Research On Technologies Of Space Non-cooperative Area Targets Tracking

Space area target tracking is the international research focus recently, because it’s not restricted by earth’s atmosphere, weather, it has signigicant advantages compared with ground based space target tracking. In the process of tracking, targets’ attitude change constantly and there is relative motion between targets and tracking system, so high-precision tracking of the target in the dynamic environment is the key and difficult point of the research. Further more, in some applications, there is a need for pointing the target in high accuracy at the same time of stable tracking. Tracking and pointing precision directly determines success or not of the system. High-precision tracking system is needed to track space non-cooperative area target in high precision. Research on space area target tracking technologies and factors that influence tracking and pointing precision has some value to the development of space area target tracking.The demand of space area target tracking is first analyzed in this thesis. Kinetic characteristics and optical characteristics of space area targets are analyzed through theoretical calculation and simulation. Improved fitting algorithm and template updating algorithm are put forward for increasing accuracy of matching, and the validity of these algorithms is verified by experiment and simulation. Design parameters are analyzed, and key technologies involved in the design of system are discussed from the point of engineering realization. Fine tracking system is mainly studied, including component characteristics, simulation model, design and implementation. Finally, the demonstration experiment is set up using fine tracking system. This experiment verified the feasibility of locating target by sub-pixel matching algorithm and tracking the target by tracking system.Main innovation points of this thesis are:(1). High-precision image matching algorithm: conventional subpixel fitting algorithm is improved. The accuracy of conventional algorithm and improved algorithm is compared through experiment. The results show that error of improved algorithm is less than conventional algorithm, and the error is less than 0.1pixel. The conventional template update algorithm is improved, and a kind of variable parameter template updating algorithm is put forward. Accuracy of algorithm in this paper and conventional algorithm is compared by changing the brightness and attitude of target. The results show that when the target rotating 5 degrees and shrink 1.25 times at the same time, the matching precision of algorithm in this paper is higher than that of conventional algorithm about 0.1pixel.(2). Fine tracking system control model: system design parameters is analyzed and fine tracking system was introduced in detail. The properties of various components of fine tracking system are analyzed. Simulation model of fine tracking system is set up. Tracking precision under different DAC resolutions is studied making use of the simulation model.(3). Fast steering mirror modeling and performance test: control model of piezoelectric fast steering mirror is analyzed. Performances of piezoelectric fast steering mirror are tested through experiments. These performances contain open-loop characteristics, frequency response and reliability. The resonant frequency of fast steering mirror is about 1.4 k Hz. These tests and analysis provide basis and reference for applications of piezoelectric fast steering mirrors in aerospace engineering.(4). Analysis of space target optical properties: reflection characteristics of space target surface materials are researched and optical characteristics of space target are analyzed in detail. According to the theoretical calculation, we obtain the relationship between observation distances, surface reflectivity and the target magnitude, the irradiance the tracking system receives. The analysis provides theoretical foundation for the space area target tracking.(5). Indoor demonstration experiment: making use of collimator and target plate to simulation space far field non-cooperative targets, and completing the tracking demonstration experiment making use of the fine tracking system designed. This experiment verifies the feasibility of target tracking with image matching.Research of this thesis explores non-cooperative space target tracking technology, completes the key technology research, verifies the scheme through demonstration experiment, and pave the way for implementation of space non-cooperative area target tracking.