Patent GB-604213-A (GB)
Title: Improvements in and relating to electric orienting, electric aiming and fire control systems and apparatus therefor
IPC: G08C19/06
Filed: 1945-06-25
Abstract: 604,213. Ordnance. SPERRY GYROSCOPE CO., Inc. June 25, 1945, No. 16213. Convention date, June 23, 1944. [Class 92 (ii)] [Also in Group XXXVIII] In a, system for parallax correcting signals representative of the position of a remote point, e.g. a target, relative to a transmitting point, which may be a gunfire control point, the signals are corrected during transmission to a controlled point, such as a gun turret, by deriving a correcting voltage partially or wholly from the transmitted signals, and combining it with the original signals. As described with reference to Figs. 1 and 2, selsyns 32, 33 and 20, 21 associated with target position computing means A, give coarse and fine signals representative of the target elevation angle (Eg) and azimuth direction angle (Ag) respectively, these signals are supplied to gun controlling selsyns 36, 37 and 30, 31 through parallax correcting rotary transformers 34, 35 and 24, 25 which introduce a relative displacement between the respective receivers and transmitters depending in magnitude and sign, on the angle through which they are rotated. The rotary transformers, 34, 35, and 24, 25 are coupled to motors 41 and 40 which are controlled by a correcting voltage proportional in magnitude to cos Ag sin Eg/Do and sin Eg cos Ag/Do for the elevation and azimuth angles, where Do represents the slant range, and run until displacement signals from rotary transformers 96 and 230, coupled to motors 41 and 40, cancel the correction voltages. Deviation computing circuit. A transformer 45 having its primary connected to the coarse elevation selsyn stator gives a secondary voltage proportional to sin Eg, this voltage is combined with a reference A.C. voltage by means of a resistor chain 49, 50 and rectified by diodes 55, 56 so as to give a differential bias to variable Á pentodes 60 and 61 in accordance with the magnitude and sign of sin Eg. A voltage proportional to cos Ag is similarly obtained by means of transformer 71 and is applied to the grids of pentodes 60 and 61. Owing to the differential bias, and hence gain, of 60 and 61 an A.C. output proportional to sin Eg cos Ag is applied to variable Á pentode 87 by transformer 85, together with a negative bias proportional to Do which is obtained by rectifying the voltage from A.C. range potentiometer 94 in the computer A by means of diode 90. The output of pentode 87 which is proportional input/Do, is applied to one of the control grids of double pentode 105 which has its other pairs of electrodes connected. The opposing displacement voltage from transformer 96 is applied to the other control grid by means of potentiometer 100. The output is fed through amplifier stage 111 and cathode follower stage 124 to the balanced demodulator valve 155 which differentially varies the grid potential of the two halves of the A.C. operated double triode 165, so that relay arms 173 and 174 are tilted one way or the other to actuate motor 41, which runs until balance obtains in double pentode 105. In the azimuth correction computing circuit transformer 211 supplies a signal proportional to cos Eg which is amplified by valve 214 and rectified to give a bias for variable Á valve 210 which amplifies a signal from transformer 207 proportional to sin Ag, which is further amplified by variable valve 224 inversely with the range. The signal is then applied to double pentode 228 to control motor 40 or a similar manner to the elevation system. A switch 10 is provided whereby the correction circuits may be switched from computer A to another computer B. The above arrangement only gives correction where the computing means A and the gun turrets are disposed along an axis, such as the fore and aft axis of a craft. Fig. 3 shows an arrangement for computing the azimuth and elevation correction signals when this is not the case, these being, S. sin (α-Ag)/Do cos Ag, and S. sin Eg cos (α-Ag)/Do, respectively, where S and a are the polar co-ordinates of the turret with respect to the computer. The units 300- 305 give outputs as indicated from the indicated inputs. For example, unit 301 gives an output proportional to cos Ag/Do which is applied to unit 304 (and also unit 305) which gives an output proportional to sin Eg. cos Ag/Do. The outputs of units 302-305 are fed to transformers 305-309, which have turn ratios as indicated, e.g. 306 has a turn ratio corresponding to S. sin α, so that when their secondaries are connected as shown the resultant secondary voltages are proportional to the desired corrections, which are applied to the servo amplifiers through switches 10, which select the correct secondaries according to which of spaced computers A and B is being used. Fig. 4 shows the wiring of transformers 200, 71 and 211, which each comprise three transformers two of which (e1, e2) have primaries delta connected to the transmitter selsyn stators, and the third (e3) a relatively reversed delta connected primary. The secondaries are connected in series to give the desired voltage e 0  Fig. 5 shows an arrangement for obtaining the effective secondary centre tap which is required in the case of transformer 45.