New Computational Methods for Solving Problems of the Astronomical Vessel Position

Abstract

In this paper, a simplified and direct computation method formulated by the fixed coordinate system and relative meridian concept in conjunction with vector algebra is developed to deal with the classical problems of celestial navigation. It is found that the proposed approach, the Simultaneous Equal-altitude Equation Method (SEEM), can directly calculate the Astronomical Vessel Position (AVP) without an additional graphical procedure. The SEEM is not only simpler than the matrix method but is also more straightforward than the Spherical Triangle Method (STM). Due to tedious computation procedures existing in the commonly used methods for determining the AVP, a set of optimal computation procedures for the STM is also suggested. In addition, aimed at drawbacks of the intercept method, an improved approach with a new computation procedure is also presented to plot the celestial line of position without the intercept. The improved approach with iteration scheme is used to solve the AVP and validate the SEEM successfully. Methods of solving AVP problems are also discussed in detail. Finally, a benchmark example is included to demonstrate these proposed methods.K E Y W O R D S 1. Astronomical vessel position.2. Spherical trigonometry. 3. Intercept method.

Celestial Navigation Fix Based on Particle Swarm Optimization

“…It can be seen from Table 1 that the observed altitude of Alkaid is as high as 77° 34.9', which exceeds the upper limit of 70° specified in the IM. Hsu et al, (2005) found that for high-altitude observation, an LOP drawn using the IM was shifted due to curvature error, thus resulting in an inaccurate vessel position. It can be seen in Table 2 that all methods but the traditional IM can find the correct vessel position when the first DR position (DR 1) is used; i.e., the distance between the DR position and the actual vessel position is less than 30 NM.…”

Genetic algorithm for solving celestial navigation fix problems

“…This is also aimed at future celestial navigation education and integration with an Electronic Chart Display and Information System (ECDIS). The data in this case study is taken from Hsu et al [6]. The authors used the Simultaneous Equalaltitude Equation Method (SEEM) to perform a two-body celestial fix.…”

“…Either the assumed position is not needed or the knowledge of an approximate position is sufficient. Some researchers have studied a two-body fix [2,3,5,6,12,14]. It is proposed that at a given time, the astronomical vessel position can be determined by observing circles of equal altitude of two celestial bodies.…”

“…It can be seen from Table 1 that the observed altitude of Alkaid is as high as 77°34.9', which exceeds the upper limit of 70° of the intercept method. Hsu et al [6] found that the LOP drawn using the intercept method shifted due to curvature error, thus resulting in an inaccurate vessel position estimate. The present study however is free from this drawback.…”

Anchorage Deviation Ship Management and Monitoring Scheme

“…VTS is essential for marine traffic control to be liberated from the existing management methods simply based on wired/wireless communication and to respond quickly to the potentially dangerous situations. The Vessel Traffic Service is to improve the safety and efficiency of vessel traffic, and its marine traffic control service is very important for safe navigation and departure and arrival as a national backbone network [3,10].…”