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1

Improving positioning accuracy of aircraft using SPP method in GLONASS system

Krasuski Kamil, Ciećko Adam, Grunwald Grzegorz, Kirschenstein Małgorzata

Archives of Transport

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2024

|

Vol. 69, iss. 1

21--37

EN

The paper presents the results of a study showing the accuracy of the determination of aircraft position coordinates based on the SPP (Single Point Positioning) solution in the GLONASS (Globalnaja Navigatsionnaya Sputnikovaya Sistema) system. For this purpose, the paper develops and implements an algorithm for the correction of position errors as parameters describing positioning accuracy. The proposed algorithm uses position error values determined for a single GNSS (Global Navigation Satellite Systems) receiver, which are joined in a linear combination to deter-mine the positioning accuracy of the aircraft. The algorithm uses linear coefficients as an inverse function of the number of GLONASS satellites being tracked by the GNSS receiver. The developed algorithm was tested for GLONASS satellite data recorded by Topcon HiPer Pro and Javad Alpha geodetic receivers, during a flight test carried out with a Cessna 172 aircraft around the military airport in Dęblin. Navigation calculations were carried out using RTKLIB v.2.4.3 and Scilab v.6.0.0 software. On the basis of the tests carried out, it was found that for single Topcon HiPer Pro and Javad Alpha receivers, position errors were up to ±11.4 m. However, by using the position error correction algo-rithm for both receivers, GLONASS positioning accuracy is up to ±3.6 m. The developed algorithm reduces position errors by 60-80% for all BLh (B-Latitude, L-Longitude, h-ellipsoidal height) coordinates. The paper shows the possibility of testing and implementing the proposed mathematical algorithm for the SPP solution in a GPS (GlobalPositioning System) navigation system. In this case the position errors from the GPS SPP solution range from -0.9 m to +0.9 m for all BLh coordinates. The obtained results showed that application the GLONASS and GPS system in air transport is important. The algorithm used in this work can also be applied to other global GNSS navigation systems (e.g. Galileo (European Navigation Satellite system) or BeiDou (Chinese Navigation Satellite System)) in air transport and navigation.

2

Methodology to improve the accuracy of determining the position of UAVS equipped with single-frequency receivers for the purposes of gathering data on aviation obstacles

Lalak Marta, Krasuski Daniel, Wierzbicki Damian

Zeszyty Naukowe. Transport / Politechnika Śląska

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2023

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z. 119

83--104

EN

Low-altitude photogrammetric studies are often applied in detection of aviation obstacles. The low altitude of the Unmanned Aerial Vehicle (UAV) flight guarantees high spatial resolution (X, Y) of the obtained data. At the same time, due to high temporal resolution, UAVs have become an appropriate tool for gathering data about such obstacles. In order to ensure the required accuracy of orientation of the photogrammetric block, Ground Control Points (GCPs) are measured. The recently introduced UAV positioning solutions that are based on Post-Processing Kinematic (PPK) and Real Time Kinematic (RTK) are known to effectively reduce, or, according to other sources, even completely eliminate the necessity to conduct GCP measurements. However, the RTK method involves multiple limitations that result from the need to ensure continuous communication between the reference station and the rover receiver. The main challenge lies in achieving accurate orientation of the block without the need to conduct time-consuming ground measurements that are connected to signalling and measuring the GCPs. Such solution is required if the SPP code method is applied to designation the position of the UAV. The paper presents a research experiment aimed at improving the accuracy of the determination of the coordinates of UAV for the SPP method, in real time. The algorithm of the SPP method was improved with the use of IGS products.

3

Monitoring of Icelandic plate movement with GNSS method and GPS signal jamming effects in Iceland

Pırtı Atınç, Hoşbaş Ramazan Gürsel, Yücel Mehmet Ali

Reports on Geodesy and Geoinformatics

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2023

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Vol. 116

15--22

EN

Jamming is electromagnetic radiation or reflection that impairs the function of electronic instruments and equipment or communication tools. Intentionally disrupting or interfering with GPS signals, which are used for positioning, navigation, and timing, known as "GPS jamming", is accomplished using a radio frequency emitting device. On January 8, 2022 (the day of a NATO exercise), it was investigated how GPS signal jamming affected the position accuracy at three IGS points in Iceland. The obtained coordinate differences between kinematic processing and static processing reached values of about 0.5-10 meters for the MAYV, and HOFN stations in this study. In addition to GPS signal jamming effect in Iceland, horizontal and vertical velocity fields of the three IGS stations in Iceland covering a twenty-two year period (2000-2022) in this study. According to the obtained results, a motion of about 2cm-2.5cm per year (horizontal) and 0.1cm-2.1cm per year (vertical) was computed at the three IGS stations (HOFN, REYK, and MAYV) located in Iceland.

