Wyniki wyszukiwania - Biblioteka Nauki

1

Assessing the Limits of eLoran Positioning Accuracy

100%

Safar J. , Vejrazka F. , Williams P.

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

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2011

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tom Vol. 5, no. 1

93--101

EN

Enhanced Loran (eLoran) 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. The next generation of the Loran systems, eLoran, improves upon Loran-C through en-hancements in equipment, transmitted signal, 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. The Czech Technical University in Prague (CTU) participates in the eLoran research activities coordinated by the General Lighthouse Authorities of the United Kingdom and Ireland (GLAs). In our work we have focused on questions that arise when considering introducing new eLoran stations into an existing network. In particular, this paper explores the issue of Cross-Rate Interference (CRI) among eLoran transmissions and possible ways of its mitigation at the receiver end. An eLoran receiver performance model is presented and validated using an experimental eLoran signal simu-lator developed by a joint effort of CTU and GLAs. The resulting model is used to evaluate the achievable positioning accuracy of eLoran over the British Isles.

2

Receiver of Doppler multistatic system for moving target detection and tracking

100%

Ostrowski Z. J.

Hydroacoustics

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2015

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tom Vol. 18

141-152

EN

The article presents a method for solving major structural problems that occur in the receiver used in the multistatic Doppler system, aimed at determination of the trajectory and velocity of a moving target. In the system two transmitters emit acoustic continuous sinusoidal waves at different frequencies. The signals, scattered from a moving target are received by four hydrophones. Beside of the echoes, much larger signals coming directly from transmitters are recorded. It has been proved that in the presence of the direct high-amplitude signal, using currently available A/D converters, there is no possibility to detect the Doppler shift of small signals. The proposed approach is based on the homodyne frequency conversion of the received signals. Subsequently, the constant component and other unwanted products of the frequency conversion are filtered. The results of computer simulation have shown the effectiveness of the adopted design solution.

3

An Algorithmic Study on Positioning and Directional System by Free Gyros

100%

Jeong T. , Park S. C.

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

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2011

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tom Vol. 5, no. 3

297--302

EN

The authors aim to establish the theory necessary for developing free gyro positioning system and focus on measuring the nadir angle by using the motion rate of a free gyro. The azimuth of a gyro vector from the North can be given by using the property of the free gyro. The motion rate of the spin axis in the gy-ro frame is transformed into the platform frame and again into the NED (north-east-down) navigation frame. The nadir angle of a gyro vector is obtained by using the North components of the motion rate of the spin axis in the NED frame. The component has to be transformed into the horizontal component of the gyro by using the azimuth of the gyro vector and then has to be integrated over the sampling interval. Meanwhile the au-thors suggest north-finding principle by the angular velocity of the earth’s rotation. That is, ship's heading is obtained by using the fore-and-aft and athwartship components of the motion rate of the spin axis in the NED frame.

4

Recent Advances in Wide Area Real -Time Precise Positioning

100%

Lapucha D. , Jong K. , Liu X. , Oerpen O. , Vigen E.

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

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2011

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tom Vol. 5, no. 1

87--92

EN

This paper describes briefly new high precision wide area real time positioning systems, dis-cusses their evolution, implementation and presents recent results. In the latter part the paper is primarily fo-cused on discussing the benefits of GLONASS augmented high precision positioning.

5

Ground-based, Hyperbolic Radiolocation System with Spread Spectrum Signal - AEGIR

100%

Ambroziak S. J. , Katulski R. J. , Sadowski J. , Stefański J. , Siwicki W.

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

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2011

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tom Vol. 5, no. 2

233--238

EN

At present the most popular radiolocation system in the world is Global Positioning System (GPS).As it is managed by the Department of Defence of the U.S.A., there is always the risk of the occasional inaccuracies or deliberate insertion of errors, therefore this system can not be used by secret services or ar-mies of countries other than the U.S.A. This situation has engender a need for development of an autono-mous, ground-based radiolocation system, based on the hyperbolic system with spread spectrum signals. This article describes the construction and operation of such a system technology demonstrator which was devel-oped at the Technical University of Gdansk. It was named AEGIR (god of the ocean in Norse mythology). This paper presents preliminary results and analysis of its effectiveness.

