Meteorological Route Dynamic Optimization Method Based On Improved A-star Algorithm

Global economic globalization has led to an increasing frequency of trade between countries around the world,and the dependence of countries’ foreign trade on the shipping market has continued to rise.The greenhouse gases generated by shipping have also increased,which is inconsistent with the concept of green economy.In addition,the safety and economy of maritime transportation are deeply affected by the complex and changeable oceanic meteorological conditions.Therefore,it is of great practical significance to ensure the safety and economy of shipping under complex sea conditions and reduce the greenhouse gases produced by shipping industry.In order to meet the safety,green and economic requirements of ship navigation,it is necessary to design more efficient routes for ocean-going ships.Therefore,this thesis takes the total voyage,voyage time and fuel consumption of ships during the voyage as indicators to optimize ship routes,and proposes A dynamic optimization method of meteorological routes based on the improved A-star algorithm.The main research contents are as follows:(1)In order to improve the optimization effect of meteorological routes,maximize the use of meteorological conditions to achieve the goal of minimizing ship operating costs.In this thesis,a navigational environment model is established considering wind,wave,current and surge.Firstly,the meteorological data required by the voyage was obtained from ECMWF.According to the resolution of the meteorological data,the above various meteorological conditions were combined with the latitude and longitude grid of the navigation waters to establish a ship navigation environment model with various meteorological conditions.According to the actual operation characteristics and ship type,navigable nodes and nonnavigable nodes were automatically set.(2)In order to overcome the disadvantages of the traditional A-star algorithm,such as low operating efficiency,many inflection points and inapplicability to sea navigation,this thesis improves its operating efficiency by improving its search direction and optimizing its cost function,and makes it suitable for ocean navigation.Combined with the motion characteristics of ships sailing on the sea,the search direction of the traditional A-star algorithm is reduced,which greatly improves the operation efficiency of the algorithm and reduces the inflection point of the optimized route.According to the operating principle of the A-star algorithm,combined with the optimization objectives of reducing the total distance,voyage time and fuel consumption,the cost function was improved to achieve the goal of minimizing the total distance,voyage time and fuel consumption.(3)By calculating the ship’s position and estimated arrival time,timely updating meteorological data,and combining dynamic programming method to realize dynamic optimization of meteorological routes.The ship’s position and arrival time at a certain time in the near future can be accurately calculated from the ship’s current position,course,speed and other information,which can be fed back to the navigation environment model.The navigation environment model can be constantly updated and the route can be continuously optimized by combining the dynamic planning idea.Based on the above research content,two sets of control experiments were set for the eastbound route and the westbound route.Simulation experiments were conducted based on MATLAB and electronic chart and information system to verify the optimization performance of the proposed optimization method.The experiment shows that compared with the initial recommended climate route,the route generated by this algorithm conforms to the design rules of the route,and the generated route has the advantages of economy and reliability.