Key Technologies Of Node Access For UAV Swarm Based On Radar And Communication Integration

Unmanned aerial vehicle(UAV)is widely applied in various scenarios due to its characteristics of flexibility,low cost,strong robustness and so on.UAV Ad Hoc Network is important to support the applications of UAV in military and civil scenarios.Since UAV Ad Hoc Network does not rely on the insfrastructure,has strong anti-destruction ability,and can be deployed flexibly,it has a broad application prospect.The design of Joint radar and communication(JRC)enables radar and communication to work in the same system,which is scheduled by multiple access control(MAC)protocol.How to schedule the radar and communication in the MAC protocol to ensure the flight safety of UAV,how to design MAC protocol for UAV network to achieve efficient and secure transmission and how to realize the anti-collision of UAV swarm are the main contents of this thesis.The research contents of this thesis are as follows:1)Facing the problem of UAV flight insecurity caused by radar scanning direction following communication direction under the signal-level integration for radar and communication,a new working mode of radar and communication scheduled in the UAV MAC method is proposed.And the radar echo protection interval is introduced to ensure that radar and communication will not interfere with each other.Based on the JRC technology,facing the characteristics of UAV network such as high mobility,large-scale deployment,and large number,a multi-channel MAC method based on reservation mechanism is proposed,and the corresponding channel multiplexing mode and related data packet format are designed.In addition,higher priorities are given to the emergency packets to ensure the timely transmission of UAV emergency information.The simulation results demonstrate that compared with the dynamic channel assignment(DCA)protocol,the throughput performance and node access efficiency of the proposed method are improved and the control channel is less likely to block,when there are a large number of accessing nodes.For example,when the packet size is 1000 bytes and the number of accessing nodes is 25,the throughput performance of the proposed protocol is improved by 9%,and the DCA protocol reaches the control channel bottleneck when the number of data channels is four,while the proposed method reaches the control channel bottleneck when the number of data channels is six.In addition,the proposed method can meet the low delay transmission of emergency data packets,and the delay is less than 1ms when the number of security information packets is less than 8.2)Facing the problem of obstacle type recognition and low accuracy of obstacle trajectory prediction in UAV flight environment,we use JRC signal for detection and target recognition,and prove that in this scenario,the fusion of communication and radar information can obtain better prediction accuracy.Then the simulation results demonstrate that the improvement of detection accuracy can shorten the minimum reaction distance of UAV,which has a positive effect on UAV collision avoidance.Secondly,based on the research status of UAV anti-collision algorithm,a path replanning algorithm is proposed,with which UAV escapes dangerous situations first and then uses the historical information to replan the path.Finally,the simulation results prove the feasibility of the proposed algorithm and show that compared with the traditional path replanning algorithm,the proposed algorithm has better delay performance.In our simulation environment,the delay of the proposed path replanning algorithm is less than 10s.