Research On Key Technologies Of UAV Formation Network

Unmanned aerial vehicle(UAV)is an aircraft without a human pilot aboard which has the advantages of convenient deployment,simple structure,good concealment,flexible takeoff and landing.It is widely used in emergency assistance,investigation and surveillance,geographic mapping,circuit inspection,meteorological monitoring,news shooting,logistics and many other fields.UAV formation network can give full play to the advantages of multi-UAVs cooperation and improve the ability of cluster UAVs to perform tasks.Therefore,it is necessary to study the technologies of UAV formation network combined with communication technology.It provides effective and reliable theoretical and technical support for UAV to accomplish the task cooperatively in the complex environment.On the basis of multi-aircraft cooperation,the number of UAV is effectively expanded,and the cooperation efficiency of UAV is improved and the load consumption is reduced.This dissertation mainly studies the related technology of UAV formation network,and deeply analyses and verifies the communication security algorithm of UAV network.The main works are as follows:1.A relative positioning method of master-slave UAV in multi-UAV formation network is proposed.The master node in the formation network completes its own positioning through RTK-GPS carrier phase difference,and the distance between the independent node and the master node is measured by radio pulse method.When the distances between the independent node and the four non-coplanar master nodes are obtained,the location of the slave node is determined by geometric solution.The relative positioning of the master-slave UAV is accomplished through the real-time dynamic GPS carrier phase differential positioning method and the wireless pulse ranging method.The master node completes own positioning through the real-time dynamic GPS carrier phase differential method,which can obtain high accuracy,so as to realize the global accurate positioning.2.A parallelogram UAV formation cover method is propose.The mission monitoring area is regarded as a parallelogram with more flexible interior angle in this method.The UAVs deploy is arranged using the grid division method,It can effectively overcome the deficiency of traditional formation coverage method which has large coverage redundancy.In the simulation environment of node moving,the coverage of parallelogram is s obviously larger than that of the traditional rectangular coverage algorithm,and the number of UAVs can be reduced while the coverage is enough.3.Based on the improvement of RREQ message processing method,an IAOMDV multipath routing protocol considering energy consumption is proposed.In UAV communication network,after receiving RREQ messages,the internal node first determines whether the residual energy of its own node is sufficient to use.Only when the energy is sufficient,the message is forwarded to the neighbor UAV node according to the information table.IAOMDV classifies the nodes according to the residual energy,which can reduce the numner of flooding.The link protocol in the simulation environment adopts IEEE 802.11 protocol.The results show that the packet loss rate and end-to-end delay of the improved AOMDV protocol are significantly lower than that of AOMDV with the increase of uav movement speed,which effectively reduces the routing overhead.4.Considering the energy consumption of UAVs,the wireless communication energy consumption model of UAV swarm is established,and a new clustering communication algorithm ILEACH for UAV swarm is proposed.The improved cluster-head selection method can effectively optimize the cluster-head selection process through the soft threshold,so as to optimizing the traditional algorithm.The results show that the network lifetime increases obviously and the energy consumption speed of nodes decreases effectively under ILEACH algorithm.Therefore,the ILEACH algorithm can improve the network survival time and balance the network energy consumption.The improved algorithm is applied to the simulation of different node density and digital packet length,the simulation results are consistent with the theoretical analysis.5.A trust evaluation method for UAV cluster structure based on cloud model is proposed.By introducing cloud theory,the randomness and the fuzziness of trust relationship in UAV network environment are considered,and the trust level of nodes is reasonably calculated.According to the characteristics of the UAVs network,the direct trust degree is calculated by considering communication factors,message factors,energy factors,and realizes sensitive identification of intrusion behavior.At the same time,this method refers to recommendation trust to ensure tolerance to environmentally reasonable anomalies.Based on the LEACH protocol,the simulation model of the UAV network is established,and the correctness and effectiveness of the proposed cluster structure trust evaluation method are verified and analyzed.The proposed trust evaluation method is applied to the experiment to demonstrate its correctness and effectiveness.The experimental results show that the algorithm in this paper can effectively resist the communication attack,data attack,energy attack and other types of malicious attacks,and effectively insure the security performance of the uav network.