US2213874A - Wireless direction finding system - Google Patents

Wireless direction finding system Download PDF

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Publication number
US2213874A
US2213874A US209186A US20918638A US2213874A US 2213874 A US2213874 A US 2213874A US 209186 A US209186 A US 209186A US 20918638 A US20918638 A US 20918638A US 2213874 A US2213874 A US 2213874A
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Prior art keywords
frequency
aerial
oscillograph
sub
modulator
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Expired - Lifetime
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US209186A
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English (en)
Inventor
Wagstaffe Charles Freder Allen
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International Standard Electric Corp
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International Standard Electric Corp
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO 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
    • G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
    • G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
    • G01S3/14—Systems for determining direction or deviation from predetermined direction
    • G01S3/143—Systems for determining direction or deviation from predetermined direction by vectorial combination of signals derived from differently oriented antennae

Definitions

  • This invention relates to wireless direction nding systems and more particularly to such systems ofthe kind in which the signal waves .are received on a plurality of xed directional aerial systems which areiso positioned that their respective directions of maximum pick-up are arranged at an angle to one another.
  • the main object of the present invention is the provision of a system which will enable one amplifying channel torbe used for amplifying the ysignal waves from two or more aerial systems and thus to obviate the above-mentioned difficulties.
  • the signal waves received ⁇ from each aerial system are passed to a modulating device wherein they are modulated v.each at adiierent sub-frequency, the combined modulated outputs being then amplified in a common high frequency amplifier from the outputof which the sub-frequency components are selected, and used to actuate a device for indicating the direction of the signal waves incident upon the aerial systems, which device may, for 35 example, comprise a cathode ray oscillograph.
  • the incoming signal waves are subjected also to modulation by a beating oscillator in order to permit of their amplication by an intermediate frequency amplifier.
  • Fig. 1 shows schematically one embodiment of the invention
  • Fig. 2 shows the arrangement of the aerial systems of the system of Fig. 1;
  • Fig. 3 shows a portion of the arrangement of Fig. 1 modified to provide a simultaneous indication of the bearing and sense of an incoming signal
  • Fig. 4 is a schematic circuit diagram of another system according to the invention.
  • a2, az are :the two :pairs cof4 aerialsi of an ⁇ Adcock system.
  • A1, .A2, A3 are Vaerial couplingfdevices.. iMi, M2 ⁇ Mtb-aire.modulating devices of any known type.
  • F. 1500,@2000 and F. ⁇ 2500 are filters .of knowntype forgselecting respectively frequencies of .1500, '.2000 and 2500 cycles persecond.
  • VO1 andfOzare' oscillators for generating waves of 500 and 2000 cycles per second respectively.
  • I..F. A. is the intermediate ⁇ frequency.amplifier of asuperheterodyne, :D .is a rectifier or detector, PI and yP2 are phase-shifting.-networks,.and GI, G2, G3 are low frequency amplifiers.
  • .LO is an oscillator for supplying :a .local -signalfor lining .up the equip ment.
  • the oscillators O1 and G2 supplymhemodulator M3 from the output of whichthe .intermodulation yfrequencies .of .1500.and v2500 cycles *per second areselectedby theglters F. .1500;andfF.2500.
  • the signal from.Al passesto'the modulator Ml where it is modulatedby the heating oscillator yBO and also by a frequency of 15000.11). s. from the lter 1500.
  • the component cf the-output from'the modulator MI consisting of-.a carrier of intermediate frequency-together with its two'side bands ⁇ corresponding to 1500 c. YYp. s. .is selected and passedlto the amplier.IF. A.
  • the two output frequencies .1500 c. p. s. and 2500 c. p. s. from the vdetector D are selected by filters F. 1500 and F. 2500 and arepassed to mod- .n
  • ulators Mil and M5 respectively, in which they are modulated by a current of 500 c. p. s. from the oscillator 0.500.
  • modulator M4 the sum modulation product of 2000 c. p. s. and from M5 the difference modulation product, also 2000 c. p. s. are selected by the filters shown.
  • the output from M passes through a phase changing network P1, filter F. 2000 and amplifier G3 and then on to one pair of the oscillograph deflector plates, say PX.
  • the output from M passes in a similar manner over a filter F. 2000 to the PY plates of the oscillograph except that it does not pass through any phase changing network.
  • the network P1 is adjusted so that the phase change in it plus the sum of the phase changes in the two 1500 c. p. s. lters, is equal to the sum of the phase changes in the two 2500 c. p. s. filters. It can be arranged by the design of the lters and phase shifting circuit that the total phase shift in the 1500 c. p. s. circuit, while not remaining constant with frequency, does remain closely the same as that for the 2500 c. p. s. circuit over an appreciable band of frequencies, (say from 50 c. p. s. below to 5.0 c. p. s. above the mean frequencies).
