Study On The Measuring Techniques Of The Symmetry Axes Of Warhead Based On Indoor GPS

The warhead is one of the most important parts of a missile. Symmetry axis is an important geometric specificity of it which affects the hit precision of a missile; therefore it is significant to study measuring techniques of symmetry axis. The warheads of medium-long range missiles have some features such as special contour, large size and heavy weight, etc., thus, the measurement of symmetry axis is a kind of large-scale measurement. Indoor GPS is a new technique in large scale three-dimensional coordinate measurement, which has some specialties such as high measuring efficiency, no need to move stations, and it also can satisfy multi-user to work simultaneously. Because of these merits, it is meaningful to study on the measuring techniques of the symmetry axes of warheads based on Indoor GPS in improving the producing and developing efficiency of missiles.First in this thesis, the work principle of Indoor GPS measuring system is studied; its structure as well as the application characteristic is analyzed. Then the measuring principles of the symmetry axis and point coordinate are introduced in detail. According to Indoor GPS system, not only the best measuring disposition plan is given in the thesis, but also the establishment process, the conversion relations of the instrument coordinate and the product coordinate are researched.Second, the mathematical model of geometry element is established and a linear least-square fitting model is deduced; Nonlinear least-square fitting method is developed to improve precision in fitting circles; also some key questions about point project, compensation of probe's radius and so on are studied.And then, the critical factors that affect measuring accuracy of the system were listed in the thesis, the quantitative analysis of them and an estimated formula of the single-axes uncertainty was given. At last, the simulation tests of the measuring technique and the measurement precision of the system described in the thesis were taken based on one real warhead's dimensions. The simulation results indicated that the measuring technique mentioned in this paper had high precision, and its measuring uncertainty could satisfy the requirements of the symmetry axes.