US2070178A - Airplane navigating apparatus - Google Patents

Airplane navigating apparatus Download PDF

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US2070178A
US2070178A US729216A US72921634A US2070178A US 2070178 A US2070178 A US 2070178A US 729216 A US729216 A US 729216A US 72921634 A US72921634 A US 72921634A US 2070178 A US2070178 A US 2070178A
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pointer
wire
contact
eye
relay
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Jr Francis M Pottenger
James R Balsley
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S1/00Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
    • G01S1/02Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using radio waves

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  • ICE Our invention relates to devices for ascertaining the position of one point'in space with respect to a second point, having special reference to such devices incorporated in navigation apparatus, and is directed particularly to an automatic position-indicating system involving calculationby triangulation and providing guidance for the safe landing of aircraft under conditions of substantially no visibility.
  • the requisites of such apparatus for successful application to airplane navigation are: iirst, that the apparatus be independent of weather and light conditions; second, that the apparatus be accurate Within certain limits and be absolutely dependable; third, that the apparatus function with sufficient rapidity to keep pace with the ⁇ continuous change in location of Va speeding airplane; fourth, that the apparatus be fully automatic, requiring no manipulation or adjustment by the pilot; and, fth, that the apparatus include a visual indicator that Will clearly and conveniently reveal the position of the airplane eitherin units of distance from the landing field and altitude above the ground or reveal graphically the relation of the planes position to a desired line of approach to the landing 4 eld, or both.
  • pointers that will automatically be trained on the source of the radiation and have further provided automatic means for deriving the distance in question from the angular positions of these pointers.
  • pointers automatic by associating with them photoelectric cells having circuits selectively responsive to the electro-magnetic radiation, and we have provided automatic calculation by utilizing certain characteristics of electric circuits, as will be more fully disclosed hereafter.
  • the position continuously reckoned by iour apparatus is continuously indicated to the pilot in a manner that reveals not only the altitude of the airplane and the distance from the airport, but also reveals the relation of the planes position to a desired line of approach to the airport.
  • Fig. 1 diagrammatically represents the plan view of an airplane approaching a beacon at an airport
  • Fig. 2 diagrammatically represents the side view of an airplane approaching a beacon at an airport
  • Fig. 3 is the front elevation of a pointer, with its associated photoelectric eye
  • Fig. 4 is a plan view of Fig. 3;
  • Fig. 5 is a central longitudinal section taken as indicated by the line 5-5 of Fig. 4;
  • Fig. 6 diagrammatically presents the arrange- ⁇ ment of quadrant cathodes in a photoelectric eye
  • Fig. 'l is a diagram representing the outer lens of the photoelectric eye divided into quadrants for the purposes of description;
  • Fig. '7a is an enlarged central portion of Fig. 7;
  • Fig. 8 is a schematic arrangement of our system, showing the inter-relationships of the moving parts and the electric circuits involved;
  • Fig. 9 is a simplified diagram of certain circuits in Fig. 8.
  • Fig. 10 is a suggested arrangement of the indlcating instruments on a panel or chart:
  • Fig. 11 is the side elevation of a typical resistor employed in our apparatus
  • Fig. 12 is a transverse section taken as indicated by the lines
  • Fig. 13 is the side elevation of a resistor arranged vfor compensating movement; 5 Figs. 14, 15 and 16 are diagrams of circuits arranged for calculation by voltage measurements;
  • Figs. 17 and 18 are diagrams of circuits arranged for calculation by current measurements
  • Fig. 19 is a diagram of a circuit for calculation 10 by both voltage and current measurements
  • Fig.- 20 is4 a diagram of an electrical arrange-v ment for ground speed indication
  • Fig. 21 indicates the arrangement of cathodes in a second form of photoelectric eye in a pointer 15 construction
  • Fig. 22 is a diagram of the outer lens of the eye as divided into sectors corresponding to the cathodes of Fig. 21;
  • Fig. 23 is a wiring diagram of the circuits in- 20 volved in this second form of pointer
  • Fig. 24 is a plan view of a third form of pointer involving two arms here shown spread apart;
  • Fig. 25 is a similar View showing the two arms closed together in their normal positions
  • Fig. 26 is a longitudinal section through Fig. 25;
  • Fig. 27 is a fragmentary transverse section taken as indicated by line 21-21 of Fig. 25;
  • Fig. 28 is an enlarged view of a switch construction in this third form of pointer
  • Fig. 29 is a wiring diagram showing the circuits used in this third form o eye.
  • Fig. 30 is a diagram suggesting, as viewed from the front, the disposition on the airplane of three of this third form of pointer.
  • beacon N may generate any type of electro-magnetic radiation, but, for the4 purposes of the preferred form of our invention,
  • infra-red wave-length of approximately ten thousand angstrom units
  • pointers L and R may be understood by reference to Figs. 3 to 5.
  • a base plate 24 is fixed to the wing of the plane, with its longitudinal axis parallel with the longitudinal'axis of the ship.
  • the front end of the base plate supports a vertical bearing, generally designated 25, and afllxed to and supported by the rear of the base plate is an encased motor 26.
  • a horizontally movable turntable 21 is pivotally supported in parallel spaced relation to the base plate by bearing 25 and a series of steel balls 28 that are retained in a ball race 29 formed by complementary arcuate grooves in the turntable and base plate, respectively.
  • headed pin 30 fixed to the under side of turntable 21, extends through a suitable arcuate slot 3l in base plate 24.
  • turntable 21 The rear edge of turntable 21 is provided with an arcuate rack 32 concentric to bearing 25, the teeth of the rack being engaged by worm gear 33 driven by motor 26.
  • a second motor 34 mounted on turntable 21, near the rear, is a second motor 34.
  • a vertical pair of standards 35 presenting horizontal bearings 35a, the axis of these bearings intersecting the extended axis of vertical bearing 25.
  • An underslung cradle 36, pivotally supported by bracket 35, is provided with a vertically disposed arcuate rack 38, the teeth of which are .engaged by worm gear 39 driven by motor 34.
  • a globular photoelectric eye 40 having a base portion 4
  • the center of the spherical photoelectric eye is the pivotal point for movement in two planes, and this assemblage may be considered, therefore, as, in eiect, a pointer pivoted for universal movement about said center, the axis of the pointer being an imaginary line :r- (Fig. which line is also the longitudinal axis of photoelectric eye 40.
  • Motor 34 through worm gear 39, controls the disposition of this pointer through vertical arcs and motor 26, through worm gear 33, controls the angular disposition of the pointer through horizontal arcs.
  • one revolution of motor 26 produces thesame degree of angular displacement of the pointer as is caused by one revolution of motor 34, such provision being made by designing worm gear 33 as a double-pitch screw and worm gear 39 as a single-pitch screw.
  • a lens cylinder 42 mounted on the front of photoelectric eye 40 is a lens cylinder 42, coaxial with line :xx-rc, incorporating lens 42a. and a lter or light screen (not shown) excluding all but a narrow band of the selected electromagnetic radiations.
  • the photoelectric eye itself comprises, in effect, a plurality of photoelectric cells in a single bulb, there being a ring-shaped plate or anode indicated at 43, common to all the cells. and four separate cathodes 44, each being a semi-spherical quadrant in the rear hemisphere of eye 40, as indicated in Figs. 5 and 6. These quadrants or sectors are insulated from each other by spaces or avenues 45, the arrangement of the four cathodes being as shown in Fig. 6. It will be noted that these avenues intersect on axis @-2, so
  • the four cathodes, or cells, 44 will be considered as having correspond- Ving numbers I, 2, 3 and 4, the numeral of the cell corresponding to the quadrant of the front lens through which light passes and eventually falls upon the cell.
  • the numerical arrangement of the cells will depend upon the type of lens system used. If a single convex lens is employed, the numerical arrangement of the cells Will be as indicatedrin Fig. 6. Where in the appended claims the position oi a cell is given relative to the axis of the pointer, it will be understood that reference is made to the apparent position of the cell indicated by I', 2', 3', or 4 in Fig. 7.
  • Cathodes 44 are ⁇ of a material such as thalophide, having maximum sensitivity at 10,000 angstroms. It is also a requisite of the lens system that the electromagnetic radiations passed therethrough be focused to a sharp image point or circular spot of substantially unvarying magnitude as the airplane approaches the beacon.
  • Each individual photoelectrlc cell distinguished by a quadrant cathode 44, controls a separate input circuit, the 'description of one of which will suftlce for all.4
  • 'Ihe input circuit may be traced as follows: cathode I, wire 41, band pass illter comprising condenser 48 and two parallel tuned circuits 49, wire 58, ground 5
  • This circuit is tuned and filtered to the modulation frequency 500 cycles and controls the potential of grid 55 in amplifying vacuum tube 56.
  • Tube 56 is a heater type, having heating element 51 energized by a suitable source conventionally indicated at 58, the energizing circuit by condenser 63.
  • Grid 55 controls the output or Y plate circuit, which may be traced as follows: plate 64, wire 65, solenoid coil of relay 66, wire 61 wire 68, source of current conventionally indicated at 69, ground 18, ground 5
  • Relay 66 is normally open, i. e., open'when de-energized.
  • photoelectric cathode 2 is associated with vacuum tube 1
  • Numeral 11 indicates the armature of shuntwound motor 26 associated with horizontal movements of the left pointer L.
  • the ileld winding of that motor generally designated by the numeral 18, is center-tapped to oer the choice of a rightpropelling electromagnetic ileld or a left-propelling fleld, the two halves of the eld winding being, in eiect, independent, thereby providing means to ⁇ reversibly control the rotation of armature 11.
  • armature 19 of shuntwound motor 34 controlling the vertical position of the left pointer is reversibly controlled by similarly tapped field winding, generally designated 88.
  • a source of electromotive force to energize the motors is indicated conventionally at 8
  • the circuit through armature 11 may be traced: source 8
  • a parallel circuit through armature 19 may be traced as follows: wire 9
  • the circuit through the right propelling eld of motor 26 is: source 8
  • the circuit through the left propelling eld is: wire 96 to the center tap of field winding 18, the left-propelling half of eld Winding 18, wire
  • the circuit through the upward propelling field is: wire
  • the circuit through the downward propelling field is: wire
  • Relays 85, 86, 92 and 93 are normally closed and open only when energized.
  • the cathodes should be balanced, i. e., either that all four motor relays 66, 12, 14 and 16 be open, or that, as
  • the image diameter is slightly greater than that of circle I I5
  • the image at dead center will cause all four relays to be actuated, with the result that neither of the associated motors will be energized, and when the slightly oversized image shifts from dead center, three of the four relays will be opened.
  • the image is made too large, however, it may be possible for the image to shift diagonally from dead center without vdeenergizing more than one relay, in which case the motors do not respond. Because of this possibility, it is advisable to focus the image at slightly less than the diameter of circle H5.
  • the image will be reduced to what is virtually a point, the avenues being correspondingly narrow. Obviously, the problem of accuracy is simplified by focusing to a minute image. Absolute control of the size of the image may be accomplished by using an iris diaphragm within the lens system.
  • the automatic action of the pointers will be understood, the image of the beacon, in effect, seeking the center of the photoelectric eye that is xed to the pointer.
  • armature 11 rofates indirect proportion to the right and left movements of the left eye or pointer, and armature 'I9 moves in direct proportion to the up and down movements of the left eye or pointer; armature
  • 08 moves in direct proportion to the up and down movements of the right eye or pointer; and armature
  • An equation or formula for computing distance by triangulation involves a minimum of three factors in the case of an oblique triangle, or two lfactors in the case of a right-angle triangle, and
  • one of these factors must be a side of the triangle.
  • the base line represented by the distance between the pointers, is constant, while the other factor or factors are continuously variable.
  • any of the formulas for triangulation may be employed. If, for instance, the right pointer, while trained on the beacon, is perpendicular to the base line B, as shown in Fig. 1, the distance to the beacon measured along the axis of the right pointer will equal B tan p being the angle of the left pointer with respect to the base line. In such a calculation. there is only one variable, angle If one' of the pointers isnot perpendicular to the base line, a formula involving two variables is necessary.
  • the altitude of the airplane can be computed from the angular position of one of the pointers with respect to the horizontal.
  • Eig. 14 shows a potentiometer in which resistor
  • 22 is in series with one terminal of resistor
  • 24 limits the movement of contact
  • 22 will represent the sum of these logarithmic values, and, if the ,voltmeter have a suitably calibrated logarithmic scale, the numerical product of the constant and the variable may be ascertained directly from the position of the indicating needle of the voltmeter with respect to that scale.
  • Fig. 15 represents a similar arrangement, in which contact
  • Fig. 16 provides for multiplying two variable factors by a constant.
  • 28 wound-to vary as the logarithmic value of one factor, bridges battery
  • wound to vary as the logarithm of the second variable shunts the terminals of battery
  • 34 having its terminals connected .respectively to the lower ends of resisters
  • 35 calibrated to-indicate the product of the three factors, has one terminal connected with contact
  • Figures 14, 15 and 16 are offered to illustrate the principles of calculation by electric circuits. How these principles may be applied to our specific problem, as contemplated in the preferred form of our invention, may be understood by considering Fig. 9 together with Figs. 1 and 2. f
  • 38 of Fig. 9 wound to vary in accordance with the logarithmic tangent of an angle, shunts battery
  • 38 is controlled by movements of ,pointer L with respect tobase line B lower end of resistor
  • ,wound to vary as the logarithmic cosine of an angle shunts the terminals of a third battery
  • 43 is controlled by vertical movements of either pointer L or pointer R.
