Gun fire control systems

Abstract

A gun fire control system comprises a computer (15) having a first memory (15A) preprogrammed with true range to standard ballistic range conversion data and is operable on receipt of a true range value from a rangefinder (16) to output the corresponding standard ballistic range value. A second memory (15B) of the computer (15) is preprogrammed with correction coefficients (A,B,M,N) arranged in sets pertaining to different types of ammunition one set being operable according to the position of a selector switch (13) and being delivered to a calculator (15C) together with an operator correction value (COR) (from buttons 14A, 14B) which is a judgment on the magnitude and direction by which a projectile misses a target sighted according to the range value presented at display (11). Calculator (15C) operates according to a predetermined algorithm to establish parameter correction changes (.DELTA.AD, .DELTA.CT) and delivers these changes to calculator/store (15D) which updates and stores parameter values (AD, CT). An arithmetic unit (15F) evaluates a range correction factor from the data available from memory (15B) and unit (15D) at the ballistic range established by memory (15A). This range correction factor is combined with the ballistic range established by memory (15A) in unit (15G) and the corrected ballistic range made visibly available in display (11) to the operator. To establish initial values of the parameters (AD, CT) for use in a system restart mode when elapsed time between consecutive operations of the rangefinder (16) exceeds a preset value high and low operator correction averages (HCOR, LCOR) are evaluated on each operation of the system and stored in memory (15E).