RU2326393C2 - Method of determination of position of antenna phase centre - Google Patents

Abstract

FIELD: antenna measurements.

SUBSTANCE: measured and tested antennas are placed in distant zone, and for probing ultrabroadband signals are used. During preliminary probing the tested antenna is turned around the rotation axis for selected angles and such fixed reception widow is found so that received signals hit it. During the main probing in the found window the time difference of signal distribution between phase centres of antennas at different angles of tested antenna turn is estimated. For that purpose either the difference in position of received ultrabroadband signals is estimated in the time reception window, or their phase-frequency spectrum is calculated, and coordinates of tested antenna phase centre are calculated for the frequency spectrum. The axis of tested antenna phase centre is found, in relation to which the time of signals distribution between the phase centres of antennas does not depend on the turn angle of tested antenna. For determination of spatial position of antenna phase centre the rotation axis of tested antenna is measured, and the other axis of phase centre is found. Phase centre of tested antenna is found at the intersection of phase centre axes.

EFFECT: provides fast and accurate determination of tested antenna phase centre position for frequency spectrum.

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Description

The invention relates to the measurement of electrical and magnetic quantities, in particular to antenna measurements using ultra-wideband (UWB) signals, and can be used in the design, testing and calibration of antennas.

The antenna phase center is the point at which a single spherical wave emitter can be placed, which is equivalent to the antenna system under consideration with respect to the phase of the created field [1]. In real antennas, the phase center is usually considered within the limited angles of the main lobe of the radiation pattern. The position of the phase center depends on the frequency of the signal used, the direction of radiation / reception of the antenna, its polarization, and other factors. Some antennas do not have a phase center in the conventional sense.

In the simplest cases, for example, for a parabolic antenna, the phase center coincides with the focus of the paraboloid and can be determined from geometric considerations. However, structural and technological errors lead to a displacement of the phase center even in the simplest antenna designs. For these cases, a known method for determining the phase center of the antenna [2], which consists in the fact that the measuring antenna is placed in the double focal length of the studied parabolic antenna, the antenna system is moved to the point of maximum reception of the reflected signal, the coordinates of the specified point are determined, and taking them as the center approximating a paraboloid sphere, find the focus of the paraboloid, which is considered as the phase center of the studied parabolic antenna. By determining the direction of the Poynting vector of the antenna radiation field, it is possible to determine the axes of the phase center that intersect in the phase center of the antenna. To determine the intersection point, it is sufficient to define two axes.

The disadvantage of this method is the limited scope - only for parabolic antennas, as well as the significant complexity of the measurements, if necessary, determine the phase center for the frequency spectrum.

In more complex cases, for example, horn antennas, the position of the phase center is not obvious and requires appropriate measurements. A known method for determining the phase center of the emitting horn [3], which consists in exciting the horn with a microwave signal, receiving a signal reflected from a special screen, estimating the phase of the received signal and determining the coordinates of the phase center of the antenna under test.

The disadvantage of this method is the limited scope of application - only for horn antennas, as well as the considerable complexity of the measurements if it is necessary to determine the phase center for the frequency spectrum.

A known method for determining the phase center of an element of the antenna array [4], which consists in installing two antennas in the far zone, probing the element of the antenna array under test, for which they rotate it around the axis of rotation, emit signals from the model antenna in each position, and accept them as the antenna under test , estimate the amplitude and phase of the received signals and find the phase center vector that minimizes the difference between the measured and calculated phase patterns.

The disadvantage of this method [4] is the high complexity of the measurements, if necessary, determine the phase center of the antenna for the frequency spectrum.

Closest to the claimed is a method for determining the position of the phase center of the antenna [5], which consists in installing two antennas in the far zone, probing the antenna under test, for which they rotate it around the axis of rotation at selected angles, in each position they emit signals with constant characteristics one, take them with a measuring antenna and evaluate the received signals, the phase center of the antenna under test is found at the intersection of the axes of the phase center. In this case, the measuring antenna is placed sequentially at two points of the electromagnetic field, at each position the amplitudes and phases of the received signal are measured for the three orthogonal components of the electric field vector, two axes of the phase center are determined, starting at the phase centers of the auxiliary antenna (in two positions) and ending at the phase the center of the antenna under test.

The disadvantages of the method are their suitability only for elliptical polarization of the antenna, low accuracy, and also the high complexity of the measurements, if necessary, determine the phase center for the frequency spectrum. The low accuracy is explained by the fact that the exact determination of the components of the electric field vector is not an easy task, and finding the intersection point of two inaccurate vectors from the far zone leads to even more significant errors.