  • 44 is connected with contact
  • This second voltmeter is calibrated to give the instantaneous value of altitude H in Fig. 2.
  • one of the three batteries for instance battery
  • 48 is controlled by horizontal movements of pointer R.
  • 41 is in series with contact
  • Fig. 9 The circuit shown in elementary form in Fig. 9 may be recognized in the schematic arrangement of Fig. 8, corresponding numbers indicating corresponding parts.
  • 48 indicates an operative connection between armature and contact
  • 49 indicates an operative connection between armature
  • 50 likewise indicates an operative connection between armature
  • Fig. 13 shows a modication of such a resistor to provide for compensating movements of the resistor winding as required, for instance, in resistor
  • Angle in Fig. 2 is measured from the true vertical; therefore, resistor
  • the resistor shown in Fig. 13 is similar to that shown in Figs. 11 and l2, identical parts having corresponding prime numbers, but resistor ⁇ form
  • the voltmeters may be' simply independent in- .dicating devices on a panel, as shown in Fig. 8,
  • (Fig. 10).
  • a chart graphically indicates the position of the ship.
  • 39 on one side of the chart has an indicating needle
  • 44 positioned on the opposite edge of the chart is Voltmeter
  • will vary with thel position of the airplane in space, and, obviously, lines may be drawn on the chart to aid in the visualization of the position of the airplane in space.
  • 66 may be drawn to correspond to the movement of the intersection of the needle across the chart, as the airplane follows a desirable gliding angle or line of optimum glide to the landing i-leld (no signincance is to be attached to the specific disposition of line
  • the aviator can be informed continuously of his position in space relative to such a line of optimum glide, as well as his position relative to the beacon. It will be noted that the accuracy of our system increases as the beacon is approached.
  • 41 may be arranged at the bottom of chart
  • Such an arrangement has the advantage of confining the pilots attention to a relatively small area on the chart, and reveals the maximum amount of information at a glance.
  • the resistors may be standard, battery
  • our invention may be arranged to utilize the current characteristics of an electric circuit for the purpose of calculating the position of the airplane automatically.
  • a modification may be understood by considering diagrams given in Figs. 17 and 18.
  • L and R are pointers corresponding respectively to L and R of Fig. 1.
  • Pointer R' controls, as by arm
  • 69 is a right-angle bell crank having arms
  • 12 will always be equal to angle at beacon N, and contact
  • Operatively connected with pointer L is a movable contact
  • the base line for calculation by triangulation is represented by dotted line B' and the arrangement is such that when pointed L' is perpendicular to line B', contact
  • 16 varies in resistance as the logarithmic sine of an angle, the purpose of the arrangement being that as far as resistance 16 is concerned, the maximum current will ow when contact
  • 14 cooperating with winding 10, will further reduce the current of the circuit in accordance with the logarithmic cosecant of Ammeter
  • the electrical calculating circuit in effect adds logarithms electrically
  • the calculating circuit in effect subtracts logarithms electrically, the end being the same.
  • Fig. 18 is a duplicate circuit associated with the pointers L' and R' in the same manner as the circuit shown in Fig. 17, ⁇ having prime numbers corresponding to numbers in Fig. 17.
  • This duplicate circuit has, additionally, a movable resistor
  • 86 will be recognized as corresponding to resistor I4 l, and contact
  • This duplicate circuit is arranged to have a minimum current corresponding to the maximum value of the sum of the four logarithmsV involved in the equation:
  • Fig. 19 indicating an electrical arrangement for calculation in which both current and voltage are utilized, serves to further illustrate the scope of our invention.
  • 89 is shunted by resistor
  • 89 also energizes a parallel circuit through resistor
  • beacon and a second Wattmeter associated with a may be arranged to indicate distance to the -ing grounded at 202.
  • Such a diaphragm is omitted and a more simple lens system is used in a second type of eye we have developed.
  • This eye by virtue of its associated control circuit, automatically centers a relatively large image, and, having centered the image, thereafter responds to minute displacements of the image from the desired central position. Such response to minute displacements of the image is accomplished. as will be further explained, by what may be described as electrically balancing the energized areas of opposed cathodes in the eye.
  • the cathodes of an eye are arranged as three spaced sectors of a circle, lx, 2x and 3x, as shown in Fig. 21, the corresponding areas of the lens of the pointer eye being indicated as Iy. 2y and 3y in Fig. 22.
  • the negative pole of the battery be- Cathode sectors lx, 2x and 3.1:, respectively, of the photoelectric eye control the input circuits of corresponding amplifying tubes Iz, 2z and 32.
  • current through the photoelectric eye affecting tube la may be traced in the following circuit; ground 202. battery 20
  • This circuit is tuned and filtered to the modulation frequency and controls the potential of grid 208 in tube la.
  • the three amplifying tubes are of the heater type, each having a heating element 209 suitably energized (source not shown), and cach having a grid-bias battery 2
  • Current through photoelectric cathode la: will affect the potential of grid 208, thereby causing a proportional current
  • controls the plate circuit of tube 2z, and
  • 2 controls the plate circuit of tube 32.
  • 3 controlling the horizontal movements of the pointer
  • 4 controlling the vertical movements of the pointer.
  • 3 is connected by wire 2
  • 9 is connected to plate 22d of tube Iz, plate 22
  • 9 is connected to the positive pole of battery 2
  • 3associated with the half of the relay coil marked Right is connected by wire 225 to cathode 226 of tube Iz, and theA other terminal associated with the left portion of the relay coil, is connected by wire 221 to cathode 228 of tube 2z.
  • 4 at the up side of the relay coil is connected by Wire 229 and wire 225 to cathode 226 of tube Iz, and the, opposite terminal of relay 2
  • 3 is normally held at a central position by a pair of opposed springs 2'33, and maintains its central position both when neither the right coil nor the -leit coil is energized and also when both of the coils are equally energized. If the right coil alone is energzed, or, both coils being energized, if the right coil carries the greater current, armature 232 will swing against contact 234, thereby closing the circuit through wire 235, the right field in the eld winding of the motor that controls the horizontal 'J movement of the pointer, wire 236, armature 231 of the motor,.wire 238, motor-energizing battery 239, and relay armature 232.
  • relay armature 232 When the left coil of relay 2
  • 4 is normally held in a central position by opposed springs 243, and maintains its central position both when neither the up nor down coil is energized and also when both coils are equally energized.
  • relay armature 242 will swing against contact 244, thereby completing a circuit through wire 245, the up field of the field winding of the motor' that controls the vertical movements of the pointer, wire 246, armature 241 of the motor, wire 248, motor-energizing battery 249, and relay armature 242.
  • relay armature 242 When only the down coil of relay 2
  • the total current through the photoelectric eye is proportional to the total areas of the three cathode sectors energized by the image from the distant beacon, and* may change with the size of the image in accordance with changes of distance to the beacon.
  • the response of the pointerl itself i. e., the action of the two pointer motors,
  • the image will move hori zontally to the right until a larger portion of its area overlies sector 3y than overlies sector 2y, at which time the image will turn diagonally upward to the right. Subsequently, the image will change to movement vertically upward, followed by horizontal movement to the left above the midpoint of the eye, and continue in the somewhat spiral path oi' progression to the center of the eye. While the image does not move directly to the center of the eye, the response of the pointer is sufficiently rapid to complete the spiral within the short time interval required for the navigation of a rapidly flying plane.
  • a third form of pointer construction is based on the principle of bracketing the image of the beacon by a pair of eyes.
  • seeks the margin of the image at one side, and a second photoelectric eye 262 seeks the margin at the opposite side of the image, so that the pointer proper, a pivotally mounted rod 263 mechanically held exactly midway between the two eyes, is continuously directed at the center of the image.
  • This combination of two photoelectric eyes and an intermediate pointer is pivotally mounted on a stub shaft 264 extending from fixed base 265.
  • a lower gear 266 rotatably mounted on shaft 264 has a sleeve portion 261 extending to the top of shaft 264.
  • An arm 268 secured at its inner end to gear 266, as by screws, 269, carries at its outer end photoelectric eye 26
  • a collar 210 embraces sleeve 261 at the top and is provided with a depending arcuate ange 21
  • These members may be retained on shaft 264 by a suitable washer 213, the washer being retained in turn by a nut 214 threaded to the reduced end 215 of stub shaft 264.
  • Pointer 263 is rotatably mounted on sleeve261, the pointer being provided with an integral sleeve V216 rotatably embracing the first;v mentioned sleeve 261 and extending upward to collar 210.
  • a second collar 211 keyed toth'ef'upper end of this second sleeve by key 218 isfintegral with a radially extending contact arc 219.
  • This contact arm terminates in a downwardly extending finger 280.
  • This eye also radiallyl disposed relative to the axis of shaft 264, is at the outer end of arm 282, secured to the gear as by screws 283.
  • worm gear 288 meshing with lower gear 266, and
  • worm gear 289 meshing with gear 28
  • motor 292 is connected byshaft' V293 to worm gear 289 to control the movements of eye 262.
  • switch 296 comprises a fixed contact 293 and -a second contact 299 mounted on mem-v
  • switch-member 295 is deected by the opposite end of flange 21
  • contact arm 219 being virtually an extension of pointer 263, will move with the pointer.
  • An electric contact 305 of suitable construction is mounted on arm 219 to press continuously against a resistor -306, the resistor being curved concentric to the axis of stub shaft 264.
  • This resistor is wound to vary in accordance with the functions or the logarithm of a function of an ang-le. For example, if this pointer construction is substituted for pointer L 'of Fig. 1, resistor 306 will be wound to vary as the logarithm of a function angle p of the pointer with respect to the base line defined by the two pointers on the airplane.
  • a flexible switch member 301 is positioned near one end of resistor 306 in a position to be deflected by the overhanging end or iinger 280 of the pointer, and a similar exible switch member 308 is positioned near the opposite end of resistor 306.
  • Deection of member 301 opens two switches, designated generally by the numerals 309 and 3
  • deflection of member 308 opens two switches, generally designated by numerals 3
  • 2 are in their normal closed positions, while switch 302 is in its normal open position.
  • Each of the two photoelectrlc eyes comprises a suitable casing 3
  • each cathode of each eye is semicircular, as viewed'from the front, and, in a pair of eyes, the cathodes are oppositely disposed, as indicated in Fig. 24, and, again, in Fig. 30, the latter figure showing diagrammatically the disposition of three pairs of eyes on an airplane as viewed from the front.
  • each cathode takes in approximately half the field of vision of an eye, so that a pair of eyes having complementary cathodes, as shown. will, together, cover the entire field of vision of one eye of the type shown in Fig. 6 or the type shown in Fig. 22.
  • switch 302 is arranged to close only when the two cathodes are moved into definitely overlapping relation, such relationship being the normal relationship of the two eyes when not aiected by the distant beacon.
  • An amplifying tube 324 is associated with eye 26
  • Grid 326 of tube 324 is connected to the photoelectric anode side of the associated band pass filter and cathode 321 of tube 324 is connected through grid bias battery 328 to the opposite side of the band pass filter.
  • grid 329, of tube 325 is connected to the photoelectric anode side of the associated band pass filter, and Acathode 338 of tube 325 is connected to the opposite side of the associated band pass lter through grid bias battery 33
  • Each of the amplifying tubes is a heater type
  • heating element 332 having a heating element 332 energized from al suitable source (not shown).
  • Theplate circuit of tube 324 includes a suitable battery 333 and the solenoid coil 334 of a relay that is generally designated by numeral 335.
  • the plate circuit of tube 325 includes battery 336 and solenoid coil 331 of a second relay generally designated by numeral 338.
  • v Armature 348 .of relay 335 carries two spaced insulated contact members 34
  • armature 349 of relay 338 carries two spaced insulated contact members 358 and 35
  • relay 338 is energized by current through coil 331, armature 349 moves contact member 358 from a normal position electrically connecting contacts 352 and 353 to a second position electrically connecting contacts 354 and 355, and simultaneously moves contact member 35
  • Relay 335 controls the action of motor 298, thereby controlling the movements of the lower photoelectric eye 26
  • the armature and the split eld coil of motor 298 are generally designated by numerals 358 and 359, respectively; and, on the other side of the diagram, the armature and the split eld coil of motor 292 are generally designated. by numerals 368 and 36
  • Contact 341 is connected to the left eld' of the motor associated with eye 26
  • Contact 343, associated with left relay 335; is connected to the right eld half of eld coil 359 of the same motor, the connection being through switch 389, previously described, and in series therewith, a second switch 362, the ⁇ purpose of which second switch will be described later.
  • Contact 351, associated with right relay 338, is connected with the right field of the motor controlling the right eye 262, the connection being through the two switches 291 and 3
  • Contact 353 is connected to the left eld of the motor controlling the right eye 262, the connection being through two switches in series, switch 3
  • connection is made from the center tap of field coil 359 of the motor controlling the left eye through armature 358 of that motor to contact 345 of left relay 335.
  • connection is made from the center tap of iield coil 36
  • Wire 364 interconnects contact 345 of the left relay and contact 354 of the right relay, and is connected to one terminal of motor-energizing .battery 365 by a branch wire 366, this branch wire being controlled by switchV 382, previously described, (Fig. 24).