4

Progression of clock DBD changes over time

Maciuk Kamil, Varna Inese, Kudrys Jacek

Metrology and Measurement Systems

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2023

|

Vol. 30, nr 3

499--505

EN

Day-boundary discontinuity (DBD) is an effect present in precise GNSS satellite orbit and clock products originating from the method used for orbit and clock determination. The non-Gaussian measurement noise and data processing in 24 h batches are responsible for DBDs. In the case of the clock product, DBD is a time jump in the boundary epochs of two adjacent batches of processed data and its magnitude might reach a couple of ns. This article presents the four GNSS (Global Navigation Satellite System) systems DBD analysis in terms of change over an 8 year period. For each of 118 satellites available in this period, the yearly value of DBD was subject to analysis including standard deviation and frequency of outliers. Results show that the smallest DBDs appear in the GPS system, the biggest - for the BeiDou space segment. Moreover, the phenomenon of changes in DBDs over time is clearly seen at the beginning of the analysed period when the magnitude and number of the DBDs were larger than for current, newest clock products.

5

Development Of A Monitoring System For Electric Power Substations Based On Ios And Implementation Of Designs On FPGA

Kalimoldayev Maksat, Wójcik Waldemar, Shermantayeva Zhazira

International Journal of Electronics and Telecommunications

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2023

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Vol. 69, No. 4

819--824

EN

In this article, a monitoring system based on IoT technologies of the substation electrical system in the Republic of Kazakhstan was developed. At the moment, the operation of power systems is extremely important to maintain the frequency of electric current over time. For management and monitoring applications, it is necessary to take into account communication within acceptable limits. IoT technologies are considered the main functions in applications for monitoring and managing energy systems in real time, as well as making effective decisions on both technical and financial issues of the system, for monitoring the main form of data registration on an electric power substation in the city of Shymkent of the Republic of Kazakhstan, for consistent effective decision-making by system operators. In this work, an Internet of Things-based monitoring system was implemented and implemented for the substation of the power system using a specialized device built into the FPGA controller for fast integrated digitalization of transformer substations of real-time distribution electrical networks. The IoT platform also provides complete remote observability and will increase reliability for power system operators in real time. This article is mainly aimed at providing a practical application that has been implemented and tested.

6

NFC technology for precise localization in areas with limited global navigation satellite system signal

Szewczyk Robert, Hanus Paweł

Geomatics, Landmanagement and Landscape

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2023

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no. 4

169--180

EN

The emergence of modern technologies and widespread access to the Internet has led to an increase in interest in mapping websites. The data provided by online mapping geoportals is a rich source of information for society. Today, thanks to these geoportals, the location of objects in the field is widely available. This approach makes it possible to locate objects that are not visible in the field, such as underground electrical cables, underground water lines, or property boundaries. The technology used for object localization is GNSS (Global Navigation Satellite System). GNSS technology is based on the transmission of signals from satellites. However, this technology is limited in areas where satellite signals are restricted, such as high-rise buildings in city centers, dense forests, or tunnels. NFC technology is becoming increasingly available thanks to mobile phones that are equipped with NFC tags. This technology is widely used for payments via a mobile phone. This article presents a method of using the near-field communication (NFC) for easy positioning of infrastructure objects in a given area. This technology is particularly useful in areas with limited GNSS signals, such as urbanized, forested, or mountainous areas.

