Astronomical position without observed altitude of the celestial body

2017 ◽  
Vol 71 (2) ◽  
pp. 454-466
Author(s):  
Zvonimir Lušić
Keyword(s):  
Information System ◽  
Celestial Body ◽  
Precise Measurement ◽  
Dead Reckoning ◽  
Great Circle ◽  
Position Determination ◽  
Straight Line ◽  
Electronic Chart ◽  
Celestial Bodies ◽  
The Dead

The basis of all recommended methods for obtaining position by using celestial bodies is the known altitude of the celestial body being observed. Accordingly, it is necessary to have a sextant, classic or with an artificial horizon, or some other device that can measure altitude. However, there is a way to obtain position using astronomical navigation without determining the altitude of a celestial body, and this method will be analysed in this paper. The introduced method requires only precise measurement of the azimuth, and is based on determining two positions close to the dead reckoning position and lying on the isoazimuthal curve, i.e. a curve of the same great circle azimuths of a celestial body. Furthermore, the model assumes that a part of this curve, between the selected positions, can be replaced by a straight line. Special attention will be given to the analysis of errors of the line of position for various azimuth errors and various dead reckoning (assumed) positions. It will also be shown how a modern Electronic Chart Display and Information System (ECDIS) can help in approximate position determination, knowing only the azimuths of celestial bodies.

Automated Determination of the Position of Ships by Satellites

1967 ◽  
Vol 20 (03) ◽  
pp. 281-285
Author(s):  
H. C. Freiesleben
Keyword(s):  
Celestial Body ◽  
World Wide ◽  
Artificial Satellites ◽  
Radio Waves ◽  
The Moon ◽  
Position Determination ◽  
The Earth ◽  
Navigational Aids ◽  
Automated Determination

It has recently been suggested that 24-hour satellites might be used as navigational aids. To what category of position determination aids should these be assigned ? Is a satellite of this kind as it were a landmark, because, at least in theory, it remains fixed over the same point on the Earth's surface, in which case it should be classified under land-based navigation aids ? Is it a celestial body, although only one tenth as far from the Earth as the Moon ? If so, it is an astronomical navigation aid. Or is it a radio aid ? After all, its use for position determination depends on radio waves. In this paper I shall favour this last view. For automation is most feasible when an object of observation can be manipulated. This is easiest with radio aids, but it is, of course, impossible with natural stars.At present artificial satellites have the advantage over all other radio aids of world-wide coverage.

scholarly journals Peningkatan Pemahaman Para Mualim Terhadap Penggunaan ECDIS Guna Menunjang Keselamatan Pelayaran

2020 ◽  
Vol 2 (1) ◽  
pp. 36-42
Author(s):  
Capt. Mochamad Hermawan ◽  
Mohammad Shohibul Anwar ◽  
Erwin Junius
Keyword(s):  
Information System ◽  
Electronic Chart

Electronic Chart  Display And Information System (ECDIS) adalah suatu alat navigasi berupa peta elektronik sesuai persyaratan peta terbaru konvensi SOLAS 1974 V/20 yang dapat diintegrasikan dengan ala-alat navigasi lainnya sehingga diperoleh posisi dan informasi navigasi lain untuk para mualim melakukan perencanaan pelayaran serta monitoring rute pelayaran. Tujuan dari penelitian ini adalah untuk meningkatkan pengetahuan para Mualim dalam penggunaan ECDIS agar mencapai keselamatan dalam berlayar. Metode yang digunakan dalam penelitian ini adalah metode kualitatif yang mendeskripsikan melalui kata-kata dan bahasa dalam menjelaskan masalah atau fenomena yang  diteliti. Untuk menjabarkan masalah digunakan jenis penelitian deskriptif yaitu dengan mendeskripsikan suatu gejala, peristiwa dan kejadian yang terjadi. Pengumpulan data dilakukan melalui wawancara, dan observasi dalam melakukan penelitian, studi pustaka dan studi dokumentasi. Hasil penelitian ini menunjukkan bahwa para mualim belum maksimal dalam penggunaan ECDIS sehingga diperlukan peningkatan pemahaman dan pengetahuan dalam menggunakan ECDIS agar keselamatan bisa diutamakan saat berlayar.