  • the second terminal of battery 365 is connected to wire 361, which wire interconnects contacts 344 and 348 of the left relay and contacts 356 and 352 of the right relay.
  • Motor 298 will cause eye 26
  • switch 382 will automatically close. Whenever relay 335 is deenergized while switch 382 is closed eye 26
  • switch 382 When switch 382 first closes at the beginning of the leftward movement of the left eye, the movement described above, the right eye will also move to the left following the rst eye, because of the following circuit: battery 366, wire 366, switch 382, wire 364, motor armature 368, left field of 75 coils 36
  • right relay 338 will be energized and the eye willreverse tov the right because of y the following circuit: battery 365, wire 361, contact 356, contact member 35
  • each eye thus moves outward when energized and inward lwhen deenergized, it may -be said that the two eyes bracket" the image.
  • an auxiliary motor-energizing battery 369 (Fig. 29) is connected by one terminal to wire 364, the other 4ten'ninal being connected to a switch 310.
  • This switch is movable to one position connecting with wire 31
  • Switch 310 is mechanically connected to switch 362 to open that switch when connection is made with wire 31
  • Switch 363 be.
  • Thisl third pointer construction has several advantages. It will accommodate itself to an image of any diameter, the two eyes spreading apart to accommodate the dimensions of the image while the pointer proper is automatically directed at the center of the image.
  • the eye construction itself is relatively simple, there being no critical relationship between cathode spacing in an eye and the size of the image. It is important to note, also, that in the case of the previously described pointer constructions. the image may conceivably vibrate so fast across two opposed cathodes as to have the same eiect as an inordinately large image simultaneously overlying the two opposed cathodes.
  • Vacuum tube 316 is shown here as a batteryoperated screen grid tube, although other types may be employed.
  • Filament 311 is heated by an A battery 318,'the current being controlled by rheostat 319.
  • screen 333 of the tube is connected to a central cell of B battery 38
  • Plate 333 of the tube is connected to ammeter 334 by wire 335, the ammeter, in turn, being connected to the positive pole of battery 33
  • the negative pole oi C battery 336 is connected to grid 331 of thi ⁇ tube through a relatively high resistance 338.
  • a n independent circuit comprises a suitable battery 339, shunted .by a suitable resistor 393l wound to varyfdirectly as the tangent of an angle.
  • This resistor is provided' with a movable contact 39
  • This contact is mechanically controlled by tential of contact 39
  • is connected by wire 392 to grid 381 and, therefore, to the grid end of resistance 388.
  • a suitable condenser 393 is inserted between the low potential end of resistor 390 and the neg-ative pole of C battery 386. It is suggested that the condensor have a capacity of one microfarad and that resistance 388 have a rating of 106 ohms, -if a time constant ofv approximately one second is desirable. It is apparent that charges on opposite sides of condensor 393 will balance at values determined by the position of contact 39
  • This compensating current is dependent solely upon changes in potential of contact 39
  • Ammeter 384 is indexed to serve as a speed indicator, being set to show zero speed at normal amperage in the plate circuit as determined by normal potential of grid 381.
  • angle p becoming progressively more acute, contact 39
  • This transitory compensating current by making grid 381 less negative, causes a proportionate increase in the current through the plate circuit of ⁇ tube 316, so that ammeter 384, being properly calibrated, will 'indicate the instantaneous speed with which the airplane approaches the beacon.
  • Apparatus for computing 4the distance between two points comprising, in ⁇ combination: means generating electro-magnetic radiations from one of said points, the otherbeing the receiving point; means at the receiving point for receiving said generated electro-magnetic radiation; two pointers associated with the receiving point spaced to ceaA base line for computing distance by triangulation; means connected with each pointer responsive to said electro-magnetic radiations to automatically train each pointer on the source of the radiations; and means operatively connected to at least one of said pointers to automatically derive the distance between the two points from the angular disposition of said pointers with respect to said base line.
  • Apparatus for computing the distance between two points comprising, in combination: means generating electro-magnetic radiations from one of said points, the other being the receiving point; means at the receiving point for receiving said generated electro-magnetic radiation; two pointers associated with the receiving point spaced to dene a base line for computing distance by triangulation; means connected with each pointer responsive to said electro-magnetic radiations to automatically train each pointer on the source of the radiations; an electric circuit having a variable energy characteristic determined by two factors, said characteristic corresponding in value with the distance between the two points to be measured, said factors corresponding in value with factors in an equation for computing the distance by triangulation; means interconnecting the pointers and circuit whereby the pointers control said characteristic through at least one of said factors in accordance with said equation; and means controlled by the circuit to indicate the instant value of said characteristic, said means being adapted to express the Value as distance between the two points.
  • Apparatus for computing the distance between two points comprising, in combination: means generating electro-magnetic radiations from one of said points, the other being the receiving point; means at the receiving point for receiving said generated electro-magnetic radiations; two pointers associated with the receiving point spaced to define a base line for computing distance by triangulation; means connected with each pointer responsive to said electro-magnetic radiations to automatically train each pointer on the source of the radiations; an electric circuit; at least one voltage-regulating means associated with the circuit corresponding with two or more factors in a triangulation equation and adapted to vary the voltage of said circuit in accordance with said factors, one of said pointers being operatively connected to said voltage regulator; and a voltmeter in said circuit calibrated in units of distance.
  • Apparatus for computing the distance between two points comprising, in combination: means generating electro-magnetic radiations from one of said points, the other being the receiving point; means at the receiving point for receiving said generated electro-magnetic radiations; two pointers associated with the receiving point spaced to define a base line for computing distance by triangulation; means connected with each pointer responsive to said electro-magnetic radiations to automatically train each pointer on the source of the radiations; an electric circuit having a minimum voltage corresponding in value to the logarithm of a constant in a.

Description

F. M. POTTENGER, JR., E-r AL 2,070,178
AIRPLANE NAVIGATING APPARATUS Filed June e, 1934 8 shee'ts-sneet 1 D= Dis-ance Feb. 9, 1937.
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AIRPLANE NAVIGATING APPARATUS Filed June 6, 1954 8 Sheets-Sheet 2 Feb. 9, 1937. F. M. POTENGER, JR., TAL 2,070,178
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AIRPLANE NAVIGATING APPARATUS Filed June 6, 1954 8 Sheets-Sheet 7 f wwf-mm 2@ 205 A? 1, kz', wir:
y 2/9 04 226 f 2 /z Patented Feb. -9, 1937 2,070,178 AmPLANE NAVIGATING APPARATUS Francis M. Pottenger, Jr., Monrovia, and James R. Balsley, La Canada, Calif.; said Balsley assignor of twelve and one-half per cent to Paul Whittier and twelve and one-half per cent to Keith Scott, both of Los Angeles, Calif.
Application June 6, 1934, Serial No. 729,216
22 Claims. (Cl.- 250-11) ICE Our invention relates to devices for ascertaining the position of one point'in space with respect to a second point, having special reference to such devices incorporated in navigation apparatus, and is directed particularly to an automatic position-indicating system involving calculationby triangulation and providing guidance for the safe landing of aircraft under conditions of substantially no visibility.
The application of such a device to blind iiying involves numerous dimculties, the solution of which demonstrates certain objects and advantages of our invention as will become apparent in our later detailed description.
In general, the requisites of such apparatus for successful application to airplane navigation are: iirst, that the apparatus be independent of weather and light conditions; second, that the apparatus be accurate Within certain limits and be absolutely dependable; third, that the apparatus function with sufficient rapidity to keep pace with the` continuous change in location of Va speeding airplane; fourth, that the apparatus be fully automatic, requiring no manipulation or adjustment by the pilot; and, fth, that the apparatus include a visual indicator that Will clearly and conveniently reveal the position of the airplane eitherin units of distance from the landing field and altitude above the ground or reveal graphically the relation of the planes position to a desired line of approach to the landing 4 eld, or both.
' our system, and, in addition, we have providedA than mechanical interlocking connections; and.. we have entirely eliminated the human equation from the functioning of the device.-- These provisions all have a bearing on the dependability of for modulating the infra-red rays and making our apparatus selectively responsive to the modulated rays in orderto avoid any possibility of interference from infra-red rays extraneous to our system.
Our apparatus keeps pace with the rapidly changing factors involved, because it functions electrically rather than mechanically.
To meet the fourth requirement, the characteristic of being automatic, in a system of measuration by triangulation involving electro-magnetic radiation, we have provided pointers that will automatically be trained on the source of the radiation and have further provided automatic means for deriving the distance in question from the angular positions of these pointers. We have made the pointers automatic by associating with them photoelectric cells having circuits selectively responsive to the electro-magnetic radiation, and we have provided automatic calculation by utilizing certain characteristics of electric circuits, as will be more fully disclosed hereafter.
Finally, the position continuously reckoned by iour apparatus is continuously indicated to the pilot in a manner that reveals not only the altitude of the airplane and the distance from the airport, but also reveals the relation of the planes position to a desired line of approach to the airport.
The objects and advantages of our invention,
`indicated by the above summary, will become more apparent in the detailed description to follow, as will certain other features illustrated by our preferred embodiment of the invention.
In the accompanying drawings:
Fig. 1 diagrammatically represents the plan view of an airplane approaching a beacon at an airport;
Fig. 2 diagrammatically represents the side view of an airplane approaching a beacon at an airport;
Fig. 3 is the front elevation of a pointer, with its associated photoelectric eye;
Fig. 4 is a plan view of Fig. 3;
Fig. 5 is a central longitudinal section taken as indicated by the line 5-5 of Fig. 4;
Fig. 6 diagrammatically presents the arrange-` ment of quadrant cathodes in a photoelectric eye;
Fig. 'l is a diagram representing the outer lens of the photoelectric eye divided into quadrants for the purposes of description;
Fig. '7a. is an enlarged central portion of Fig. 7;
Fig. 8 is a schematic arrangement of our system, showing the inter-relationships of the moving parts and the electric circuits involved;
Fig. 9 is a simplified diagram of certain circuits in Fig. 8;
Fig. 10 is a suggested arrangement of the indlcating instruments on a panel or chart:
Fig. 11 is the side elevation of a typical resistor employed in our apparatus;
Fig. 12 is a transverse section taken as indicated by the lines |2-I2 of Fig. 11;
Fig. 13 is the side elevation of a resistor arranged vfor compensating movement; 5 Figs. 14, 15 and 16 are diagrams of circuits arranged for calculation by voltage measurements;
Figs. 17 and 18 are diagrams of circuits arranged for calculation by current measurements; Fig. 19 is a diagram of a circuit for calculation 10 by both voltage and current measurements;
Fig.- 20 is4 a diagram of an electrical arrange-v ment for ground speed indication;
Fig. 21 indicates the arrangement of cathodes in a second form of photoelectric eye in a pointer 15 construction;
Fig. 22 is a diagram of the outer lens of the eye as divided into sectors corresponding to the cathodes of Fig. 21;
Fig. 23 is a wiring diagram of the circuits in- 20 volved in this second form of pointer;
Fig. 24 is a plan view of a third form of pointer involving two arms here shown spread apart;
Fig. 25 is a similar View showing the two arms closed together in their normal positions;
Fig. 26 is a longitudinal section through Fig. 25;
Fig. 27 is a fragmentary transverse section taken as indicated by line 21-21 of Fig. 25;
Fig. 28 is an enlarged view of a switch construction in this third form of pointer;
Fig. 29 is a wiring diagram showing the circuits used in this third form o eye; and
Fig. 30 is a diagram suggesting, as viewed from the front, the disposition on the airplane of three of this third form of pointer.
In applying our invention to the problem of navigating an airplane, we have the choice of establishing our base for triangulation either on the landing eld or on the plane. The principal advantage of having the base on the landing field 40 's that such a base may be of relatively great extent compared to a base established on the plane, with consequent greater permissible variation from absolute accuracy on the part of the calculating apparatus. One disadvantage of a base on 45 the minding new arises from the fact that with changing wind conditions the airplane must approach the landing field from different directions, so that, if but one base is established on the field, the relation of the line of approach of 50 the airplane to that base is not the same for each direction of approach. Such difficulties may be .met by providing for a selection of bases on the landing neld, or by providing for adjustments in the computing apparatus of the airplane to 55 be made in accordance with the direction of approach. We prefer, however, to establish the base of triangulation at the airplane, so that only one radiating beacon is required at the airport. Figs. 1 and 2 indicate the relations involved in 60 the approach of an airplane having such a base line, to a single beacon on the landing field. n
the airplane, generally designated 20, are two pointers, L and R, the position of which and alignment of which with respect to beacon N are in- 65 dicated by dotted lines 2l and 22. In Fig. 2, dotted line 23 represents either or both lines 2| and 22 of Fig. 1. Beacon N may generate any type of electro-magnetic radiation, but, for the4 purposes of the preferred form of our invention,
70 we contemplate employing quasi-optical waves,
as, for example, an infra-red wave-length of approximately ten thousand angstrom units, and we further contemplate modulating to one hundred per cent (100%) such' .radiation with some de- 75 sirable frequency, as ve hundred (500) cycles per second. By arranging the eyes to be selectively responsive to such modulation, we avoid interference by stray infra-red radiation extraneous to our system.