7

Using GPS and Run-Off Rates Data to Study the Close Monitoring Networks for Dams – Al-Kut Barrages as a Case Study

Saiwan Malik Khalaf, Hamdoon Rana Mozahim, Al-Zuhairy Mudhaffar Sadiq

Ecological Engineering & Environmental Technology

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2023

|

Vol. 24, iss. 2

87--93

EN

The dams and barrages are among the most important engineering structures for water supply, flood control, agriculture, and electric power generation. Monitoring the horizontal and vertical deformation of the barrage’s body and identifying the risk it’s so important to maintain the dam and also to reduce costs. Where in this research the case of the Al-Kut barrage is studied by observing the body of the barrage using surveying devices through (GPS) by taking spatial observations of the two networks of stations, the horizontal and vertical networks. Then compare them with the observations of previous years to determine the magnitude of the deformation through the differences between the observations. By calculating the differences and finding the displacement of surveying observations from 2014 to 2021, It was found that the highest and least displacements in the horizontal stations is 50 and 11 mm, respectively. Also, for the vertical network observations, the highest and lowest differences in elevation were 11and 3 mm, respectively. Where, the results showed a slight deformation within the acceptable limits. In addition, the annual and monthly discharge rates for a number of years were evaluated to observe the extent of the impact of run-off rates on increasing sedimentation at the upstream of Al-Kut barrage. It was found that the accumulation of sediment on the river’s left bank affected the gates’ efficiency and put pressure on the other gates, which led to some operational issues in the barrage gates.

8

Review on application of location tracking to monitor people in health field against COVID-19

Syamsudin H., Mohammed M. N., Aljibori H. S. S., Al-Tamimi Adnan N. Jameel, Alfiras M., Yusuf Eddy, Abdullah Oday I.

Diagnostyka

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2023

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Vol. 24, No. 4

art. no. 2023408

EN

Location tracking stands for technologies that physically identify and electronically register and monitor the tracking of individuals or objects. This technology is widely implemented in the health field for tracking clinicians and patient locations. The history of visited location data is used for many purposes and is mainly applied to monitor and assess the patient’s movement to provide helpful knowledge. This data is obtained using the Global positioning system (GPS), Bluetooth, and Radio-frequency identification (RFID) built into the device such as smartphones, smart watches, or wearable devices. In some Research, other technologies like Google Location History (GLH) provide the history of visited locations made by the Google Account. Location tracking can be an alternative and potentially help monitor and track Covid-19 infectee to prevent wider diffusion. This paper reviews location tracking applications in healthcare based on how the location data is obtained and analyzed. The application of location tracking was differentiated and reviewed based on the applied methods in acquiring knowledgeable data. Furthermore, the data analysis used to track location was also discussed to know what knowledge that obtained from the location history data. Getting the location and assessing the data for specific purposes was also highlighted.

9

Accuracy analysis of aircraft positioning using navigational data from AVIA-W radar

Goś Artur, Krasuski Kamil, Mazur Wojciech

Aviation and Security Issues

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2023

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No. 1

287--312

EN

The paper presents an analysis of the accuracy of determination of parameters of the position of aircraft using data from the AVIA-W radar. In the first place, the authors determined the position of the aircraft as well as the range and azimuth parameters by the AVIA-W radar, located in Dęblin. This was followed by a determination of the absolute position error of the aircraft and the determination of the range and azimuth measurement error by the AVIA-W radar. The research test was carried out using a Diamond DA40 NG aircraft on which a GPS satellite receiver was mounted in order to determine the flight reference position. In addition, the range and azimuth measurements for the aircraft were acquired from the AVIA-W radar. Navigational calculations were conducted for polar and rectangular planar coordinates. Based on the performed research, the azimuth error was found to be -1.4°, while the radar range measurement error was equal to -0.04 km. The conducted research is experimental in its character. In the future it will be repeated and extended to the GCA-2000 radar, which is also located at Dęblin military airfield.

PL

W pracy przedstawiono analizę dokładności wyznaczenia parametrów pozycji statku powietrznego z użyciem danych z radaru AVIA-W. W pierwszej kolejności dokonano wyznaczenia pozycji statku powietrznego oraz określenia parametru zasięgu i azymutu przez radar AVIA-W, zlokalizowany w Dęblinie. Następnie dokonano wyznaczenia błędu absolutnego pozycji statku powietrznego oraz określenia błędu pomiaru zasięgu i azymutu przez radar AVIA-W. Test badawczy przeprowadzono z użyciem samolotu Diamond DA40 NG, na pokładzie którego zamontowano odbiornik satelitarny GPS w celu wyznaczenia pozycji odniesienia lotu. Dodatkowo z radaru AVIA-W pozyskano pomiary zasięgu i azymutu do statku powietrznego. Obliczenia nawigacyjne zrealizowano dla współrzędnych biegunowych i prostokątnych płaskich. Na podstawie wykonanych badań stwierdzono, że błąd azymutu wynosi -1,4°, z kolei błąd pomiaru zasięgu radaru wynosi -0,04 km. Przeprowadzone badania mają charakter eksperymentalny i w przyszłości zostaną powtórzone i rozszerzone o radar GCA-2000, który także znajduje się na lotnisku wojskowym Dęblin.

