多段恆向線航法－最短距離之航路規劃

Minimizing the Traveling Distance for Piecewise-Rhumb Line Sailing

10.29770/JTCMT.200809.0011

曾維國(Wei-Kuo Tseng)

恆向線 ； 最佳轉向點 ； 大圓航線 ； 航路規劃 ； rhumb line ； great circle ； turning point

台北海洋技術學院學報

1卷2期（2008 / 09 / 01）

123 - 135

繁體中文

運輸學的定義是如何將人員或貨物以便利、經濟、迅速及安全的方法從A點運送到B點，以創造時間及地域效用的科學。如果在陸地航行因為路線或地形的限制，一般可由道路的交通狀況、距離及幾何佈置關係等來決定航行路線，在不考慮天候及政治關係下，航空航海的航行最短路線一般採用大圓路徑，但是大圓航行由於航向不斷的變化，在實務上都是以多段恆向線來逼近大圓路徑，因為恆向線有固定的航向的優點，航行人員不需要一直改變航向，航行人員只要航行到有限的轉向點，分別設定航向就可以完成航行任務，但是航行人員或航路規劃人員通常都是任意毫無法則選取分段轉向點，不同的轉向點會產生不同的距離總和，本文的目的是建立及研究一套選取多段恆向線轉向點的方法，使得總航行距離最短。

The great circle distance represents the shortest distance between two points on a sphere, such as the Earth. A great circle is that portion of a plane that cuts through the Earth and its center. In order to navigate a Great Circle route, the heading will be changing continually. The most convenient course for a ship to steer is a steady course; on along which the bearing of her head remains constant. Her track must then cut all meridians at the same angle, and in general it will spiral towards the nearer pole. In practice the great circle track is divided into suitable lengths, successive points on the great circle being joined to form a succession of rhumb lines. But there are many different distances between many different turning points on the Earth. How to choose the turning points on the great circle in order to sail on minimum distance? The gist of his paper is to propose an effective and efficient method of calculating the minimum distance of piecewise rhumb lines among finite turning points.

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