The construction of pointers L and R, may be understood by reference to Figs. 3 to 5. For each pointer-a base plate 24 is fixed to the wing of the plane, with its longitudinal axis parallel with the longitudinal'axis of the ship. The front end of the base plate supports a vertical bearing, generally designated 25, and afllxed to and supported by the rear of the base plate is an encased motor 26. A horizontally movable turntable 21 is pivotally supported in parallel spaced relation to the base plate by bearing 25 and a series of steel balls 28 that are retained in a ball race 29 formed by complementary arcuate grooves in the turntable and base plate, respectively. To prevent the two parts from separating unduly, headed pin 30, fixed to the under side of turntable 21, extends through a suitable arcuate slot 3l in base plate 24.
The rear edge of turntable 21 is provided with an arcuate rack 32 concentric to bearing 25, the teeth of the rack being engaged by worm gear 33 driven by motor 26. Mounted on turntable 21, near the rear, is a second motor 34. Integral with the forward portion of the turntable is a vertical pair of standards 35 presenting horizontal bearings 35a, the axis of these bearings intersecting the extended axis of vertical bearing 25. An underslung cradle 36, pivotally supported by bracket 35, is provided with a vertically disposed arcuate rack 38, the teeth of which are .engaged by worm gear 39 driven by motor 34.
A globular photoelectric eye 40, having a base portion 4|, is supported on cradle 36, with its spherical center coincident with the aforesaid intersection of the horizontal pivotal axis of the cradle with the vertical axis of pivot bearing 25 of the turntable. It will be noted that by virtue of the described arrangement the center of the spherical photoelectric eye is the pivotal point for movement in two planes, and this assemblage may be considered, therefore, as, in eiect, a pointer pivoted for universal movement about said center, the axis of the pointer being an imaginary line :r- (Fig. which line is also the longitudinal axis of photoelectric eye 40. Motor 34, through worm gear 39, controls the disposition of this pointer through vertical arcs and motor 26, through worm gear 33, controls the angular disposition of the pointer through horizontal arcs. Preferably, one revolution of motor 26 produces thesame degree of angular displacement of the pointer as is caused by one revolution of motor 34, such provision being made by designing worm gear 33 as a double-pitch screw and worm gear 39 as a single-pitch screw.
Mounted on the front of photoelectric eye 40 is a lens cylinder 42, coaxial with line :xx-rc, incorporating lens 42a. and a lter or light screen (not shown) excluding all but a narrow band of the selected electromagnetic radiations. The photoelectric eye itself comprises, in effect, a plurality of photoelectric cells in a single bulb, there being a ring-shaped plate or anode indicated at 43, common to all the cells. and four separate cathodes 44, each being a semi-spherical quadrant in the rear hemisphere of eye 40, as indicated in Figs. 5 and 6. These quadrants or sectors are insulated from each other by spaces or avenues 45, the arrangement of the four cathodes being as shown in Fig. 6. It will be noted that these avenues intersect on axis @-2, so
"42 may be considered as divided into four quadrants, I', 2', 3', and 4', respectively, as indicated in Figs. 3 and 7. The four cathodes, or cells, 44 will be considered as having correspond- Ving numbers I, 2, 3 and 4, the numeral of the cell corresponding to the quadrant of the front lens through which light passes and eventually falls upon the cell. Obviously, the numerical arrangement of the cells will depend upon the type of lens system used. If a single convex lens is employed, the numerical arrangement of the cells Will be as indicatedrin Fig. 6. Where in the appended claims the position oi a cell is given relative to the axis of the pointer, it will be understood that reference is made to the apparent position of the cell indicated by I', 2', 3', or 4 in Fig. 7.
Cathodes 44 are` of a material such as thalophide, having maximum sensitivity at 10,000 angstroms. It is also a requisite of the lens system that the electromagnetic radiations passed therethrough be focused to a sharp image point or circular spot of substantially unvarying magnitude as the airplane approaches the beacon.
The manner in which a photoelectric eye and the associated mechanisms may serve automatically to train the pointers L and R continuously upon beacon N will now be explained. The terms upward", downwardright and left, used to ydescribe movements of the pointer, will be understood as movements having such appearance to an observer facing the pointers from the front. It will be apparent, then, that because of the disposition of the photoelectric eye with respect to its associated pointer, when an image is projected on cathode or cell quadrant I (quadrant of the lens), thereby energizing the photoelectric circuitv through that particular cell, the pointer should react by moving upward to the left, in a direction tending to center the image at neutral square 46, thereby training axis :v of the pointer on the distant beacon. The arrangement of apparatus associated with the two pointers for providing such reaction to radiations from the distant beacon is set forth schematically in Fig. 8.
Each individual photoelectrlc cell, distinguished by a quadrant cathode 44, controls a separate input circuit, the 'description of one of which will suftlce for all.4 For example, consider cell I of the left wing. 'Ihe input circuit may be traced as follows: cathode I, wire 41, band pass illter comprising condenser 48 and two parallel tuned circuits 49, wire 58, ground 5|, ground 52, battery 53, wire 54, and ring plate ory anode 43,
vpreviously mentioned. This circuit is tuned and filtered to the modulation frequency 500 cycles and controls the potential of grid 55 in amplifying vacuum tube 56.
Tube 56 is a heater type, having heating element 51 energized by a suitable source conventionally indicated at 58, the energizing circuit by condenser 63. Grid 55 controls the output or Y plate circuit, which may be traced as follows: plate 64, wire 65, solenoid coil of relay 66, wire 61 wire 68, source of current conventionally indicated at 69, ground 18, ground 5|, wire 58,
resistor 62 and tube cathode 6|. Relay 66 is normally open, i. e., open'when de-energized.
It is apparent from this arrangement that when cathode 6| is energized by the focused infra-red image modulated at the selected frequency, an alternating current voltage of the modulation frequency will be developed across tuned circuits 49 and the plate current of the tube will be increased suciently to close relay 66.
In like manner, photoelectric cathode 2 is associated with vacuum tube 1| and normally open relay 12; photoelectric cathode 3 is associated with tube 13 and normally open relay 14; and photoelectric cathode 4 is associated with tube 15 and normally open relay 16.
Numeral 11 indicates the armature of shuntwound motor 26 associated with horizontal movements of the left pointer L. The ileld winding of that motor, generally designated by the numeral 18, is center-tapped to oer the choice of a rightpropelling electromagnetic ileld or a left-propelling fleld, the two halves of the eld winding being, in eiect, independent, thereby providing means to` reversibly control the rotation of armature 11. In the same Way, armature 19 of shuntwound motor 34 controlling the vertical position of the left pointer is reversibly controlled by similarly tapped field winding, generally designated 88.
A source of electromotive force to energize the motors is indicated conventionally at 8|. The circuit through armature 11 may be traced: source 8|, wire 82, wire 83, wire 84,' either relay or relay 86, Wire 81, armature 11, Wire 88, wire 89, wire 98, back to source 8|. A parallel circuit through armature 19 may be traced as follows: wire 9|, branchingirorn wire 83, either relay 92 or 93, Wire 94, armature 19, and wire connecting with wire 89.
The circuit through the right propelling eld of motor 26 is: source 8|, wire 68, wire 89, wire 96 to the center tap of eld Winding 18, the right-propelling half of field winding 18, wire 81, solenoid coil of relay 85, wire 98 through either relay 12 or relay 16, wire 99, thence to Wire 83 on the other side of source 8|. The circuit through the left propelling eld is: wire 96 to the center tap of field winding 18, the left-propelling half of eld Winding 18, wire |88, solenoid coil of relay 86, wire 8| through either Arelay 66 or relay 14 to wire 99 on the other side of source 8|.
The circuit through the upward propelling field is: wire |82 branching from wire 89, center tap of eld winding 80, the up-propelling half of field Winding 88, wire |83, solenoid coil of relay 92, wire |84, either relay 66 or relay 12, to wire 99 on the other side of source 8|. The circuit through the downward propelling field is: wire |02 to center tap of eld winding 88, the down-propelling half `of field winding 88, wire |85, solenoid coil of relay 93. wire |86, through either relay 14 or relay 16 to wire 99 asbefore.
Relays 85, 86, 92 and 93 are normally closed and open only when energized.
In the other half of Fig. 8 the parts corresponding to the above enumerated elements are correspondingly situated and need not be recited. Armature |88 controls the vertical movement of pointer R, and armature |89 controls the horizontal movement of that pointer.
'I'he functional relation of a photoelectric eye` to its associated pointer vmay be understood by describing the effect of an infra-red image at the selected modulation cast upon quadrant I of left eye L. To avoid confusion arising from any inversion in the order of the quadrants on the four cathodes with respect to the order of the quadrants on the front lens, the path of the image will be described with respect to the receiving quadrants I, 2', 3', 4' on the lens, as may be understood by reference to Fig. '7.
When the infra-red image spot appears on quadrant I of the lens at the position III) (Fig. 7), cathode quadrant I thereupon becoming activated discharges electrons that are attracted by anode 43 of the photoelectric eye. This action closes the input circuit associated with tube 56, which tube thereupon serves as an amplifying relay to close the circuit through the solenoid coil of relay 66, closing the relay. The closing of relay 66 energizes the up-propelling half of field Winding 80 associated with armature 19, and also energizes the left-propelling half of lleld winding 18 associated with armature 11. The simultaneous movements of these two armatures move the eye upward and to the left so that the path of the image is a-component of those two movements, the image moving diagonally, as indicated by dotted line I I I. When the image spot has moved diagonally sulciently to encroach upon quadrant 2 of the lens, as indicated at II2, cathode 2 also is energized, causing relay 12 to close. Both sides of field coil 18 are now energized and, being opposed, cancel each other as far as they affect armature 1-1. Since both relays 85 and 86 are now energized, the circuit through armature 11 is broken. Rotation stops in armature 11 of motor 26, but continues in armature 19 of motor 34, so that the image spot now moves vertically downward asndicated by dotted line II3. When the image arrives at the exact center of the lens, as indicated at II4, it bridges all four quadrants, thereby causing all four relays 66, 12, 14 and 16 to close and relays 85, 86, 92 and 93 to open, stopping-movement of pointer L. At this position, pointer L is trained on beacon B. The same result will be attained if the image when centered clears all the quadrants or encroaches upon none of the quadrants suiciently to operate any of relays 66, 12, 14 and 16.
It has been indicated above that when the imageis centered on neutral square 46, the cathodes should be balanced, i. e., either that all four motor relays 66, 12, 14 and 16 be open, or that, as
1 an alternate situation, all four said relays 'le closed, and that when the image shifts slightly energized suiliciently to close, then the diameter of the image should be approximately that of circle IIS. If the image is slightly less In diameter than this circle, then the image at dead center will cause none` o-f the relays to be actuated, and, if shifted from dead center, will cause one, or not more than two, relays to be actuated.
If, on the other hand, the image diameter is slightly greater than that of circle I I5, the image at dead center will cause all four relays to be actuated, with the result that neither of the associated motors will be energized, and when the slightly oversized image shifts from dead center, three of the four relays will be opened. If the image is made too large, however, it may be possible for the image to shift diagonally from dead center without vdeenergizing more than one relay, in which case the motors do not respond. Because of this possibility, it is advisable to focus the image at slightly less than the diameter of circle H5. Preferably, the image will be reduced to what is virtually a point, the avenues being correspondingly narrow. Obviously, the problem of accuracy is simplified by focusing to a minute image. Absolute control of the size of the image may be accomplished by using an iris diaphragm within the lens system.
From the above description, the automatic action of the pointers will be understood, the image of the beacon, in effect, seeking the center of the photoelectric eye that is xed to the pointer. It will be noted that armature 11 rofates indirect proportion to the right and left movements of the left eye or pointer, and armature 'I9 moves in direct proportion to the up and down movements of the left eye or pointer; armature |08 moves in direct proportion to the up and down movements of the right eye or pointer; and armature |09 rotates in direct proportion to the right and left movements of the right eye or pointer.
There remains the problem of deriving the distance to the airport and the altitude of the airplane from the angular positions of the two pointers as represented by the rotary positions of their associated armatures.
An equation or formula for computing distance by triangulation involves a minimum of three factors in the case of an oblique triangle, or two lfactors in the case of a right-angle triangle, and
one of these factors must be a side of the triangle. In the present arrangement, when the airplane approaches the beacon, one of these factors, the base line, represented by the distance between the pointers, is constant, while the other factor or factors are continuously variable.
Any of the formulas for triangulation may be employed. If, for instance, the right pointer, while trained on the beacon, is perpendicular to the base line B, as shown in Fig. 1, the distance to the beacon measured along the axis of the right pointer will equal B tan p being the angle of the left pointer with respect to the base line. In such a calculation. there is only one variable, angle If one' of the pointers isnot perpendicular to the base line, a formula involving two variables is necessary.
After the distance has been derived, the altitude of the airplane can be computed from the angular position of one of the pointers with respect to the horizontal. In Fig. 2, for instance, Athe distance D and angle being known, the altitude H=D cos We contemplate solving such equations by electrical means associated with the two pointers. In doing so, we have the choice of utilizing either the'voltage characteristic or the current characteristic of an electric circuit, or both characteristics. In the preferred form of our invention we utilize the voltage characteristic, in a manner that will now be explained.
