Study On The Takeoff And Landing Timing Of Seaplanes Based On Collision Risk Assessment

In recent years,civil seaplanes have developed rapidly in China.Since the seadrome is mostly built in the port waters with convenient transportation,the highfrequency coexistence of seaplanes and ships during the period of takeoff and landing on water will lead to an increase of the collisions probability between seaplanes and ships.At present,in order to avoid such collisions during the seaplanes takeoff and landing,the on-site alert mode is usually adopted by using alert ships.In this situation,ships are prohibited to enter the area for takeoff and landing.Such method leads to a significantly negative impact on the navigation efficiency and a waste of much alert resources.To solve this problem,in this thesis,a system to select the takeoff and landing timing based on collision risk assessment between seaplanes and ships is proposed and developed.The system,as far as possible,ensures the takeoff and landing seaplanes operated without any collision danger with nearby ships.And if necessary,some appropriate alert means are also incorporated to guarantee the safety of seaplanes.A reasonable selection of takeoff and landing timing is theoretically and practically significant to ensure the safety of both seaplanes and ships.It also improves the navigation efficiency in the relevant area and saves the alert resources as the results.The main research content of this paper is as follows.(1)To investigated the domestic and overseas research status and the development level of navigation safety for seaplanes on water.The relevant methods of collision avoidance and collision risk assessment are intensively analyzed.Based on the characteristics of takeoff and landing of seaplanes on water,the method to comprehensively analyze DCPA and TCPA for collision risk assessment is determined.(2)To develop the three-dimensional dynamic domain model of seaplanes.According to the characteristics of takeoff and landing of seaplanes on water,a threedimensional structure for the seaplane domain with horizontal and vertical direction is proposed based on Fujii ship domain model and Davis P.A.ship domain model.A speed variation coefficient k is introduced to correlate the size of the seaplane domain to the speed of seaplanes and the average speed of the nearby ships.So far,a threedimensional dynamic domain model of seaplanes is developed.The horizontal dynamic domain of seaplanes on water based on the three-dimensional model is ascertained to assess the collision risk between seaplanes and ships.(3)The timing for seaplane takeoff and landing is determined as the moment when the collision risk disappears.Based on this principle,the safe distance model between seaplanes and ships is constructed and adopted as the boundary value of DCPA.Meanwhile,the method to calculate the boundary value of TCPA is determined.Based on the geometric principle of ship collision avoidance,a collision avoidance model between seaplanes and ships is developed to calculate DCPA and TCPA.The function between ship trajectory and time is defined under the assumption that the ships keep course and speed.Thus,both DCPA and TCPA can be calculated simultaneously.(4)By comparing DCPA with safe distance and TCPA with its boundary value,the judgement of collision risk can be drawn.The takeoff and landing timing of seaplanes without collision risk is determined,accordingly.The GUI system to select takeoff and landing timing of seaplanes is developed by C++ programming language which is object-oriented.The system is applied in Sanya for model validation.The simulation results show that the system can be used to determine the best takeoff and landing timing without any collision risk when the seaplane encounters single ship or multiple ships.