  • the two frequencies 1500 c. p. s. and 2500 c. p. s. for modulation in Ml and M2 are produced not by yoscillators of these frequencies but by intermodulation of the frequencies 500 c. p. s. and 2000c. p. s. in the modulator M3.
  • the 500 c. p. s. oscillator is then also used to supply the modulators Mtl and M5.
  • the voltages applied to the plates of the oscillograph being of the same frequency and in phase, produce a line on the oscillograph screen.
  • the amplifiers Gl and G3 are regulated for gain to give a line on the oscillograph forming an angle of 45 with each of the deecting axes of the oscillograph. This of course corresponds to a signal arriving in a direction 45 to either of the diagonals of an Adcock aerial system.
  • the aerial For the determination of sense the aerial as is brought into operation. This will be, in the case of an Adcock Direction Finder, avertical conductor placed at the centre of the square formed by the remaining aerials of the system.
  • the 2000 c. p. s. output from D is selected by the filter F. 2000 and passed through the phase changing network P2 and then to the amplifier G2.
  • the frequency at this point is, of course, that of the oscillator O2 which is also that of the voltage applied to the plates of the oscillograph.
  • the output from G2 is then injected into the high tension supply circuit of the oscillograph by means of the transformer T.
  • this relationship of phase can be made to remain stable over a band of frequencies.
  • the effect of injecting the voltage in series with the high tension supply is to vary, in a periodic manner, the sensitivity of the oscillograph and in such a way that the portion of the line on the oscillograph screen on one side of the origin, is considerably different in length from that on the other. In this Way the sense of the bearing will be clearly indicated and will be arranged for example, to be on the side of the longer portion of the line.
  • Fig. 3 An alternative and preferred way of carrying out this part of the invention therefore is shown in Fig. 3.
  • the amplifier G2 of Fig. 3 feeds a transformer T1, the secondary of which is connected to a unilateral conducting device such as a metal rectifier R and resistance 1' in series.
  • the resistance is also included in series with the feed to the focussing, control or other electrode, El, in the oscillograph.
  • Iamasar YAdcock principle of compounding the signal outputs from the diagonally opposite aerials of the system that the signals from A1 and A2, Fig. 1, may be in phase or in anti-phase according to the direction of the signal. If they are in antiphase and equal, corresponding to a signal arriving from a direction making an angle of 45 with the direction of one of the diagonals of the aerial system, the carriers at intermediate frequency, emerging from the modulators Ml and M2 (assumed of equal conversion conductance) will cancel out though the side bands corresponding to modulations of 1500 c. p. s. and 2500 c. p. s. will remain.
  • phase reversal is introduced in the output from say Mi by a reversing switch arrangement Si.
  • this phase reversal of the output from Ml must also be accompanied by a similar phase reversal by a switch S2 in the 1500 C. p, s. modulation supply entering Ml (or elsewhere in the low frequency arm of the circuit corresponding to the aerial input Ai.)
  • An alternative method is to make Ml and M2 balanced modulators so that the carrier is eliminated from their output.
  • the carrier is then supplied from the aerial as, via modulator M6.
  • modulator M6 For the determination of the bearing the 2000 c. p. s. modulation from oscillator O2 is cut olf from M6.
  • the modulation is switched on. The operation of the remainder of the circuit is as previously described.
  • Fig. 4 shows an alternative arrangement.
  • the modulating frequencies of 1500 c. p. s. and 2500 c. p. s. for supplying modulators ME and M2 are obtained from oscillators of these frequencies 0.1500 and 0.2500.
  • Modulator M4 is then supplied by oscillator 0.2500 and M5 by oscillator 0.1500.
  • the frequency, selected by lters F. 1000, for the deecting plates of the oscillograph is, in this case, 1000 c. p. s. From modulator M3, 1000 c. p. s. is selected by the lter shown for the modulator MS.
  • the characteristics of the circuit and also its manner of operation are then as in the previous arrangement.
  • a radio direction nding system including a plurality of fixed directional aerial systems so positioned with respect to one another that their respective directions of maximum pick-up are at an angle to one another, means to produce under control of the signals from each aerial separate carriers each modulated locally at a diiferent sub-frequency, a common' high fre..
  • a radio direction finding system including a plurality of fixed directional aerial systems so positioned with respect to one another that their respective directions of maximum pick-up are at an angle to one another, a modulator device individual to each aerial, a local beat frequency oscillator common to said modulator devices, separate sources of oscillations of different subfrequencies; means to impress on each modulator the signals from the associated aerial, the signals from said beat frequency oscillator, and one of said sub-frequency signals, to produce two separate carriers of a common ⁇ intermediate frequency each modulated in accordance with only one yof said sub-frequencies; a common intermediate frequency amplifier upon which said carriers are impressed, means associated With the output of said amplifier to select said sub-frequencies, means for producing separate waves of the same frequency from said sub-frequencies, an indicating device for giving an indication of the direction of the signal waves incident upon said aerials and means for applying said produced separate waves to said indicator.
