Research On High-precision Positioning For Reentry Target

The theory and technology of target positioning play a great important role in national defense and military industry, and they are the basis of reentry measurement data processing. Basing on the theory and technology of target positioning, and considering current equipments and measurement system, the existing methods of reentry measurement data processing still leave something to be desired. This paper, which took modeling and filtering for targets' state and data pretreatment as two main threads, aimed at the reentry phase of target, and studied several problems in processing of reentry measurement data.With the increasing cognition to the dynamic and kinetic characteristic of reentry target and the emerging of advanced filtering techniques, we studied and summarized the issue of modeling and filtering for tracking reentry target. In the part of state modeling, for obtaining the equation of state transition for reentry trajectory in real time filtering, the model for trajectory tracking was studied. In order to gain the prior information needed in building tracking model, we adopted three methods in the process of modeling which are determinate function, the characteristic of maneuverable target and dynamic parameters, and the last two were investigated by demonstration. In the part of state filtering, the techniques commonly used were summarized, and their principles, character, advantages and disadvantages were also analyzed. In the background of reentry trajectory, the detailed process of EKF and UKF filtering were given. After that, we analyzed and compared their performance in reentry trajectory real time tracking via simulation.In the problem of measurement data pretreatment, the methods for outlier detection and denoising of measurement data were studied. In the part of outlier detection, we concluded the theory of errors firstly, and then introduced the detailed measurement error and their classification mainly. Afterward, combining the background of reentry target tracking, two classes of measurement data were described—time series and point of fall. We put the emphases on the data of point of fall. The existing classic techniques in outlier test were summarized. Integrating some situation appeared in practice, a new approach for test was proposed and compared with classic techniques. In the part of denoising, we explored the new method in signal decomposition—the EMD algorithm. The basic theory and idea were introduced firstly, and then came into the simulation for non-maneuverable and maneuverable trajectory directly. In the simulation, we introduced the approach to generate three degree-of-freedom trajectory. Some advises were proposed in the application of EMD algorithm in measurement data denosing according to the result from simulition.