不变线 meaning in English

invariable line

The head on situation and overtake situation can be regarded as a special case of cross situation ; 5 through the comprehensive analysis of all kinds of schemes , to determine a best scheme of radars collision avoidance , which may be applied to the following three circumstances : cross situation , head on situation as well as overtake situation , thus to take any measures to alter course , slow down or slow down with alteration ; 6 through the analysis of a special situation , to study the method how to calculate the range of dangerous angle of collision avoidance ; 7 through the statistics of action of collision avoidance , to find out the rules of taking actions to revise the " best scheme " ; 8 the principle and method of optimization are presented
6 、对一种特殊的会遇情况：位于转向不变线或其平行线上的来船的dcpa和tcpa的变化作分析，探讨出“转向忌讳角”的求取方法，在避碰方案中应避免使用“转向忌讳角。 ”在多船避让时，如采取一次转向行动让清所有船舶，则该理论的应用将使避碰方案更加完美。 7 、对驾驶员的避碰行为作调查统计(交叉相遇) ，得出驾驶员在交叉相遇局面中的行动幅度和行动时机(距离)的统计数据，得到行动幅度和行动时机的平均值，对“最佳方案”进行修正。