The Research Of Great Ellipse Route Algorithm

The route design is one of the most basic and important problems in navigation,and the high precision route can provide more reliable basis for the on deck officers.With the development of modern navigation technology,the era of electronic navigation has come,the development and application of ECDIS makes all kinds of navigation information can be integrated into this platform.Because of the great circle route earth model simple and convenient calculation in mathematics,the ocean route course and distance is still the earth sphere,and the shortest distance between two points the earth ellipsoid model of(geodesic)has a big difference.Uniform between the ship voyage plan(great circle route)on sphere model and modern navigation equipment design on the earth ellipsoid model,affecting the normal sailing and the safety of the ship.In this paper,the algorithm of great elliptical route can not only reduce the error,but also provide reference and basis for the research and development of ECDIS in China.Under the above background,this paper provides a high accuracy and more realistic route design method for the ocean going navigation.By using the vector method of variable ellipse,the algorithm of the large ellipse route is deduced.Combined with the navigation practice,the space vector analysis method is used to determine the great elliptical route;The vector calculation is carried out on a great elliptical route,and the latitude of a given point can be obtained when the longitude is known,and vice versa;By solving ellipse vertices,with the intersection of the equator route points in the geocentric latitude,will be converted to the corresponding geodetic latitude,the range between two points is calculated by the integral formula of meridian arc length;Compared to the great circle route,rhumb line,geodetic line and great ellipse route,the method is verified;Combined with the navigation practice,this paper gives an algorithm to realize the electronic chart,and shows several ocean going routes.Through theoretical derivation and comparison of the above calculation can be drawn,elliptic and geodesic routes in ocean going routes difference is very small,so it can meet the requirements of electronic navigation with high precision,easy to implement in the electronic chart.Therefore,great elliptical route is indeed a high accuracy,with navigation features and Mercator chart suitable for navigation practice course.