Knowing the exact position of the phase center of the antenna is of great importance for high-precision navigation measurements, since errors in determining the position of the phase center directly affect the accuracy of determining the navigation parameters of objects. Measures to clarify the position of the phase center are taken in the design, manufacture and calibration of antennas. In modern antenna systems, antenna arrays are widely used, for which the very concept of “phase center” becomes complex, and even more so its measurement [6]. For example, in Global Positioning Systems (GPS), the exact ephemeris supplied by the International Geodynamic Service (IGS) and other organizations transmit information about the center of mass of the satellite, and when generating and using such ephemeris to process GPS data, you need to know the exact position of the antenna phase center in relation to the center of mass of the satellite, taking into account design errors in manufacturing the antennas and satellite, the influence of the navigation satellite itself on the operation of the antenna, viewing angles, polarization and other factors. To increase accuracy, resort to calibration [7]. In addition, modern antenna systems often use complex, non-monochromatic signals, which greatly complicates antenna measurements.

The tasks to be solved by the claimed method is the fast and accurate determination of the position of the phase center of the antenna under test for the frequency spectrum.

To solve this problem, the method of determining the position of the phase center of the antenna is to install two antennas in the far zone, probe the antenna under test, rotate it around the axis of rotation at selected angles, emit signals with constant characteristics of one in each position, receive them another antenna and evaluate the received signals, the phase center of the antenna under test is found at the intersection of the axes of the phase center, UWB signals are used for sounding, preliminary sounding is carried out, at which The minimum size of the reception time window and its position relative to the moment of radiation are estimated and chosen by the oror such that the received signals fall into the reception window, conduct basic sensing, in which the signals are received in the selected reception time window, and the differences in the propagation times of the signals between the phase centers of the antennas are estimated at the angles of rotation of the test antenna and find the axis of the phase center of the test antenna parallel to the axis of rotation, relative to which the propagation time of the signals between the phase the centers of the antennas does not depend on the angle of rotation of the antenna under test, select a different axis of rotation of the antenna under test, repeat the preliminary and main soundings and find another axis of the phase center.

In the main sensing, to roughly determine the position of the antenna phase center, the difference in their position in the reception time window is used as an estimate of the difference in the propagation times of the signals between the phase centers of the antennas,

To accurately determine the position of the antenna phase center to estimate the difference in the propagation times of the signals between the phase centers of the antennas during the main sensing, their phase-frequency spectrum is calculated, and the coordinates of the phase center of the antenna under test are calculated for the frequency spectrum.

Significant differences of the proposed method in comparison with the prototype are:

UWB signals are used as probing. Such signals make it possible to accelerate antenna measurements by simultaneously performing them in a wide spectrum of frequencies.

The prototype uses monochromatic signals. Work with such signals is technically simpler and more obvious, since the characteristics of the antenna are taken directly at each frequency individually. However, if it is necessary to determine the position of the phase center for the frequency spectrum, the complexity of measurements increases many times.

A preliminary sounding is carried out, in which the minimum size of the reception time window and its position relative to the radiation moment are estimated and selected such that the received signals fall into the reception window. The choice of a fixed reception time window makes it possible to take into account all informative parts of the received signal at all selected angles of rotation of the antenna under test, makes it possible to carry out further measurements under the same conditions, and ensures the accuracy of calculating the phase-frequency characteristics of the received signal during subsequent processing of the measurement results. The minimum size of the reception window also provides improved measurement accuracy, since for a selected number of samples in the reception window, the time sampling step is minimal. In addition, as a result of the selection of the minimum reception time window, due to the difference in travel, signals reflected from foreign objects in the research area do not fall into it, and due to this, the cost of antenna measurements is reduced.

In the prototype, the signal reception is continuous, not synchronized with the moment of radiation. In this case, the phase of the monochromatic signal is determined ambiguously, which leads to the necessity of using special circuits, for example, [3] AS USSR No. 1125559. In addition, the solution of the problem with incidental reflections in this case is accompanied by serious material costs for creating anechoic chambers, absorbing coatings that work only in certain frequency ranges, conducting expensive take-off measurements, etc.

