Research On Key Issues Of Cooperative Ground Targets Tracking For Multi-UAVs In Complicated Environment

Nowadays,the performance of UAV continues to be improved and the scope of application continues to be expand.Cooperative target tracking for multi-UAVs is one of the typical tasks of UAVs,which has received extensive attention.Due to the clustering of general military tasks,the situation that we need to track multi-targets occurs in actual mission,which makes cooperative multi-targets tracking for multi-UAVs meaningful.In this paper,the key problems of cooperative multi-targets tracking for multi-UAVs in complicated environment are studied.This paper focuses on three aspects of the research,including multi-targets allocation,state fusion of ground target,and the guidance algorithm for UAV.(1)The logical process of multi-target tracking is analyzed?This paper presents a framework to solve the problem of multi-targets tracking for multi-UAVs in a complex environment,and describes the components.And the key components are modeled(2)Considering the presence of shaded regions in the environment,a target allocation algorithm based on hierarchical clustering is proposed.Aiming at the situation that the ground targets are scattered and uncertain and the limit of view of the UAVs,a variable radius for targets tracking is designed.On the basis of hierarchical clustering,the cover area is taken into account in the algorithm.Then,the allocation strategy of UAVs is designed after the target grouping is completed.A numerical simulation experiment is carried out to verify the feasibility of the target grouping algorithm and the UAV allocation strategy.(3)Aiming at the problem of uncertain target state,the IMM_UKF algorithm is used to filter the target state information,and the federated filter structure is used to fuse the data.An adaptive motion model is established for the inaccurate estimation of the bending angle of the moving mode.According to the error ellipse in observing and locating ground targets for UAV,the confidence calculation method of current UAV observation value is designed.Then the confidence is added to the target state fusion algorithm.The effectiveness of the algorithm based on the adaptive motion model is verified by numerical simulation.(4)In the environment where there are obstacles or no fly area,a standoff tracking method based on Lyapunov navigation vector field is proposed for UAVs to track ground targets by standoff.The collision avoidance potential field is used to solve the problem of obstacles or no fly zone.Aiming at the slow convergence of Lyapunov guidance law in cooperative target tracking for multi-UAVs,the feedback structure of distance between UAV and target and the phase angle between the UAVs is established.The convergence of the algorithm is verified by simulation experiments.According to the existing conditions of the laboratory,the guidance algorithm was tested in real flight.The results of experiments show that the proposed guidance algorithm also has the advantages of fast convergence and high stability in practical applications.