10

Slip deformation along the Gyaring Co fault from InSAR and GPS

Zhang Qingyun, Li Yongsheng, Zhang Jingfa, Tian Yunfeng, Tian Tian, Li Bingquan

Acta Geophysica

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2023

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Vol. 71, no. 1

53--63

EN

Interferometric synthetic aperture radar (InSAR) can monitor large-scale small deformation. Because the Sentinel-1 satellite has a stable orbit control and the data coherence in Qinghai–Tibet Plateau is good, we utilize data from Sentinel-1 to analyze the slip deformation of the Gyaring Co fault (GCF) in the central Tibetan Plateau. Data are obtained from ascending and descending tracks covering the research area, and the deformation results are obtained by the stacking and analysis of time series. The results demonstrate that the GCF exhibit slow slip overall. An analysis of different sections indicates that the fault displays both right-lateral strike-slip and normal faulting behaviors, and the movement is particularly obvious in the middle section of the GCF. Furthermore, we investigate the contemporary slip rate of the GCF using GPS data and construct two velocity profiles perpendicular to the fault strike at the southeastern and northwestern ends of the fault. The southeastern profile shows ~4 mm/year of right-lateral strike-slip movement and a modest (<1 mm/year) amount of crustal thickening across the fault, while the northwestern profle shows much slower (~ 1 mm/year) right-lateral strike-slip motion and 0.5 mm/ year of crustal extension. The GPS results are consistent with the InSAR deformation map derived using Sentinel-1 A/B data from 2014 to 2017. Our results support the distributed crustal motion model in which most crustal deformation (shortening/ extension/strike-slip) occurs on various active faults in the central Tibetan Plateau rather than being concentrated on several fast-moving fault zones, e.g., the GCF-BCF. Finally, we analyze the distribution of historical earthquakes and the gravity and aeromagnetic felds. We speculate that a fault may exist north of Gyaring Co Lake that may be an extension of the fault north of Mujiu Co Lake.

11

Realizacja układu do pomiaru wpływu poziomu zurbanizowania terenu na jakość wyznaczania pozycji w systemie GPS

Bielawski Antoni, Lazarowska Agnieszka

Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

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2022

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Nr 75

9--12

PL

W artykule zaprezentowano projekt układu do rejestrowania położenia bezwzględnego z wykorzystaniem systemu GPS, który umożliwił przeprowadzenie badań nad wpływem poziomu zurbanizowania terenu na jakość wyznaczania pozycji. W tym celu dokonano rejestracji położenia w dwóch miejscach, w terenie zurbanizowanym oraz w dwóch w terenie niezurbanizowanym. Następnie dokonano analizy wyników w oparciu o parametr HDOP (ang. Horizontal Dilution Of Precision – współczynnik geometrycznej dokładności w płaszczyźnie poziomej) oraz liczbę widocznych satelitów.

EN

The article presents the design of the absolute position recording system with the use of the GPS system, which made it possible to conduct research on the influence of the level of urbanization of the area on the quality of determining the position. For this purpose, position registration was made in two places in urbanized areas and in two in non-urbanized areas. Then, the results were analyzed based on the HDOP (Horizontal Dilution of Precision) parameter and the number of visible satellites.

12

Stability of GPS and GLONASS onboard clocks on a monthly basis

Ziętala Michał

Zeszyty Naukowe. Transport / Politechnika Śląska

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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.