The main sounding is carried out, in which the signals are received in the selected reception time window, the differences in the propagation times of the signals between the phase centers of the antennas are estimated at different angles of rotation of the antenna under test, and the axis of the phase center of the tested antenna parallel to the axis of rotation is found, relative to which the propagation time of the signals between the phase centers of the antennas is not Depends on the angle of rotation of the antenna under test. The main difference is the use of differences in the propagation times of the signals, which allows us to proceed to measurements of the position of the phase center relative to the axis of rotation of the antenna under test.

The prototype finds the axis of the phase center, proceeding from the locations of the measuring antenna in the far zone, which gives rise to significant measurement errors.

Select another axis of rotation of the antenna under test, repeat the preliminary and main soundings, and find another axis of the phase center. The other axis of rotation can be chosen arbitrarily, including at an angle of 90 ° to the first axis, which increases the accuracy of finding the point of intersection of the axes, and, consequently, the coordinates of the phase center.

In the prototype, the axis of the phase center are located within the limited angle of the main lobe of the radiation pattern, which reduces the accuracy of finding the intersection point of these axes.

As an estimate of the difference in the propagation times of the signals during the main sensing, a difference in their position in the reception time window is used. This method allows only a rough estimate of the position of the phase center without taking into account the dependence of the position of the phase center on frequency.

In the prototype, the lack of synchronization between the moments of radiation and reception does not allow us to find the difference in the times of signal reception during rotation of the antenna under test.

A more accurate position of the phase center can be obtained when their phase-frequency spectrum is calculated to estimate the difference in the propagation times of the signals during the main sounding. The phase differences of the received signal at each frequency can be easily converted to the differences in the signal propagation times, and the coordinates of the phase center of the antenna under test are calculated for the frequency spectrum. This approach reduces the complexity of the work due to the fact that in one measurement cycle it is possible to obtain the coordinate spectrum of the phase centers of the antenna under test.

The prototype determines the phase center of the antenna for one frequency. If it is necessary to obtain the indicated results for the frequency spectrum, there are large time and hardware costs for the reconstruction of probing signal generators, phase meters, and other elements of devices that implement this method.

The inventive method is illustrated by the following graphic materials:

Figure 1 - Scheme for rough calculation of the position of the phase center of the antenna.

Figure 2 - Scheme for accurate calculation of the position of the phase center of the antenna.

Figure 3 - A device that implements the inventive method.

Consider the implementation of the proposed method.

Before starting the measurements, Fig. 1, two antennas are installed in the far zone, i.e. choose the distance L between the proposed phase centers of the test 1 and measuring 2 antennas, and the distance L itself does not matter, since the measurements are carried out relative to the axis of rotation of the tested antenna. The characteristics of the measuring antenna also do not matter, since its amplitude-frequency characteristic and the position of its phase center also do not affect the measurements. The angles of rotation of the antenna under test are selected so that in the measurement sector there are no zeros of the amplitude radiation pattern of the antenna under test, which correspond to phase jumps. The test or measuring antenna can act as the radiating one, respectively, the other antenna turns out to be the receiving one.

For measurements, UWB signals are emitted by one and received by another antenna. As such signals, identical (with constant characteristics) short video pulses with a duration from fractions to units of picoseconds that have a spectrum from zero to tens of gigahertz can be used. This pulse can be received by a stroboscopic converter [8] - a device that in a window of reception, fixed with respect to the moment of radiation of the probing signal, extracts one sample at a given moment from the received signal. Sounding with the same pulses at the same position of the antennas is repeated many times (thousands of times) with an arbitrary frequency, and the timing of the selection is shifted along the reception window. As a result of this method of reception, a time-scale transformation occurs, i.e. The received sounding “fast” impulse is perceived as a set of its readings, but on a different time scale. At the same time, it becomes possible to process each of the samples “slowly” using conventional analog-to-digital converters and computer processing methods.

Let before starting the measurements, Fig. 1, the axis of rotation 0Y of the antenna under test 1 is perpendicular to the XOZ plane and does not coincide with the axis of the phase center parallel to it passing through the point Z _c (FC). When the tested antenna 1 is rotated by an angle α _i , the distance between the phase centers of antennas 1 and 2 changes, and therefore, the propagation time of the UWB signal between them by ΔТ and the phase of the received signal by ΔФ (f). The magnitude of the phase change depends on the frequency f under consideration.

A preliminary sounding is carried out, in which the test antenna is rotated at selected angles. UWB signals are emitted and received. The time of the start of the signal reception window of the antenna 2 is selected so that at any rotation angles α of the tested antenna 1, the beginning of the pulse received by the antenna 2 is observed. Then, the minimum duration of the reception time window is changed and found so that for any rotation angles of the tested antenna 1, the entire received pulse into it.