6

Testing of a Device for Positioning Measuring Microphones in Anechoic and Reverberation Chambers

100%

Felis J. , Flach A. , Kamisiński T.

Archives of Acoustics

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2012

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tom Vol. 37, No. 2

245-250

EN

This paper presents a mechanical positioning system for a measuring microphone designed for acoustic studies in anechoic and reverberation chambers at the Department of Mechanics and Vibroacoustics, AGH. The results are discussed in the context of mechanical positioning and its impact on the outcome of the execution of individual measurement procedures. Moreover, areas for research were identified and solution concepts shown for further development of the automation of acoustic measurements in different research rooms in order to reduce the human involvement in them.

7

Positioning systems for agricultural field operations

100%

Hellebrand H. J. , Beuche H.

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1994

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tom 08

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nr 4

8

Implementation of a system of the mobile terminal position tracking using Google Maps

88%

Pluta S.

Computer Applications in Electrical Engineering

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2013

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tom Vol. 11

478--484

EN

The article describes how to implement part of the tasks of geolocation system and mobile data terminal registration related to servicing tasks by a central node. The entire system consists of two parts. The first part - mobile node, is situated on the side of the user, who uses the mobile data terminal equipped with GPS module and connected to the Internet, e.g. through GPRS system. The second part of the system (central node) is responsible for collecting essential data from the database, processing it, and displaying current position of the device along with additional information (time, speed) on a map from Google Maps resources. The article describes the rules of implementing Google Maps API - programming interface which allows using Google Maps on websites. Google Maps API allows for integrating a fully functional map on a website, including the features for handling events connected with the mobile data terminals geolocation process.

9

Zastosowanie enkoderów inkrementalnych w systemach odwzorowania położenia kabiny dźwigu osobowego w szybie

75%

Kolano K.

Pomiary Automatyka Kontrola

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2010

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tom R. 56, nr 5

433-436

PL

Kluczowym elementem układu sterowania dźwigu osobowego jest kontrola odwzorowania położenia kabiny w szybie. Najczęściej stosowanym rozwiązaniem jest system oparty na zestawie zamontowanych na prowadnicach dźwigu magnesów oraz umieszczonych na kabinie kontaktronów, reagujących na ich obecność w strefie zadziałania. Proces sterowania pracą dźwigu jest oparty o eksperymentalny dobór odpowiedniego położenia magnesów, co znacznie wydłuża i utrudnia proces jego instalacji. W artykule przedstawiono nowe rozwiązanie systemu odwzorowania położenia kabiny w szybie z użyciem enkodera inkrementalnego, który wykorzystując minimalną liczbę czujników może dokładnie pozycjonować kabinę w szybie.

EN

Modern lift drive systems are very sophisticated and allow affecting almost any part of the speed curve to achieve the desirable level of passenger comfort. A user interface clearly provides all information according to the passenger needs. Mechanical and electrical construction is optimised to meet all the designer requirements. Unfortunately, there are still many problems with the magnetic positioning system in passengers lifts, especially in old buildings. The problems caused by malfunction of sensors and levelling accuracy with variable loads are often met. Also the installation and maintenance time is much longer than that in modern positioning systems which use absolute encoders. Despite all advantages, encoder based positioning systems are not widely used because of their cost. A rotary encoder, also called a shaft encoder, is an electro-mechanical device that converts the angular position of a shaft or axle to an analog or digital code, making it an angle transducer. Rotary encoders are used in many applications that require precise shaft rotation-including industrial controls, robotics, expensive photographic lenses, computer input devices (such as optomechanical mice and trackballs), and rotating radar platforms. A traditional incremental encoder works differently by providing an A and B pulse outputs which deliver no usable count information in their own right. Rather, the counting is done in the external electronics. The point where the counting begins depends on the counter in the external electronics and not on the encoder position. To provide useful position information, the encoder position must be referenced to the device to which it is attached, generally using an index pulse. The distinguishing feature of the incremental encoder is that it reports an incremental change in position of the encoder to the counting electronics. This paper describes a prototype of the positioning system using a popular incremental encoder supported by two sets of induction sensors and a specialised microcontroller unit.

10

Fuzzy Evidence in Terrestrial Navigation

75%

Filipowicz W.

