Wyniki wyszukiwania - Biblioteka Nauki

1

Modelling GPS positioning performance in Northwest Passage during extreme space weather conditions

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Špoljar D. , Jukić O. , Sikirica N. , Lenac K. , Filjar R.

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tom Vol. 15 No. 1

165--169

EN

New shipping routes are emerging as a result of iceberg melting in polar regions, allowing for more efficient transport of people and goods. Opening of the Northwest Passage, the maritime route connecting Pacific Ocean with Atlantic Ocean through Arctic region, is considered such a development. The increasing transport exploitation of the Northwest Passage requires the quality assessment of maritime navigation aids for compliance with the established requirements. Here we contribute to the subject with addressing the polar commercial-grade GPS positioning performance in the Northwest Passage in the extreme positioning environment conditions during the massive 2003 space weather storm, a space weather event similar to the Carrington Storm of 1859, the largest space weather event recorded. The GPS positioning environment in the Northwest Passage during the Carrington-like storm in 2003 was reconstructed through the GNSS SDR receiver-post processing of the experimental GPS observations. The raw GPS dual-frequency pseudoranges and navigation messages were collected at the International GNSS Service (IGS) reference station at Ulukhaktok, Victoria Island, Canada. Pseudorange processing and GPS position estimation were performed in three scenarios of pre-mitigation of the ionospheric effects, known as the single major contributor GPS positioning error: (i) no corrections applied, (ii) Klobuchar-based corrected GPS positioning, and (iii) dual-frequency corrected GPS positioning. Resulting GPS positioning error vectors were derived as positioning error residuals from the known reference station position. Statistical properties of the northing, easting, and vertical components of the GPS positioning error vector were analyzed with a software developed in the R environment for statistical computing to select suitable methods for the GPS positioning error prediction model development. The analysis also identified the most suitable theoretical fit for experimental statistical distributions to assist the model development. Finally, two competitive GPS positioning error prediction models were developed, based on the exponential smoothing (reference) and the generalized regression neural networks (GRNN) (alternative) methods. Their properties were assessed to recommend their use as mitigation methods for adverse massive space weather effects in polar regions.

2

AIS R-mode trilateration for GPS positioning and timing insurance

84%

Shyshkin O. V. , Konovets V. I. , Koshevyy V. M.

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2024

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tom Vol. 18 No. 2

369--374

EN

Satellite navigation is the backbone of maritime navigation today. However, the technical vulnerability of on-board Global Navigation Satellite System (GNSS) receivers the satellite system greatly destabilizes maritime security due to the loss of ship’s position and accurate time. This article devoted to study an alternative method for obtaining coordinates and accurate time based on the use of automatic identification system (AIS) radio channels, so-called range mode (R-Mode). We use other AIS ship stations with reliable position data as reference stations and determine time of arrival for received AIS transmissions. To improve the accuracy of measuring signal arrival instance in the time difference of arrival (TDOA), that we utilize for trilateration, it is proposed signal oversampling and applying the fast Fourier transform (FFT) to the product of quadrature components of the baseband Gaussian minimum shift keying (GMSK) signal in the window of AIS time slot. To take into account the movement of other ships, appropriate coordinate corrections are foreseen, which can be calculated by dead reckoning or by the inertial navigation system of our ship. The proposed method is fully compatible with the existing AIS signals and may be employed in critical situations of locally limited (jamming, spoofing) GNSS abilities. It can be implemented as a separate unit, working for receiving in parallel with the mandatory AIS transponder.

3

Estimation of UAV Position with Use of Smoothing Algorithms

84%

Kaniewski P. , Gil R. , Konatowski S.

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nr 1

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Low bandwidth network-RTK correction diissemination for high accuracy maritime navigation

84%

Alissa S. , Håkansson M. , Henkel P. , Mittmann U. , Hüffmeier J. , Rylander R.

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tom Vol. 15 No. 1

171--179

EN

More than half of the incidents reported to EMSA relate to nautical events such as collision, groundings and contacts. Knowledge of accurate and high-integrity positioning is therefore not only a need for future automated shipping but a base for today’s safe navigation. Examples on accidents include Ever Given in the Suez Canal and HNoMS Helge Ingstad in Norway. A Network-RTK (NRTK) service can be used as an augmentation technique to improve performance of shipborne GNSS receivers for future positioning of manned and unmanned vessels in restricted areas, such as port areas, fairways, and inland water ways. NRTK service providers generate RTK corrections based on the observations of networks of GNSS reference stations which enables the users to determine their position with centimeter accuracy in real-time using a shipborne GNSS receiver. Selection of appropriate communication channels for dissemination of NRTK corrections data is the key to a secure positioning (localization) service. In PrePare-Ships project, the modern maritime communication system VDES (VHF Data Exchange System) is proposed to distribute SWEPOS (NRTK in Sweden) correction data to shipborne positioning modules. VDES is a very reliable technique and it is compatible with most onboard functionalities. In order to minimize the impact on the overall VDES data capacity in a local area, NRTK correction data shall only occupy a single VDES slot with a net capacity of 650 bytes. Update rates may vary but are preferably at 1Hz. However, NRTK correction data size changes instantly, depending on the number of visible GNSS satellites, and the data rate can therefore sometimes reach in excess of 1000 byte/s. In this study, a smart technique is proposed to reduce size of NRTK correction data to instantly adapt with the VDES requirements by choosing a combination of specific signals, satellites or even constellations such that the data rate is not more than 650 byte/s, and at the same time it achieves optimal positioning performance with the accuracy required by the PrePare-Ships project application.

