US3286261A - Direction-determination system employing unequal directional patterns - Google Patents

Direction-determination system employing unequal directional patterns Download PDF

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Publication number
US3286261A
US3286261A US291355A US29135563A US3286261A US 3286261 A US3286261 A US 3286261A US 291355 A US291355 A US 291355A US 29135563 A US29135563 A US 29135563A US 3286261 A US3286261 A US 3286261A
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Prior art keywords
antenna
frequency
modulation
determination system
sideband
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US291355A
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English (en)
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Hofgen Gunter
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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
    • G01S1/00—Beacons 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
    • G01S1/02—Beacons 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
    • G01S1/08—Systems for determining direction or position line
    • G01S1/38—Systems for determining direction or position line using comparison of [1] the phase of the envelope of the change of frequency, due to Doppler effect, of the signal transmitted by an antenna moving, or appearing to move, in a cyclic path with [2] the phase of a reference signal, the frequency of this reference signal being synchronised with that of the cyclic movement, or apparent cyclic movement, of the antenna
    • G01S1/40—Systems for determining direction or position line using comparison of [1] the phase of the envelope of the change of frequency, due to Doppler effect, of the signal transmitted by an antenna moving, or appearing to move, in a cyclic path with [2] the phase of a reference signal, the frequency of this reference signal being synchronised with that of the cyclic movement, or apparent cyclic movement, of the antenna the apparent movement of the antenna being produced by cyclic sequential energisation of fixed antennas

Definitions

  • Aircraft landing direction-determination systems are known in which the directional patterns serving the navigation purpose, are lying uniformly and symmetrically in relation to a center line (landing runway). These patterns may be e.g. directional patterns of either the modulation or frequency deviation type. These systems, however, require the additional transmission of a reference signal.
  • the invention is based on the problem of providing a system which can be simplified by doing away with this requirement.
  • the present invention relates to a direction-determination system operating on the basis of unequally produced directional patterns, i.e. of such ones which are produced by two spatially separated antenna systems (with the spacing being large with respect to the wavelength) operated at different frequencies.
  • the frequencies are thus that they can represent both the carrier and a sideband of an amplitude-modulated oscillation.
  • the direction-determination system consists in that one of the two directional patterns is of the amplitude modulation type, while the other one is of the frequency-deviation type.
  • the two directional patterns are preferably symmetrical with respect to the connecting line between the two antenna systems, but may also be unsymmetrical.
  • FIG. 1 shows two antenna systems with symmetrical patterns in respect to the mid-vertical to the line connecting the two arrays
  • FIGS. 2 and 3 each show two antenna systems with unequally produced antenna patterns
  • FIGS. 4 and 5 are plots of radiation fields of lines having a constant phase difference
  • FIG. 6 is a block diagram of a navigation system according to FIG. 2.
  • FIG. 7 is a block diagram of a navigation system in accordance with FIG. 3.
  • FIG. 1 shows two antenna systems A and B whose directional patterns extend symmetrically in relation to the mid-vertical to the common connecting line.
  • the antenna system A is eg supposed to radiate a carrier oscillation (frequency F which is amplitude-modulated with the signal frequency f, in such a way that the degree of amplitude modulation is dependent upon the direction.
  • the directional pattern is supposed to have a figure-ofeight characteristic.
  • the antenna system B consists of one row comprising a number of single antennas which are successively fed in a rhythmical succession, so that in this way, and in the conventional manner, there is simulated an antenna motion of the individual radiators on the linear antenna array.
  • the function of the velocity is supposed to be the same as at the modulation of the carrier oscillation, hence a sine wave function with the frequency f.
  • the frequency deviation caused on account of the Doppler effect is direction-dependent. It reaches its maximum in the direction of the linear antenna array, while being zero vertically in relation thereto.
  • This directional pattern likewise has a figure-of-eight characteristic.
  • the function of time, as well as the pure carrier oscillation which is radiated in an undirected manner, are not represented, because they do no longer appear after having been rectified in the receiver.
  • the directional patterns are e.g. supposed to have a figure-of-eight characteristic, as shown in FIG. 3.
  • e E(m -sin w-sin wi+m 'COS w'cos wt)
  • h H -sin fi-sin wt+H -cos B'cos wt
  • the fields of lines having a constant phase difference is given by:
  • the realization of the directional patterns may be effected in the case of the antenna system A with the aid of crossed dipoles, and in the case of the antenna system B by providing an elliptical path of the simulated sideband radiation (arrangement of the single antennas in elliptical array).
  • FIG. 6 shows the block diagram relating to a navigation system according to FIG. 2, and FIG. 7 likewise shows a block diagram of an arrangement for carrying out the method according to FIG. 3.
  • This oscillation controls two parallel-arranged output amplifier stages 2 and 3 in the ovenbiased condition, so that they are capable of being anode-modulated with a low distortion.
  • the two outputs of the output amplifiers are coupled via a bridge network 4 consisting of three M4 cables 5 and one 3M4 cable 6, so that at the output A the sum voltage of both output amplifiers 2 and 3, and at the output A the difference voltage is obtainable.
  • the signal oscillation is subjected to a phase shift by +90 and by 90" with the aid of the phase-shifting devices 8 and 9.
  • the functions of time at the two outputs of the phase shifters are thus +sin wt and sin wt.
  • the output voltages of these modulation amplifiers are signified as U cos wt+U sin wt and U cos wt -U sin wt; with the aid of these voltages there is carried out the amplitude modulation of the two RF-output amplifiers 2 and 3. Accordingly, the output voltages of the output amplifiers may be expressed as follows:
  • an unidirectedly radiating antenna e.g. Alford loop
  • the difference voltage is fed to an antenna 4 having a figure-of-eight pattern (e.g. dipole). way the system A of FIG. 2 is realized.
  • the output of this stage is fed via a distributor 17 to the individual or single antennae B B B of the linear antenna array.
  • the distributor 17 is controlled by the low-frequency oscillation as produced in the control generator 7; it serves to forward the energy as derived from the sideband-output generator 15, in such a way to the individual or single antennae B B B that a movement of the radiation center on the linear antenna array is simulated with a sinusoidal velocity thereby.
  • An example of such a distributor which can be used herein is disclosed in the copending patent application of E. Kramar and F.
  • a frequency controller In order to maintain the frequency spacing between the carrier and the sideband with the necessary accuracy, there is provided a frequency controller.
  • the mixer 21 there is constituted the difference frequency between the carrier and the sideband. Whenever it deviates from the rated value a control voltage will be produced at the output of the controller 22 acting upon the capacitive diode (not shown) of the servo-system 20. In this way the generator 15 is readjusted to the rated frequency spacing between the carrier and the sideband.
  • FIG. 7 shows an RF-generator 30 for producing the carrier voltage (signal) which controls the three parallelarranged output amplifier stages 31, 32 and 33. Since the output voltage s of the output amplifier 31 remains unmodulated, the two others (32 and 33) are amplitudemodulated.
  • the function of modulation is that of the control generator 34.
  • the low-frequency signal oscillation of the control generator 34 whose function of time is cos wt, is directly fed to the modulation amplifier 35 via a -phase shifter 36 and to the second modulation amplifier 37.
  • the output voltages of the modulation amplifiers are U sin wt and U cos wt; with the aid of these there is carried out the amplitude modulation of the two RF-output amplifiers 32 and 33.
  • the output voltages of the three output amplifiers may be represented as follows:
  • the RF-voltage available at the output A is the un- In this modulated carrier voltage (signal) as radiated by an antenna without a directional effect (e.g. Alford loop).
  • the RF-voltages available at the outputSgA1 and A are the pure sideband voltages (signals) differing from one another by the modulation amplitude and the modulation phase.
  • the construction of the circuit arrangement for producing the sideband oscillation (angular frequency Q -i-AQ), including the frequency controller, is the same as that shown in FIG. 6.
  • the difference with respect to the radiation merely resides in the fact that the sideband radiation must not be moved in a simulated fashion on a linear antenna array, but on an elliptical path.
  • a direction-determination system operating on the basis of two directional patterns which are produced by two spatially separated antenna systems operated at different frequencies, Whose spacing is a plurality of wavelengths with respect to the transmitted wavelengths, comprising means to produce at one of said antenna systems a pattern of the amplitude modulation type, and means to produce at the other antenna system a pattern of the frequency-deviation type.
  • a direction-determination system wherein a first antenna system of said two antenna systems comprises two antennas, means to produce a first signal which is the sum of two other signals, means to produce a second signal which is the difference of said two other signals, means to couple said first signal to said first antenna and means to couple said second signal to said second antenna.
  • a direction-determination system wherein said first antenna is an Alford loop and said second antenna is -a dipole.
  • a direction-determination system comprising a linear antenna array, means to produce a sideband modulation of one of said signals, and means to couple sequentially said sideband signal to the antennas of said linear array.
  • a direction-determination system wherein a first antenna system of said two antenna systems comprises three antennas, means to produce a carrier signal, means to produce sideband signals of said carrier and a modulation signal, means to couple said carrier signal to a first of said three antennas and means to couple each said sideband signals to respective second and third antennas of said three antennas.
  • a direction-determination system wherein said first antenna is an Alford loop antenna and each of said second and third antennas is a dipole antenna.
  • a direction-determination system according to claim 6 wherein the second antenna system comprises an antenna array movable on an elliptical path.
  • a direction determination system further comprising means to produce a sideband of said carrier signal and means to couple sequentially said modulation signal to the antennas of said antenna array.
US291355A 1962-07-09 1963-06-28 Direction-determination system employing unequal directional patterns Expired - Lifetime US3286261A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEST19460A DE1259969B (de) 1962-07-09 1962-07-09 System zur Richtungsbestimmung auf der Grundlage von zwei ausgestrahlten Richtdiagrammen

