Wyniki wyszukiwania - BazTech

1

A method and a model for risk assessment of GNSS utilisation with a proof-of-principle demonstration for polar GNSS maritime applications

Malić E., Sikirica N., Špoljar D., Filjar R.

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

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2023

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Vol. 17 No. 1

43--50

EN

The GNSS positioning performance is commonly defined and described in terms unspecified to particular GNSS-based application. The approach causes difficulties to GNSS application developers, operators, and users, rendering the impact assessment of GNSS performance on the GNSS application Quality of Service (QoS) particularly difficult. Here the Probability of Occurrence (PoO) Model is introduced, which allows for a risk assessment of the probability for the GNSS positioning accuracy failure to meet the requirements of the particular GNSS-based application. The proposed PoO Model development procedure requires a large set of position estimation errors observations, which shall cover a range of classes of positioning environment (space weather, troposphere, multi-path etc.) disturbances affecting GNSS positioning accuracy. As result, the PoO Model becomes a tool that returns the probability of failure in meeting the positioning accuracy requirements of the GNSS applications considered, thus providing the input for a GNSS deployment risk assessment. The proposed PoO Model and its development procedure are demonstrated in the case of polar region positioning environment, with raw GNSS pseudorange observations taken at the International GNSS Service (IGS) Network reference station Iqualuit, Canada are used for the PoO Model development. The PoO Model proof-of-principle is then used to estimate the probability of the unmet required positioning accuracy for a number of polar maritime navigation applications. Manuscript concludes with a discussion of the PoO Model benefits and shortcomings, a summary of contribution, and intentions for the future research.

2

Materials with shape memory effect for applications in maritime

Ivošević Špiro, Rebeka Rudolf

Scientific Journal of Polish Naval Academy

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2019

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R. 60 nr 3 (218)

25--41

EN

In this review it is presented the insight of challenges faced by all branches of industry in the new age, and especially the maritime industry, strive for sustainable development, better energy control, use of materials with functional properties such as shape memory, all in the direction of increasing safety and comfort. Therefore, the development of new materials with shape memory, which is associated with the introduction of optimized production and the achievement of better func-tional properties. This leads to new applications in different systems and possible use on devices, which meet the rigorous requirements of the modern industry. The research into new materials with shape memory effect and their applied use in maritime is a challenge that many researchers have encountered in recent decades, and this is why in this paper we look at the basic engineering aspect of these materials and their current as well as future applications in the maritime industry. An overview of several innovations that testify shape memory effect and superelasticity in different maritime fields will be presented in this review.

PL

W artykule przedstawiono badania prowadzone nad nowymi materiałami z pamięcią kształtu. Opisano podstawowe aspekty inżynieryjne tych materiałów, ich właściwości funkcjonalne oraz przyszłe wykorzystanie w obszarze morskim. Dokonano przeglądu niektórych zastosowań materiałów z efektem shape memory alloy (SMA), pokazując ich innowacyjne rozwiązania. Opracowanie optymalnego procesu technologicznego do produkcji materiałów SMA i transfer wiedzy na po-ziomie przemysłowym stworzy nowe perspektywy dla żeglugi morskiej.

3

Accuracy Performance of eLORAN for Maritime Applicaations

Safar J., Lebekwe C. K., Williams P.

Annual of Navigation

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2010

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No. 16

109-121

EN

E-Loran, or enhanced Loran, is the latest in the longstanding and proven series of low frequency, LOng-RAnge Navigation systems. eLoran evolved from Loran-C in response to the 2001 Volpe Report on GPS vulnerability. It improves upon previous Loran systems with updated equipment, signals, and operating procedures. The improvements allow eLoran to provide better performance and additional services when compared to Loran-C, and enable eLoran to serve as a backup to satellite navigation in many important applications. Different applications impose specific requirements on the navigation system's accuracy, availability, integrity and continuity performance. In the maritime sector, accuracy requirements are the most stringent. In order to comply with the requirements of the International Maritime Organisation (IMO) for harbour entrance approach, eLoran has to provide an accuracy of better than 10 m (95%). Achieving this target is possible if the eLoran navigation receiver is equipped with an up-to-date database of signal propagation corrections and if real-time differential Loran corrections are applied. When these conditions are met, the achievable accuracy is largely determined by the transmitters' geometry, signal strengths and atmospheric noise levels, but also by the mutual interference among eLoran stations. This is also referred to as Cross-Rate Interference (CRI) and is inherent to the way all Loran systems operate. In this paper we present results of the eLoran research that is being conducted at the Czech Technical University in Prague (CTU) and the University of Bath (UK) in cooperation with the General Lighthouse Authorities of the United Kingdom and Ireland. In our work we have focused on questions that arise when considering introducing new eLoran stations into an existing network. This particular paper investigates the achievable accuracy performance of eLoran for maritime applications. The sources of measurement error in eLoran are reviewed, and an eLoran accuracy performance model is presented. Special attention is paid to the problem of CRI and possible ways of its mitigation. This paper is an abridged version of a more detailed unpublished paper which can be found at the following address: http://safar.me.uk/pub/js_cl_pw_navsup_2010.pdf.

4

Modernization of satellite navigation systems and theirs new maritime applications

Januszewski J.

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

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2007

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Vol. 1, no. 1

39--45

EN

The last years gave a rise to many important changes in the operational status and practical exploitation of satellite navigation systems (SNS) GPS & GLONASS, differential mode of these systems (DGPS, DGLONASS) and Satellite Based Augmentation Systems (SBAS) as EGNOS or WAAS. Therefore the modernization of these systems as new satellites, new civil signals, new codes, new monitoring stations etc. and the details about new systems under construction as Galileo, Compass and IRNSS, the problem of interoperability and new maritime applications are presented in this paper.