A Radio Frequency Oscillator Technique for Measuring Projectile Transverse Displacement at Muzzle Exit.

The alignment of a projectile or projectile subcomponent relative to the gun tube axis at muzzle exit is a very important parameter to be considered in gun system investigation. The angle and magnitude of the displacement are usually quite small and can only be obtained by extremely complex instrumentation. Described in this report is a radio frequency oscillator technique which will provide a simple and reliable means for the measurement of the projectile displacement. A four segment sensor arrangement which forms part of a radio frequency oscillator circuit is mounted on the muzzle of the gun. Each segment is responsive to the passage of the projectile, with its output proportional to the proximity of the projectile to the individual sensor segments. By properly combining the detection signals, the horizontal and vertical components of the projectile displacement can be measured. From this, the angle and magnitude of the projectile or projectile subcomponent displacement relative to the gun tube axis can be derived.