Patent GB-833341-A (GB)
Title: Improvements in indicating and computing apparatus
IPC: G01S1/02
Filed: 1956-01-17
Abstract: 833,341. Course-recording apparatus. DEGEN, A. A. C. April 17, 1957 [Jan. 17. 1956(2)], Nos 1513/56 and 1514/56. Class 97(2) An instrument for representing in Cartesian co-ordinates the position of a moving vehicle or craft with respect to two given axes comprises means for setting an indicator in accordance with the Cartesian co-ordinates of an initial position of the vehicle or craft, resolving means responsive to the movement of the vehicle or craft and to the angle made by the said movement with the said axes for providing discrete electrical signals representing components of movement along the said axes, each signal representing the movement of the vehicle or craft through a given distance along the corresponding axis, and summing means for adding the components to the corresponding co-ordinates representing the initial position of the vehicle or craft, whereby there is provided a substantially continuous indication of the values of the Cartesian co-ordinates. In the form shown in Fig. 2 for converting polar co-ordinates data into Cartesian data, the range instrument 10 of an aircraft is coupled by a synchro link, represented by conductors 11, to a range switching unit 12 driven by a reversible motor 15 and including contacts 13 which produce pulses representing equal increments of range of the aircraft from an origin. The pulses are fed by a conductor 14 to a radial resolving unit 16 and energize a relay MR, the contact MR1 of which pulses the magnet of a rotary stepping switch M. A sine-cosine computing device 18 is driven by a reversible motor 19 under control of the existing bearing instrument 20 to which it is connected by a synchro link represented by conductors 22. Rotary switches 1S, 2S in the device 18 apply potentials by way of conductors 23 to contacts of the switch M so selected that, as the switch is stepped at a rate representing the radial speed of the aircraft, pulses are fed to conductors 24, 26 representing components of radial movement along mutually perpendicular axes. The switch 1S deals with the sines of angles between 0 and 45 degrees and the cosines of angles between 45 and 90 degrees and the resulting pulses corresponding to low value sines and cosines are fed to conductor 24. The pulses corresponding to high value sines and cosines dealt with by switch 2S are fed to conductor 26. The pulses are switched by the octant switch 28, according to whether the bearing is in the 0-45 degrees range or the 45-90 degrees range and depending the quadrant in which the bearing is contained, to provide pulses representing positive and negative increments in the x direction on the conductors 30, 32 and similar y increments on the conductors 34, 36. Each pulse represents the same increment of movement. Pulses are also obtained representing equal increments of components, resolved in the co-ordinate directions of movement perpendicular to the range vector. For any rate of change of bearing these components will be inversely proportional to range. A number of contacts 38 are operated by changes of bearing to produce pulses representing bearing increments of different sizes. These are fed to the unit 12 over conductors 40. Each size of bearing increment corresponds to a standard distance increment for a particular range of the aircraft from the origin. A switching system in the unit 12, described in detail in the Specification and operated in accordance with the target range, selects the train of bearing pulses most nearly appropriate. These pulses operate a relay 'TR of which the contact TR1 actuates a stepping which TM. The contacts of this - switch are so energized by conductors 48 in accordance with the actual range value that the pulses appearing on the conductor 50 represent increments of transverse movement. These are resolved, similarly to the increments of radial movement, in the unit 52. The pulses actuate a relay MRT the contact MRT 1 of which pulses a rotary switch MT, the contacts of which are connected to the rotary switches 1S, 2S to provide, on conductors 54, 56, pulses representing components of the transverse movement in the co-ordinate directions. These are also fed to the octant switch 28 which feeds pulses representing positive and negative x increments to the conductors 58, 60, and similar y increments to the conductors 62, 64. All the positive and negative x and y increments are fed to magnets associated with positive and negative sunwheels of x and y differentials 68, 70, the output shafts of which drive cams 88, 98 co-operating with contacts 90, 100 to pulse driving units 92, 102 which, respectively, move an indicator 94 in the x direction and an associated chart 96 in the y direction. The sine-cosine device 18 and the octant switch 28 are as described in Specification 833,342.