The Study Of Fixing By Landmarks In The Implementation Of ECDIS

Position fixing is one of the most essential and important issues in practical navigation.High-precision position fixing contributes to constantly understanding the navigational environment and monitoring the implementation status of ship routes for duty officers in order to make right decisions immediately and ensure safety of navigation.The emergence of ECDIS to traditional navigation brings new development opportunity.Therefore,this paper studies the method of implementing fixing by landmarks,as a traditional navigation,on ECDIS,which will meet the IMO performance standard requirements of ECDIS,but also provide the basis for the algorithm reference of ECDIS domestic research and development.This paper derives the mathematical model,verifies the model with test data and analyzes the error,and the fixing by landmarks system is implemented in ECDIS.The main content of this paper is divided into the following parts:(1)Studying on the bearing and distance LOP and the position error of fixing;(2)A mathematical model is established by using the rhumb line to replace the azimuth gleiche of the ship.For fixing by single bearing and distance,cross bearing and distances,the intersection of two lines of position is the most probable position.For fixing by three cross bearing,Weighted Point of Intersection is utilized to process the error triangle under the condition of unequal precision and then get the most probable position.Through the center of gravity,inner center and Steiner point obtained in MATLAB simulation Weighted Point of Intersection,the optimal algorithm for getting the most probable position is obtained by comprehensive analysis;(3)Comparing the position get by mathematical model with the position get by manual plotting under measured data,and takes GPS position as a reference;(4)Programming by VS 2013 and adding landmark positioning module in the electronic chart,the landmark positioning system is implemented in ECDIS.