US1831465A - Radio compass system - Google Patents

Description

Nov. 10, 1931.

G. T. ROYDEN l,831,465

'RADIO COMPASS SYSTEM Filed Dc. 28', 1925 /4 /6 f /lz4 /Za /NVE/vrn By eorge Z' @agde/7 M/w Q ArTaHHEY- Patented Nov. lO, 1931 UNITE@ STATt-.S

miem carica GEORGE '1". ROYIDEN, OF PALO ALTO, CALIFORNIA, ASSIGNOR FEDERAL TELEGRAPH COMPANY, OF 'SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA RADIO COMPASS SYSTEM Application led December 28, 1926. Serial No. 157,482.

This invention relates generally to radio signalling receiving systems especially applicable for locatingvthe direction of a signal source. Y 4 f y 5 In radio compass installations, the receiving apparatus usually includes a. rotatable loop antenna connected to a cascade amplifier vand detector. Connected to the detector there is a translator Which may either consist of a 0 telephone receiver orone or more relays for controlling a visual or audible indicating device. Generally the system is operated by rotating the loop until the signal response is of minimum strength, the position of the loop 5 ythen indicating the direction of the signal source. In case of a translator employing relays, this condition may befindicated by a visual indicator such as a flashing light. While arrangements of this sort give good D results, it is possible that an inexperienced yoperator may obtain a false bearing due to a cessation of signals from causes other than a critical position of the loop. For example, the signals may become Weak due to fading 5 effects or because of the condition of the signal transmitter.

Itis an object of this invention to devise a radio compass system Which Will prevent errors by providing means by Which an observer D may be assured of a proper critical position of the loop. v vIt is a further object of this invention to devise a signalling system which Will indicate Athe nature of a signal being received by one 5 apparatus by the combined effect of that apparatus and another receiving apparatus upon a common translator. Y

Further objects of this'invention will 4appear from the following description in which 3 Ihave sert forth the preferred embodiment of my invention. It is to be understood that the appended claims are to be accorded a range ofelectrical and mechanical equivalents consistent with the state of the prior art. In the central ligure of the drawing I have shown a radio compass system incorporating the principles of this invention.v Such a system utilizes a directional radio -receiver comprising for example-a rotatable loop antenna r1() connected to suitable receiving apparatus such as a radio frequency amplifier 11, detector 12 and audio frequency amplifier 13. The system is preferably made selective by timing one or more stages of the radio frequency amplifier 11. vFor purposes of illustration I have indicated a selectively tuned system'by showing a radio frequency transformer 14 coupling together the loop antenna 10 and thev amplifier 11, this transformer being tuned by means of 'a'variable condenser Associated With the directive receiving apparatus described above, there isa non-directional receiver Which in a typical instance may comprise a radio frequency amplifier 17, detector 18 and audiov frequency amplifier Y 'is adapted to be influencedby both of the receivers, indicates a critical adjustment of loop antenna 10 When both of the receivers'are tuned to the same signal. One suitable form of translator utilizes a mirror galvanoineter 26 having its armature 27 connected to the output of ampliner 13. A beam of light-from a .lamp 28 is focused upon the mirror 29 of this galvanometer, and is reflected upon a l screen 31. The lamp 28 is energized from a V local battery 32 through a circuit controlled by relay 33. The windings of this relay are connected to the amplifier 19 ofthe non-directional receiver sov as to be energized .from the received inthe directional receiver.

output of the last amplifier stage. The relay 33 is designed so that for the ordinary audible signal frequency, its armature 34 will not flutter but will be held against contact 36. The armature, however, is biased as by means of a spring 37 so that when no signals are being received by the nondirectional receiver, armature 34 breaks the energizing circuit for battery 3:2. For observing the position of the light beam, the screen 3l is provided with a Window 3S, and another ,window 39 may be providedy for observing the condition of lam-p 28. Y