The main sensing is carried out, in which UWB signals are received in the selected reception time window. The main sensing task is to find the axis of the phase center passing through the phase center (FC) and parallel to the axis of rotation 0 of the antenna 1.

For a rough estimate of the position of the axis axis of the phase center of antenna 1, the differences in the propagation times of the signals between the phase centers of antennas 1 and 2 are estimated for different angles of rotation of the antenna under test 1. In particular, you can find the 0Z axis (base axis) passing through the axis of rotation of the antenna 1, the phase center antenna 2 and the intersecting axis of the phase center of antenna 2 at point Z _c . To do this, find the angular position of the antenna 1 at which the received signal is closest to the beginning of the reception window (if the phase center is shifted forward relative to the axis of rotation) or to the end of the reception window (if the phase center is behind the axis of rotation). Then rotate the antenna 2 by a known angle α _i and determine the difference DT of the propagation time of the UWB signal in these two positions. From geometric considerations, an unknown quantity can be determined:

Z _c = СΔТ / (1-cos (α _i )),

where C is the speed of light. The quantity _q and Z axis position 0Z unambiguously define the position of the phase center axis.

The low accuracy of the described method for determining the axis of the phase center is explained by the following circumstances:

1. The position of the phase center of the antenna depends on the frequency, and therefore the coordinate Z _c found for the UWB signal is only a kind of "integral approximation" to the phase center, but can be used, for example, in range measurements.

2. The estimation of the temporary position of the UWB signal in the reception window is ambiguous, since when the antenna 1 is rotated, the shape of the received signals changes, so what moment of the received signal should be considered the moment of reception is not obvious.

3. The position of the 0Z axis is not determined exactly, since in the vicinity of α _i = 0 the difference ΔT of the UWB signal propagation times varies little.

To solve the last problem, it is possible to measure at least three different angular positions of the antenna 1 and solve, as will be shown below, the corresponding system of equations.

. Для решения этой задачи, используя дискретное преобразование Фурье (ДПФ), вычисляют фазочастотный спектр принятого сигнала при нескольких

угловых положениях антенны 1. При n=3 методика расчета положения оси фазового центра антенны 1 для одной частоты f_j состоит в следующем. Пусть ось фазового центра антенны 1 на частоте f_j находится на расстоянии Z_ц от оси вращения Y ортогональной системы координат XYZ. По определению фазового центра расстояние Zn остается неизменным при любых выбранных углах ее поворота. Начальное угловое положение антенны 1, фиг.2, отстоящее на неизвестный от оси 0Z угол α₀, будем считать базовым, при этом ось фазового центра антенны 1 проходит через точку Z_ц0 с неизвестными координатами. Проводят зондирование, по результатам которого с использованием ДПФ вычисляют фазу Ф₀(f_j) принятого сигнала. При повороте антенны 1 вокруг оси 0Y относительно базового положения на известный угол α_i ось фазового центра будет проходить через точку Z_ц1. В результате аналогичных зондирований и вычислений находят фазу Ф₁ принятого сигнала на той же частоте, но при другом положении антенны 1. Разность этих фаз позволяет оценить разность времен распространения сигналов:The exact determination of the position of the axis of the phase center is possible only separately for each frequency f _{j of the} required frequency spectrum

. To solve this problem, using the discrete Fourier transform (DFT), the phase-frequency spectrum of the received signal is calculated for several

angular positions of the antenna 1. For n = 3, the procedure for calculating the position of the axis of the phase center of the antenna 1 for one frequency f _j consists in the following. Let the axis of the phase center of the antenna 1 at a frequency f _j be at a distance Z _c from the rotation axis Y of the orthogonal coordinate system XYZ. By definition of the phase center, the distance Zn remains unchanged at any chosen angles of rotation. The initial angular position of the antenna 1, figure 2, spaced by an angle α ₀ unknown from the 0Z axis, will be considered basic, while the axis axis of the phase center of the antenna 1 passes through the point Z _c0 with unknown coordinates. Sensing is carried out, according to the results of which, using the DFT, the phase Ф ₀ (f _j ) of the received signal is calculated. When the antenna 1 is rotated around the 0Y axis relative to the base position by a known angle α _{i, the} axis of the phase center will pass through the point Z _c1 . As a result of similar soundings and calculations, the phase Ф _{1 of the} received signal is found at the same frequency, but at a different position of antenna 1. The difference of these phases allows us to estimate the difference in the propagation times of the signals:

ΔТ ₁ = (Ф ₀ -Ф ₁ ) / 2πf _j .