scholarly journals Bridge officers’ operational experiences with electronic chart display and information systems on ships

2016 ◽  
Vol 52 (1) ◽  
pp. 49-61 ◽  
Author(s):  
Goran Bakalar ◽  
Myriam Beatriz Baggini
Keyword(s):  
Information System ◽  
System Failures ◽  
Existing Problems ◽  
Starting Point ◽  
Study Results ◽  
Electronic Chart ◽  
Maritime Navigation ◽  
Survey Results ◽  
Good Starting Point ◽  
Taking Action

In this paper, authors suggest an improvement in the electronic chart display and information system handling. Electronic nautical charts provide significant benefits to maritime navigation as a real time navigation system and all updates are important. This paper analyses the electronic chart use experiences on board ships. A questionnaire and survey were used so as to ascertain and corroborate the existing problems with corrections and maintenance of electronic charts on ships, and reliability of the systems was calculated. The survey results have shown that ship’s officers had serious problems with ECDIS systems which were difficult to solve during ship’s operation. A survey was done which showed that a significant percentage of the surveyed bridge officers and captains had problems with ECDIS system operation, such as operation stoppage due to different reasons. They did not always report failures of these systems while having continued to operate ECDIS. The reliability of those systems was also calculated and it resulted 0.916 or 91.6%. Compared to results of previous similar researches done by other scientists, the results of this research show an improvement in the ECDIS handling. It was concluded that a proper action was needed toward finding the solution to the future chart corrections procedure through remote monitoring and maintenance. The study results emphasized that taking action was necessary in the interest of safety protection on ships, with particular attention to be paid to better safety of navigation, of life, and of potential environmental pollution due to this type of information system failures. The results obtained by this study represent a good starting point for future researches in the field.

The Limitations of Airborne Dead Reckoning Today

1960 ◽  
Vol 13 (1) ◽  
pp. 19-22
Author(s):  
E. W. Anderson
Keyword(s):  
Dead Reckoning ◽  
The Dead

Development of Dead Reckoning in the Air. Air navigation is the child of sea navigation. Hence navigation across the skies tended to follow the pattern of navigation across the oceans. It was built around the dead-reckoning plot, into which was fed all varieties of information. At take-off and landing, there was also a little pilotage, but this was hardly mentioned in polite air navigation circles.

An Electronic Chart Display and Information System

2005 ◽  
Vol 28 (2) ◽  
pp. 175-189
Author(s):  
Xiaoxia Wan ◽  
Chaohua Gan ◽  
Chun Huang
Keyword(s):  
Information System ◽  
Electronic Chart

scholarly journals Direct and Inverse Solutions with Geodetic Latitude in Terms of Longitude for Rhumb Line Sailing

2012 ◽  
Vol 65 (3) ◽  
pp. 549-559 ◽  
Author(s):  
Wei-Kuo Tseng ◽  
Michael A. Earle ◽  
Jiunn-Liang Guo
Keyword(s):  
Information System ◽  
Complete Solution ◽  
Oblate Spheroid ◽  
Original Data ◽  
Inverse Solution ◽  
Direct Solution ◽  
Electronic Chart ◽  
Inverse Solutions ◽  
Computer Based ◽  
High Degree

In this paper, equations are established to solve problems of Rhumb Line Sailing (RLS) on an oblate spheroid. Solutions are provided for both the inverse problem and the direct problem, thereby providing a complete solution to RLS. Development of these solutions was achieved in part by means of computer based symbolic algebra. The inverse solution described attains a high degree of accuracy for distance and azimuth. The direct solution has been obtained from a solution for latitude in terms of distance derived with the introduction of an inverse series expansion of meridian arc-length via the rectifying latitude. Also, a series to determine latitude at any longitude has been derived via the conformal latitude. This was achieved through application of Hermite's Interpolation Scheme or the Lagrange Inversion Theorem. Numerical examples show that the algorithms are very accurate and that the differences between original data and recovered data after applying the inverse or direct solution of RLS to recover the data calculated by the direct or inverse solution are very small. It reveals that the algorithms provided here are suitable for programming implementation and can be applied in the areas of maritime routing and cartographical computation in Graphical Information System (GIS) and Electronic Chart Display and Information System (ECDIS) environments.

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