotu oraz poziomy wiarygodności HPL/VPL. W artykule dokonano porównania i weryfikacji uzyskanych współrzędnych samolotu z rozwiązania DGLONASS oraz DGPS. W tym celu w artykule wyznaczono parametr RMS-3D oraz różnicę wysokości elipsoidalnej samolotu. Wartość średnia parametru RMS-3D wynosi 1.71 m, zaś odpowiednio różnica wysokości elipsoidalnej samolotu wynosi 1.46 m.

14

Application of the GLONASS code observations for the designation of coordinates of an aircraft in flight test mode: a case study

Krasuski K., Ćwiklak J.

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2017

|

z. 97

69--80

EN

The aim of this article is to present the results of GLONASS positioning in kinematic mode in air navigation. The flight experiment was conducted at Dęblin Airfield on a Cessna 172 aircraft. The aircraft position was recovered on the basis of the single-point positioning (SPP) method of the GLONASS code observations. The numerical computations of aircraft coordinates were executed in the RTKPOST library of the RTKLIB software. The standard deviations in aircraft position in a BLh geodetic frame were checked with the ICAO standards on civil aviation for the GLONASS system. The typical accuracy of aircraft positioning on the horizontal plane is better than 12 m, whereas, on a vertical plane, it is better than 17 m. In this paper, standard deviations in aircraft position were also compared with the theoretical accuracy of the non-precision approach (NPA) landing procedure for the GNSS system. In this paper, the MRSE parameter was also calculated during the flight test.

15

Dokładność pomiaru RTN odbiornikiem Septentrio Altus Nr2

Oleniacz G., Skrzypczak I., Świętoń T.

Zeszyty Naukowe. Inżynieria Środowiska / Uniwersytet Zielonogórski

|

2017

|

nr 166 (46)

16--24

PL

Przeprowadzona seria testów odbiornika GNSS Septentrio Altus NR2 umożliwiła określenie rzeczywistych dokładności pomiaru RTN. Wielokrotnie powtarzane pomiary pozwoliły na oszacowanie dokładności w zależności od wykorzystanego systemu nawigacji satelitarnej (wyłącznie GPS oraz połączone GPS i GLONASS), czasu pomiaru na stanowisku oraz warunków panujących na stanowisku związanych z przesłonięciem horyzontu przez przeszkody terenowe (zarośla). Rezultaty badań wskazują na brak zależności pomiędzy zastosowaną technologią pomiaru a uzyskiwanymi dokładnościami oraz istotny wpływ warunków panujących na stanowisku na wyniki pomiarów.

EN

Series of GNSS receiver tests allowed to determine real accuracy of RTN measurements. Repeated measurements allowed to estimate accuracy in function of used navigation satellite system, duration of measurements and field conditions on measurement site which are related to horizon visibility by obstacles (bushes). Research results indicate no dependency between the technology used and the measurement accuracies obtained and significant impact of the conditions on set-up on the measurement's results.

16

Lifetime performances of modernized GLONASS satellites: A review

Sarkar Shreya, Bose Anindya

Artificial Satellites : Journal of Planetary Geodesy

|

2017

|

Vol. 52, No. 4

87--97

EN

GLONASS, successfully operating during 1990s became unusable by early 2000s. Following a revitalization and modernization plan since 2004, GLONASS constellation has been completed again by the end of 2011 and the use of GLONASS is gaining popularity. Because of the previous experience, some scepticism exists among the stakeholders in using GLONASS for reliable solution and application development. This paper critically reviews the operational lifespan of GLONASS satellites launched between 2004 and 2016, as this is an important contributor towards reliability and sustained operation of the system. For popularization and extracting full benefits of GLONASS as stand-alone system or as an active component of multi-GNSS, major issues of assuring the minimum sufficient GLONASS constellation (of 24…23 satellites), efficient design implementation and the modernized ground control segment development and operation need to be properly taken care of by the system operators.

17

GNSS antenna caused near-field interference effect in precise point positioning results

Dawidowicz Karol, Baryła Radosław Baryła

Artificial Satellites : Journal of Planetary Geodesy

|

2017

|

Vol. 52, No. 2

27--40

EN

Results of long-term static GNSS observation processing adjustment prove that the often assumed "averaging multipath effect due to extended observation periods" does not actually apply. It is instead visible a bias that falsifies the coordinate estimation. The comparisons between the height difference measured with a geometrical precise leveling and the height difference provided by GNSS clearly verify the impact of the near-field multipath effect. The aim of this paper is analysis the near-field interference effect with respect to the coordinate domain. We demonstrate that the way of antennas mounting during observation campaign (distance from nearest antennas) can cause visible changes in pseudo-kinematic precise point positioning results. GNSS measured height differences comparison revealed that bias of up to 3 mm can be noticed in Up component when some object (additional GNSS antenna) was placed in radiating near-field region of measuring antenna. Additionally, for both processing scenario (GPS and GPS/GLONASS) the scattering of results clearly increased when additional antenna crosses radiating near-field region of measuring antenna. It is especially true for big choke ring antennas. In short session (15, 30 min.) the standard deviation was about twice bigger in comparison to scenario without additional antenna. When we used typical surveying antennas (short near-field region radius) the effect is almost invisible. In this case it can be observed the standard deviation increase of about 20%. On the other hand we found that surveying antennas are generally characterized by lower accuracy than choke ring antennas. The standard deviation obtained on point with this type of antenna was bigger in all processing scenarios (in comparison to standard deviation obtained on point with choke ring antenna).

