GB1381945A - Gun - Google Patents

Abstract

1381945 Gun and sight arrangement BOFORS AB 25 Feb 1972 [26 Feb 1971] 8891/72 Heading F3C A gun which is arranged to be aimed at a target comprises a barrel, a gun sight coupled to the barrel so that its line of aim is in fixed alignment with the line of the barrel, common servo driving means for moving the barrel and sight together, aiming 7 and rangefinding 8 means controllable by a gunlayer for producing aiming and range signals, and a tracking unit 11 adapted to produce signals for controlling the servo driving means and having two phases of operation. The tracking unit is arranged in its first phase of operation to produce signals in dependence on the aiming and range signals such that the controlling signals represent the behaviour of the target as sensed by the gunlayer and is arranged in its second phase of operation to maintain a predetermined function of the controlling signals constant so that the controlling signals represent a predicted behaviour of the target. The servo-driving means consists of two servo motors 1, 2 for rotating the gun and sight which may be mounted together or connected via mechanical linkage in elevation and azimuth respectively. The aiming means 7 provides in polar co-ordinate form the co-ordinates LVr and SVr and the rangefinding means 8 the range r m and these values together with the slant range signal rl derived from the servo-driving means are fed into the tracking unit 11 in which the polar coordinates are converted to Cartesian coordinates. In the tracking unit 11 each coordinate is integrated to produce the velocity components of the target which in the second phase of the tracking unit operation remain constant. At or after the changover from the first phase to the second phase aim off correction signals X t , Y t , Z t are added by means of adders 10a, 10b, 10c respectively to the constant signals x m , y m , z m . The signals x k , y k , z k so produced are used to control the servomotors 1, 2. Error signals e hv and e sv are produced by resolvers 3, 4 mounted on shafts controlled by the servomotors and are fed through amplifiers 5, 6 to the respective servomotors. The time of flight of a projectile is calculated using the alert range signal r e correction values corresponding to varying muzzle velocities of projectiles and varying atmospheric conditions being fed into the time of flight calculator (Figs. 4, 5, not shown). If the gun is to be mounted for aiming in training and elevation a coordinate converter in the tracking unit requires two resolvers (Fig. 3a, not shown) whereas if the gun is to be mounted for training or elevation only the co-ordinate converter requires only one resolver (Fig. 3b, not shown).