Circuit Design and Signal Analysis of a Sandwich-Type Sky Screen for Hypervelocity Projectile Velocity Measurement

Aiming at the problem that conventional sky screens cannot measure hypervelocity projectiles due to the frequency response limitations of photoelectric detection devices and signal processing circuits, a sandwich-type sky screen velocity measurement technique is proposed. A single lens paired with a dual-slit aperture plate forms two detection light curtains at a specific angle in space. When a hypervelocity projectile passes through both light curtains, the transit time is extended.High-speed PIN-type silicon photodiodes are employed in conjunction with a transimpedance preamplifier circuit to capture the projectile's passage-through signal. The sensitivity formula for the sandwich light curtain is derived, and the signal characteristics of projectiles passing through the curtain is analyzed. Through simulation equivalent testing and live-fire testing, the designed sandwich-type sky screen has been verified to extend the projectile's transit time through the screen, thereby reducing the frequency response requirements for subsequent circuitry and enabling the measurement of hypervelocity projectile.