Research On Independent Coordinates Filtering And Parametrized Trajectory Fusion Technology For Aerial Targets

As foundational technologies for air defense system, target tracking and informationfusion have attracted great attention due to their wide application potential in military andcivil areas. In order to deal with the dynamic variance of measured dimensionality foraerial targets in complicated jamming environments, this dissertation mainly discusses thetechniques of target tracking and information fusion for real battle environments. Based onthe information processing principle of acquired independent coordinates of targets, a newtracking and fusion framework is proposed, which consists of independent coordinatefiltering and parameterized trajectory fusion. The major achievements are summarized asfollows:1. A new concept of independent coordinate processing is proposed, which integratesthe target motion analysis into the data processing system for measuring the varyingdimensionality in real battle environments. Then, a joint framework of independentcoordinate filtering and parameterized trajectory fusion is illustrated, followed by theflowchart of independent coordinate processing and the structure of parameterizedtrajectory.2. Several algebra relations are summarized based on the geometrical invariants, bycomparing similar theorems of geometry graphics. Cotangent theorem and3-R locationtheorem are proposed, respectively. New range function and dihedral angle model are alsointroduced. Moreover, target tracking principles are discussed for bearings-only,range-only and elevation-only measured coordinates under single or multiple sensors,which will facilitate the following high-accuracy computing of target trajectory parametersand evaluating the correlation.3. For single-sensor single-dimension coordinate scenario, several methods of thesingle-dimension coordinate based filtering and parameterized trajectory tracking areproposed, which can deal with the bearing-only, range-only and elevation-only parametertrajectory accordingly. The bearing-only processing method is to estimate the parametersof the target trajectory by the geometrical invariants, parameterized trajectory filtering andcircular error approximation. The range-only processing technique is designed accordingto target models of constant velocity, conic and circular motions. However, theelevation-only processing method works through projection relation, direct description anditerative operation. Simulation results show the effectiveness of the proposed methods.4. For single-sensor (more than)2-dimension coordinate scenario, a new frameworkof combined coordinate filtering and parameterized trajectory tracking is proposed. Based on geometrical invariants, target trajectory can be tracked accurately by computing thebearings and elevations. Further, the trajectory parameters can be estimated in Cartesiancoordinate by utilizing the angle-only information. The situation for obtaining parameterswith range-bearing or range-elevation information is also researched. Finally, a targettracking algorithm based on conic model with3-dimension measurements is presented.Simulation results validate that the combined coordinates are more suitable to estimate thetarget trajectory than single coordinate.5. For multi-sensor asynchronous network, trajectory parameters computing andparameterized trajectory fusion are discussed with the information of single-single,single-combined, and combined-combined coordinates, respectively. The trajectorycorrelation is evaluated according to the parameters invariant to observer stations. Whilethe trajectories with unknown parameters are further solved by the parameters related withthe observer stations, in order to perform the final fusion. When all parameters aredetermined, the target trajectory can be tracked in3-D coordinates. Furthermore, locationmodels based on the sum of range-only and its difference to observer location areestablished with multi-sensor synchronous measurements. Simulation results show theeffectiveness of the proposed models.6. The concepts of inner and outer accelerations are introduced for moving air targets.The motion model with constant circular acceleration is proposed. The unified motionmodel of air target is further established, which can be applied for many flight modes andprovides a novel solution to estimate the target trajectory.7. Several classical filtering algorithms for nonlinear system based on particle filtersare discussed. The simulation comparisons find out the possible problems in currentresearch, which are helpful for future improvements.Finally, practical applications of the proposed independent coordinate processingtechniques in this research validate its potential in real target tracking systems.