18

Evaluation of Quad-constellation GNSS Precise Point Positioning in Egypt

El Manaily Emad, Rabbou Mahmoud Abd, El-Shazly Adel, Baraka Moustafa

Artificial Satellites : Journal of Planetary Geodesy

|

2017

|

Vol. 52, No. 1

9--18

EN

Commonly, relative GPS positioning technique is used in Egypt for precise positioning applications. However, the requirement of a reference station is usually problematic for some applications as it limits the operational range of the system and increases the system cost and complexity On the other hand; the single point positioning is traditionally used for low accuracy applications such as land vehicle navigation with positioning accuracy up to 10 meters in some scenarios which caused navigation problems especially in downtown areas. Recently, high positioning accuracy can be obtained through Precise Point Positioning (PPP) technique in which only once GNSS receiver is used. However, the major drawback of PPP is the long convergence time to reach to the surveying grade accuracy compared to the existing relative techniques. Moreover, the PPP accuracy is significantly degraded due to shortage in satellite availability in urban areas. To overcome these limitations, the quad constellation GNSS systems namely; GPS.GLONASS, Galileo and BeiDou can be combined to increase the satellite availability and enhance the satellite geometry which in turn reduces the convergence time. In Egypt, at the moment, the signals of both Galileo and BeiDou could be logged with limited number of satellites up to four and six satellites for both Systems respectively. In this paper, we investigated the performance of the Quad-GNSS positioning in both dual- and single-frequency ionosphere free PPP modes for both high accurate and low cost navigation application, respectively. The performance of the developed PPP models will be investigated through GNSS data sets collected at three Egyptian cities namely, Cairo, Alexandria and Aswan.

19

Evaluation of integration degree of the ASG-EUPOS Polish reference networks with Ukrainian GeoTerrace network stations in the border area

Siejka Zbigniew

Artificial Satellites : Journal of Planetary Geodesy

|

2017

|

Vol. 52, No. 3

71--84

EN

GNSS systems are currently the basic tools for determination of the highest precision station coordinates (e.g. basic control network stations or stations used in the networks for geodynamic studies) as well as for land, maritime and air navigation. All of these tasks are carried out using active, large scale, satellite geodetic networks which are complex, intelligent teleinformatic systems offering post processing services along with corrections delivered in real-time for kinematic measurements. Many countries in the world, also in Europe, have built their own multifunctional networks and enhance them with their own GNSS augmentation systems. Nowadays however, in the era of international integration, there is a necessity to consider collective actions in order to build a unified system, covering e.g. the whole Europe or at least some of its regions. Such actions have already been undertaken in many regions of the world. In Europe such an example is the development for EUPOS which consists of active national networks built in central eastern European countries. So far experience and research show, that the critical areas for connecting these networks are border areas, in which the positioning accuracy decreases (Krzeszowski and Bosy, 2011). This study attempts to evaluate the border area compatibility of Polish ASG-EUPOS (European Position Determination System) reference stations and Ukrainian GeoTerrace system reference stations in the context of their future incorporation into the EUPOS. The two networks analyzed in work feature similar hardware parameters. In the ASG-EUPOS reference stations network, during the analyzed period, 2 stations (WLDW and CHEL) used only one system (GPS), while, in the GeoTerrace network, all the stations were equipped with both GPS and GLONASS receivers. The ASG EUPOS reference station network (95.6%) has its average completeness greater by about 6% when compared to the GeoTerrace network (89.8%).

20

Estimation differential code biases (DCB) P1-C1 using GLONASS data in flight experiment on the Dęblin aerodrome (01.06.2010)

Krasuski K.

Aparatura Badawcza i Dydaktyczna

|

2017

|

T. 22, nr 1

72--77

EN

The studies results of instrumental biases DCB (Differential Code Biases) P1-C1 and their accuracy are presented in this paper. The research test was realized using GLONASS kinematic data (e.g. code observations P1 and C1) from dual-frequency Topcon Hiper Pro receiver. The Topcon Hiper Pro receiver was installed in Cessna 172 plane during flight experiment on the Dęblin military aerodrome on 1st June 2010. The instrumental biases DCB P1-C1 were estimated in SciTEC Toolbox software package in post-processing mode. The instrumental biases DCB P1-C1 are applied for correction the values of receiver and satellite clock bias in adjustment processing of GLONASS observations. In this article, the instrumental biases DCB P1-C1 for satellites are also compared with CODE products. The mean differ- ence of DCB P1-C1 bias for satellites between SciTEC and CODE solution amounts to 0.136 ns, whereas the RMS bias equals to 3.783 ns.

PL

W artykule zaprezentowano rezultaty badań dotyczące wyznaczenia opóźnień sprzętowych DCB P1-C1 oraz ich dokładności. Test badawczy został zrealizowany z użyciem obserwacji kinematycznych GLONASS (P1 i C1) z dwuczęstotliwościowego odbiornika Topcon Hiper Pro. Odbiornik Topcon Hiper Pro został zainstalowany w samolocie Cessna 172 podczas eksperymentu lotniczego na lotnisku w Dęblinie w dniu 01.06.2010. Opóźnienia sprzętowe DCB P1-C1 zostały wyznaczone w programie SciTEC Toolbox w trybie post-processingu. Opóźnienia sprzętowe DCB P1-C1 są stosowane w opracowaniu obserwacji GLONASS do korekcji wartości poprawki chodu zegara odbiornika i satelity. W artykule dokonano rów- nież porównania opóźnień sprzętowych dla satelitów DCB P1-C1 z produktami CODE. Średnia różnica wartości opóźnień sprzętowych dla satelitów DCB P1-C1 pomiędzy rozwiązaniem SciTEC i CODE wynosi 0,136 ns, a błąd RMS jest równy 3,783 ns.