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Astronomical position without observed altitude of the celestial body

Published online by Cambridge University Press:  11 October 2017

Zvonimir Lušić*
Affiliation:
(Faculty of Maritime Studies in Split, Croatia)
*

Abstract

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.

Type
Research Article
Copyright
Copyright © The Royal Institute of Navigation 2017 

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References

REFERENCES

Benković, F., Piškorec, M., Lako, Lj., Čepelak, K. and Stajić, D. (1986). Terestrička i elektronska navigacija. [in Croatian, Terrestrial and electronic navigation]. Split: Hidrografski Institut Ratne mornarice.Google Scholar
Bowditch, N. (2002). The American Practical Navigator. Bethesda, Maryland: DMAHTC; Brown's Nautical Almanac, 2015.Google Scholar
Coolen, E. (1987). Nicholls's Concise Guide to Navigation - Volume 1. 10th ed. Glasgow: Brown, Son & Ferguson Ltd.Google Scholar
Čumbelić, P. (1990). Astronomska navigacija II [in Croatian, Astronomical Navigation II]. Pomorski fakultet u Dubrovniku, Dubrovnik.Google Scholar
Flexner, W.W. (1943). Azimuth Line of Position. The American Mathematical Monthly, 50(8), Mathematical Association of America, 475484. doi:10.2307/2304185.Google Scholar
Hohenkerk, C., Kemp, J. and Nibbs, B. (2012). Astro Navigation Remembered. The Journal of Navigation, 65, 381395.Google Scholar
Lipovac, M.Š. (1981). Astronomska navigacija [in Croatian, Astronomical Navigation]. Hidrografski institut Jugoslavenske ratne mornarice, Split.Google Scholar
Malkin, R. (2014). Understanding the accuracy of Astro Navigation. The Journal of Navigation, 67, 6381.Google Scholar
MGC. (2014). MGC R3-Product Sheet-Gyro Compass and INS, Kongsberg. (https://www.km.kongsberg.com)Google Scholar
Tablice, Nautičke. (1984). [in Croatian, Nautical Tables]. Hidrografski institut Ratne mornarice, Split.Google Scholar
Norie's Nautical Tables. (1991). Imray Laurie Norie and Wilson Ltd., St Ives, Cambridgeshire.Google Scholar
STCW. (2011). The International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW) - including Manila Amendments (2011). International Maritime Organization.Google Scholar
Raytheon. (2012). Operator manual-STD 22 GYRO COMPASS (2012). RaytheonAnschützGmbH. (http://www.raytheon-anschuetz.com/fileadmin/content/Operation_Manuals/Compass/4007_STD22_NG002.pdf)Google Scholar
SkyMate. (2016). SkyMate Pro, Ver.2.0Google Scholar
Transas ECDIS. (2010). Transas Navi-Sailor ECDIS simulator.Google Scholar
Xu, B., Liu, Y., Shan, W., Zhang, Y. and Wang, G. (2014). Error Analysis and Compensation of Gyrocompass Alignment for SINS on Moving Base. Mathematical Problems in Engineering 2014, 18 pages (http://dx.doi.org/10.1155/2014/373575)Google Scholar