Patent GB-555052-A (GB)
Title: Radio fire control device for ordnance, artillery and the like
IPC: G01S3/42
Filed: 1941-03-25
Abstract: 555,052. Locating objects by reflected waves. ROST, H. F., THUNELL, K. H., VIGREN, S. D., and CLAESSON, P. H. E. March 25, 1941, No. 4018. Convention date, Jan. 10, 1940. [Class 37] [Also in Group XL] In order to locate and follow objects such as aircraft, radio transmitting and receiving means are arranged to sweep automatically in one or more planes, which sweeping action is automatically stopped when a reflected pulse is received and the driving means for the transmitter and receiver is automatically controlled so as to follow the aircraft. Fig. 2 shows an apparatus for seeking and following a target in three dimensions. A directed short wave transmitter 49 such as a magnetron tube has four receivers 50, 51, 52, 53 arranged symmetrically around it. The assembly is caused to rotate or oscillate about a vertical shaft 76 driven by a motor 78. On this shaft is mounted a horizontal shaft 77, driven by a motor 54, about which the transmitter and receivers can rotate or oscillate, so that the seeking device makes a spiral movement. The receivers 50 ... 53 are successively connected to an amplifier 61 by means of collectors 55-59, each one during a quarter of a revolution of the shaft 60. The amplifier 61 is connected to a rectifier 62, from which current is passed to condensers 68, 69 or 70, 71 by means of collector rings 63 ... 67 having insulated quadrants so arranged that current is passed to the condensers at the same moment as the corresponding collector rings 55 ... 59 make their contacts. The condensers 68 ... 71 are connected through amplifiers 72, 73 to polarized relays 74, 75 each of which has two windings. If the condensers 68, 69 receive equal charges they discharge equally through the windings of the relay 74 but in opposite directions, so that the relay is not actuated. If the target is not located symmetrically with respect to the receivers 52, 53 one condenser receives more charge than the other and the relay armature 82 engages one or other of the fixed contacts 81, 83. A similar action takes place with respect to the receivers 52, 53, condensers 70, 71, and the polarized relay 75. When either of the relays 74, 75 closes either of its contacts a relay 79 is operated and energizes one of the polechanging relays 87, 88, 90, 91 that control the motors 54, 78 in such a manner that the receivers are moved until the target is located in the common axis of the receivers. By means of scales on the shafts 76, 77 or by remote control devices the elevation and side angles can be observed, or the guns of a battery can be synchronously operated. The range is obtained by reading a frequency meter 105. In a modification the receiving means consists of a single directed receiver in front of which is located a rotating screen provided with an eccentric hole arranged to divide and scan the seeking field and adapted to allow reflected energy from two different equal parts of the seeking field to pass successively to the receiver and to the respective driving means. An auxiliary apparatus for observing the distance from and side angle to the target on a fluorescent screen, while on a second screen the elevation and side angles are observed is shown in Fig. 1. A transmitter 26 for directed frequency modulated ultra short radio waves, and a receiver 27 are mounted on a shaft 28 which is rotated by a motor. The transmitter and receiver are at the same time rotated through a right angle about a centre pin 29 by means of worm gear 31 and a shaft 30 rotated by a motor 32, so that they move in a spiral for searching the whole or part of the sky. Waves reflected from an aircraft are received by the receiver 27, and the beat frequency between the transmitted and received waves is a measure of the distance. The received waves are passed through an amplifier 33 to a frequency-sensitive device comprising condensers 34 which pass more current at high than at low frequencies. They are then passed through a rectifier 35 to potentiometers 37, 38 mounted on the shaft 28 and thence to the deflecting plates of a cathode ray tube 39. The spot on the screen indicates by its distance from the centre the distance of the aircraft and by its angular position the bearing thereof. A portion of the amplified current is passed through a rectifier 40 and amplifier 41 to the baffle plates of the cathode ray tube 39 and of a second cathode ray tube 46, having a hemispherical screen. By means of potentiometers 42, 43 on the shaft 28, which are connected to the deflecting plates of the tube 46, a light spot is obtained showing the side angle of the receiver 27 and therefore of the target. A potentiometer 44 on the shaft 29 is connected to the potentiometers 42, 43 so that the ray shows also the elevation angle. The tube 46 alone may be used for obtaining both the side and elevation angles, the distance being read on a frequency and distance indicating instrument connected in place of the frequency sensitive device 34 and the tube 39 being omitted. In a modification the condensers 34 are charged proportionally to the beat frequency and are connected to the deflection plates of the tube 46 by an electron relay actuated by the received amplified currents. An extra deflection of the cathode ray is thus obtained which indicates the distance of the target.