DE1233032B - Method for polarization error-free direction finding - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

GOIs

German KL: 21 a4-48 / 23

Number:
File number:
Registration date:
Display day:

T28338IXd / 21a4
April 7, 1965
January 26, 1967

The invention relates to a method for polarization error-free Bearing of the incident at a bearing location, from the sky wave and at the highly conductive Earth's surface reflecting wave existing field of any polarization.

The method according to the invention is characterized in that with the aid of an antenna system known per se, consisting of a vertical cross frame and two horizontal dipoles arranged in the frame planes , voltages Udx, Udy, Urx and Ury proportional to the field components E _x , Ey, H _x and H _y it can be obtained that from these voltages using elements influencing the amplitude of individual voltages as a function of the operating frequency, as well as addition and subtraction stages, the expressions method for directional finding without polarization errors

Applicant:

Telefunken

Patentverwertungsgesellschaft mb H.,
Ulm / Danube, Elisabethenstr. 3

Named as inventor:

Dipl.-Phys. Dr. Karl Baur, Ulm / Danube

U ₁ = Uj _0x

= UDY -

~ Urx

The factor γ is applied with the help of a corresponding element. With HiKe from known means that can be varied in the angle cc , this stress γ Udz is divided into two components

and

U ₃ = - Udz sin X _x

U » = - Udz cos K _x

are formed (where in α the height h of the antenna installation site is above the ground and α is a constant and λ is the operating wavelength) and that these voltage terms are known per se

Way by forming the quotient - = £ · for display

of the angle of incidence O ₁ can be used.

In the method according to the invention, however, it must be assumed that the height of the installation site of the antenna above the ground is small compared to the operating wavelength. In many frequency ranges this requirement is automatically fulfilled.

The direction finding method just described can be used when the field present at the direction finding location is composed of a sky wave and a wave reflected on the ground. It can also be used if the ground wave is also added, but this has approximately the same angle of incidence as the sky wave. If, on the other hand, the angle of incidence of the ground wave is different from the angle of incidence of the sky wave, the method described above must be modified as follows. With the help of an additional dipole arranged in the cross frame axis, the voltage Udz is obtained, the amplitude of which is also split up. These voltage components U ₃ and U ₄ are then subtracted from the voltages U ₂ , that is to say U ₂ - EZ ₃ and CZ ₁ , that is to say U ₁ -U _4. Thereafter, the angle value tx _x is changed in a manner known per se until the ellipse written on the display tube degenerates into a line, the angle value then set oc _x = K _{2 being} a measure of the direction of incidence of the bump.

It is already known (German Auslegeschrift 1039 586), similar to that described above, the bump components to compensate for an incident field, so that only the linearly polarized Space wave is displayed. A known direction finding arrangement for carrying out this method consists of a cross frame and a dipole arranged in the cross frame axis. The dipole voltage is combined with the tension of one frame of the cross frame, such that one Cardiod arises. With this known DF arrangement you have a directional diagram of the DF antenna system, which consists of a Beilacht and a Cardiode, whereby the zero point of the Cardiode with a Zero point of the bearing coincides. By rotating the antenna system or a connected Go-

609 759/148

3 4

niometers with two perpendicular to each other, the magnetic components H _x

Search coils, the angular position is sought in which, "... _, h,. ,,.

the bump is hidden on the d reasonable ™ / 7, the factor _T mrt applied werdender-

In this case, the closed indicator tube degenerates into the following expressions:
displayed ellipse to a line. From position 5

of the antenna system or the crossed search j ^ ₌ jj _{DX + Ury} ± _{= KEv sin} 2 _ε A _cos ^ _>

The goniometer can then be rewound to the incident λ λ

in the direction of the bump. (1)

Another direction finding arrangement for carrying out the method described above is known ίο υ ₌ u _DY _ jJrx- = KEv sin ² ε -— sin α
OAEÜ ", Vol. 18, 1964, Issue 11, pp. 657 to 662, ins- λ λ * '
special picture 2). With this well-known Peilanord- (2)
The antenna system is a three-level system

The addition or subtraction means that triple frames are provided. The two vertical components, the horizontally polarized components in the bearing frame, are compensated for by the two stator winding equations for E _x and E _y. Guided through the bilge of a goniometer whose search coil with,, _,. , u ,, ,,. _n,. ,.
connected to one channel of a two-channel ^{receiver dun} S of ^the Q uotie »** - ^ one can finally be the one. The horizontal frame is connected to the second channel angle of incidence «1 on a display tube, the two-channel receiver. With any 20 An arrangement for carrying out the invention position of the goniometer search winding is also here according to the method is shown in the drawing, an ellipse is recorded on the display tube. In FIG. 1 is the on-angular position to be used for the bearing according to the method according to the invention, in which the ground wave is masked out by rotating the goniometer search winding. It consists of is, here too the ellipse degenerates into a line. From the two vertical frames R _x and R _y as well as the position of the goniometer search coil, the direction of incidence of the wave can also be inferred from the two horizontally arranged in the frame planes. talen dipoles D _x and D _v . In FIG. 2 is this

The two direction finder-antenna combinations just described are only shown schematically.