Eig. 14 shows a potentiometer in which resistor |20. shunts battery I2I. A voltmeter |22 is in series with one terminal of resistor |20 and a movable resistor contact conventionally indicated at |23. A stop |24 limits the movement of contact |23 at a minimum voltage corresponding to the logarithmic value of a constant which is to be electrically multiplied by a variable. That portion of resistor |20 over which contact |2315 free to range is wound to vary in accordance with the logarithmic value of the said variable. The voltage registered by voltmeter |22 will represent the sum of these logarithmic values, and, if the ,voltmeter have a suitably calibrated logarithmic scale, the numerical product of the constant and the variable may be ascertained directly from the position of the indicating needle of the voltmeter with respect to that scale.
Fig. 15 represents a similar arrangement, in which contact |25a is free to traverse the length of resistor |25, the minimum voltage that represents the constant involved in the equation being supplied by auxiliarybattery |28 in series with voltmeter |21.
The arrangement shown in Fig. 16 provides for multiplying two variable factors by a constant. Resistor |28, wound-to vary as the logarithmic value of one factor, bridges battery |29 and is traversed by movable contact |30. In like manner, resistor |3| wound to vary as the logarithm of the second variable, shunts the terminals of battery |32 and is traversed by a second contact |33. A third battery, |34, having its terminals connected .respectively to the lower ends of resisters |28 and |3|, has a voltage corresponding to the logarithm o f the constant involved. Volt# meter |35, calibrated to-indicate the product of the three factors, has one terminal connected with contact |30 and the second terminal connected with contact |33,'so that it is in series with battery |34 and variable portions of resistors |28 and |3|.
Figures 14, 15 and 16 are offered to illustrate the principles of calculation by electric circuits. How these principles may be applied to our specific problem, as contemplated in the preferred form of our invention, may be understood by considering Fig. 9 together with Figs. 1 and 2. f
Resistor |38 of Fig. 9, wound to vary in accordance with the logarithmic tangent of an angle, shunts battery |31, and is traversed by a movable contact |38. Contact |38 is controlled by movements of ,pointer L with respect tobase line B lower end of resistor |36 are voltmeter |39 and a battery |40,` having a voltage corresponding to the logarithm of base line B. From the foregoing explanation, it will be clear .that if pointer R, of Fig. 1, is perpendicular to base line B, voltmeter i39, having a properly calibrated logarithmic scale, will indicate the instant value of distance D.
A second resistor |4|,wound to vary as the logarithmic cosine of an angle, shunts the terminals of a third battery |42 and is traversedby movable contact |43. Contact |43 is controlled by vertical movements of either pointer L or pointer R. One terminal of' a second voltmeter |44 is connected with contact |38, and the second terminal is connected with contact |43, with the result that the indicating needle of voltmeter `|44 will take a position corresponding to the voltage registered by voltmeter |39 plus a voltage corresponding to the logarithmic cosine of angle This second voltmeter is calibrated to give the instantaneous value of altitude H in Fig. 2.
For the purpose of indicating to the pilot of the airplane the deviation of pointer R from the desired disposition perpendicular to base line B, one of the three batteries, for instance battery |42, may be shunted by resistor |45l the resistor being the usual type wound to vary linearly and being traversed by a movable contact |46. Contact |48 is controlled by horizontal movements of pointer R. Voltmeter |41 is in series with contact |46 and one end of resistor |45. This third voltmeter is so calibrated that at a given point, as, for instance, the midpoint of resistor |45, pointer R is 90 from base line B and the indicating needle shows zero deviation.
It is apparent that if contact |38 is suitably connected with pointer L, or the mechanism associated with the horizontal movement of pointer L, contact |43 connected to either pointer, or the mechanism controlling the vertical movement of Veither pointer, and contactY |46 properly connected with pointer R, or the mechanism controlling the horizontal movement of pointer R, the system will function automatically, voltmeter |39 indicating the distance to the beacon, voltmeter |44 indicating the altitude of the airplane, and voltmeter |41 indicating the deviation of the flying axis of the ship from the line of approach necessaryV for triangulation involving a right triangle.
The circuit shown in elementary form in Fig. 9 may be recognized in the schematic arrangement of Fig. 8, corresponding numbers indicating corresponding parts. Dotted line |48 indicates an operative connection between armature and contact |38; dotted line |49 indicates an operative connection between armature |08 and contact |43; and dotted line |50 likewise indicates an operative connection between armature |09 and contact |48.
How the pointers may be mechanically associated with the various resistors, may be understood by considering the construction of a typical resistor as illustrated in Figs. l1 and 12. Resistor form wound transversely with wire |5| is supported at each end by spaced standards |52, the assembly being reinforced by two spaced rods |53 fixed to the standards above and parallel with the top edge of form |5|. Form |5| may be of any suitable insulating material, preferably of sheet material, such as fibre board. Wire |5|a is of uniform resistance, and, if it is desired that the resistor vary linearly in resistance, the upper and lower edges of the form will be parallel. If, however, the resistance is to follow the values of a variable. the lower edge of the form will be cut to follow the curve of the variable, as indicated by Fig. 1l.
Journalled in standards |52, parallel with the top edge of form |5|, is a worm or screw |54 operatively connected, as by coupler |55, with a shaft |56 of one of the four armatures. Screwthreadedly engaging screw |54 and slidingly engaging rods |53 is a carrier |51, from which one or more contacts |58 extend downward to slide upon the windings of resistor wire |5|a. Obviously, since the pointer associated with a given varmature and the contact carrier |51 are both Vlarge as 4necessary to obtain accurate changes of resistance commensurate with small changes in the angular position of the pointer.
Fig. 13 -shows a modication of such a resistor to provide for compensating movements of the resistor winding as required, for instance, in resistor |4| of Fig. 8. Angle in Fig. 2 is measured from the true vertical; therefore, resistor |4| must have a fixed relation to the vertical regardless of the inclination of the ship. Therefore, resistor winding |4|, is movably mounted and controlled by suitable means such as a gyroscope, pendulum, or other similar device. The resistor shown in Fig. 13 is similar to that shown in Figs. 11 and l2, identical parts having corresponding prime numbers, but resistor` form |59 is slidably mounted in brackets |52' and is 0poperatively connected with some vertical-seeking device (not shown), as by pivotally connected rmi |60.
The voltmeters may be' simply independent in- .dicating devices on a panel, as shown in Fig. 8,
or the indicators may be mounted on a panel or calibrated chart |6| (Fig. 10). Such a chart graphically indicates the position of the ship. Voltmeter |39 on one side of the chart has an indicating needle |6 2 positioned totraverse a `distance-reading scale |63. Similarly positioned on the opposite edge of the chart is Voltmeter |44, having its indicating needle |64 movable along altitude-reading scale |65.
The position of the intersection of needles |62 and |64 relative to chart |6| will vary with thel position of the airplane in space, and, obviously, lines may be drawn on the chart to aid in the visualization of the position of the airplane in space. For instance, a line |66 may be drawn to correspond to the movement of the intersection of the needle across the chart, as the airplane follows a desirable gliding angle or line of optimum glide to the landing i-leld (no signincance is to be attached to the specific disposition of line |66 in Fig. 10) By such an arrangement the aviator can be informed continuously of his position in space relative to such a line of optimum glide, as well as his position relative to the beacon. It will be noted that the accuracy of our system increases as the beacon is approached.
The third Voltmeter |41 may be arranged at the bottom of chart |6| with its indicating needle |61 having a normal vertical position at the middle of a scale |68 calibrated in degrees of deviation from the desired course. Such an arrangement has the advantage of confining the pilots attention to a relatively small area on the chart, and reveals the maximum amount of information at a glance.
The resistors may be standard, battery |40 and the calibration of the Voltmeter varying with the base line that a given airplane can accommodate.
The operation of the preferred form of our invention will be readily understood from the foregoing explanation. As the airplane approaches the desired airport, pointers L and R are automatically trained on the beacon at the airport, and the lelectrical arrangement described calculates the instant position of the ship in distance to the airport and altitude above the ground. The calculations are continuously and automatically corrected to give the successive instant positions of the ship, such corrections being made at a rate commensurate with the ying speed of the ship. The photo-electricy eyes respond only to infra-red rays, and only to intersection of the needles moving along line |66 advises the pilot of his approximate speed and his distance from the landing eld. It will be obvious that where the beacon itself is at a substantial elevation above the ground, scale |65 associated with needle |64 and the disposition of line |66 may be arranged to compensate for such elevation.
The specific form of our invention selected for the purposes of illustration and disclosure suggests a Wide range of possible changes and structural modifications, and we reserve the right to all such changes and modifications that properly come within the scope of our appended claims.
For instance, our invention may be arranged to utilize the current characteristics of an electric circuit for the purpose of calculating the position of the airplane automatically. In view of our disclosure above, such a modification may be understood by considering diagrams given in Figs. 17 and 18. A
L and R are pointers corresponding respectively to L and R of Fig. 1. Pointer R' controls, as by arm |69, movable winding |10 of a resistor. Pivoted to the same axis as arm |69 is a right-angle bell crank having arms |1| and |12, arm |1| being connected as by link |13 or other means with pointer L', so that pointer L and arm |1| are always parallel. By virtue of this arrangement, the angle between arm |69 and arm |12 will always be equal to angle at beacon N, and contact |14 on arm |12 will measure on winding |10 a distance corresponding to the magnitude of angle Operatively connected with pointer L is a movable contact |15 associated with a fixed resistor |16, the resistor being taped at an intermediate point |11 and being free at the ends. The base line for calculation by triangulation is represented by dotted line B' and the arrangement is such that when pointed L' is perpendicular to line B', contact |15 is at tap |11 of resistor |16.
The formula to be used here for the distance measured along one length of the triangle is distance D=B' sin 0 cosec or log D=log B'+log sin @-l-log cosec 'I'he electric circuit may be traced as follows: contact |15, wire |18, battery |19, wire |80, limiting resistance IBI, wire |82, contact |14, resistor |10, wire |83, ammeter |84, Wire |85, and resistor |16. When both pointers are trained ninety degrees from base line B', no part of either resistor Winding |16 or resistance winding 10 is included in the calculating circuit, at which positions of the pointers the current in the circuit as determined by battery |19 and the resistance of the circuit plus limiting resistance |8| will correspond in value to the logarithm of approximately the maximum distance from the beacon at which it is desired the apparatus become operative, say, a distance of ten thousand feet. This value may be termed the normal amperage of the system. Resistor |16 varies in resistance as the logarithmic sine of an angle, the purpose of the arrangement being that as far as resistance 16 is concerned, the maximum current will ow when contact |15 is at center tap |11 and the current at other positions of contact |15 will be decreased in according with the logarithmic sine of angle 0. Similarly, contact |14, cooperating with winding 10, will further reduce the current of the circuit in accordance with the logarithmic cosecant of Ammeter |84 has a logarithmic scale in units of distance and is so calibrated that the position of the ammeter needle will indicate the true distance to beacon N. Whereas, in the preferred form of our invention, the electrical calculating circuit in effect adds logarithms electrically, in the present arrangement the calculating circuit in effect subtracts logarithms electrically, the end being the same.
Fig. 18 is a duplicate circuit associated with the pointers L' and R' in the same manner as the circuit shown in Fig. 17,` having prime numbers corresponding to numbers in Fig. 17. This duplicate circuit has, additionally, a movable resistor |86 controlled by a vertical-seeking dcvice, asbefore described (Fig. 13), the resistance being associated with a movable contact V|81 controlled by armature |08. Resistor |86 will be recognized as corresponding to resistor I4 l, and contact |81 as corresponding to contact |43 in Fig. 8. This duplicate circuit is arranged to have a minimum current corresponding to the maximum value of the sum of the four logarithmsV involved in the equation:
brated to read in units required, and corresponds to voltmeter |44 in Fig. 10 just as ammeter |84 "in Fig. 17 corresponds to voltrneter |39 in Figs.
8 and 10.
Fig. 19, indicating an electrical arrangement for calculation in which both current and voltage are utilized, serves to further illustrate the scope of our invention. Battery |89 is shunted by resistor |90. 'Ihe positive end of resistor |90 is connected by wire |9| with a voltage terminal of indicating wattmeter |92, the other voltage terminal of the wattmeter being connected by wire |93 with a Contact |94 lmovable along resistor |90. Battery |89 also energizes a parallel circuit through resistor |95, a movable contact |96, wire |92a, the current coils of Wattmeter |92, and wire |9217 back to battery |89.
Battery |89 represents the base line of the triangle, resistor |90 is wound to vary as a desired function ofA one angle; and resistor |95 is wound to vary as the desired function of. another angle. Inasmuch as a Wattmeter multiples current by voltage, it will be clear that the scalel of wattmeter |92 may be calibrated to read in units of the product of these factors. It will be 'noted that this arrangement multiples directly, instead of, as in the case of the previous arrangements, by adding or subtracting logarithmic values and then translating the sum of the logarithmic values 'into an arithmetic product. In view of the detailed explanations of the earlier described arrangement, it will be clear that a wattmeter asj` sociated with the arrangement shown in Fig. 19
beacon and a second Wattmeter associated with a may be arranged to indicate distance to the -ing grounded at 202.
n to ow through the plate circuit of tube le.
in the lens system of the preferred form of our invention heretofore described. .l
Such a diaphragm is omitted and a more simple lens system is used in a second type of eye we have developed. This eye, by virtue of its associated control circuit, automatically centers a relatively large image, and, having centered the image, thereafter responds to minute displacements of the image from the desired central position. Such response to minute displacements of the image is accomplished. as will be further explained, by what may be described as electrically balancing the energized areas of opposed cathodes in the eye.