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US3286261A true US3286261A (en) 1966-11-15

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US (1) US3286261A (xx)
BE (1) BE634674A (xx)
CH (1) CH414774A (xx)
DE (1) DE1259969B (xx)
NL (1) NL295108A (xx)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2543081A (en) * 1948-03-16 1951-02-27 Int Standard Electric Corp Pulsed localizer
US2690558A (en) * 1950-02-04 1954-09-28 Sylvania Electric Prod Radio navigation system
US2717735A (en) * 1953-06-30 1955-09-13 Rca Corp Means for locating the position of a mobile craft
US3130407A (en) * 1960-09-24 1964-04-21 Int Standard Electric Corp Twin beacon system
US3181159A (en) * 1958-07-16 1965-04-27 Int Standard Electric Corp Omnidirectional bearing system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2543081A (en) * 1948-03-16 1951-02-27 Int Standard Electric Corp Pulsed localizer
US2690558A (en) * 1950-02-04 1954-09-28 Sylvania Electric Prod Radio navigation system
US2717735A (en) * 1953-06-30 1955-09-13 Rca Corp Means for locating the position of a mobile craft
US3181159A (en) * 1958-07-16 1965-04-27 Int Standard Electric Corp Omnidirectional bearing system
US3130407A (en) * 1960-09-24 1964-04-21 Int Standard Electric Corp Twin beacon system

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Publication number Publication date
NL295108A (xx)
CH414774A (de) 1966-06-15
BE634674A (xx)
DE1259969B (de) 1968-02-01

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