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

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2011

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tom Vol. 5, no. 2

225--232

EN

Measurements taken in terrestrial navigation are random values. Mean errors are within certain ranges what means imprecision in their estimation. Measurements taken to different landmarks can be subjec-tively diversified. Measurements errors affect isolines deflections. The type of the relation: observation error – line of position deflection, depends on isolines gradients. All the mentioned factors contribute to an overall evidence to be considered once vessel’s position is being fixed. Traditional approach is limited in its ability of considering mentioned factors while making a fix. In order to include evidence into a calculation scheme one has to engage new ideas and methods. Mathematical Theory of Evidence extended for fuzzy environment proved to be universal platform for wide variety of new solutions in navigation.

11

Wspólne przetwarzanie danych nawigacyjnych AHRS i GPS za pomocą filtru Kalmana

75%

Kaniewski P.

Biuletyn Wojskowej Akademii Technicznej

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2006

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tom Vol. 55, nr 1

271-284

PL

W artykule przedstawiono projekt zintegrowanego systemu pozycjonującego AHRS/GPS, w którym dane nawigacyjne obu urządzeń są wspólnie przetwarzane za pomocą scentralizowanego algorytmu komplementarnego filtru Kalmana. Zastosowano metodę integracji systemu według schematu kompensacji z korekcją wstecz. Rolę referencyjnego przyrządu nawigacyjnego spełnia AHRS, zaś odbiornik GPS jest wykorzystywany jako źródło danych korekcyjnych. W artykule przedstawiono opis struktury systemu, przeprowadzono analizę modelu projektowego i zaprezentowano zasadę działania algorytmu wspólnego przetwarzania danych nawigacyjnych. Opracowany system AHRS/GPS poddano badaniom symulacyjnym, których wybrane wyniki zawarto w artykule.

EN

The paper presents a project of integrated positioning system composed of an Attitude and Heading Reference System (AHRS) and a GPS receiver. The data from AHRS and GPS are jointly processed via an algorithm of centralized complementary Kalman filter working in a feed-backward correction loop. The AHRS fulfils the role of the reference navigation device and the GPS receiver is used as a source of correcting data. As advantages and disadvantages of GPS and AHRS are to large extent complementary, their appropriate integration can eliminate drawbacks of both devices and make the best use of their strengths. The paper presents the structure of system and describes its data flows. Next, it presents a state-space description of AHRS/GPS integrated positioning system and the algorithm of Kalman filter. The designed AHRS/GPS system has been modelled and tested in a series of computer simulations. The paper presents chosen simulation results and conclusions resulting from these simulations.

12

Sensorless step positioning of hydraulic linear actuator

75%

Dindorf R. , Woś P.

Technical Transactions

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2018

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tom Vol. 115, iss. 11

169--174

EN

The paper presents a design, working principle and simulation of a sensorless position system whose hydraulic linear stepper actuator is controlled by a combination of single binary on/off valves. For dynamic modelling and digital simulation of stepper actuator, the bond graph method was used. Preliminary simulation tests were conducted to determine the dynamic characteristics and dynamic properties of the stepper actuator.

PL

W artykule przedstawiono projekt, zasadę działania i symulację bezczujnikowego układu pozycjonowana hydraulicznego liniowego aktuatora krokowego sterowanego kombinacją pojedynczych binarnych zaworów włączających/wyłączających. Do modelowania dynamicznego i symulacji cyfrowej aktuatora krokowego wykorzystano metodę grafów wiązań (bond graph). Przeprowadzono wstępne testy symulacyjne w celu określenia charakterystyk dynamicznych i właściwości dynamicznych aktuatora krokowego.

13

Badanie efektu przesunięcia środka fazowego anten w systemie lokalizacyjnym

75%

Bajurko P. , Bury M. , Yashchyshyn Y. , Kurek K.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2009

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tom nr 6

223-226

PL

Przedstawiono wyniki badań efektu przesunięcia środka fazowego anten, który może wystąpić, gdy antena zostanie umieszczona w bezpośrednim sąsiedztwie przewodzących obiektów. Badania przeprowadzono dla dwóch anten o różnych charakterystykach kierunkowych i polaryzacyjnych, zaprojektowanych dla systemu lokalizacyjnego.