When the antenna 1 is rotated by a known angle α ₂ relative to the base position, the axis of the phase center of the antenna passes through point Z _c2 . In a similar manner, the difference in the propagation times of the signals between the base and current positions of the axis of the phase center ΔT _{2 is} calculated. As a result of three soundings, a system of two equations can be compiled:

ΔT ₁ = Z _c (cosα ₀ -cos (α ₀ -α ₁ )) / C

ΔT ₂ = Z _c (cosα ₀ -cos (α ₀ -α ₂ )) / C,

where C is the speed of light.

This system contains two unknowns α ₀ and Z _c. and can be solved by known methods. The obtained values of α ₀ and Z _C are the polar coordinates of the axis of the phase center of the antenna 1 for the frequency f _j relative to the axis of rotation 0.

. Для повышения точности вычислений количество углов поворота испытуемой антенны 1 выбирают большим трех, тогда система уравнений становится избыточной, а ее решение может быть получено, например, методом наименьших квадратов (МНК).Similar calculations are performed for all frequencies f _j of the frequency spectrum

. To increase the accuracy of calculations, the number of rotation angles of the tested antenna 1 is chosen to be greater than three, then the system of equations becomes redundant, and its solution can be obtained, for example, by the least squares method (least squares).

The phase center of the antenna 1 can be located not only on the XOZ plane, but also separated from it by a value of Y _c . To find the spatial position of the phase center of the antenna 1 change the axis of its rotation. The axis 0X can be selected as the new axis. Repeating the measurements and calculations described above, the second axis of the phase center is found. In this case, the second axis of rotation of the antenna 1 is perpendicular to the first. In the ideal case, the found axes of the phase center intersect. The intersection point of the indicated axes, which is considered the phase center of the antenna 1, is calculated. Under real conditions, the axes found are crossed. In this case, find the phase center of the antenna 1, minimizing the distance between the axes, for example, along the least squares.

Thus, the inventive method allows you to quickly and accurately determine the position of the phase center of the test antenna for all selected frequencies. The obtained coordinates of the phase centers allows you to use complex signals for radar measurements, take into account variations in the position of the phase center, and thereby increase the accuracy of measurements using a calibrated antenna.

A device that implements the inventive method is depicted in figure 3, where:

1 - test antenna;

2 - measuring antenna;

3 - slewing ring;

4 - computer;

5 - delay line;

6 - probe signal generator;

7 - a stroboscopic receiver;

8 - analog-to-digital Converter;

9 - input manual delay control.

The test antenna 1 is a measurement object with an unknown position of the phase center. Measuring antenna 2 is intended for measurements, its characteristics may not be known, because it does not affect accuracy due to the relative nature of the measurements.

The rotary support device 3 is designed to rotate the antenna 1 at known angles under the control of code messages from the computer 4.

Computer 4 controls the operation of the device, processes the measurement results and calculates the coordinates of the phase center of the antenna under test 1.

The delay line 5 is designed to select and fix the window for receiving sounding signals, as well as for changing the position of samples of the received signal in the time window for receiving. The delay line contains coarse delay and precise delay blocks. The first block allows you to delay the moment of emission of UWB signal relative to the moment of its reception, i.e. sets the start of the receive window. It can be performed on a clock generator and a digital counter, the conversion number of which is controlled by a computer 4. The exact delay unit consists of a digital-to-analog converter and a charge accumulating diode. The code from computer 4 sets the threshold for the diode, which changes the delay of the trigger signal.

The probe signal generator 6 generates UWB signals.

The stroboscopic receiver 7 extracts one sample from the received signal from the strobe signal.

An analog-to-digital 8 converter is designed to convert the samples of the received signal into digital form.

The input of the manual delay control 9 is used to select the reception window during preliminary sounding.

Test 1 and measuring antenna 2 are installed in the far zone at an approximately known distance L. Test antenna 1 is mounted on a rotary support device 3 with a fixed axis of rotation. We assume that the tested antenna 1 is emitting, and the measuring antenna 2 is the receiving one. Before sounding, the computer 4 by sending control code signals to the slewing ring 3 sets the required angles α _{i of} rotation of the measured antenna 1 within the selected range.