The cathodes of an eye, in this second form of the pointer construction, are arranged as three spaced sectors of a circle, lx, 2x and 3x, as shown in Fig. 21, the corresponding areas of the lens of the pointer eye being indicated as Iy. 2y and 3y in Fig. 22.
The manner in which such a tri-cathode photoelectric eye contros an associated pointer may, in view of the complete description of the first form of our invention above, be readily understood by referring to the wiring diagram of Fig. 23.
Each eye is incorporated in a pointer construction in the same manner as heretofore described, reference being made to Figs. 3. 4 and 5 of the drawings. This modification of our invention shows the use of series-wound motors to illustrate that either type of motor may be used by employing a suitable relay arrangement.
In each photoelectric eye, cathode sectors Lr. 2a: and 3:1: have a common plate 200, which plate or anode is maintained at a positive potential by battery 20|. the negative pole of the battery be- Cathode sectors lx, 2x and 3.1:, respectively, of the photoelectric eye control the input circuits of corresponding amplifying tubes Iz, 2z and 32.
For example. current through the photoelectric eye affecting tube la may be traced in the following circuit; ground 202. battery 20|, photoelectric plate or anode 200, cathode sector Ix, wire 203, band pass filter comprising condenser 204, and two parallel tuned circuits 205, wire 206 and ground 201. This circuit is tuned and filtered to the modulation frequency and controls the potential of grid 208 in tube la.
The three amplifying tubes are of the heater type, each having a heating element 209 suitably energized (source not shown), and cach having a grid-bias battery 2| 0. Current through photoelectric cathode la: will affect the potential of grid 208, thereby causing a proportional current In similar manner. cathode 2x associated with grid 2|| controls the plate circuit of tube 2z, and
cathode 3x associated with grid 2|2 controls the plate circuit of tube 32.
'I'he output circuits of these three tubes control two split-wound polarized relays, relay 2|3 controlling the horizontal movements of the pointer, and relay 2|4 controlling the vertical movements of the pointer. The center tap of relay 2| 3 is connected by wire 2|5 to the negative pole of battery 2|6, and the center tap of relay 2|4 is connected by wire 2|`| to the negative pole o battery 2|8. Wire 2|9 .is connected to plate 22d of tube Iz, plate 22| of tube 2a, and plate 222 of tube 3e. Wire 2| 9 is connected to the positive pole of battery 2|6 by Wire 223 and the positive pole of battery 2|8 by wire 224. Theend terminal in relay 2|3associated with the half of the relay coil marked Right, is connected by wire 225 to cathode 226 of tube Iz, and theA other terminal associated with the left portion of the relay coil, is connected by wire 221 to cathode 228 of tube 2z. The end terminal in relay 2|4 at the up side of the relay coil is connected by Wire 229 and wire 225 to cathode 226 of tube Iz, and the, opposite terminal of relay 2|l| at the down end of the relay coil is connected by wire 230 to cathode 23| of tube 32.
Again, the terms right, left, up and down are used as occurring to a spectator viewing the pointer from the front.
Pivoted armature 232 of relay 2|3 is normally held at a central position by a pair of opposed springs 2'33, and maintains its central position both when neither the right coil nor the -leit coil is energized and also when both of the coils are equally energized. If the right coil alone is energzed, or, both coils being energized, if the right coil carries the greater current, armature 232 will swing against contact 234, thereby closing the circuit through wire 235, the right field in the eld winding of the motor that controls the horizontal 'J movement of the pointer, wire 236, armature 231 of the motor,.wire 238, motor-energizing battery 239, and relay armature 232.
When the left coil of relay 2|3 alone is energized, or when both coils of the relay are energized but the greater current flows through the left coil, relay armature 232 will` swing against contact 240, thereby closing a circuit through wire 24|, the left field of the motor controlling the horizontal movements of the pointer, wire 236, armature 231, wire 238, battery 239, and relay armature 232.
Pivoted armature 242 of relay 2|4 is normally held in a central position by opposed springs 243, and maintains its central position both when neither the up nor down coil is energized and also when both coils are equally energized. When only the up vcoil is energized, or when, both the up coil and down coil being energized, the more current flows through the up coil, relay armature 242 will swing against contact 244, thereby completing a circuit through wire 245, the up field of the field winding of the motor' that controls the vertical movements of the pointer, wire 246, armature 241 of the motor, wire 248, motor-energizing battery 249, and relay armature 242.
When only the down coil of relay 2|4 is energized, or, both coils of the relay being energized, if greater current flows through the down coil, relay armature 242 will swing against contact 250, thereby closing the circuit through wire 25|, the down iield of the motor controlling the vertical movements of the pointer, wire 246, armature 241, wire 248, battery 249 and relay armature 242.
In the arrangement being described, the total current through the photoelectric eye is proportional to the total areas of the three cathode sectors energized by the image from the distant beacon, and* may change with the size of the image in accordance with changes of distance to the beacon. But the response of the pointerl itself, i. e., the action of the two pointer motors,
depends upon the distribution of the energized areas among the three cathode sectors, the response being such that the pointer automatically seeks a position at which the energized areas are in equilibrium and at which the axi's of the pointer is directed at the distant beacon. It is apparent. then, that changes in the size of the An image appearing on the periphery of a sector of the photoelectric eye will be caused to travel by a somewhat spiral path to a central position at which the same proportion of the image will overlie each of the three sectors of the photoelectric eye. The reaction of the pointer to an image on the pliotoelectric eye may be illustrated by considering what happens when an image appears, for instance, at dotted position .252 as indicated in Fig. 22. A current being set up across the plate circuit of amplifying tube Iz, the right coil of relay 2|3 and the up coil of relay 2|4 will be energized simultaneously, causing the pointer to move to the right and up, thereby shifting the image left and downward at an angle of forty-iive degrees, as indicated by the arrow 253 of Fig. 22.
When the image first touches sector 2y there will be no change in the movement of the pointer because, while current controlled by tube 2z will flow through the left coil of relay 2 I 3, that current will be less than the current flowing through the right coil of relay 2|3. Momentarily, at dotted position 254, the up coil, right coil and left coil will be equally energized. 'I'he right and left coils cancelling the effect of each other, only the up coil will be eiective and the image will move downward. Immediately thereafter, however, the greater area of the image will lie on the 2y sector, causing a greater iiow of current through the left coil than through the right coil, with the result that the pointer will move up and left, causing the image to move downward and to the right, as indicated by dotted line 255.
Since the image is moving at forty-five degrees from the vertical, whereas the line of division between sectors Iy and 2y is disposed at sixty degrees vertical, the image will clear sector 2y at position 256. As sector Iy is cleared, however, all relay coils except the left coil are deenergized and the image moves to the right into sector 2y again. The result is that the image progresses in the general direction indicated by dotted line 251, alternating between movements to the right towards sector 2y and movements downward away from sector2y.
As soon as the image touches sector 3y at the dotted position 258, the image Will move hori zontally to the right until a larger portion of its area overlies sector 3y than overlies sector 2y, at which time the image will turn diagonally upward to the right. Subsequently, the image will change to movement vertically upward, followed by horizontal movement to the left above the midpoint of the eye, and continue in the somewhat spiral path oi' progression to the center of the eye. While the image does not move directly to the center of the eye, the response of the pointer is sufficiently rapid to complete the spiral within the short time interval required for the navigation of a rapidly flying plane.
A third form of pointer construction, shown in Figs. 24-29, is based on the principle of bracketing the image of the beacon by a pair of eyes. One photoelectric eye 26| seeks the margin of the image at one side, and a second photoelectric eye 262 seeks the margin at the opposite side of the image, so that the pointer proper, a pivotally mounted rod 263 mechanically held exactly midway between the two eyes, is continuously directed at the center of the image.
This combination of two photoelectric eyes and an intermediate pointer is pivotally mounted on a stub shaft 264 extending from fixed base 265. A lower gear 266 rotatably mounted on shaft 264 has a sleeve portion 261 extending to the top of shaft 264. An arm 268 secured at its inner end to gear 266, as by screws, 269, carries at its outer end photoelectric eye 26|, the axis of the eye.
being radially disposed with reference to the axis of the shaft 264. A collar 210 embraces sleeve 261 at the top and is provided with a depending arcuate ange 21|, for a purpose to be described later, the angular relation of ange 21| to arm 268., being fixed by virtue of a. suitable key 212 between the collar and sleeve 261. These members may be retained on shaft 264 by a suitable washer 213, the washer being retained in turn by a nut 214 threaded to the reduced end 215 of stub shaft 264.
Pointer 263 is rotatably mounted on sleeve261, the pointer being provided with an integral sleeve V216 rotatably embracing the first;v mentioned sleeve 261 and extending upward to collar 210. A second collar 211 keyed toth'ef'upper end of this second sleeve by key 218 isfintegral with a radially extending contact arc 219. This contact arm terminates in a downwardly extending finger 280. Rotatably mounted to sleeve 216 between pointer arm 263 andcollar 211,'isa second and upper gear'28l for controlling the second eye 262. This eye, also radiallyl disposed relative to the axis of shaft 264, is at the outer end of arm 282, secured to the gear as by screws 283.
263 will always bisect the angle between arms 268 and 282, 4so that if eye-26| is directed 'at one edge of the beacon and eye 262 is directed at an opposite edge, the axis of pointer 263 will be directeti at the center of the beacon.
Journalled in a suitable bracket 281 are a worm gear 288 meshing with lower gear 266, and
worm gear 289 meshing with gear 28| (Fig. 27). Gear 288, controlling eye 26| .is in turn controlled by motor 290, being connected therewith by shaft 29|. In a similar manner, motor 292 is connected byshaft' V293 to worm gear 289 to control the movements of eye 262.
To deenergize either motor, if it tends to move its associated photoelectric eye so far from the other eye as to make the pointer linkage inoperative, and again, to deenerg-ize either, or both,
motors when the two arms are closed together inl the normal position shown'in Fig. 25, certain mechanical switching arrangements are necessary.
For such purpose, the previous identified arcuate flange. 21|, controlled by gear 266, overhangs upper -gear 28|.. Relative movement of flange 21| with respect to geary 23| in a direction to separate the two eyes will; at a desired limit, deflect a flexible switch-member 294 (Fig. 24) and relative movement in the opposite direction tending to bring the two arms together will, at a desired limit, deect a second suitably positioned flexible` switch-actuating member 295 (Fig. 25). Deection` of mex'ber 294 opens two switches, generally designated by numerals 296 and 291. The construction of such a switch may be readily understood by referring to Fig. 28, where it is seen that switch 296 comprises a fixed contact 293 and -a second contact 299 mounted on mem-v When switch-member 295 is deected by the opposite end of flange 21|, a switch generally designated 302 is opened, the switch comprising a iixed contact 303 and a complementary contact 304 mounted on member 295.
It is apparent that contact arm 219, being virtually an extension of pointer 263, will move with the pointer. An electric contact 305 of suitable construction is mounted on arm 219 to press continuously against a resistor -306, the resistor being curved concentric to the axis of stub shaft 264. This resistor is wound to vary in accordance with the functions or the logarithm of a function of an ang-le. For example, if this pointer construction is substituted for pointer L 'of Fig. 1, resistor 306 will be wound to vary as the logarithm of a function angle p of the pointer with respect to the base line defined by the two pointers on the airplane.
To prevent pointer contact 305 being carried past the ends of resistor 306, means should be provided .to break the energizing circuits of motors 290 and 292 when the desired limits of pointer movements are reached. For this purpse, a flexible switch member 301 is positioned near one end of resistor 306 in a position to be deflected by the overhanging end or iinger 280 of the pointer, and a similar exible switch member 308 is positioned near the opposite end of resistor 306. Deection of member 301 opens two switches, designated generally by the numerals 309 and 3|0. Similarly, deflection of member 308 opens two switches, generally designated by numerals 3|| and 3|2.- The construction of these switch mechanisms is similar to that shown in Fig. 28.
It will be apparent that when the pointer assembly is in the normal closed position, directed straight ahead, as shown in Fig. 25, switches 296, 291,309, 3|0, 3|I, and 3|2 are in their normal closed positions, while switch 302 is in its normal open position.
Each of the two photoelectrlc eyes comprisesa suitable casing 3|3 housing a lens system 3|4 at Athe front and a suitable photoelectric cell 3|5 at the rear, each photoelectric cell having cathode 3|6 and a ring-shaped anode 3|1.
,Preferably the cathode of each eye is semicircular, as viewed'from the front, and, in a pair of eyes, the cathodes are oppositely disposed, as indicated in Fig. 24, and, again, in Fig. 30, the latter figure showing diagrammatically the disposition of three pairs of eyes on an airplane as viewed from the front. In such an arrangement, each cathode takes in approximately half the field of vision of an eye, so that a pair of eyes having complementary cathodes, as shown. will, together, cover the entire field of vision of one eye of the type shown in Fig. 6 or the type shown in Fig. 22. To preclude any possibility of there being a gap in the eld of visin covered by the complementary cathodes, switch 302 is arranged to close only when the two cathodes are moved into definitely overlapping relation, such relationship being the normal relationship of the two eyes when not aiected by the distant beacon.
