DE1239371B - Antenna arrangement for Doppler radio back-beam systems for speed and drift measurement in aircraft - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

Number:
File number:
Registration date:
Display day:

GOIs

HOIq

German class: 21 a4- 48/63

D 26175IX d / 21 a4
August 8, 1957
April 27, 1967

The invention relates to an antenna arrangement for Doppler radio reflection systems for speed and drift measurement in aircraft.

Such antennas must generate four directional beams, all of which are directed towards the ground, and one forward on the port side, the second forward on the starboard side, the third aft on the port side and the fourth aft on the starboard side. The first and the fourth ray must be sent out at the same time, as must the second and the third. It is with this one special navigation system common practice, linear antenna arrangements, such. B. slotted Waveguide, the antenna array being substantially horizontal in a longitudinal direction attached to the aircraft. If necessary, the antenna arrangement can be partially or fully stabilized to keep them in their horizontal position.

So far, two different forms of antenna design have been used. With one construction are four separate linear antenna systems in the form of four waveguides horizontally provided in the longitudinal direction of the aircraft, the four antenna systems being arranged in such a way that their rays point in the required directions. In the other embodiment uses two linear antenna systems, one forward-facing and the other creates a rearward beam. Each of the antenna systems is mechanically adjustable Provided reflector, which serves to direct the beam either to the port or the starboard side deflect, the two reflectors are coupled and designed such that when the forward beam is deflected to port, the aft beam is deflected to starboard distracted, and vice versa.

Antennas intended for the above-mentioned navigation device are used for both transmission and also used for reception. The following description is only concerned with the emission of rays Has been referred to. The antennas can, however, be used for both reception and transmission will.

In microwave Doppler on-board navigation technology, it was already known to use a beam to the right ahead and a beam to the left backwards, i.e. a first double beam, and to switch alternately to a beam to the left ahead and one to the right backwards, i.e. a second double beam . In the case of the antenna arrangement for
Doppler radio reflection systems for
Speed and drift measurement in
Aircraft

Applicant:

Decca Limited, London

Representative:

Dr. M. Herzfeld, patent attorney,
Düsseldorf, Kreuzstr. 32

Named as inventor:
Michael James Moran, London

This facility was made up of four separate directional spotlights and mechanical switching of the same Made use of.

In contrast, with Doppler navigation radar systems for measuring speed and drift, the simultaneous generation of two sharp directional beams by a single row of dipole or slot radiators not known.

The invention is accordingly based on a known antenna arrangement for Doppler radio reflection systems for speed and drift measurement in aircraft, which consists of a large number of im arranged essentially parallel to the longitudinal axis of the aircraft, with radiation slots on the underside provided waveguides, for the simultaneous generation of two with the same depression angle downwardly inclined and azimuthally oppositely directed rays that alternate in two directions be switched, which by a certain same azimuth angle left or right from the axis of the waveguide.

According to the invention, in such an antenna arrangement for generating the two beams, each Waveguide with a number of in-phase coupled, at a distance of half a waveguide wavelength provided radiation slots. The radiation slots of neighboring waveguides are included shifted in the axial direction of the waveguide by about a quarter of a waveguide wavelength, wherein all waveguides in a known manner for dipole walls for the purpose of beam pivoting from the be fed from the same side in a specific, and indeed in such a phase sequence that the swivel

709 577/123

kung takes place in azimuth direction. To generate one of the two beams at an angle of ± Θ Biae phase sequence of 90 ° each are the inputs of the phased antenna arrangement can contain a waveguide to a transverse feed row of slots in a waveguide, waveguides at a distance of about a quarter that all emit signals in the same phase. Feed waveguide wavelength coupled, whereby the 5 An antenna arrangement not brought into phase Phase sequence for direction switching in can contain a series of slots in a waveguide switching of a single beam in a known manner, from which alternating slots radiate in the opposite direction by alternating the excitation of the feed hollow phase. If two such slotted conductors were superimposed from one side or the other from reverse waveguides, it would be possible. io cancel the two signals in antiphase so that

In this embodiment of the invention, the effect of the superposition of two such all waveguides to a parallel plate array antenna assemblies by using a one be summarized. umpteen waveguide is achieved in which every second

