DE1766174A1 - Method and device for improving the accuracy of the radiation direction of an antenna - Google Patents

Description

Dipl.-Ing. Egon Prince

.Dr. Gertrud Hauser

Dipl.-Ing. Gottfried Head Patent attorneys

Telegrams: Labyrinth MOnchaa

Telephone 83 15 19 postal checking account, Munich 117371

• ooo Miich .. to, April 11, 1968

Ernsbergerstrasse 19

our mark; C 2520

CSP-COMPAGNIE GENERALE DE TELEGRAPHIE SANS PIL Ί7, Rue Dumont d'Urville, Paris 16 / France

Method and device for improving the accuracy of the radiation direction of an antenna.

The present invention relates to antennas with electronic deflection comprising a network of radiation sources, which are fed in such a way that they emit a beam which, depending on the time, according to a periodic puncture shifts, as is the case in particular with the so-called "counter-rotation" antennas, which at

Board

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Used on board satellites and via a transformer circuit fed in the form of a Butler matrix.

In any case, the shift in the emitted beam is obtained by taking the phase shifts between the successive ones Inputs of the matrix changed. The phase shift to be generated when feeding each input is a function of the rank or number of the entry of the matrix and the desired location of the beam.

For practical purposes of technology, such phase shifters are used that the phase shifts generated by them can only be equal to certain values in arithmetic progression. These phase shifters are called "quantized". This results in a jerky rotation and disadvantageous errors in the direction of radiation, which are particularly serious because so far the direction of the systematic based on this quantization Phase error has been chosen according to a simple function, making each phase value independent of any other consideration has been rounded down to the nearest quantized value. This resulted in certain desired locations of the beam of rays occurring at the same time on several phase shifters phase "jumps", which still the jerk white Indicated the character of the shift in the beam and increased the directional error.

Purpose 109825/1649

The purpose of the invention is to reduce these disadvantages based on the quantization of the phase shifts. For this purpose, according to the invention, simultaneous Changes to several phase shifts are prohibited and the theoretical phase-time function of the phase shifter changed in such a way that the errors due to the quantization are compensated for. The rounding calculator, which determines the actual phase of each input based on the theoretical phase, has a logic circuit, which prohibits the simultaneous changes in the phase shifts supplied by several phase shifters or prevented, and one connected to the circuit for calculating the theoretical, i.e. not yet quantized, phase Auxiliary circuit changes the theoretical phase-time relationship in such a way that taking into account the quantization the changes in state of the phase shifters at times that are favorable for reducing the directional rejection appear.

The invention is explained in more detail, for example, with the aid of the figures. Show it

Figure 1 is a basic scheme of a known antenna, to which the invention is applicable,

FIG. 2 shows a basic maintenance scheme of an inventive

antenna

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Antenna,

FIGS. 3 to 5 are graphic representations and are used for explanatory purposes

FIGS. 6 and 7 show details of the circuit diagram of FIG.

In order to explain the basic idea, the invention is described below for the special case of an antenna, which is arranged on a stationary, rotation-stabilized satellite. The direction of the beam should match the coincide with the geocentric axis or form a fixed angle with it. The beam 1 should therefore receive the same uniform rotational movement with respect to the satellite as this, but in the opposite direction.

The general case of an antenna with periodic scanning is derived from this particular case by adding the linear Changes in the phase shift can be replaced by changes according to any function.

The antenna consists of η radiation sources A ₁ , A ^ ... A, which are arranged around the satellite in a circle. The axial direction of the maximum radiation rotates around the axis of the circle in the plane of the same or by enclosing a constant angle with it. the

Turn 1 0982S / 1649

·. Rotation of the beam is obtained by

i between the input terminal of the arrangement and the i, radiating elements T a known circuit switched [on which a power divider D, which is fed at a ■ transmitting antenna, for example, a power generator GC, variable phase shifter Ph _1, ... Ph

and a Butler matrix B with η inputs and η outputs I. A linear and continuous phase change

to the phase shifters a progressive encryption i shift of excitation corresponds to the radiating elements A. ... A _n t and a uniform rotation of the radiated beam.

j The phase shifts i required at each input of the matrix are linear punctures of the rank or number of the input and the desired angle of rotation. The phase shifters Ph ₁ ... Ph _n are expediently quantized. The control of the value of the _{quantized phase shift generated by the phase shifters Ph 1} (i = 1,2 ... n) is effected by a phase calculator 3, a rounding calculator h and a control device 5 for the phase shifters.