  • a radio direction finding system including a plurality of fixed directional aerial systems so positioned with respect to one another that their respective directions of maximum pick-up are at an angle to one another, a modulator device individual to each aerial, sources common to said modulators for producing two separate sub-frequency oscillations, means to intermodulate said sub-frequency oscillations to produce other subfrequency oscillations of respectively diiferent frequencies, means to apply said other oscillations to respective onesvof said modulators to produce correspondingly modulated separate carriers, a common high frequency amplier on which said carriers are impressed, means associated with the output of said amplier to select said sub-frequency components, a further modulator device for each of said selected components each of said further modulators being supplied with oscillations of the same frequency from said source to produce sub-frequency waves of the same frequency, each having an amplitude proportionate to that of the waves incident on a corresponding aerial, and a device controlled by said same sub-frequency waves for giving an indication of the direction of the signal waves incident upon said aerials.
  • a system according to claim 3 in which said source comprises two oscillator generators of different frequency, and a modulator is provided for intermodulating the waves from said generators to produce respective sum and diiference frequencies, means to apply the sum frequency to one of the modulators individual to one aerial, means to apply the difference frequency to the other modulator individual to the other aerial.
  • a direction nding system including a plurality of fixed directional aerial systems so positioned with respect to one another that their respective directions of maximum pick-up are at an angle to one another, a modulator device individual to each aerial, a pair of separate subfrequency oscillator sources one for each of said aerialsl for producing sub-frequency oscillations, means toapply said sub-frequency oscillations to respective ones of said modulators to produce correspondingly modulated high frequency carriers, a common high frequency amplifier on Which said carriers are impressed, means associated with the output of said amplifier to select said sub-frequency components, a separte further modulator for each of said components, means to impress oscillations from said sources on correspondingr ones of said further modulators to produce separate sub-frequency Waves of the same frequency each having an amplitude proportionate to the signals incident on a corresponding one of said aerials, and an indicator device controlled by said separate sub-frequency Waves of the same frequency for giving an indication of the direction of the signal waves incident upon said aerials.
  • a radio direction finding system including a plurality of xed directional aerial systems so positioned with respect to one another that their respective directions of maximum pick-up are at an angle to one another, means to produce vunder control of the signals from each aerial separate carriers modulated at a different subfrequency, the last-mentioned means including a pair of local oscillator sources of different subfrequency, a common high frequency amplier on Which said carriers are increased, means associated with the output of said amplifier to select said sub-frequency components, a device controlled by said selected sub-frequencies for giving an indication of the direction of the signal waves incident upon said aerials, and means are provided for determining the sense of direction of said waves, the last-mentioned means including a non-directional aerial, a third modulator into which said non-directional aerial feeds said third modulator being also fed With local oscillations to produce a third sub-frequency modulated high frequency carrier, means l aerial is supplied with oscillations from one of said local oscillation sources.
  • a system according to claim 1 in which a linear detector is provided for rectifying the output of said common amplifier prior to impression of the amplifier output on said selecting means.
  • said indicator device is a cathode-ray tube oscillograph, and means are provided for applying the said separate produced Waves respectively to the deflecting systems of said oscillograph.
  • phase changing networks are connected between the output of said amplier and said indicator device, said networks being adjusted to bring the selected sub-frequency Waves into phase alignment.
  • said indicator device comprises a cathode-ray oscillograph having a beam focussing system, and there are provided a rectifier for rectifying the selected sub-frequency component of said third carrier and means for applying said rectifled component toextinguish the cathode-ray spot during each half cycle.
  • an amplier for amplifying the selected sub-frequency component of said third carrier and said indicator device comprises a cathode-ray oscillograph having means to control the side of the cathode-ray spot, the last-mentioned means including a transformer connected in the output of said sub-frequency amplier, a uni-lateral conducting device and resistance in. series with the secondary of said transformer, and a connection from said resistance to the focussing control electrode system of said oscillograph.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Superheterodyne Receivers (AREA)
US209186A 1937-05-28 1938-05-21 Wireless direction finding system Expired - Lifetime US2213874A (en)