To explain the effect of such a slit is missing. The number of slots can be based on the antenna arrangement reduced from a number of in 15 half that number while in the same Radiators arranged at a distance from one another still only generate two main rays. It treatment elements, in particular a number of in, it can thus be seen that a linear Doppelstrahleinem Waveguide provided slots, antenna arrangement is made by means of a series of beams the following carried out: lungsschlitzen can be obtained, and that one

The main beam generated is located in such an arrangement that generates two beams.
Angle to the row of radiating elements that proceeds from another embodiment of the invention

the distance between the elements as well as the radiation is also dependent on the known antenna arrangement for the development phase of the various elements. Doppler radio retro-reflective systems for the speed of this angle Θ (measured from the row of radiation and drift measurements in aircraft, which ventilation elements) is given in the case of an antenna arrangement placed in phase 25 from a large number of essentially parallel antenna arrangements, ie an Aircraft longitudinal axis arranged on the underside order, in which all elements are similarly provided with radiation slits waveguides, so that they - if fed individually in phase - would radiate in phase for the simultaneous generation of two, according to the downward slope at the same angle inclined formula 30 below and beams directed opposite in azimuth

serves, which alternately in two directions

ß _ J ^ _ _ η X are switched, soft around a certain

~ Xg s ' same azimuth angle to the left or right of the

Axis of the waveguide lie.

where λ denotes the free wavelength, l _g denotes the wave length, according to the invention, to generate the two length in the conductor (or any other over-beam, each waveguide with a square transverse transmission system between the elements) is designated, cut and is formed with two in the right s is the linear distance of the elements and H = O, angle to each other fed polarized waves. Da- + 1, ± 2, ... etc. means. at each waveguide has radiation slots that

In the case of an out-of-phase antenna 40, an in-phase arrangement for one of the nen arrangement in which alternating elements of both shafts and a different type standing in antiphase are designed that they form out of order for the other wave in antiphase, the radiate, is both waves through the two waveguides through ge

separated dining halls lying across from them.

n_ i, / _ ^ W 45, which are suitable for feeds in the

~~ Ig \ 2 J ensure s' phase relationship with the square waveguides so that equal but opposite when is taken the distance between the elements to set the azimuth angle for the two beams erdaß only n-0 yields a solution is merely an be generated . Available to switch the direction of the main jet. It is then 50 len are the phase relationships in themselves

known way by alternately stimulating the

Q _ J ^ ^ _ transverse feeder waveguide from the eäneo

~~ Xg 2 s or reversible from the other side.

The antenna arrangements according to the invention are

for an anti-phase arrangement and 55 therefore particularly advanced since it is built into

Aircraft do not require much depth because they are mechanically

_COS 0 _ _Ä_ niscn are very stable and since they are not movable

Own Xg parts.

for a phased arrangement. _t ^With both of the above-mentioned designs

6a forms of the invention, the slotted Wd-

By means of an antenna arrangement working in opposite phase and an antenna arrangement all brought about by a common transverse phase for cross-beam feeding waveguides, which do not have the same amplitude distribution at the ends, but at an intermediate point of the main beams are therefore slit at angles ± Θ Waveguide is arranged.
testifies, provided that the distance between the 65 It can also be used in the second embodiment * -

Radiation elements is equal to \ . By agree- ^f _Q ^orm } ^e L ™ ^ndu ? ^g f * ^ "f? ^r ν ****« * »

4 SpeisehohUeiter designed as a conductor of the same type

other storage of two such arrangements will be, with the coupling links in different

Is provided spaced along the two lines, these form radiation elements in the

are. essentially an antenna arrangement for cross-beam

The two transverse feed waveguides development, through which a directional beam is generated, the

can also be used as a conductor at various transverse angles to the row of radiating elements Section be designed in such a way that it is different from what the distance between the elements and the

dene conductor wavelengths for the radiation phase continued in the conductors. The head 20

Planted waves result, with the lines sitting according to the drawing a number of such

are designed such that the physical distance slots, which are shown schematically at 21 and

the coupling links in both feed lines which all radiate in phase, as indicated by the physical spacing of the rows of the slotted io-like inclination of the slots. A two-

Waveguide is the same. ter head 22 has a row as shown in the drawing

The coupling members can also consist of slots of StraWungsschlitzen 23, of which every second

exist in the transverse feed waveguides, the slot does not radiate in phase, as shown in the diagram

the conductivity of the slots being symmetrical, due to the opposite inclination of the alternate Similar radiation characteristics are indicated for the slots. The two conductors 20 and

aiming if both ends of a transverse 22 would produce beams going into different

Hollow feed line are fed. Directions are directed. Provided,

Below are two embodiments of the that the distance between the slots so taken

Invention with reference to the drawings is that only one beam from each of these conductors is made for example to be discribed. 20 goes, then the rays are separated from the