13

Accuracy analysis of aircraft positioning using real radar and GPS data

Ciećko Adam, Goś Artur, Krasuski Kamil, Krześniak Kacper

Zeszyty Naukowe. Transport / Politechnika Śląska

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2022

|

z. 116

71--82

EN

This paper presents an analysis of the accuracy of aircraft positioning using radar and GPS satellite data. In particular, this study shows the results of research on determining the position of an aircraft, as well as the range and azimuth parameters for the GCA-2000 radar to the GPS solution. The research used measurement data from the GCA-2000 radar and the Thales MobileMapper Pro receiver placed onboard a Diamond DA-40NG aircraft. The flight experiment was carried out at the EPDE military airport in Dęblin. It was found that the average error in determining the position of the aircraft for the GCA-2000 radar was 295.57 m. Moreover, the average error in determining the range for the GCA-2000 radar is 138.12 m. Additionally, the average error in determining the azimuth for the GCA-2000 radar is equal to 0.408°.

14

Accuracy analysis of aircraft positioning using GPS dual receivers in aerial navigation

Krasuski Kamil, Ciećko Adam, Wierzbicki Damian

Zeszyty Naukowe. Transport / Politechnika Śląska

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2022

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z. 115

23--34

EN

This study presents a modified algorithm to determine the accuracy of GPS positioning in aerial navigation. To achieve this, a mixed model with measurement weights was used to determine the resultant value of accuracy of aerial vehicle positioning. The measurement weights were calculated as a function of the number of GPS tracking satellites. The calculations were performed on actual GPS measurement data recorded by two onboard GNSS receivers installed onboard a Cessna 172 aircraft. The flight test was conducted around the military airport in Dęblin. The conducted analyses demonstrated that the developed algorithm improved the accuracy of GPS positioning from 62 to 91% for horizontal coordinates and between 16-83% for the vertical component of the aerial vehicle position in the BLh ellipsoidal frame. The obtained test results show that the developed method improves the accuracy of aircraft position and could be applied in aerial navigation.

15

Rozwój koncepcji bezzałogowego holownika szybowców i dronów towarowych o napędzie elektrycznym

Jafernik Henryk, Muszyński Tomasz, Puzio Łukasz

Przegląd Komunikacyjny

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2022

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R. 77, nr 2/3

10--15

PL

W artykule przedstawiono kilka wybranych propozycji zastosowań BSP rozwijanych w Polsce. Przedstawiono opis projektu bezzałogowego holownika, nowego rozwiązania technicznego, zgłoszonego do urzędu patentowego w grudniu 2017 roku i rozwijanego do chwili obecnej. Proponowany system holu składa się z uniwersalnej stacji naziemnej kontroli lotów bezzałogowców, BSP-holownika i dodatkowego systemu sterowania umieszczonego na obiekcie holowanym. Proponowane rozwiązanie ma na celu zmniejszenie kosztów eksploatacji oraz poprawę osiągów statków powietrznych o napędzie elektrycznym.

EN

The article presents a few selected ideas for AUV usage which are being developed in Poland as well as the description of a project of an unmanned tug, a new technological solution which was submitted to the Patent Office in December 2017 and which has been being developed since then. The proposed towing system consists of a universal ground-based air traffic control station for unmanned flights, an AUV-tug and an additional control system placed on the towed object. The proposed solution aims at maintenance costs reduction and increase of performance of aircrafts with electric drive.

16

Wkład systemu satelitarnego Galileo w rozwój geodezji

Mikoś Marcin, Nowak Adrian, Lackowski Maciej, Sośnica Krzysztof

Przegląd Geodezyjny

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2022

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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.

17

Solar energy harvester for pet GPS collar

Yusop Azdiana Md, Ahmad Yusry Syahidan Arshad, Sulaiman Noor Asyikin, Khamil Khairun Nisa, Mohd Isira Ahmad Sadhiqin

Przegląd Elektrotechniczny

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2022

|

R. 98, nr 8

47--51

EN

The power source of wireless technology depends on the device’s battery life and need to be plugged in for recharge purpose. This problem can be solved using energy harvesting system which directly converts solar energy radiated from the sun into electricity. In this project a solar energy harvesting pet collar is developed to harness solar energy and charge the installed battery. The GPS system used a minimum of 2.2V up to 3.6V input voltage. The result obtained shows that the solar panel can give enough power to power up the GPS system as that energy harvester circuit and is able to deliver output up to 4.3V in direct sunlight with an input voltage as low as 3.25V.

