No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
The Use of Horizontal and Vertical Angles in Terrestrial Navigation
Abstract
The methods of determining a ship’s position in terrestrial navigation by using vertical and horizontal angles are nowadays rarely used. The reason is the relative complexity of the procedure and the lack of accuracy of some methods. Different methods of using horizontal and vertical angles to obtain the line of position (LOP) will be presented in this paper, as well as the occurring errors and recommendations for use. In this paper, the sextant will be considered a basic instrument for measuring horizontal and vertical angles. The sextant allows a very precise measuring of angles from which very accurate lines of position can be obtained.
... Different schools of thought of the Muslim communities of Indonesia may use a different approach for determining and measuring the time elapsed to indicate the occurrence of twilight at a region (Mateshvili et al. 2005). In this work, "dep" is defined as the sun vertical depression and can be measured from the local horizon to a line of sight from an observer to celestial object (Beutler et al. 2005;Lušić 2013;Boddice et al. 2017). The use of "dep" of the horizon has been found to be different in different schools of thought (Nor and Zainuddin 2012), which have not yet been confirmed scientifically through the valid data, and commonly ranged from −20°to −14°; however, when the "dep" of −20°is an indicator used to determine the beginning of false dawn. ...
Sky brightness data have been widely used to document the light pollution and to localise the direction of the sun during both dawn and dusk twilight. The use of the most common data analysis techniques of graphical interpretation can give less accurate final results. This study used a Sky Quality Metre to record the brightness of night sky in mag arcsec⁻² at Depok city of Indonesia during 26 days for the months of June and July 2015. Analytical technique of third-degree polynomial was established to predict dawn astronomical twilight and provides a good fit to the experimental data. The modelling results have been experimentally verified that astronomical twilight in the morning at Depok city with its environment begins when the sun is at the position of −14° ± 0.6 below the eastern horizon and ends at sunrise. In conclusion, the Muslim communities of Indonesia begin their dawn prayer 6° too early and have been found to calculate the true dawn incorrectly when the centre of the sun is at a depression angle of −20° below the horizon.
... If measured from ship's heading, bearings are termed, relative. There are still more visual methods available, both simultaneous or running fix, but they are applied rarely because of added complexity for measuring and graphical solutions (Lušić, 2013). ...
The mandatory ECDIS transitional period has ended just recently. The technology matured and the progress towards the ECDIS as a primary means of navigation has continued. Safe and effective navigation mostly relies on accurate and valid positioning despite the system’s technological advancement. In general, the frequency of plotting and monitoring of ship's position depends on two factors: employed navigational means and navigational areas. When using paper charts for primary means of navigation, position plotting frequency usually ranges from several minutes to one hour according to the Safety Management System (SMS) or other relevant requirements. In the case of ECDIS navigation, primary position is continuously displayed, mostly by the employment of satellite positioning means, with the possibility of secondary positioning display, depending on the source. Validation by position cross-checking is therefore essential for preventing overreliance on ECDIS primary position. In different navigational stages the navigator can use well known methods from celestial, coastal or electronic navigation. In the proposed paper, accuracy and complexity of positioning methods commonly used by the navigators are evaluated. The obtained results are correlated to primary positioning validation in ECDIS and compared with maritime user requirements, recommendations and respective resolutions. The research is accompanied with survey results on position checking methods conducted among the navigators. Results revealed that most of the navigators validate primary position, however there are misinterpretations between position validation, position fixing and secondary position source. Among stated, other overall and specific findings are presented and discussed. Future research directions are proposed in terms of the necessity of position checking, availability of positioning sources and further development of the system.
... Optical measure device in mapping is a good choice for the target mapping because it is unnecessary to mount the sensor in the target. On the basis of the known self-position, the target position can be measured accurately by means of angle measurement [6]. For example, the total station can output precise slope distance from the instrument to a particular point by a theodolite integrated with an electronic distance meter (EDM). ...
Making the sensor rigidly mounted in the target is the common characteristic of conventional navigation system. However, it is difficult or impossible to realize that for special applications such as the positioning of hostile aircraft. A novel new algorithm for target navigation and mapping is designed based on the position, attitude, and ranging information provided by laser distance detector (electronic distance measuring, LDS) and MEMS/GPS navigation, which can solve problem of the target navigation and mapping without any sensor in the target. The detailed error analysis shows that attitude error of MEMS/GPS is the main error source which dominated the accuracy of the algorithm. Based on the error analysis, a calibration algorithm is designed so as to improve the accuracy to a large extent. The result shows that, by using this new algorithm, the performance of target positioning can be efficiently improved, and the positioning error is less than 2 meters for the target within 1 kilometer range.
Finding Distance – Not Knowing Height - Volume 55 Issue 3 - Peter Ifland
The American Practical Navigator, Bethesda: National Imaginary and Mapping Agency
- N Bowditch
Bowditch, N., (2002), The American Practical Navigator, Bethesda: National
Imaginary and Mapping Agency.
Nicholls's Concise Guide to Navigation
- E Coolen
Coolen, E., (1987), Nicholls's Concise Guide to Navigation -Volume 1 (10th Edition),
Glasgow: Brown's, Son & Ferguson Ltd.
Nicholls's Concise Guide to the Navigation examinations
- E Coolen
Coolen, E., (1995), Nicholls's Concise Guide to the Navigation examinations -Volume
2 (12th Edition), Glasgow: Brown's Son & Ferguson Ltd.
Finding Distance-Not Knowing Height (Forum) The Journal of Navigation
- P Ifland
Ifland, P., (2002), Finding Distance-Not Knowing Height (Forum), The Journal of
Navigation, 55(3), pp. 495-500.,
http://dx.doi.org/10.1017/S0373463302212023
Annex 34, Adoption of the revised performance standards for radar equipment
Resolution MSC.192(79)-Annex 34, Adoption of the revised performance standards
for radar equipment, available at: http://www.imo.org/blast/blastDataHelper.
asp?data_id=15568&filename=192%2879%29.pdf
Simović, A., (2001), Terestrička navigacija, Zagreb: Školska knjiga.
(bearing sight), [accessed 15
- Nautical Compasses
Nautical Compasses, avaialble at: http://www.compassmuseum.com/nautical/
nautical_2.html (bearing sight), [accessed 15 December 2012].
Adoption of the revised performance standards for radar equipment
- Msc A Resolution
Resolution MSC.192(79)-Annex 34, Adoption of the revised performance standards
for radar equipment, available at: http://www.imo.org/blast/blastDataHelper.
asp?data_id=15568&filename=192%2879%29.pdf
Simović, A., (2001), Terestrička navigacija, Zagreb: Školska knjiga.
Split: Hrvatski hidrografski institute. Nautical Compasses
Nautičke tablice, (1999), Split: Hrvatski hidrografski institute.
Nautical Compasses, avaialble at: http://www.compassmuseum.com/nautical/
nautical_2.html (bearing sight), [accessed 15 December 2012].