It must be assumed that the space wave is made. The antennas are equipped with a receiver

is linearly polarized at the bearing location. Only then can 1 connect. In terms 2 and 3 are

lent the ellipse to the frame voltages Urx and Ury with one of when the bump was faded out

degenerate into a single line. For this bearing arrangement,. _x ". "..... ". α,

However, the applicable prerequisites should by no means determine ^the frequency-dependent factor _y

always be given. If the incident sky wave hits, the factor α also includes the height of the

due to the reflection at the ionosphere, the antenna is elliptical 35 above the ground,

polarized, so these known Peilanord- these links 2 and 3 are favorably

nings can no longer be taken. The invention together with the coordination of the receiving device

The underlying task is to set a bearings 1. In the subtraction element 4 is the

to create a system which expresses itself with any polarization

of the sky wave incident at the bearing location, the 40 a

guidance of a bearing allows. ^u * ^{= Udy} ~~ ^RX ~ J

In the following the method according to the invention

are explained in more detail. The first described formation, while in the addition element 5 the expression driving requires a field at the bearing location, which is only

from space wave and wave reflected on the ground 45 U = Uox + Ury ~
consists. If, as mentioned above, one sets one in the A
equal to the operating wavelength low height of the installation location DF antenna system ahead, then formed. With the direction finding procedure described above, the output voltages of the GHe determined field components E _x , Ey, H _x and H _{y are} fed to the 4 and 5 amplification channels 6 and 7, as follows: their output voltages on the display tube 8

I ₁ I _{1 result in} a line display, whereby the position of the

E _x = -Ic ₁ Er- cos ² e cos X ₁ + Ar ₁ E _H ~ - cos e sin (X ₁ , the line drawn is a measure of the incidence

* · Angle Oc is ₁ .

I ₁ I ₁ 55 As already mentioned above, the described

Ey = -Ic ₁ Ev- cos ² ε sin X ₁ -Jc ₁ Eh- cos ε cos / X ₁ , arrangement can also be used if additional

^ still borrowed for the space wave and the reflected wave

H _x = -IC ₂ EvSkIa ₁ -Ic ₂ EHCOSeCOSx ₁ , ^the bump occurs, but the same

Has angle of incidence.

Hy = Ic ₂ EvCOSOc ₁ - Ic ₂ Eh cos ε sin K ₁ . e ₀ Dj _e described arrangement, however, must be something

be modified when facing the bump

Here Ic ₁ and k _{2 are} constant quantities, Ev is that of the space wave at a different angle of incidence

vertically polarized component of the electrical incident. For this case there is an additional one in the

Field, Eh is the horizontally polarized component axis of the cross frame of FIG. 1 shown

of the field, ε is the elevation angle, and A ₁ is the 65 dipole Dz , the voltage of which is in the link 9

E _x and Hy or E _y and H _{x in} terms of voltage together - operating frequency dependent factor applied

Claims (2)

will. To compensate for the bump in the output voltages of members 4 and 5, the output voltage of member 9 is fed, for example, to the search coil of a goniometer 10, to whose stator winding the outputs of members 4 and 5 are connected. According to the set angular value Oix of the search coil of this goniometer, a voltage U3 = - Udz sin Oix = - Udz cos kx IO is subtracted from the output voltages of elements 4 and 5. The search coil is rotated until the bump share in the output voltages of links 4 and 5 is compensated. If the bump is not compensated, an ellipse appears on the display tube 8. In the case of compensation, this ellipse degenerates into a line, as in the known bearing arrangements described above. In the event that, in addition to the sky wave and the reflected wave, the ground wave also comes with a different angle of incidence, the display tube 8 is used as an indicator for setting the goniometer search coil. The direction of incidence of the compensated ground wave can be deduced from the position of the search coil in the case of compensation. It should also be mentioned that in the case of the occurrence of a bump with different directions of incidence to equations (1) and (2), the expressions a - cos α2 Eze - sin «a 40 add up. Ezb means the vertical electric field strength of the bump. These expressions are compensated for with the aid of the portion of the voltage received via the dipole dz which originates from the bump in the road. The field component E2 in this case is Ez = Er sin e + EZb claims: 1. A method for polarization-error-free direction finding of the field of any polarization incident at a bearing location, consisting of sky waves and waves reflected on the highly conductive surface of the earth, characterized in that with the aid of a per se known, from a vertical cross frame and two horizontal dipoles arranged in the frame planes existing antenna system the field components E _x , Ey, H _x and H _y proportional voltages Udx, Unr, Urz and Ury are obtained that from these voltages using elements influencing the amplitude of individual voltages depending on the operating frequency as well as addition or subtraction stages the expressions U ₁ = Udz U ₂ = UDY - URX ~ are formed (where in α the height h of the antenna installation location is above the ground and λ is the operating wavelength) and that these voltage expressions in a manner known per se by forming the quotient ~ to display the Angle of incidence K ₁ can be used. 2. The method according to claim 1, characterized in that with the additional occurrence of the bump at the bearing with a different angle of incidence from the sky wave with the help of an additional dipole arranged in the cross frame axis, the voltage Udz is obtained that this with the help of a member influencing the amplitude with the factor - = - applied becomes that with the help of known _{means which can be changed in the angle α Λ} this voltage is divided into two components U ₃ = - Udz sin K ₁ U ₁ = - Udz cos K ₁ is split so that these voltages U ₃ and U ₄ are subtracted from the voltages U ₂ and U ₁ and that the angular value K _x is changed in a manner known per se until the ellipse written on the display tube degenerates into a line , the angle value Oc ₂ then set being a measure of the direction of incidence of the bump. 1 sheet of drawings 609 759/148 1.67 © Bundesdruckerei Berlin