GB825005A - Improvements in or relating to apparatus for determining the distance of a projectile from a target - Google Patents

Abstract

825,005. Photo-electric position determination. RANK CINTEL Ltd. Jan. 16, 1957 [Jan. 16, 1956], No. 1482/56. Class 40 (3). [Also in Group XL (c)] Apparatus for determining the distance of the flight path of a projectile from the centre of a target space defined by conical surfaces 2, 3 originating at the centre and extending to a narrow spherical zone 4 comprises a photoelectric device 1 receiving light from the zone 4 through a circumferential slot 6 in an enclosure 5, this light being directed on to a photo-electric cell 11 by a convex mirror 7, a lens 8 and an annular slit 10 in a partition 9 defining the target space. Thus passage of a projectile along a flight path such as A or B produces a signal which is fed to a device 22 through an amplifier 12. A further signal is derived from an acousto-electrical transducer 13 which responds to the shock wave of the projectile, this signal also being fed to the device 22 through an amplifier 14. Considering the flight path A the shock wave traverses path 20 and arrives at 13 at a point in time after generation of a signal in 1 corresponding to the time taken for the projectile to travel from 18 to 19. This time interval is directly proportional to the distance dA or dB of the projectile from the target and the device 22 indicates this distance. A delay circuit 15 compensates for the time taken for the projectile to travel between 13 and 1. A device 21 enables corrections to be made for the ambient temperature and the relative velocities of the target and projectile.