Design And Simulation Of Publish/Subscribe System For Multi-UAV Task Scenarios

UAV(Unmanned Aerial Vehicle)is dispatched to perform category tasks based on it's flexible and reusable characteristics.As the mission environment becomes more and more complex,the single-UAV combat mode expands to multi-UAV cooperation mode gradually.The UAV communication system must fulfill the needs of information sharing between UAVs and adapt to the changing conditions of the communication members.The publish/subscribe mode can meet the above requirements because of its loosely-coupled communication properties and multipoint communication functions.Publishers and subscribers who interact with each other through communication agents can join or exit the system at any time.This characteristic improves the adaptability of the system to the frequently changing task environment.Compared with the fixed location server,the performance of the UAV is limited,and the publish/subscribe mode cannot guarantee the security of data transmission.Therefore,the publish/subscribe mode cannot be applied directly to multi-UAV mission scenarios.This paper deals with the limited performance of UAV from two aspects: reducing the amount of communication data and improving load balancing mechanism.Members of the system communicate with each other by means of the lightweight protocol MQTT(Message Queuing Telemetry Transport)to reduce the amount of communication data.MQTT has a small fixed header and is suitable for environments with limited network and hardware performance.The improved load balancing mechanism is used to balance the load of the communication agent UAVs.This mechanism assigns communication tasks according to the real-time state of each communication agent UAV,and prevents communication agent UAVs with weak performance from going down because of the excessive load.For the lack of security in data transmission,this paper uses information hiding technology and data encryption technology to ensure the security of important data,but the existing MQTT covert channel has the problem of slow transmission speed.In this paper,variable protocol fields are used to carry secret information instead of message sequences which can increase the amount of data carried by a single message.The improved covert channel can transmit more secret information with few communication packets.In this paper,the load balancing improvement strategy and the hidden channel improvement strategy are simulated respectively.Final results exhibit that the improved load balancing algorithm enables servers to obtain better load balancing results;the improved covert channel increases the transmission speed of secret information by about 1.5 times.In the simulation environment,UAVs share battlefield information through publish/subscribe mode,and use battlefield information to gradually determine the execution process of the mission.UAVs cooperate to destroy the enemy targets.This paper investigates the application of publish/subscribe mode in multi-UAV mission environment,which is useful for UAVs to share information in the case of limited performance.