The device 3 receives the angle Q _{Q of} the theoretical orientation, where θ is the angle between the beam and a reference direction in the plane of the sources, if the axis of the beam lies in this plane, or the angle of the projection of the beam and the reference direction ,

if

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when the bundle is at a constant angle with the Axis of the circle of sources rotates.

The input Q _Q is coupled, for example, to a scanner 6 for the position of the satellite. The computer 3 gives η outputs the theoretical values of the phases of the η phase shifters. These values are compared at different quantized levels in the rounding-off computer 4, which determines the commands for giving up on different phase shifters. In the most frequently occurring case of voltage-controlled phase shifters, for example, these commands are translated into control voltages in the device 5 for generating control signals for the phase shifters.

The rounding off calculator in this Pail is a simple comparator, for example with flip-flops, and the rounding off is effected "in the shortest possible way" with the stated disadvantages.

In order to keep the figure clear, the arrangement of η connections between the devices 3, * and 5 is shown by a double line, whereby it is stated for the following that a calculation of the phase, a calculation of the rounding and a generation of control

tensions

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voltages for the phase shifter takes place.

The antenna according to the invention shown in FIG. 2 has a modified circuit for determining the theoretical phase and the quantized phase, which on the one hand are simultaneous "phase jumps" several phase shifters, i.e. avoids a major jolt and on the other hand "accelerates" the beam in this way or delayed that it is brought back to the desired position in the shortest possible way.

According to the invention, this circuit has: on the one hand a device 7 for correcting the puncture V * (Θ), which determines the phase as a function of the desired beam direction (Θ), this device between the input θ and the phase calculator 3 is arranged; on the other hand, a device for determining the rounding, which replaces the computer 4 and has a test circuit 8 with which a source 9 of aleatoric Connected to signals.

The device 7 is, for example, a memory in which a number of values of θ are registered, each corresponding to a number of such values of θ that γ * (θ _ο ) = ^ ₁ (Q), where γ> (θ) ) the function

1 09825/1649

the phase of the computer 3 in Figure 1 and U ^ (G) is the corrected function, which radiation in the direction
θ + d θ which is equal to the desired direction.

An exemplary embodiment for the device 7 is described further below.

The circuit for determining the rounding is designed in such a way that that the simultaneous change of several phase shifters is avoided.

In summary, it should be noted that the circuit for correcting the phase function compensates for the mean Error in direction deviation with periodic change is allowed by accelerating the movement of the beam or is delayed, and that the circuit for determining the direction of the rounding off the compensation of the sudden changes to this error are permitted.

The graphs of Figures 3, 5% and enable a better understanding of the benefits of · contemporary fiction, arrangement.

Figure 3 shows in a solid line the change in phase ψ (on the ordinate) as a function of the rank ρ of the phase

glue 10982S / 1649

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slide (on the abscissa). When θ is given, is the theoretical change linearly (solid straight line).

As a result of the quantization, the phase function actually traversed is the one in hatched lines reproduced curve, where ψ is the level of quantization represents.

; The circuit according to the invention for determining the direction

The rounding enables at the same time a reduction in the error of the deviation in direction due to the rounding and the avoidance of the sudden changes in the direction }. the radiation axis by preventing simultaneous jumps of several * phase shifters.

For this purpose, the theoretical phase is compared with the odd multiples of ώ / 2. If they are like one of these multiples, the choice of the direction of the rounding is based on a randomly varying stress £ determines which is supplied by a noise generator connected to each phase shifter of rank ρ (p = 1 to n) will. Depending on whether this voltage is smaller or larger than a predetermined threshold value, it is rounded to the lower one or higher quantized value down or up.

On the other hand, if all other conditions are retained, 109825/1649 is obtained

conditions as a result of the quantization for a linear change in the phase as a puncture of θ such a deviation error dQ as a puncture of θ, as shown for example at 41 in FIG .

By replacing another puncture ψ ₁ (9 _Q ) for the linear function ψ (© _Q ), one can induce accelerations or decelerations, depending on whether d Q _{Q is} negative or positive, and one obtains, for example, the one at 42 in FIG 4 corrected function d Q ₀ (G ₀ ) shown.

In FIGS. 6 and 7, exemplary embodiments of the devices 7 and 8 are shown.

To illustrate the basic idea, it is assumed that in the absence of the "return" of the beam according to the invention, the deviation error d θ is a sinusoidal function with the perlode 2 JTVn of the angle θ .

If one disregards rapid changes in dO, which are based on "jumps" in © of the phase shifters and are minimized by the circuit for determining the rounding , the mean error dQ has the form d © - K sin η θ.