Vhen operating` the system as described above, both the directional and non-directional" receivers are tuned to a certain transmitting station or to a given source of radio signals. This may be accomplished by using telephone receivers inrplace of the translator, or the two receiving apparatuses may previously be adjusted sov that the operator may merely operate the-simultaneous control until lamp Q8 is lighted.l The galvanometer may then be `adjusted so that the beam of light striking' the mirror 29 will bev reflected along path L1 to illuminate the. window 38. l`o secure a bearing indieatiom the loop is then` slowly rotated to a; position of minimum signal; strength. Thisis indicatedy to the observer by darkening-'of Window 38 due Vto a deection ini the galvanometer 'whichl changes the angle of reflection and; thus shifts the beam to path 4Q. By notingthat window 39 is illuminated when window 38 is darkened, the operator may be assured that the bearing observation in the mirror is a true indica.- tion of a criticalv position; of the loop 10. It is obvious-that instead of having a window 38 darken toindicate critical condition, the gaflvanometer 26' may be arrangedL to, deflect the beam tonormally darken the window and illuminate it when` the signal strengthr in the directional receiver is at a minimum.

It will be apparent that this system isk a decided improvement on radio' compass systems whichl utilize a singleV receiver.A The response of the translator which indicates a criticall position of the loop is not merely due tov'theabse'nce of signal energy, but is due to the reception of signal energy inthe one receiver when substantially no energy isv being Thus the response is more reliable inv that it is positive rather than negative. It is obvious that'V a dill'erentially wound relay, or a system of interlocking' relays may be substituted for the galvanometer arrangement.

y l. In Va radio signaling system, two receiving apparatus, each'ha'ving an'independent antenna, a light source adapted to be illuminated by reception of signalenergy by oneapparatns, and'mejans controlled byv the other Aapparatus for-aliecting light rays fromy Ycontrolled by received signal energy from the other apparatus for varying the visual indicatibn produced by said lamp.

a. In a radio signaling system, two receiving apparatus each having an independent antenna, indicating means including a lamp adaptedr to be illuminated by reception' of signal energy by one apparatus,- and' means controlled by received signal energy IOm the other apparatus for variably defiecting light f froml said lamp.

Y 5. In a radioy system,y a direction-V find-ing apparatus lincluding a. rotatablel directional antenna associated with: a radio detector, indicating means controlled by the output of said detector, and means` for preventinga false 'bearing indication comprising Aa nondirectional receiving apparatus includinglanother radio detectoxgnnd means correlating said last detector withv saidindicating means for independently indicatingV reception of a bearing signal by said non-directional apparatus.- y

.6. InV aV radio system.I a directionalfinding apparatus' including a rotatable directional antenna associated with a radio dectector, `indicating means controlledby the output. of saidl detector, and means. for preventing a. tal-se bearing indication comprisingya nondirectional receiving apparatus includinganother radio detector, and means' correlating said last vdetector with Said indicatingmeans for independently indicating' reception of a. bearing signal by said? nonLdirectional apparatus, said' lastV means serving to render said iirst named indicating meansoper'ative in response to'receptioi'iof the"directionsignal by said non-directional apparatus. n

7. In a radio compass, a receiving s tem having movable absorption structure, t e received energy varying with the amplitude of radiant energy andthe position of said structure with respect to thewave-front thereof, a second receiving system of the received energy of which varies solely with the amplitude of said radiant energy, an indica-torl associated with said lirstgsystem responsive to the received energy thereof for indicating ositi'on and means res onsive to the ener 5 P Y y of said second system controlling the operativeness of said indicator.

8. In a radio compass, a directional receiving system, an indicator having a. deflecting member Whose position is determined by the direction of propagation of energy received by said system, a second receiving system, and means responsive to energy received by said second system controlling the ability of said defleeting member to produce an indication.

In testimony whereof, I have hereunto set my hand. y

GEORGE T. ROYDEN.

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