PL

Źródło zasilania technologii bezprzewodowej zależy od żywotności baterii urządzenia i musi być podłączone w celu naładowania. Problem ten można rozwiązać za pomocą systemu pozyskiwania energii, który bezpośrednio zamienia energię słoneczną wypromieniowaną ze słońca na energię elektryczną. W ramach tego projektu opracowano obrożę do zbierania energii słonecznej, która wykorzystuje energię słoneczną i ładuje zainstalowaną baterię. System GPS używał napięcia wejściowego minimum 2,2 V do 3,6 V. Uzyskany wynik pokazuje, że panel słoneczny może zapewnić wystarczającą moc do zasilania systemu GPS, jak obwód urządzenia do pozyskiwania energii i jest w stanie dostarczyć do 4,3 V w bezpośrednim świetle słonecznym przy napięciu wejściowym tak niskim, jak 3,25 V.

18

Experimental studies on the relationship between HDOP and position error in the GPS system

Specht Mariusz

Metrology and Measurement Systems

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2022

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Vol. 29, nr 1

17--36

EN

2D position error in the Global Positioning System GPS depends on the horizontal dilution of precision (HDOP) and User Equivalent Range Error UERE. The non-dimensional HDOP coeffcient, determining the influence of satellite distribution on the positioning accuracy, can be calculated exactly for a given moment in time. However, the UERE value is a magnitude variable in time, especially due to errors in radio propagation (ionosphere and troposphere effects) and it cannot be precisely predicted. The variability of the UERE causes the actual measurements (despite an exact theoretical mathematical correlation between the HDOP value and the position error) to indicate that position errors differ for the same HDOP value. The aim of this article is to determine the relation between the GPS position error and the HDOP value. It is possible only statistically, based on an analysis of an exceptionally large measurement sample. To this end, measurement results of a 10-day GPS measurement campaign (900,000 fixes) have been used. For HDOP values (in the range of 0.6-1.8), position errors were recorded and analysed to determine the statistical distribution of GPS position errors corresponding to various HDOP values. The experimental study and statistical analyses showed that the most common HDOP values in the GPS system are magnitudes of: 0.7 (𝑝 = 0.353) and 0.8 (𝑝 = 0.432). Only 2.77% of fixes indicated an HDOP value larger than 1. Moreover, 95% of measurements featured a geometric coeffcient of 0.973 - this is why it can be assumed that in optimal conditions (without local terrain obstacles), the GPS system is capable of providing values of HDOP ≤ 1, with a probability greater than 95% (2𝜎). Obtaining a low HDOP value, which results in a low GPS position error value, calls for providing a high mean number of satellites (12 or more) and low variability in their numer.

19

A review of the importance of synchrophasor technology, smart grid, and applications

Baba Maveeya, Nor Nursyarizal B. M., Sheikh Aman, Nowakowski Grzegorz, Masood Faisal, Rehman Masood, Irfan Muhammad, Arefin Ahmed Amirul, Kumar Rahul, Baba A. Momin

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

|

Vol. 70, nr 6

art. no. e143826

EN

The electrical network is a man-made complex network that makes it difficult to monitor and control the power system with traditional monitoring devices. Traditional devices have some limitations in real-time synchronization monitoring which leads to unwanted behavior and causes new challenges in the operation and control of the power systems. A Phasor measurement unit (PMU) is an advanced metering device that provides an accurate real-time and synchronized measurement of the voltage and current waveforms of the buses in which the PMU devices are directly connected in the grid station. The device is connected to the busbars of the power grid in the electrical distribution and transmission systems and provides time-synchronized measurement with the help of the Global Positioning System (GPS). However, the implementation and maintenance cost of the device is not bearable for the electrical utilities. Therefore, in recent work, many optimization approaches have been developed to overcome optimal placement of PMU problems to reduce the overall cost by providing complete electrical network observability with a minimal number of PMUs. This research paper reviews the importance of PMU for the modern electrical power system, the architecture of PMU, the differences between PMU, micro-PMU, SCADA, and smart grid (SG) relation with PMU, the sinusoidal waveform, and its phasor representation, and finally a list of PMU applications. The applications of PMU are widely involved in the operation of power systems ranging from power system control and monitor, distribution grid control, load shedding control and analyses, and state estimation which shows the importance of PMU for the modern world.

20

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

Farah Ashraf

Artificial Satellites : Journal of Planetary Geodesy

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2022

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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.