Inversion Technique Of Structural Parameters Of Sky Screen Vertical Target Under The Uniform Straight Trajectory Model

Sky screen vertical target measurement system is used in the measurement of high frequency terminal trajectory firing dispersion commonly. Six screens are formed by the double-N shape sky screen vertical target in the air according to a predetermined angle. The target coordinates, the pitch, azimuth and flight velocity of the projectile can be calculated by measuring the intervals of projectile through the six screens, the target distance and the screen angle parameters. Regarding the angle parameter as the basic parameters of the test system, which is difficult to measure accurately in the system structure adjustment process, so it affects the precision directly. A kind of inversion about angle parameter of sky screen vertical target with double-N shape six-screen array is studied in this paper. The approximation of angle parameters are obtained by reversion to the paper target coordinates and the time sequence of the firing practice of projectile through the light screen arrays.Firstly, the measuring principle, which is the measurement system of sky screen vertical target with double-N shape six-screen array is studied. The measuring formula of the sky screen target measuring system is analyzed and simplified. The measuring formula is deduced from testing coordinate projections to the paper target coordinates, which is laid the foundations to investigate the sky-screen vertical target angle parameters inversion algorithm.Secondly, the method of reverse screen angle parameters using measuring results is studied. On the basic of the measurement formula for the measurement system of sky screen vertical target with double-N shape six-screen array, the angle parameters inversion algorithm is deduced, when the testing coordinate correspond exactly to the paper target coordinates or translation and rotation exist between them, and the inversion algorithm of angle parameters of two coordinate systems is simulated, its validity with oblique incidence angle in the latter case is confirmed.Thirdly, the error analysis and simulation of inversion algorithm of angle parameters in sky-screen target test system are studied. When the measurement error of bullet holes, time measurement error and other errors are given, the influence of angle parameter error indifferent shooting position and angle of the sky-screen vertical target measurement system is obtained. So, the measuring accuracy of the angle parameter can be improved by choosing proper shooting position and shooting angle in the test process.Finally, indoor test platform is designed for the measurement system of sky screen vertical target with double-N shape six-screen array.The light source of the sky screen target and the time signal generating device of projectile through the light curtain are designed. The whole process of installation and testing of the measurement system sky screen vertical target with double-N shape six-screen array is realized in room.The test results verify that the design of the indoor test platform can meet the requirements of the practical engineering.