DE1255742B - DF method - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

GOIs

German class: 21 a4- 48/31

Number:
File number:
Registration date:
Display day:

T 29817 IX d / 21 a4
November 20, 1965
7th December 1967

DF method

The invention relates to a DF method in which, firstly, the DF voltages of a crossed DF system or one after the other the bearing voltages of two or more remote ones and equally aligned crossed DF antenna systems fed to a two-channel direction finder secondly from the output voltages

U ₁ = U · cos χ ■ cos Ω t t / „= U · sin α -cosut

(α = angle of incidence, Ω = high and intermediate frequency) of the two-channel direction finder DC voltages CZ ₃ and CZ are generated ₄ whose amplitudes and polarities characterize the incident direction, in which ¹ S Third, these DC voltages devices for time release or for the formation of the mean value of the voltages originating from the various antenna systems are fed in and in which the direct voltages obtained by forming the mean value are ultimately used to display the angle of incidence.

It is known (German patent specification 1115 790) that in visual radio direction finders on the display tube ellipses can arise that constantly change their shape and position. The cause of these changes are so-called Multi-beam effects that z. B. in the case of the sky wave by reflection on the partially inhomogeneous and wavy Ionospheric layers are formed. Due to these phenomena, the amplitude 3 » and phase positions of the individually arriving waves, resulting in a permanent change in the display image occurs.

A method for determining the direction of incidence of a wave has already been proposed (German Auslegeschrift 1246 053), in which this disadvantage does not occur. At this proposed Procedure, the DF voltages of two or more remote locations are set up one after the other and equally aligned crossed DF antenna systems fed to a two-channel receiver. The output voltages of this two-channel divider are in phase rectifiers, which on the one hand the high-frequency or intermediate-frequency DF voltages and, on the other hand, the associated azimuth-independent voltage are supplied, rectified in such a way that two DC voltages arise, which characterize the direction of incidence by their polarity and amplitude. These DC voltages are devices for the formation of the mean value from the various antenna systems resulting voltages supplied. By applicant:

Telefunken

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

Named as inventor:

Dipl.-Ing. Karl Fischer, Neu-Ulm / Danube

Formation of the quotient of the two output voltages of this device for averaging is obtained one then the direction of incidence. The previously proposed method has the disadvantage that for the formation of the DC voltages an azimuth-independent voltage is required for which one for example a third receiving channel is required.

A visual radio direction finder has also become known which is the basis for solving the invention causes a mean value display (German patent specification 1115 790). With these well-known Visual direction finders are the amplified DF voltages originating from an antenna system rectified in phase rectifiers. The DC output voltages of the phase rectifiers for which an azimuth-dependent voltage is also required, are fed to a device for averaging whose output voltages are used for Ad are exploited.

The object on which the invention is based is to find a solution to the above To propose a problem in which no azimuth-independent voltage is required and which thus becomes simpler in its structure.

With the DF method according to the invention, the DF voltages of a crossed DF antenna system or the DF voltages of two or more DF antenna systems set up at a distance from one another are fed to a two-channel direction finder, from whose output voltages the DC voltages are generated, which are used for averaging. According to the invention, the output voltage is used to form the two direct voltages CZ ₃ and CZ _{4 which characterize the direction of incidence}

U ₁ = U-cosa -cosi? /
and

U ₂ = U sin χ cos Ωί

709 707/198

3 4

of the two-channel direction finder in direction finders with rotating The amplification takes place in the case of the invention

Goniometer known circuit part supplied, in application thus before that in direction finders with rotating

the circuit part used from the two voltages U ₁ and U _{2, the goniometer.} The disadvantages

The voltage of the direction finder with the rotating goniometer can be used at

U ₁ · sin ω t - ^ U ₂ · cos ω t ^{5 of} the application according to the invention can be avoided,

because the frequency ω can be chosen to be large im

is formed (where ω is a low frequency), comparison to the maximum possible rate of change, after this voltage sum is rectified, the amplitude and phase of the intermediate and finally the phase position of the DC voltage in the DF channels. The possible direction obtained voltage of the frequency ω against io speed of the strong increase in the frequency ω is given by over two 90 ° in phase shifted reference the fact that the main selection of the voltage of the frequency ω is measured, with the direction finder in front of the circuit arrangement , through which the two frequencies ω obtained on the basis of the phase measurement is introduced, is switched on, while DC voltages represent the voltages U ₃ and U ₄ in the case of the known direction finder with a continuously rotating direction. 15 goniometers are known to be behind this part of the circuit

