Patent GB-899608-A (GB)
Title: Apparatus for controlling the angular positional relationship between airborne craft
IPC: G01V3/16
Filed: 1958-10-21
Abstract: 899,608. Automatic control systems for aircraft. INTERNATIONAL NICKEL CO. OF CANADA Ltd. Oct. 21, 1958 [Oct. 24, 1957], No. 33634/58. Class 38 (4). [Also in Groups XXXVI and XL (c)] In apparatus for detecting and measuring ore deposits of the kind in which transmitting coils and receiving coils are located in different airborne craft, the craft are maintained in substantially constant angular positional relationship inter se by electro-optical devices carried by each of them. As shown, Fig. 1, an aircraft 10 trails two birds 12, 16, containing transmitting coils and receiving coils respectively, bird 12 carrying a photo-electric device 28 which is responsive to light radiated from a source 27 on the aircraft, and which controls means to operate the control fins 19 on the bird 12 to keep the angular position of the bird 12 relative to the aircraft constant; similarly, the angular position of the bird 16 relative to the bird 12 is maintained constant by photoelectric means 40 on the bird 16 responsive to a light source 39 on the bird 12. Positional control apparatus, Fig. 6.-Each light source comprises a lamp 60 supplied from a power source 58, and a perforated disc 64 on the shaft of a motor 62 is positioned across the path of light from the lamp, so that when the disc is rotated at a constant speed the light passing through a lens 66 is modulated at a constant frequency. Light-responsive apparatus comprises a lens 68 and a four-sided regular pyramidal prism 70 coaxial therewith. The prism 70 distributes the received light to four photo-cells, one adjacent each triangular face of the prism, opposite cells being connected electrically in opposition, so that when the craft in question are in correct mutual alignment the output from each pair of cells is zero. Deviations of the follower craft from its correct relative angular position in a vertical plane results in photo-cells 72a, 72b receiving different light supplies, the outputs of the cells being passed to circuitry 74 comprising amplifying circuits, filter circuits tuned to the frequency of modulation of the radiated light, and a comparison circuit, the output of which is fed to a motor 76 to position the horizontal control fins on the follower craft to restore its relative angular position. Similarly, deviation in a horizontal plane causes differential light to impinge on two cells 72c, 72d (Fig. 7, not shown) lying in a plane normal to the cells 72a, 72b, and controlling the vertical control fins of the follower craft. Ore detection apparatus. Fig. 2.-Power sources T1, T2 operating at frequencies f1, f2, respectively, are located in the aircraft 10, and supply transmitting coils 32, 33 which are disposed at right-angles to one another in the bird 12. In the bird 16, receiving coils 37, 38, respectively coplanar with coil 32 and coaxial with coil 33, and tuned to frequencies f1, f2, pass their received signals to amplifiers A1, A2, which may comprise a single common amplifier, the output of which is fed to a modulator 44. The modulated signal is passed to a detecting and comparing circuit 46 in the aircraft 10, the output of this circuit being fed to a recorder 48. Modifications.-The electro-optical devices 28, 40 on the birds 12, 16 may both be responsive to the light source 27, or to different light sources, on the aircraft. The light link between the aircraft 10 and the bird 12 may be omitted, reliance being placed solely on maintaining the relative angular dispositions of the birds 12, 16; in this case, a second control device on bird 12, responsive to a light source on bird 16, may control the fins on bird 12. Only one bird may be used, the receiving or transmitting coils being disposed therein, and the transmitting or receiving coils, as the case may be, being housed within an extension of insulating material located below the tail section of the aircraft.