The methods of celestial navigation to fix the ship position in line with the stars are only applied in the twilight time interval when both the celestial bodies and the horizon apppear simultaneously. This means that these methods cannot be used during the night even if the stars are visible. This paper proposes a novel approach which uses the azimuth of the celestial body in order to establish the great circle equation relating the observed body to the ship position when the celestial bodies appear. In addition, the proposed method does not demand the horizon and sextant equipment as with the previous methods. The key advantage which differentiates this method from previous ones is its ability to determine the ship position during the night when the horizon is invisible. Firstly, the vector calculus is applied to find the mathematical equation for the ship position through analyzing the relationship between the ship position and the great-circle azimuth of the observed body. Secondly, the equation system for the ship position is expanded into a standard system in which the input for the proposed mathematical system are the great-circle azimuth and the coordinates of the observed body. Finally, the numerical technique is also proposed to solve the nonlinear system for the ship position. To verify the validation of this proposed method, a numerical experiment is carried out and the results show that it can be applied well in practice.

The purpose of this study was to examine drivers’ driving behaviors and eye-movements according to driving speed and navigation-position while operation of the navigation in driving. For this purpose, two driving conditions (low-speed and high-speed) and

Nowadays Hyperbolic Navigation System-LORAN, DECCA, OMEGA, OMEGA-is available on the ocean, and Spherical Navigation System, GPS (Global Positioning System) is operated partially. Hyperbolic Navigation System has the blind area near the base line extention because divergence rate of hyperbola is infinite theoretically. The Position Accuracy is differ from the cross angle of LOP although each LOP has the same error of quantity. GDOP(Geometric Dilution of Precisoin) is used to estimate the position accuracy according to the cross angle of LOP and LOP error. Hyperbola and ellipse are crossed at right angle everywhere. Hyperbola and ellipse are used to LOP in Rectangular Navigation System. The equation calculating the GDOP of rectangular Navigation System is induced and GDOP diagram is completed in this paper. A scheme that can improve the position accuracy in the blind area of Hyperboic Navigation System using the Rectangular Navigation System is proposed through the computer simulation.

In this paper, the equations calculating GDOP are induced in Hyperboic, and Spherical Navigation System, respectively, The GDOP diagram shows that the DGOP in the inner region of Beacons is similar each other, but the GDOP of Hyperboic Navigation System is much larger than that of Spherical Navigation System due to GDOP in the outer region of Beacons. The authors propose the algorithm estimating the pulse starting time using the Hyperboic Navigation System, and prove that if Navigation use the Spherical Navigation System by adopting the proposed Algorithm -in this case, "Pseudo Sperical Navigation System" - in the outer region where GDOP is becoming large, the position errors can be reduced.e reduced.