It should be mentioned that a direction finding method is already activated. For reasons of selection, in the case of the known (German Auslegeschrift 1 061 842), in the known arrangement, the frequency ω must be kept low, similar to that in the one embodiment of the.

according to the invention and already proposed _{it has been ünsti erwieserl5 the frequency} / = JL DF method successively different Peilantennen- 20 2 π systems connected to a two channel receiver to be chosen such that they z multiples. B. be a. DF antenna systems are ten times the bandwidth of the receiving channels. known method provided cross frame, which while in direction finders with rotating goniometer, are arranged on a circle. At the same time, as the name suggests, generally a mecha-occurrence of ground and sky waves are used in the case of the nisch rotated goniometer, uses known methods on the display tube one after the other with the method according to the invention three ellipses are preferably written. The tangents are an electric goniometer known per se, these ellipses indicate the direction of entry of space. 1 should and bump again. This known direction finding method, the method according to the invention explained in more detail, differs from the method according to the invention and the method according to the invention. In the exemplary embodiment shown, direction finding systems already proposed and explained above, two direction finding antenna systems 1 and 2 are provided. With drive both through a different task help of the switch 3, these antenna systems are position as well as through a different solution. one after the other with the two inputs of a two-However, individual process steps are connected in the channel pillar. This consists of the two driving similar to each other. 35 changeover devices 4 and 5 for periodic switching

In the method according to the invention, in the swapping of the receiving channels, the high-frequency channels, in one embodiment, a time averaging through amplifier stages 6 a and 6 b, the mixing stages 7 α and, is performed, which is expediently over a time interval Ib, which the voltage of the oscillator 8 is supplied stretches, which is approximately the duration of a Schwund-, and the intermediate frequency amplifiers 9a and corresponds to period. In the other embodiment 40 9 b. The periodic swapping is carried out by spatial averaging. The time generated by the generator 10, from which the switching and the averaging is carried out, voltage for the switch 3 with HMe of the Fre in this embodiment is very much shorter, since it is only derived from the frequency divider 11. At the output of the still necessary, the mean value from the downstream two-channel receiver, a display tube 12, on which the antenna systems are formed, can be connected, as previously generally incoming voltages of the various 43 usual. The time in which a direction of incidence is displayed.
Averaging is carried out, will therefore approximately correspond to the formation of two antenna systems that are identical to the direction of incidence by their time, which corresponds to a switch-on cycle for the amplitude and polarity characterizing the same. A switching stage 13 is provided for these inherent voltages, which in itself establishes the advantage of the method mentioned last in the drawing as a rotating goniometer. is. The output voltages of the two-channel divider

As already mentioned above, the direction of incidence is fed to the stator windings of this goniometer according to the formation of the two according to the invention. The rotor winding is continuously rotated by the DC voltages characteristic of the motor 14. The motor 14 is fed by the part that is used in direction finders with a continuously rotating generator 15. The goniometer on the search coil of the goniometer is already known (German patent specification 13 tapped voltage is by the following Aus-734 359). With such direction finders, however, the pressure is given:
two antenna voltages of a crossed an f / · sincoi + £ / · coswi.
antenna system directly to the two entrances of this * 2
Circuit part supplied. The input of this switch- 60 Here are U ₁ and U _2, the two intermediate parts is generally formed by a rotating, frequency output voltages of the two-channel inductive goniometer, whose stator winding ,,. 2 ω. ,. , ". ..,,
depend on the two antenna voltages ^{and f} = IT ^ents ? ^{Not the rotation frequency of the} , while a single-channel motor 14, which can for example be 6000 Hz, is attached to the search coil.
DF receiver is switched on. In contrast, 65 in FIG. 2, the output voltages of the two-channel application, the intermediate-frequency direction finder, are shown for four different cases in the known circuit part in the left-hand column of the invention. With the assumed ratio voltages supplied to a two-channel divider. nits result on the display tube on the right

Claims (1)