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Application Number Priority Date Filing Date Title
GB207371X 1937-05-28

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US (1) US2213874A (fr)
CH (1) CH207371A (fr)
FR (1) FR838506A (fr)
GB (1) GB496239A (fr)
NL (1) NL50149C (fr)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2415954A (en) * 1942-02-28 1947-02-18 Rca Corp Radio direction finding
US2415955A (en) * 1942-02-28 1947-02-18 Rca Corp Radio direction finding
US2422073A (en) * 1942-07-30 1947-06-10 Rca Corp Radio direction finder
US2444439A (en) * 1945-03-26 1948-07-06 Standard Telephones Cables Ltd Beacon receiver means
US2449553A (en) * 1945-09-14 1948-09-21 Paul G Hansel Radio compass
US2475412A (en) * 1949-07-05 Torcheux
US2485642A (en) * 1945-03-05 1949-10-25 Standard Telephones Cables Ltd Electronic switching system
US2524768A (en) * 1944-12-16 1950-10-10 Standard Telephones Cables Ltd Radio direction finder
US2642473A (en) * 1944-12-07 1953-06-16 Bell Telephone Labor Inc Wave translating system
US2666192A (en) * 1944-07-27 1954-01-12 Frederick V Hunt Apparatus for determining the direction of underwater targets
US2717374A (en) * 1942-04-30 1955-09-06 Sperry Rand Corp Deflection voltage generator
US2913721A (en) * 1953-06-20 1959-11-17 Csf Radio direction finding system
US20040032363A1 (en) * 2002-08-19 2004-02-19 Schantz Hans Gregory System and method for near-field electromagnetic ranging
US20050046608A1 (en) * 2002-08-19 2005-03-03 Q-Track, Inc. Near field electromagnetic positioning system and method
US20060132352A1 (en) * 2004-12-21 2006-06-22 Q-Track, Inc. Near field location system and method
US20060192709A1 (en) * 2002-08-19 2006-08-31 Q-Track, Inc. Low frequency asset tag tracking system and method
US8774837B2 (en) 2011-04-30 2014-07-08 John Anthony Wright Methods, systems and apparatuses of emergency vehicle locating and the disruption thereof
CN107037394A (zh) * 2016-02-03 2017-08-11 希姆通信息技术（上海）有限公司 方向定位设备及方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE965501C (de) * 1955-12-01 1957-06-13 Lorenz C Ag Peilanordnung unter Benutzung von mehr als zwei sternfoermig gekreuzten, auf je einer Basis aufbauenden Antennensystemen

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2475412A (en) * 1949-07-05 Torcheux
US2415955A (en) * 1942-02-28 1947-02-18 Rca Corp Radio direction finding
US2415954A (en) * 1942-02-28 1947-02-18 Rca Corp Radio direction finding
US2717374A (en) * 1942-04-30 1955-09-06 Sperry Rand Corp Deflection voltage generator
US2422073A (en) * 1942-07-30 1947-06-10 Rca Corp Radio direction finder
US2666192A (en) * 1944-07-27 1954-01-12 Frederick V Hunt Apparatus for determining the direction of underwater targets
US2642473A (en) * 1944-12-07 1953-06-16 Bell Telephone Labor Inc Wave translating system
US2524768A (en) * 1944-12-16 1950-10-10 Standard Telephones Cables Ltd Radio direction finder
US2485642A (en) * 1945-03-05 1949-10-25 Standard Telephones Cables Ltd Electronic switching system
US2444439A (en) * 1945-03-26 1948-07-06 Standard Telephones Cables Ltd Beacon receiver means
US2449553A (en) * 1945-09-14 1948-09-21 Paul G Hansel Radio compass
US2913721A (en) * 1953-06-20 1959-11-17 Csf Radio direction finding system
US20040032363A1 (en) * 2002-08-19 2004-02-19 Schantz Hans Gregory System and method for near-field electromagnetic ranging
US20050046608A1 (en) * 2002-08-19 2005-03-03 Q-Track, Inc. Near field electromagnetic positioning system and method
US6963301B2 (en) 2002-08-19 2005-11-08 G-Track Corporation System and method for near-field electromagnetic ranging
US20060192709A1 (en) * 2002-08-19 2006-08-31 Q-Track, Inc. Low frequency asset tag tracking system and method
US7298314B2 (en) 2002-08-19 2007-11-20 Q-Track Corporation Near field electromagnetic positioning system and method
US7414571B2 (en) 2002-08-19 2008-08-19 Q-Track Corporation Low frequency asset tag tracking system and method
US20060132352A1 (en) * 2004-12-21 2006-06-22 Q-Track, Inc. Near field location system and method
US7307595B2 (en) 2004-12-21 2007-12-11 Q-Track Corporation Near field location system and method
US8774837B2 (en) 2011-04-30 2014-07-08 John Anthony Wright Methods, systems and apparatuses of emergency vehicle locating and the disruption thereof
CN107037394A (zh) * 2016-02-03 2017-08-11 希姆通信息技术（上海）有限公司 方向定位设备及方法
CN107037394B (zh) * 2016-02-03 2020-06-23 希姆通信息技术（上海）有限公司 方向定位设备及方法

Also Published As

Publication number Publication date
GB496239A (en) 1938-11-28
FR838506A (fr) 1939-03-08
NL50149C (fr)
CH207371A (de) 1939-10-31

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