1, 2 and 3 are explanatory conductors, as explained above, at angles Θ

Graphs; occur given by the following formulas

F i g. 4 is an isometric view of the Un- are:

bottom of an antenna; χ χ

F i g. Figure 5 is an isometric view of the Un- 35 cos Θ = -y-

bottom of a second antenna; ^q

F i g. Fig. 6 is a partial view in section ^{along the lines of FIG.}

Line 6-6 in FIG. 5. _cos @ _ _ ^ _

According to FIG. 1 the shape of the radiation character 30 is shown in a diagram serving to explain λ _β

teristics shown, which in a Doppler on-board navigator so that the two beams occur at the same and opposite angles to determine the airspeed, provided that the distance between the slots of a four-plane aircraft is necessary to the ground and the drift of a. An airplane is shaky equal to one waveguide wavelength. At 10, and the point O represents an alternation of the two conductors 20, 22 is represented by a point on the ground perpendicular below which the radiation from the alternating slots of the aircraft. This point is on the course of the conductor 22, the radiation of the superimposed slot of the aircraft, which is indicated by the line XX of the conductor 20 canceled, so that the two is over. OY is a perpendicular to line XX through superposed conductors to a single slotted point O on the surface of the earth. The antenna system 40th waveguide 24 are equivalent to that shown in FIG. 3 must produce four directional beams, the intersection points of which are shown and in which the slots in the area of the earth's surface are shown at 11, 12, 13 and 14 and are half a waveguide wavelength. For the sake of simplicity, these four rays should lie on top of one another and emit in phase, hereinafter referred to as rays 11, 12, 13 and 14, respectively. In the present invention, superimposed rays are drawn; and it can be seen that the 45 conductor of FIG. 3, with a sequence of beam 11 on the port side forward, the ladders corresponding to the conductor 24 in parallel beam 12 on the starboard side to the rear, the rows being arranged in the longitudinal beam 13 on the starboard side forwards and the direction of the aircraft. From a comparison of beam 14 on the port side towards the rear, FIG. 2 and 3 it can be seen that each of the conductors is tet. The beams 11 and 12 are to be used at the same time as 50 as shown in FIG. 3, a pair of superimposed conductors with in, as are beams 13 and 14. The beam phase and non-phase radiating slots 11 and 12 are not, however, equivalent at the same time . A single conductor 24 would require one such as beams 13 and 14. A switching system can therefore be used forwards and one backwards so that in produce ab- beam. Through a compound alternating time intervals the beams 11 and 12 55 order these conductors, as illustrated in Fig. 3, and then the beams 13 and 14 are emitted. and feeding the conductors in appropriate phase - it is to be understood, as noted, that the forward beam to the antennas would be used for both reception and port side of the aircraft and rearward transmission, though Directed beam deflected towards the starboard side, for the sake of simplicity in the following description only 60, whereby the beams 11 and 12 are generated. referred to the emission of rays by reversing the phase relation of the to be. drove to the ladders would be the forward one

Fi g. Figures 2 and 3 are diagrams used for illustration purposes of deflecting the beam to the starboard side and the reverse beam deflected by double-beam linear antenna assemblies to the port side. If a waveguide, as in Fig. 2, looks 65 through which the rays 13, 14 are generated. This is indicated pictorially by the line 20, with a lateral deflections correspond with the deflection range of arrival equally spaced angles ß according F i g. 1, which - as already arranged radiation elements, z. B. Slitting, refines - from the relative phases of the feeds to

Claims (1)

