Research On Radiation Source Location And Path Planning Technology Based On Multi-UAV

The traditional passive positioning system mainly consists of multiple groundbased fixed base stations and command center,and the positioning accuracy is often influenced by the geographical location of the base station and antenna occlusion under Non Line of Sight(NLOS)conditions when positioning radiation sources.Based on the above problems,this study considers the use of a flexible and mobile multi-UAV platform instead of fixed base stations to transfer the positioning system to the air for mobile positioning of radiation sources,and also investigates the problems of flight path planning of UAVs and correction of positioning results of radiation sources in this system.The research content and innovation points of this paper are specified as follows.1.A multi-UAV-based radiation source localization system is established,the system framework and Time Difference of Arrival(TDOA)localization technology model are given,and the Cramér-Rao Lower Bound(CRLB)derivation method under this localization model is summarized,which provides an error measure and theoretical basis for the subsequent multi-UAV path planning and radiation source localization correction.2.Based on the scenario that multiple UAVs localize a single stationary radiation source,firstly,the traditional multi-UAV path planning algorithm model based on the localization task is given,and the correction methods for the constraints of the trajectory planning are discussed;secondly,on this basis,considering the problem of poor localization accuracy when UAVs are far away from the radiation source,the traditional single-point CRLB cost function is replaced by the global CRLB,and a A global CRLBbased UAV path planning algorithm is proposed,and the algorithm is further optimized by substituting the previous moment positioning a priori information,constraining the UAV flight angle and changing the sampling time interval distribution.The simulation results show that the path planning algorithm based on global CRLB and Bayesian estimation has higher localization accuracy than the traditional algorithm,and the optimization scheme for UAV flight angle and sampling interval effectively reduces the computation and improves the efficiency of the system.3.Based on the scenario that multiple UAVs locate a single moving radiation source,a UAV path planning algorithm for moving targets is proposed,which uses Kalman Filter(KF)and Extended Kalman Filter(EKF)to track and estimate the location of the radiation source at the current moment based on the stationary target localization model,and uses the CRLB at the current moment as the cost function to plan the UAV path.4.Based on the scenario of multiple UAV formations locating multiple radiation sources,the problem model in this scenario is firstly analyzed,a Gaussian Mixed Model(GMM)consisting of all the final localization results is constructed,and an Expectation-Maximization(EM)-based multi-UAV multi-source localization algorithm is proposed.algorithm based on the Expectation-Maximization(EM)algorithm;secondly,a Bayesian estimation-based multi-source localization correction algorithm is proposed by combining Bayesian estimation and introducing the prior information of the parameters to be estimated,and the factors affecting the accuracy of the parameters to be estimated in the model are analyzed.The simulation results show that the algorithm can effectively solve the duplication and missing data problem of the mixed distribution under this model,and the introduction of the prior information effectively reduces the system localization error.