i 255 bearing displays shown next to it. The output voltages of the goniometer 13 are shown in the next column, assuming the ratios shown on the left. The above sum voltage is fed to the rectifier 16, which is followed by a bandpass filter 17. A voltage of frequency ω is obtained at the output of this bandpass filter, the phase position of which depends on the azimuth. This voltage of frequency ω is fed to the two phase bridges 18 and 19, in which the phase position of this voltage is compared with the phase of two reference voltages of frequency ω shifted in phase by 90 °. At the output of the members 18 and 19, two direct voltages are obtained, the amplitudes and polarities of which depend on the phase position of the output voltage of the bandpass filter 17 and thus on the direction of incidence. These two voltages are fed to the two integrators 20 and 21, in which the mean value is formed from the two antenna voltages fed one after the other. Of course, the switch 3 can also be integrated over several switchover periods. The integration stages can, for example, be simple C elements, the time constant of which R · C is large compared to the integration time. The integration time can be set for different lengths with the aid of the device 22. The integration begins when the radio operator presses the button 23, which can be designed as a foot switch, for example, and ends automatically at the end of the duration set on the link 22. The reference voltages supplied to the phase bridges 18 and 19 can be obtained, for example, by supplying the voltage of the generator 15 to one stator winding of a goniometer 24 directly on the other after shifting the phase by 90 ° (element 25). The phase position of the reference voltages is determined by the position of the search winding of the goniometer 24. The arrangement described here is of particular interest when using a vehicle, since the search winding of the goniometer 24 can then be continuously adjusted by a course gyro drive 26 so that bearings to the north are always automatically obtained even when the direction of travel is changed. In the case of direction finding of short-term signals that only occur now and then, it is advantageous to activate the integration and thus the storage without the assistance of the direction finder. For this purpose, an azimuth-independent voltage is obtained from the two direction finding channels by means of the phase shifter 27, which effects a phase shift of 90 °, which voltage is rectified in the rectifier 28. If this direct voltage exceeds an adjustable threshold in the element 29, the integration is switched on via the switching amplifier 30. Here, too, it is switched off automatically at the end of the set integration time. In the exemplary embodiment shown, the averaged bearing direction is displayed digitally. To achieve the digital representation, the two output voltages of the integration stages 20 and 21 are fed to modulators 31 and 32, to which the low-frequency voltage of the generator 33 is also fed. The two low-frequency voltages present at the output of the modulators 31 and 32 are fed to the stator coils 34 and 35 of a position indicator 36. The output voltage of the rotor 37 of this position indicator is fed to a servomotor 39 via an amplifier 38. The reference winding of this motor is fed directly from the generator 33. The motor 39 now adjusts the rotor 37 of the position indicator 36 until its angular position corresponds to the integrated Peir figure. A converter 40 is coupled to the motor axis of the motor 39, which converts the angular position of the motor axis in a manner known per se, either mechanically with contacts or optically with a decoder disk and photocell so that the number glow tubes 41 can be controlled. The display option just described is of course only an example. The display can of course also take place on a cathode ray display tube or the generation of the control voltage can take place in a purely electronic way. In FIG. 3, there is shown an electronic goniometer which incorporates the goniometer 13 of FIG. 1 can replace. The outputs of the two-channel distributor are connected to inputs 42 and 43. This is followed by modulators 44 and 45, which are designed as push-pull or ring modulators. The output voltage of the generator 15 is fed directly to these modulators once and after a phase shift of 90 ° in the other case. The output voltages of these modulators are then added. The parts described so far correspond to the goniometer 13 of FIG. 1. As in the embodiment of FIG. 1, the rectifier 16 and the bandpass filter 17. It should also be mentioned that with the direction finding method according to the invention it is also possible to operate two direction finding receivers with two antenna systems and still carry out a diversity direction finding. The two antenna systems are always connected to one of the direction finders, but are periodically swapped. Patent claims: 1. DF procedure with which the DF voltages of a crossed DF antenna system or one after the other the bearing voltages of two or more spaced apart and identically aligned Crossed DF antenna systems are fed to a two-channel direction finder, in which from the Output voltages and U ₁ = U · cos λ · cos Qt U ₂ = [/ -sin λ -cos Qt (oc = azimuth, Ω = intermediate frequency) of the two-channel divider DC voltages U ₃ and U _{4 are} generated, the amplitudes and polarities of which characterize the direction of incidence, in which these DC voltages are supplied to devices for temporal averaging or for the formation of the mean value from the voltages originating from the various antenna systems and in which the direct voltages obtained by the averaging are used to display the angle of incidence, characterized in that to form the two direct voltages U ₃ and U ₁ characterizing the direction of incidence, the output voltages U ₁ and i / _{2 of} the two-channel direction finder animal goniometer known circuit part are supplied in which the voltage from the two voltages CZ ₁ and U ₂ U ₁ · sin cot + U _z · cos cot is formed, where ω is a low frequency, then this sum of voltages is rectified and finally the phase position of the Rectification obtained voltage of the fre- frequency ω is measured against two reference voltages of frequency shifted in phase by 90 °, the two DC voltages obtained on the basis of the phase measurement representing the voltages U ₃ and U ₁ . 2. The method according to claim 1, characterized in that that the frequency / = ^ - a multiple the bandwidth of the receiving channels. For this purpose 2 sheets of drawings 709 707/198 11.67 © Bundesdruckerei Berlin