EN

Paper presents the experiments with the antenna phase centre misplacement that occurs in the neighbourhood of the metal objects, and its impact on the accuracy in a local positioning system. Experiments were performed for two types of antennas, one with the linear and one with the elliptical polarization.

14

Testing of a Device for Positioning Measuring Microphones in Anechoic and Reverberation Chambers

75%

Felis J. , Kamisiński T. , Flach A.

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15

An Effect of Urban Development on the Accuracy of the GPS/EGNOS System

63%

Bober R. , Szewczuk T. , Wolski A.

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

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2008

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tom Vol. 2, no. 3

235--238

EN

This article presents the results of research into the accuracy of position determination by a GPS/EGNOS system in a densely built-up residential area. These results are compared with the relevant results obtained for a position in an open area.

16

Galileo satellite navigation system receiver concept

63%

Lemanczyk M. , Demkowicz J.

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

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2007

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tom Vol. 1, no. 4

375--378

EN

The paper presents the Galileo Satellite Navigation System’s Receiver concept. The receiving path and the model of GNSS receiver system for the L1 signal was shown as well as Galileo services and fre-quencies were presented.

17

Accuracy of Relative Navigation in Automated Systems of Data Communication

63%

Dzunda M.

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

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2008

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tom Vol. 2, no. 2

161--163

EN

The architecture of wide-band synchronous automated systems of data communication (ASDC) enables utilization of high accuracy measurement of the signal reception times to relative navigation in the network. In this contribution an operation analysis of such systems in the relative navigation mode is conducted. The accuracy and possibilities of the utilization of these systems were examined by modeling in air navigation.

18

Polish DGPS System: 1995-2018 – studies of reference station operating zones

63%

Specht C. , Specht M. , Dąbrowski P. S.

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

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2019

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tom Vol. 13, no. 3

581--586

EN

The operating zone of a radio navigation system is one of its main operating features. It determines the size of a water body in which the system can be used, while guaranteeing vessels’ navigation safety. The DGPS system in the LF/MF range is now the basic positioning system in coastal waters around the world, which guarantees not only metre positioning accuracy, but it is also the only one to provide navigators with signals on positioning reliability. This paper describes and summarises over twenty years of studies dealing with the operating zone of the Polish DGPS reference station network. This paper is the fifth in a series of publications whose aim was to present in detail the process of installation, testing and long-term evaluation of the navigational parameters of the Polish DGPS system, launched in 1995. This paper includes the theoretical foundations of determination of the Dziwnów and Rozewie DGPS reference station operating zones in the years 1995-2018. Moreover, it presents the measurement results for the signal levels and the results of their analyses, which determine the station operating zones.

19

Positioning with AHRS/ODOMETER/GPS system

63%

Kaniewski P. , Konatowski S.

Annual of Navigation

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2001

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tom No. 3

75-89

EN

The paper presents a project of an integrated positioning system composed of a dead reckoning unit (DR), and a GPS receiver. The DR subsystem includes an Attitude and Heading Reference System (AHRS) and an odometer. The data from DR and GPS are jointly processed via an algorithm of linearized complementary Kalman filter. The paper shortly introduces an idea of relative and absolute navigation. Next, it presents state-space description of the AHRS/ODOMETER/GPS integrated system. a functional structure of the system and Kalman filtering algorithm are presented. At last, the authors outline an adopted methodology of testing of AHRS/ODOMETER/GPS integrated system. Chosen results of the tests, conducted with use of real navigation data, are included in the paper. The presented positioning system may find its application in land vehicles.

20

Aplikacja zrealizowana przez ANIRO Grupa Handlowa. Modernizacja maszyny do wiercenia w szkle w oparciu o serwonapędy LS Mecapion

63%

Kmieciak R.

Napędy i Sterowanie

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2012

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tom R. 14, nr 3

40-41

PL

W artykule opisano modernizację maszyny do wiercenia w szkle. Modernizacja polegała na zastąpieniu istniejącego, ręcznego układu pozycjonowania układem pozycjonowania automatycznego opartego na produktach koreańskiej firmy LS Mecapion. Testy przeprowadzone po modernizacji wykazały poprawność działania nowego układu, zgodnie z założonymi wymaganiami dotyczącymi dokładności pozycjonowania.