Projectile Velocity Measurement Technology Based on Large Effective Area Laser Screen

A novel Laser screen velocity measuring method with large effective screen area is introduced for some special velocity measuring occasions like wide spreading range or big-size flying objects.The large effective screen area is formed by cylindrical mirror and fixed laser diode and large area photo-diode respectively on the two conjugate points.When flying objects with high speed pass through the laser screen,change of light flux is transformed into electronic signal and sampled by data sampling card and processed by computer.The chromatic aberration induced by cylindrical optics and the light power density distribution in laser screen are theoretically analyzed.The speed of Φ5.6 mm projectile passing through an animal and speed of one sort of large caliber projectile are measured by the laser screen system with effective screen area of 900 mm×900 mm and 500 mm×500 mm respectively.The typical sampled waveforms and measured data are given,which indicates the system has advantages of large effective target area,high sensitivity and high response.