'Ihe electric circuits incorporated in this third form of pointer construction may be understood by referring to the wiring diagram, Fig. 29. In either of the two eyes, 26| and 262, the circuit through the photoelectric cell may be traced as i follows: negative pole of battery 3|6, wire 3|9,
-photoelectric cathode 3|6, anode 3|1, wire 320, band pass lter comprising'` condenser 32| and two parallel tuned circuits 322, wire 323, and positive pole of battery 3|8.
An amplifying tube 324 is associated with eye 26|, and a similar tube 325 is associated with eye 262. Grid 326 of tube 324 is connected to the photoelectric anode side of the associated band pass filter and cathode 321 of tube 324 is connected through grid bias battery 328 to the opposite side of the band pass filter.
In like manner, grid 329, of tube 325, is connected to the photoelectric anode side of the associated band pass filter, and Acathode 338 of tube 325 is connected to the opposite side of the associated band pass lter through grid bias battery 33|.
Each of the amplifying tubes is a heater type,
having a heating element 332 energized from al suitable source (not shown).
Theplate circuit of tube 324 includes a suitable battery 333 and the solenoid coil 334 of a relay that is generally designated by numeral 335. Similarly, the plate circuit of tube 325 includes battery 336 and solenoid coil 331 of a second relay generally designated by numeral 338.
v Armature 348 .of relay 335 carries two spaced insulated contact members 34| and 342. In the normal deenergized position of armature 348, contact member 342 is free of any contacts, and contact member 34| electrically connects spaced contacts 343 and 344. When relay 335 is energized by current through coil 334, armature 348 moves contact member 34| to a second position free of contacts 343 and 344, contact member 34| in this second position electrically connecting a second pair of spaced contacts 345 and 346. This same movement of armature 348, when the relay is energized, carries contact member 342 from its normal free position to a second position electrically connecting contacts 341 and 348.
In` like manner, armature 349 of relay 338 carries two spaced insulated contact members 358 and 35|. When relay 338 is energized by current through coil 331, armature 349 moves contact member 358 from a normal position electrically connecting contacts 352 and 353 to a second position electrically connecting contacts 354 and 355, and simultaneously moves contact member 35| from a normal position free of all contacts to a second position electrically connecting contact members 356 and 351.
In describing this third form of pointer construction and its action, the words right and left will be used as occurring to a person looking outward over the pointer from a position at the rear. This direction of reference isthe opposite of that suggested inconnection with the previously described forms of pointers, but is believed to favor clarity of explanation.4
Relay 335 controls the action of motor 298, thereby controlling the movements of the lower photoelectric eye 26|, covering the left half of the eld of vision; and relay 338 controls the action of motor v282, thereby controlling movements of upper photoelectric eye 262 responsive to the right half of the field of vision. The armature and the split eld coil of motor 298 are generally designated by numerals 358 and 359, respectively; and, on the other side of the diagram, the armature and the split eld coil of motor 292 are generally designated. by numerals 368 and 36|, respectively.
Contact 341 is connected to the left eld' of the motor associated with eye 26|, the connection being through. switches 296 and 3| I, previously described, the switches being in series. Contact 343, associated with left relay 335; is connected to the right eld half of eld coil 359 of the same motor, the connection being through switch 389, previously described, and in series therewith, a second switch 362, the` purpose of which second switch will be described later.
Contact 351, associated with right relay 338, is connected with the right field of the motor controlling the right eye 262, the connection being through the two switches 291 and 3|8, previously mentioned, the switches being in series. Contact 353 is connected to the left eld of the motor controlling the right eye 262, the connection being through two switches in series, switch 3|2, previously mentioned, and a switch 363, the purpose of which will be described later.
Connection is made from the center tap of field coil 359 of the motor controlling the left eye through armature 358 of that motor to contact 345 of left relay 335. In a similar manner, connection is made from the center tap of iield coil 36| of the motor controlling the right eye through armature 368 of that motor to contact 354 of the right relay 338.
Wire 364 interconnects contact 345 of the left relay and contact 354 of the right relay, and is connected to one terminal of motor-energizing .battery 365 by a branch wire 366, this branch wire being controlled by switchV 382, previously described, (Fig. 24). The second terminal of battery 365 is connected to wire 361, which wire interconnects contacts 344 and 348 of the left relay and contacts 356 and 352 of the right relay.
Suppose, the pointer and eyes being in the normal position shown in Fig. 25, the airplane is approaching the distant beacon, the beacon being at the left extremity of the combined field of vision of the two eyes 26| and 262. This image, energizing cathode 3|6 of the left eye at the selected modulated frequency, will cause the left relay 335 to be energized, whereupon a circuit through the motor associated with the left eye will be established as follows: battery 365, wire 361, contact 348, contact member 342, contact 341, switches 296 and 3l|, left field of coil 359, armature 358, contact 345, contact member 34|, contact 346, back to battery 365. Motor 298 will cause eye 26| to move to the left, and the eye will continue to be so moved until the image passes over the inner straight edge of the semicircular cathode 3|6. This same action may be described as a movement of the eye towards the outside edge of the image of the distant beacon.
At the beginning of this leftward movement of eye 26|, switch 382 will automatically close. Whenever relay 335 is deenergized while switch 382 is closed eye 26| will move to the right because of the circuit: battery 365, wire 366, switch 382, wire 364, motor armature 358, right field of coils 359, switches 389 and 362, contact 343, contact member 34|, contact 344, and wire 361 back to the battery. Therefore, as soon as eye 26| moves sufliciently to the left to cause the image to traverse the cathode of the eye to a position clearing that cathode, the eye will automatically reverse to the right. As a result of such an arrangement, left eye 26| will tend to hover at a position Where the straight edge of its cathode will be approximately tangential to the left edge of the image.
When switch 382 first closes at the beginning of the leftward movement of the left eye, the movement described above, the right eye will also move to the left following the rst eye, because of the following circuit: battery 366, wire 366, switch 382, wire 364, motor armature 368, left field of 75 coils 36|, switch 3|2, switch 363, contact 353, contact' member 350, contact 352, and wire 331 back to battery 335. l
As soon as the right eye moves suiliciently to theleft to cause the image to be positioned on its cathode, right relay 338 will be energized and the eye willreverse tov the right because of y the following circuit: battery 365, wire 361, contact 356, contact member 35|, contact 351,
switches 291 and 3| 0, right iield of coil 36 armature 360, contact 354, contact member 353, contact 355, back to battery 365. Because these last two described circuits alternate, the iight eye will hover at a position at which the straight edge of its cathode will be approximately tangential to the image of the beacon, the eye being moved automatically to the left when the image does not touch the cathode and being moved automatically to the right when the image does touchthe cathode.
Because each eye thus moves outward when energized and inward lwhen deenergized, it may -be said that the two eyes bracket" the image.
Whenever the beacon disappears from the iield of vision of the two eyes, the two eyes will automatically close together until switch 332 automatically breaks the two motor circuits.
After a landing is made, the two eyes will usually come together and be deenergized with the pointer directed to one side. For this and other reasonsfit is desirable that there -be independent means conveniently operable by the pilot to move each pointer to a position straight ahead. For
this purpose, an auxiliary motor-energizing battery 369 (Fig. 29) is connected by one terminal to wire 364, the other 4ten'ninal being connected to a switch 310. This switch is movable to one position connecting with wire 31| to the left iield of the motor controlling the left eye, and is movable to a second position establishing connection through wire 312 with the right field of the motor controlling the 'right eye 262, the normal position beingl an intermediate neutral position. Switch 310 is mechanically connected to switch 362 to open that switch when connection is made with wire 31|, and is likewise mechanically connected to switch 363 to open that switch when connection is made to wire 312.
` Suppose it is desirable to move pointer 263 to the left in order to direct it straight ahead. The
pilot will move switch 313 from the normalcen-4 cuit will cause eye 26| to move to the left, therener, if switch 310 is moved' to the right, a circuit will be closed as follows: battery 369, Wire 364,
A.armature 360, right eld of coil 33|, wire 312,
switch 313, back to battery 369. Switch 363 be.,
ing opened automatically when switch 310 connects with wire 312, energization of the left eld of coil 36| will be prevented.
Thisl third pointer construction has several advantages. It will accommodate itself to an image of any diameter, the two eyes spreading apart to accommodate the dimensions of the image while the pointer proper is automatically directed at the center of the image. The eye construction itself is relatively simple, there being no critical relationship between cathode spacing in an eye and the size of the image. It is important to note, also, that in the case of the previously described pointer constructions. the image may conceivably vibrate so fast across two opposed cathodes as to have the same eiect as an inordinately large image simultaneously overlying the two opposed cathodes. In `the case of the present construction, however, the two eyes would automatically spread apart to the opposite limits of such vibration, and the pointer, seeking the center of the range of vibration, would thereby be directed to the center of the beacon. A further advantage of this third type of pointer construction is the rapidity with which the pointer is centered on the beacon. In the other constructions, the pointers move circuitously to the Idesired position directed at the center of the image, whereas in the present construction the pointer-movement is more nearly direct, there being no diagonal lines described by the path of the image. Another advantage is'that the area of image necessary ,to establish an ei'- fective current through the eye is immaterial.
It is suggested that three pairs of such eyes be arranged on an airplane, as indicated by Fig. 30, showing the arrangement of the eyes as viewed from the front. 'Ihe pointer controlled by the pair of eyes on the left wing, the pointer designated by numeral 313, will correspond to pointer L of Fig. 1 and will, therefore, control contact |33 of Fig. 8. The pointer controlled by thepair oi.' eyes designated by numeral 314: on the extremity of the right wingof the plane corresponds to pointer R of Fig. 1 and will, therefore, control contact |46, indicated in Fig. 8. The third pair of eyes 315 is mounted to bracket the image vertically to ascertain angle of Fig. 2. The pointer associated with this third pair of eyes will. therefore, control contact '|43 of Fig. 8. It is apparent that, with such a hook-up, the instruments designated in Fig. 8 will indicate the distance, altitude and course, afs previously described.
For the further guidance of the pilot, we nave devised a ground speed indicator. the construction of which may be understood by reference to the circuit shown in Fig. 20.
Vacuum tube 316 is shown here as a batteryoperated screen grid tube, although other types may be employed. Filament 311 is heated by an A battery 318,'the current being controlled by rheostat 319. In the usual manner, screen 333 of the tube is connected to a central cell of B battery 38| by wire 332. Plate 333 of the tube is connected to ammeter 334 by wire 335, the ammeter, in turn, being connected to the positive pole of battery 33| by wire 335 to complete the plate circuit.
The negative pole oi C battery 336 is connected to grid 331 of thi` tube through a relatively high resistance 338.
A n independent circuit comprises a suitable battery 339, shunted .by a suitable resistor 393l wound to varyfdirectly as the tangent of an angle. This resistor is provided' with a movable contact 39|, the construction of the resistor and contact being similar either to that indicated by Figs. 11 and 12 or that shown in Figs. 24 and 25.
This contact is mechanically controlled by tential of contact 39| will also vary directly as distance D.
Contact 39| is connected by wire 392 to grid 381 and, therefore, to the grid end of resistance 388. A suitable condenser 393 is inserted between the low potential end of resistor 390 and the neg-ative pole of C battery 386. It is suggested that the condensor have a capacity of one microfarad and that resistance 388 have a rating of 106 ohms, -if a time constant ofv approximately one second is desirable. It is apparent that charges on opposite sides of condensor 393 will balance at values determined by the position of contact 39| on resistor 390, and that any change in the value of the balanced charges occasioned by a change in position of contact 39| will cause a compensating ow of current through resistor 388 for a duration of approximately one second.
This compensating current is dependent solely upon changes in potential of contact 39|, dying away whenever the contact is stationary for more than a second, and is directly proportional to the rate of such changes in the potential of the contact. .Now the potential of contact 39| at any given moment corresponds to distance D, as heretofore stated, and, therefore, the value of the compensating current through resistance 388 is proportional to the rate of change of that distance, i. e., the speed with which the ship approaches the beacon.
Ammeter 384 is indexed to serve as a speed indicator, being set to show zero speed at normal amperage in the plate circuit as determined by normal potential of grid 381. As the airplane approaches the distant beacon, angle p becoming progressively more acute, contact 39| moves towards the positive end of resistance 390, as indicated by the arrow, thereby causing compensating current to ilow from the contact through resistance 388 to condensor 393. This transitory compensating current, by making grid 381 less negative, causes a proportionate increase in the current through the plate circuit of `tube 316, so that ammeter 384, being properly calibrated, will 'indicate the instantaneous speed with which the airplane approaches the beacon.
It is true that the ammeter, strictly spreaking, does not measure the ground speed, because distance D is measured in an air line at an angle from the horizontal, but this air line speed approximates ground speed so closely" that, for practical purposes, itis not deemed necessary to complicate the apparatus with further means to correct for the angle of the air line.
Having described our invention, we claim:
1. Apparatus for computing 4the distance between two points, comprising, in`combination: means generating electro-magnetic radiations from one of said points, the otherbeing the receiving point; means at the receiving point for receiving said generated electro-magnetic radiation; two pointers associated with the receiving point spaced to denne aA base line for computing distance by triangulation; means connected with each pointer responsive to said electro-magnetic radiations to automatically train each pointer on the source of the radiations; and means operatively connected to at least one of said pointers to automatically derive the distance between the two points from the angular disposition of said pointers with respect to said base line.