For stroboscopic UWB signal reception, the exact delay value in block 5 is changed. As a result, the radiation moment of the antenna 1 is shifted relative to the fixed moment of the antenna 2 reception, and the stroboscopic receiver 7 selects a different (in time) sample of the received signal. The range of exact delay values determines the duration of the receive window, and the step determines the measurement accuracy. By repeatedly changing the exact delay value, a time-scale conversion is performed and all the samples of the received UWB signal are received, which are displayed on the computer screen 4.

When sounding, the triggering signal from the computer 4 enters through the delay line 5 to the generator of the probing UWB signals 8, and also through a cable approximately equal to the distance between the antennas L to the stroboscopic converter 7 and analog-to-digital converter 8. UWB signal emitted by antenna 1, arrives at antenna 2 with a delay for the propagation time at a distance L between antennas 1 and 2.

During preliminary sounding, the coarse delay value in block 5 is first selected, and possibly the length of the cable mentioned above so that the trigger signal arrives at the stroboscopic receiver 7 immediately before the UWB signal arrives at it at any angle of rotation of antenna 1. To solve this problem, computer 4 through the slewing device 3, the angles of rotation of the antenna 1 are changed, a change in the position of the beginning of the received signal in the reception window is observed on the computer monitor 4. Manually, through the input 9 of computer 4, the magnitude of the coarse delay in block 5 is changed. Then, through the input 9 of computer 4, the magnitude and step of the exact delay in block 5 are changed, achieving full UWB signal reception. As a result of the described actions, the coarse delay value (the moment of reception start) is fixed, as well as the step and the exact delay value (accuracy and duration of the reception window).

With a rough determination of the position of the axis axis of the phase center of antenna 1, the position of the received signals is estimated at known angles of rotation α _{i of} antenna 1 and the coordinates of the point through which the axis of the phase center passes are calculated in computer 4 using the algorithms described above.

With the exact determination of the axis of the phase center in computer 4, the phase-frequency spectrum of the received signal is calculated and the coordinates of the points through which the axis of the phase centers at the corresponding frequencies pass.

Change the axis of rotation of the antenna 1 and repeat the measurement.

The phase centers of the antenna 1 are determined for each frequency separately as the intersection points of the corresponding axes of the phase centers.

Thus, the claimed method can be implemented on a modern elemental base and allows you to quickly and accurately determine the coordinates of the phase centers of the antenna under test for the frequency spectrum. Knowing these coordinates can improve the accuracy of antenna measurements using the measured antenna.

LITERATURE

1. Drabkin A.L., Zuzenko V.L. Antenna feeder devices. M .: Sov. Radio, 1961, p. 70-71.

2. AS of the USSR No. 364908.

3. AS of the USSR No. 1125559.

4. JP patent No. 2000321314.

5. USSR AS No. 1702325.

6. Patent JP 2183172.

7. Calibration of Antenna Phase Centers, GPS World, May 2002, Publisher: Advanstar Communications Inc 859 Willamette Street, Eugene, Oregon 97401-6806, USA.

8. Ryabinin Yu.A. Stroboscopic oscillography. - M .: Owls. Radio, 1972.

Claims (3)

1. The method of determining the position of the phase center of the antenna, which consists in installing two antennas so that one is in the far zone with respect to the other, probe the antenna under test, for which they rotate it around the axis of rotation at selected angles, emit signals in each position with constant characteristics of one, they are received by another antenna and the received signals are evaluated, the phase center of the antenna under test is found at the intersection of the axes passing through its phase center, characterized in that for sounding using comfort ultra-wideband signals, conduct preliminary sounding, in which the minimum size of the reception time window and its position relative to the radiation moment are estimated and selected such that the received signals fall into the reception window, conduct basic sounding, in which the signals are received in the selected reception time window, the differences are estimated the propagation times of the signals between the phase centers of the antennas at different angles of rotation of the antenna under test and find the axis parallel to the axis of rotation, passing through the phase the center of the antenna under test, relative to which the propagation time of the signals between the phase centers of the antennas does not depend on the angle of rotation of the antenna under test, choose another axis of rotation of the antenna under test, repeat the preliminary and main soundings and find another axis passing through the phase center of the antenna under test. 2. The method according to claim 1, characterized in that as an estimate of the difference in the propagation times of the signals during the main sensing, they use the difference in their position in the reception time window. 3. The method according to claim 1, characterized in that to evaluate the difference in the propagation times of the signals during the main sensing, their phase-frequency spectrum is calculated, and the coordinates of the phase center of the antenna under test are calculated for the frequency spectrum.

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