7 8 the various ranks and from the physika- is as 19.5 °. In Figs. 5 and 6 there is an execution table Distance of the rows are dependent. In the form of a directive intended for this purpose The arrangement according to the invention is illustrated for the network. According to FIG. 5 includes Change from rays 11, 12 to rays 13, the directional antenna network a number of wave 14 required reversal of the phase of the feeds to 5 conductors 40 of square cross-section, which on the various rows are provided with radiation slits 41 by a switch on one surface acts, which are diagrammatically at 25 in FIGS. 2 and 3. The conductors 40 are at the bottom of a and enables any rigid support device (not shown), e.g. Series feeding transverse feed line 26 of an aluminum plate of cellular structure, is fed from one end or the other, where- io fastened in such a way that the slots 41 are on the un- are located by the phase relationship of the various rows terfläche the conductor 40. It is known that can be reversed. The rows are in a square waveguide with two Hertzian trans- arranged at a distance from each other, which corresponds to a vertical wave whose planes of polarization are under right Quarter of a conductor wavelength of the feed line 26 system angle to each other, can conduct without is equivalent to. 15 any interference between the two waves 4 is an isometric view of the accident. Each conductor 40 is provided - as in FIG. 6 on the other side of an embodiment of a directional antenna - with two such signals, the transverse network, which the with reference to FIG. 2 and 3 have extending polarization planes, embodied by means of refined elements. This Richtanten- fed to the probes 42, 43, which are coupled with cross-network comprising a number of slotted waveguides 20 running feed lines 44 and 45, respectively. 30 of rectangular cross-section, which are provided on one of their narrow sides through each on the surface of the conductor 40 with slots 31, which are sensitive and cut through the wave course half a waveguide length apart and the slot causes a radiation; and which are fed in phase. These slots 31 must slots 41 are arranged in such a way that they are coupled to both signals in the same way on the underside of the antenna arrangement. Since the should be brought so that the radiation downward conductors 40 have a square cross-section, are directed. The various conductors 30 may conveniently set the phase velocities for the two signals on a rigid plate of lightweight the same, and the slots 41 will be so arranged, weight mounted, e.g. an aluminum plate, that they are the equivalent of superimposing a cellular structure. However, for the sake of simplicity, an antenna arrangement which is brought into phase for one is omitted in the drawings and an out-of-phase signal and an out-of-phase one. It is to be understood that the antenna arrangement for the other signal forms. Since the arrangement is completely stabilized or, if desired, each of the conductors 40 generates two beams in a similar manner can be stabilized in the plane of incline. The Licher way, as with reference to FIGS. 2 and 3 erLleiter 30 are refined by a transverse feed 35, and the entire composite antenna arrangement, which is fed from all the conduits 32 of rectangular cross-section, the conductors 40 produced is arranged in such a way that their broadsides parallel two beams, one of which runs towards the one with the general plane of the antenna arrangement on the side of the longitudinal plane and the other towards the one. As can be seen from the drawing, the side of which is deflected, depending on the phase in which this feed line 32 cuts the conductors 30. 40 feeds to the various conductors. It also has coupling-phase relationship of the feeds to the conductors 40 on one of its narrow sides, which serve to reverse the feed line 32 by coupling the two feeds to each of the conductors 30. The conductor 30 lines 44, 45 alternately from the one or are fed for signals in the feed line 32 at a distance from the other end by means of a switch 46 , which is one quarter of a conductor wavelength of 45 rather - depending on the switch setting - arranged one to the other. In order to reverse the relative phases of the or the other end with a common feed to the conductors 30, discharge 47 can be coupled. The feed lines 44, 45 have neither one or the other of the two ends of different internal dimensions, so that the feed line 32 results from a common different conductor wavelengths for which the two feed lines 33 are fed, corresponding to the setting 50 feed lines. Since a switch diagrammatically indicated at 34, these conductor cross-sections, as explained above, allow the supply 33 to be selected in such a way that the physical output or the other end of the line 32 was coupled to the feed lines 44, 45 is located. Coupling elements, which these feed lines with When coupling 55 to the slotted radiation conductors 40 described with reference to FIG.
that the deflection angle β (see. Fig. 1) a min- _Ό ...
has a minimum size of about 19.5 °, because - as in the previous patent claims:
explained standing - with smaller deflection 1. Antenna arrangement for Doppler radio backlash, unwanted beams of the second order - 60 beam systems for speed and drift stepping. In general, it is possible to use deflection measurements in aircraft, which are from a multiple angle of up to about 30 °, and the number of substantially parallel to the aircraft order according to FIG. 4 is satisfactory e.g. B. arranged longitudinal axis, on the underside with if the antenna arrangement is stabilized or provided for radiation slits waveguides are intended for transport aircraft that are not cornering, for the simultaneous generation of two under flight, which carry out a considerable oblique equal depression angle downwardly inclined position of the aircraft require. In some cases, however, and a beam directed in the azimuth in the opposite direction, a deflection angle is desired that is smaller than that which alternates in two directions.