Therefore, the problem which value of θ is to perform 109825/1649

Γ / 66174

leadership of the phase calculation is to be selected so that the beam points in a desired direction G _Q.

The value of θ is the solution of the equation Q _Q - θ + k sin ηθ (:

which can be solved graphically, as indicated in FIG

The device 7 can have a calculator which solves equation 1 and for each input signal θ the value θ on the phase calculator 3 there.

The device 7 shown in FIG. 6 can be even more simple Way from a memory 71 »in which a certain number of values θ are registered, the predetermined ones Correspond to values of θ, and an arithmetic interpolation calculator 72 exist, which the equations

9 - Θ »
chung θ = θ ¹ - (θ ¹ - θ ") solves, where θ is the exact

ο ~ ο
value given by the position sensor 6, θ · and Θ "are the two predetermined values surrounding θ and Θ 'and Θ" are the values of θ corresponding to Θ' and Q ^.

The circuit 8 for determining the rounding / _ung can in in digital or analog form.

For example, an embodiment of the first form is shown in FIG. The one supplied by the computer 3

theoretical

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theoretical phase ψ. . is compared in a comparator 81 having a plurality of stages or levels with odd multiples of the quantization stage, ie (2k + 1).

A normalized signal "1" occurs at the output of the comparator 81 if y> _{th is} equal to one of these levels, and no signal occurs if this condition is not met. This output is coupled to control inputs of two gate circuits or interrupters 821 and 822, the first of which is "normally open", ie remains open in the absence of a control signal and the second, in contrast, is "normally closed". The output of the computer is also coupled to the signal inputs of these two gate circuits. The output of the gate circuit 821 is ^{coupled to a rounding-off computer 8 1} I, which is the same as the device * i in FIG. 1 and supplies the quantized phase value closest to ψ ...

The output of the gate circuit 822 is in parallel with the inputs of two gate circuits or interrupters 831 and 832 coupled, which work in opposite directions.

The randomly varying voltage £, which, for example

1 0 9 8 2 S / 1 6 k 9

"1/66174

wise is supplied by the noise generator 9, is compared at 810 with a threshold voltage V and each According to the result of the comparison, a normalized signal "1" or "0" occurs at the output of element 810.

This output is coupled to the control inputs of gate circuits 831 and 832. If £ ^. V is

P °

so the output signal of the element 8IO is equal to "0", the gate circuit 83I is open and ψ., arrives at the device 84l, which is a computer for rounding off to the lower value. When, on the contrary?

P is, then ψ .. arrives at the computer 842 for rounding off to the upper value. The devices 84, 841, 842, of which only one is in operation at a certain point in time, feed the control device 5.

It can be seen that there are as many voltages ξ and associated circuitry as there are phase shifters in operation.

Of course, various modifications can be made to this circuit as well as to the device 8 in a manner known per se Wise can be made, for example, the gates 822, 831 and 832 are combined into a single device with several control inputs, with

the

1 0 9 8 2 5/1 6 A 1)

- l4 -

i / 66174

the essential thing is that, on the one hand, the puncture for calculating γ .. takes into account the fact that quantized phase shifters are used and, on the other hand, a logical prohibition of the simultaneous change of the phase shifts ψ is applied.

The invention has been described, for example, for the case of a satellite antenna, the angle Q is determined by a position sensor. However, it is always applicable if the angle of the direction of radiation is a periodic puncture.

Claims

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Claims (2)

Claims 1. Method for improving the accuracy of the radiation direction of an antenna with periodic electronic Deflection and quantized phase shifters, characterized in that the theoretical phase-time function of the various phase shifters is changed in such a way that the periodic one based on the quantization Error is compensated and simultaneous changes of state of several phase shifters are prevented. 2. Device for performing the method according to claim 1, with an arrangement of radiation elements and associated quantized phase shifters and a phase calculation circuit and a rounding calculator for each phase shifter, characterized in that the device has a computer or a memory, which due to the desired direction angle θ a Determines the angle θ, which is used instead of θ _ο for the calculation of the controlled phase shifts, which results in a deviation of the beam in the direction θ, since the direction error, which is based on the rounding off caused by the phase shifts ψ (θ), just 10982B / 16A9 even equals θ - θ, and that the rounding calculator has a device for comparing the phase with odd Multiples of a half level of quantization, a generator of randomly varying signals for each Has phase shifter and a logic circuit which, depending on the result of the comparison, decides whether the Rounding is effected on the shortest path or not, in this latter case the rounding on the lower one or upper value is effected, depending on whether the randomly variable voltage is smaller or larger than a predetermined one Threshold is. 109825/1649