Skip to main content

Astronomical position without observed altitude of the celestial body

  • Zvonimir Lušić (a1)

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.

Corresponding author
Hide All
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.
Bowditch N. (2002). The American Practical Navigator. Bethesda, Maryland: DMAHTC; Brown's Nautical Almanac, 2015.
Coolen E. (1987). Nicholls's Concise Guide to Navigation - Volume 1. 10th ed. Glasgow: Brown, Son & Ferguson Ltd.
Čumbelić P. (1990). Astronomska navigacija II [in Croatian, Astronomical Navigation II]. Pomorski fakultet u Dubrovniku, Dubrovnik.
Flexner W.W. (1943). Azimuth Line of Position. The American Mathematical Monthly, 50(8), Mathematical Association of America, 475484. doi:10.2307/2304185.
Hohenkerk C., Kemp J. and Nibbs B. (2012). Astro Navigation Remembered. The Journal of Navigation, 65, 381395.
Lipovac M.Š. (1981). Astronomska navigacija [in Croatian, Astronomical Navigation]. Hidrografski institut Jugoslavenske ratne mornarice, Split.
Malkin R. (2014). Understanding the accuracy of Astro Navigation. The Journal of Navigation, 67, 6381.
MGC. (2014). MGC R3-Product Sheet-Gyro Compass and INS, Kongsberg. (
Tablice Nautičke. (1984). [in Croatian, Nautical Tables]. Hidrografski institut Ratne mornarice, Split.
Norie's Nautical Tables. (1991). Imray Laurie Norie and Wilson Ltd., St Ives, Cambridgeshire.
STCW. (2011). The International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW) - including Manila Amendments (2011). International Maritime Organization.
Raytheon. (2012). Operator manual-STD 22 GYRO COMPASS (2012). RaytheonAnschützGmbH. (
SkyMate. (2016). SkyMate Pro, Ver.2.0
Transas ECDIS. (2010). Transas Navi-Sailor ECDIS simulator.
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 (
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

The Journal of Navigation
  • ISSN: 0373-4633
  • EISSN: 1469-7785
  • URL: /core/journals/journal-of-navigation
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Full text views

Total number of HTML views: 1
Total number of PDF views: 26 *
Loading metrics...

Abstract views

Total abstract views: 123 *
Loading metrics...

* Views captured on Cambridge Core between 11th October 2017 - 17th December 2017. This data will be updated every 24 hours.