2. Apparatus for computing the distance between two points, comprising, in combination: means generating electro-magnetic radiations from one of said points, the other being the receiving point; means at the receiving point for receiving said generated electro-magnetic radiation; two pointers associated with the receiving point spaced to dene a base line for computing distance by triangulation; means connected with each pointer responsive to said electro-magnetic radiations to automatically train each pointer on the source of the radiations; an electric circuit having a variable energy characteristic determined by two factors, said characteristic corresponding in value with the distance between the two points to be measured, said factors corresponding in value with factors in an equation for computing the distance by triangulation; means interconnecting the pointers and circuit whereby the pointers control said characteristic through at least one of said factors in accordance with said equation; and means controlled by the circuit to indicate the instant value of said characteristic, said means being adapted to express the Value as distance between the two points.
3. Apparatus for computing the distance between two points, comprising, in combination: means generating electro-magnetic radiations from one of said points, the other being the receiving point; means at the receiving point for receiving said generated electro-magnetic radiations; two pointers associated with the receiving point spaced to define a base line for computing distance by triangulation; means connected with each pointer responsive to said electro-magnetic radiations to automatically train each pointer on the source of the radiations; an electric circuit; at least one voltage-regulating means associated with the circuit corresponding with two or more factors in a triangulation equation and adapted to vary the voltage of said circuit in accordance with said factors, one of said pointers being operatively connected to said voltage regulator; and a voltmeter in said circuit calibrated in units of distance.
4. Apparatus for computing the distance between two points, comprising, in combination: means generating electro-magnetic radiations from one of said points, the other being the receiving point; means at the receiving point for receiving said generated electro-magnetic radiations; two pointers associated with the receiving point spaced to define a base line for computing distance by triangulation; means connected with each pointer responsive to said electro-magnetic radiations to automatically train each pointer on the source of the radiations; an electric circuit having a minimum voltage corresponding in value to the logarithm of a constant in a. triangulation equation; at least one voltage regulator in the circuit corresponding to a variable in said triangulation equation and ada;p ted to vary the voltage of the circuit above said minimum in accordance with the values of the logarithm of said variable, one of said pointers being operatively connected to said voltage regulator, whereby the instant voltage of said circuit corresponds to the instant value of the logarithm of the distance between said two points; anda voltmeter
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Cited By (49)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2421192A (en) * 1943-05-29 1947-05-27 Rca Corp Multicathode phototube
US2425059A (en) * 1943-03-06 1947-08-05 Stewart Warner Corp Detection of toxic gases
US2425956A (en) * 1944-01-27 1947-08-19 Farnsworth Television & Radio Target seeking device with phototube multiplier
US2428596A (en) * 1942-08-29 1947-10-07 Rca Corp Electronic computer
US2431510A (en) * 1944-09-29 1947-11-25 Farnsworth Res Corp Photocell multiplier apparatus
US2444771A (en) * 1943-06-28 1948-07-06 Gen Electric Height computing apparatus
US2448544A (en) * 1940-03-01 1948-09-07 Carl W Muller Automatic simulated two pointer glide path for ground training
US2457130A (en) * 1940-02-26 1948-12-28 Carl J Crane Blind flying and blind landing system for aviation flight trainers
US2471439A (en) * 1945-11-14 1949-05-31 Grant C Melvin Device for simulating runway localizer and glide path beams for training purposes
US2475314A (en) * 1943-11-25 1949-07-05 Dehmel Richard Carl Navigation apparatus for aircraft and training devices
US2489220A (en) * 1945-03-15 1949-11-22 Lafayette M Hughes Light-sensitive altitude and direction indicator
US2489218A (en) * 1944-11-07 1949-11-22 Lafayette M Hughes Instrument for landing aircraft
US2489222A (en) * 1946-06-07 1949-11-22 Lafayette M Hughes Electric means for indicating the altitude and position of a craft when landing on arunway
US2489219A (en) * 1944-12-28 1949-11-22 Lafayette M Hughes Apparatus, including an altimeter for aiding the landing of aircraft
US2492351A (en) * 1943-07-17 1949-12-27 Bell Telephone Labor Inc Smoothing network
US2492964A (en) * 1945-04-23 1950-01-03 Daniel R Butterly Photoelectric miniature radio range
US2504126A (en) * 1945-04-12 1950-04-18 Gen Electric Ceilometer recorder
US2527753A (en) * 1945-07-09 1950-10-31 Robert A Mcconnell Radio object locating system
US2529468A (en) * 1945-07-27 1950-11-07 Richard C Dehmel Radio range navigation apparatus for training aircraft personnel
US2545655A (en) * 1940-03-11 1951-03-20 Computer
US2548888A (en) * 1946-07-24 1951-04-17 Peter C Jones Radio range training device
US2560528A (en) * 1945-03-27 1951-07-10 Richard C Dehmel Training means for blind navigating systems
US2560527A (en) * 1947-11-12 1951-07-10 Dehmel Richard Carl Apparatus for simulating radio navigation aids
US2569328A (en) * 1946-01-23 1951-09-25 Bendix Avlation Corp Automatic position plotter
US2597315A (en) * 1945-11-06 1952-05-20 Us Sec War Computer for solving right triangles
US2603088A (en) * 1945-10-19 1952-07-15 Richard K Mosher Electrical circuit for straight course navigation
US2618154A (en) * 1945-06-06 1952-11-18 Albert M Uttley Navigating instrument
US2630043A (en) * 1947-09-27 1953-03-03 Continental Silver Co Inc Classifying equipment for determining the dimensions of objects
US2668288A (en) * 1947-09-23 1954-02-02 Onera (Off Nat Aerospatiale) Distance measuring device
US2681763A (en) * 1950-11-20 1954-06-22 Conveyor Company Inc Integrating system for conveyer scales
US2685747A (en) * 1950-03-11 1954-08-10 Link Aviation Inc Radio navigation trainer
US2740583A (en) * 1950-08-31 1956-04-03 Bell Telephone Labor Inc Resolving and integrating arrangement
US2766387A (en) * 1952-11-14 1956-10-09 Bolsey Jacques Autoamtic tracking apparatus for cameras and the like
US2807017A (en) * 1946-03-26 1957-09-17 Richard N Close Radio computer system
US2919350A (en) * 1957-12-13 1959-12-29 North American Aviation Inc Infrared ranging system
US3002093A (en) * 1959-01-29 1961-09-26 Packard Bell Electronics Corp Infrared navigation system
US3054898A (en) * 1960-03-14 1962-09-18 Servo Corp Of America Infrared ranging system
US3064131A (en) * 1959-12-21 1962-11-13 Lemual G Brown Solar operated louver apparatus
US3064897A (en) * 1956-03-05 1962-11-20 Texas Instruments Inc Position determining method and apparatus
US3076095A (en) * 1956-09-05 1963-01-29 Texas Instruments Inc Method and apparatus for determining altitude
US3128061A (en) * 1945-08-11 1964-04-07 Thornton W Chew Automatic self-guidance system for movable objects
US3131887A (en) * 1952-09-15 1964-05-05 North American Aviation Inc Slave missile system
US3178579A (en) * 1960-11-23 1965-04-13 Kollsman Instr Corp Photosensitive tuning fork scanner
US3226971A (en) * 1962-12-06 1966-01-04 Gen Precision Inc Compass alignment system
US3293440A (en) * 1963-11-21 1966-12-20 Litton Systems Inc Grain boundary photo-orienter with integral shields
DE1240289B (en) * 1958-03-20 1967-05-11 Zeiss Carl Fa Rangefinder sensitive to infrared radiation
US3617016A (en) * 1968-05-27 1971-11-02 Emil J Bolsey Image motion and change transducers and systems controlled thereby
US3742239A (en) * 1960-06-09 1973-06-26 Emi Ltd Discriminating devices
US3954340A (en) * 1973-03-13 1976-05-04 Ab Bofors Method of and apparatus for target tracking

Cited By (49)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2457130A (en) * 1940-02-26 1948-12-28 Carl J Crane Blind flying and blind landing system for aviation flight trainers
US2448544A (en) * 1940-03-01 1948-09-07 Carl W Muller Automatic simulated two pointer glide path for ground training
US2545655A (en) * 1940-03-11 1951-03-20 Computer
US2428596A (en) * 1942-08-29 1947-10-07 Rca Corp Electronic computer
US2425059A (en) * 1943-03-06 1947-08-05 Stewart Warner Corp Detection of toxic gases
US2421192A (en) * 1943-05-29 1947-05-27 Rca Corp Multicathode phototube
US2444771A (en) * 1943-06-28 1948-07-06 Gen Electric Height computing apparatus
US2492351A (en) * 1943-07-17 1949-12-27 Bell Telephone Labor Inc Smoothing network
US2475314A (en) * 1943-11-25 1949-07-05 Dehmel Richard Carl Navigation apparatus for aircraft and training devices
US2425956A (en) * 1944-01-27 1947-08-19 Farnsworth Television & Radio Target seeking device with phototube multiplier
US2431510A (en) * 1944-09-29 1947-11-25 Farnsworth Res Corp Photocell multiplier apparatus
US2489218A (en) * 1944-11-07 1949-11-22 Lafayette M Hughes Instrument for landing aircraft
US2489219A (en) * 1944-12-28 1949-11-22 Lafayette M Hughes Apparatus, including an altimeter for aiding the landing of aircraft
US2489220A (en) * 1945-03-15 1949-11-22 Lafayette M Hughes Light-sensitive altitude and direction indicator
US2560528A (en) * 1945-03-27 1951-07-10 Richard C Dehmel Training means for blind navigating systems
US2504126A (en) * 1945-04-12 1950-04-18 Gen Electric Ceilometer recorder
US2492964A (en) * 1945-04-23 1950-01-03 Daniel R Butterly Photoelectric miniature radio range
US2618154A (en) * 1945-06-06 1952-11-18 Albert M Uttley Navigating instrument
US2527753A (en) * 1945-07-09 1950-10-31 Robert A Mcconnell Radio object locating system
US2529468A (en) * 1945-07-27 1950-11-07 Richard C Dehmel Radio range navigation apparatus for training aircraft personnel
US3128061A (en) * 1945-08-11 1964-04-07 Thornton W Chew Automatic self-guidance system for movable objects
US2603088A (en) * 1945-10-19 1952-07-15 Richard K Mosher Electrical circuit for straight course navigation
US2597315A (en) * 1945-11-06 1952-05-20 Us Sec War Computer for solving right triangles
US2471439A (en) * 1945-11-14 1949-05-31 Grant C Melvin Device for simulating runway localizer and glide path beams for training purposes
US2569328A (en) * 1946-01-23 1951-09-25 Bendix Avlation Corp Automatic position plotter
US2807017A (en) * 1946-03-26 1957-09-17 Richard N Close Radio computer system
US2489222A (en) * 1946-06-07 1949-11-22 Lafayette M Hughes Electric means for indicating the altitude and position of a craft when landing on arunway
US2548888A (en) * 1946-07-24 1951-04-17 Peter C Jones Radio range training device
US2668288A (en) * 1947-09-23 1954-02-02 Onera (Off Nat Aerospatiale) Distance measuring device
US2630043A (en) * 1947-09-27 1953-03-03 Continental Silver Co Inc Classifying equipment for determining the dimensions of objects
US2560527A (en) * 1947-11-12 1951-07-10 Dehmel Richard Carl Apparatus for simulating radio navigation aids
US2685747A (en) * 1950-03-11 1954-08-10 Link Aviation Inc Radio navigation trainer
US2740583A (en) * 1950-08-31 1956-04-03 Bell Telephone Labor Inc Resolving and integrating arrangement
US2681763A (en) * 1950-11-20 1954-06-22 Conveyor Company Inc Integrating system for conveyer scales
US3131887A (en) * 1952-09-15 1964-05-05 North American Aviation Inc Slave missile system
US2766387A (en) * 1952-11-14 1956-10-09 Bolsey Jacques Autoamtic tracking apparatus for cameras and the like
US3064897A (en) * 1956-03-05 1962-11-20 Texas Instruments Inc Position determining method and apparatus
US3076095A (en) * 1956-09-05 1963-01-29 Texas Instruments Inc Method and apparatus for determining altitude
US2919350A (en) * 1957-12-13 1959-12-29 North American Aviation Inc Infrared ranging system
DE1240289B (en) * 1958-03-20 1967-05-11 Zeiss Carl Fa Rangefinder sensitive to infrared radiation
US3002093A (en) * 1959-01-29 1961-09-26 Packard Bell Electronics Corp Infrared navigation system
US3064131A (en) * 1959-12-21 1962-11-13 Lemual G Brown Solar operated louver apparatus
US3054898A (en) * 1960-03-14 1962-09-18 Servo Corp Of America Infrared ranging system
US3742239A (en) * 1960-06-09 1973-06-26 Emi Ltd Discriminating devices
US3178579A (en) * 1960-11-23 1965-04-13 Kollsman Instr Corp Photosensitive tuning fork scanner
US3226971A (en) * 1962-12-06 1966-01-04 Gen Precision Inc Compass alignment system
US3293440A (en) * 1963-11-21 1966-12-20 Litton Systems Inc Grain boundary photo-orienter with integral shields
US3617016A (en) * 1968-05-27 1971-11-02 Emil J Bolsey Image motion and change transducers and systems controlled thereby
US3954340A (en) * 1973-03-13 1976-05-04 Ab Bofors Method of and apparatus for target tracking

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