5

Comparative analysis of unmanned aerial vehicles used in photogrammetric surveys

84%

Specht M. , Widźgowski S. , Stateczny A. , Specht C. , Lewicka O.

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tom Vol. 17 No. 2

433--443

EN

There are many manufacturers on the market offering various types of Unmanned Aerial Vehicles (UAV). The multitude of drones available on the market means that the choice of a UAV for a specific application appears to be a decision problem to be solved. The aim of this article is a comparative analysis of drones used in photogrammetric surveys. The criteria for evaluating the UAVs were: availability and product support, payload (min. 5 kg), price (PLN 100,000), as well as space available for measurement modules. These are the requirements that must be met for the implementation of the INNOBAT project, the aim of which is to develop an integrated system using autonomous unmanned aerial and surface vehicles, intended for bathymetric monitoring in the coastal zone. The comparative analysis of drones was based on 27 companies producing UAV. Based on the analysis, 6 drones that met the project requirements were selected. They were: Aurelia X6 Pro, Aurelia X8 Standard LE, DroneHexa AG, FOX-C8 XT, Hercules 10 and Zoe X4. Selected UAVs differ from each other, among others, in the number of rotors, flight duration and resistance to weather conditions. Individual characteristics of drones may have a different rank depending on their application, therefore the selection of UAVs should be made after prioritisation criteria of a given project.

6

Application of Terrestrial Laser Scanning and Global Navigation Satellite System in the Mining Area

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Pham V. C. , Lipecki T. , Vo N. D.

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tom Vol. 2, no. 1

55--61

EN

Terrestrial Laser Scanning and Global Navigation Satellite System technologies are increasingly prevalent in geodetic mapping work, playing a significant role in mine surveying tasks such as drawing maps for volume calculation, monitoring displacement, and deformation of mine surfaces and structures above mine tunnels. Currently, there are many studies on the application of these technologies in various aspects of mine surveying work. This paper will synthesize these studies to evaluate the effectiveness of applying GNSS and TLS technologies in mining surveying. The authors has reviewed 44 papers/projects in recent years and found that these technologies are developing rapidly, with the accuracy of coordinate and altitude measurement increasingly improving to approximately millimeters in both horizontal and vertical directions.

PL

Technologie naziemnego skanowania laserowego (TLS) i globalnego systemu nawigacji satelitarnej (GNSS) są coraz bardziej powszechne w pracach związanych z kartowaniem geodezyjnym, odgrywając znaczącą rolę w zadaniach geodezyjnych w kopalniach, takich jak tworzenie map do obliczania objętości, monitorowanie przemieszczeń i deformacji powierzchni i konstrukcji nad wyrobiskami górniczymi. Obecnie prowadzonych jest wiele badań nad zastosowaniem tych technologii w różnych aspektach prac geodezyjnych w kopalniach. W artykule dokonana została synteza tych badań w celu oceny efektywności zastosowania technologii GNSS i TLS w górnictwie. Autorzy dokonali przeglądu 44 artykułów/projektów z ostatnich lat i stwierdzają, że technologie te bardzo szybko się rozwijają, a dokładność pomiaru współrzędnych i wysokości wzrasta do poziomu pojedynczych milimetrów zarówno w kierunku poziomym, jak i pionowym.

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Architektura MDGNSS : Przenośny Różnicowy Globalny Nawigacyjny System Satelitarny

67%

Dobryakova L. , Ochin E.

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2016

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tom R. 17, nr 6

135--141

PL

Pozycjonowanie GNSS i nawigacja mają znaczny wpływ na życie codzienne. Jednym z głównych problemów nawigacji współczesnej, zarówno systemów transportowych załogowych, jak i bezzałogowych jest problem bezpieczeństwa transportu. W celu zwiększania dokładności pozycjonowania transportu wykorzystuje się technologię DGNSS – Różnicowy GNSS, która opiera się na instalacji nieruchomej stacji bazowej przy użyciu znanej pozycji XY z dokładnością geodezyjną. W artykule tym rozpatrywane są zasady architektury MDGNSS – Przenośnego DGNSS, w którym stacja bazowa wykorzystuje konwencjonalny przenośny komputer, obliczający dokładną lokalizację XY poprzez analizę statystyczną wyników jej pozycjonowania w ciągu kilkudziesięciu minut.

EN

System The GNSS positioning and navigation have a significant impact on daily life. One of the main problems of modern navigation both manned and unmanned transport systems is a problem of transport safety. To improve the accuracy of positioning of transport used DGNSS technology – Differential GNSS, which is based on setting a fixed base station with a known geodetic position XY. In this article we consider the principles of MDGNSS architecture – Mobile Differential GNSS, in which a base station uses a conventional laptop, defining your location XY accurately, through statistical analysis of its positioning results for several tens of minutes.