GB1387836A - Target strike display apparatus - Google Patents

Abstract

1387836 Acoustic position-finding DEFENCE SECRETARY OF STATE FOR 5 March 1973 [21 Dec 1971] 59323/71 Heading H4D A device for indicating the position of a projectile relative to a target comprises electroacoustic transducer means arranged along opposite sides of the target plane, the transducers feeding time measuring means started by passage of the projectile through the target, the difference in times measured by the time measuring means of a particular transducer pair being obtained to obtain a position co-ordinate of the projectile, a visual display means being provided to display the projectile position. Target plane 10 is provided with, e.g. piezoelectric, transducers 14, 16 and 18, 20 feeding time measuring means 28, 30 and 32, 34. The time measuring means feed detecting means 38, 40 for obtaining the difference between the times measured. The detecting means provide signals for a display 42. As the projectile passes through plane 10 at position 44, a sound wave will be generated and will read, e.g., transducer 16, before transducer 14. Receipt of the wave at transducer 16 causes means 30 to start counting pulses from generator 36. Eventually the wave reaches transducer 14 and means 28 then starts counting. When means 30 reaches a predetermined maximum count, both counters stop and the difference in counts is related to co-ordinate x. Similarly, transducers 18, 20 provide coordinate y. The signals representing the count difference are fed to plotter 42 which determines the co-ordinates and displays position 44 on a replica 43 of the target. The plotter may be replaced by a C.R.T. having a storage display. The transducer means may be single elongated elements or may each consist of a number of separate transducers. If each transducer means comprises a number of separate transducers, only one pair of transducer means may be needed. In this case one co-ordinate is determined as above and the other co-ordinate determined by noting which transducer pair in the transducer means received the sound. The target origin 23 may be anywhere within the plane 10, the time measuring means being given initial counts to compensate. The time measuring means may be arranged so that only one means of a particular pair is limited to a maximum count.