RU2567120C1 - Method of forming compensation beam pattern in flat electronically controlled-beam antenna array - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method includes receiving signals with antenna elements of a flat antenna array with electronic beam scanning and summation of said signals to form a highly directional scanning beam pattern of the flat antenna array using selected complex amplitudes of the antenna element, taking into account the required overshooting of the level of the compensation beam pattern of the level of sidelobes of the highly directional scanning beam pattern. A weakly directional beam pattern is formed by summing the signals of the antenna elements situated in central orthogonal lines of the flat antenna array with complex amplitudes corresponding to the complex amplitudes of the antenna elements of the flat antenna array in the direction of the source of the useful signal. The compensation beam pattern is formed by subtracting the signal corresponding to the highly directional scanning beam pattern from the signal corresponding to the weakly directional beam pattern, multiplied by a weighting coefficient which is equal to the ratio of the standard highly directional scanning and weakly directional beam patterns with beam orientation of the flat antenna array in the direction of the normal to the aperture plane.

EFFECT: providing the required overshooting of the level of the compensation beam pattern of the level of sidelobes of the highly directional scanning beam pattern of the flat antenna array in a wide sector of angles while maintaining sensitivity of the receiving system.

12 dwg

Description

The invention relates to antenna technology and can be used in radio engineering systems for location and communication when receiving electromagnetic waves with a flat antenna array with electronic beam control under the influence of interference, the directions of reception of which are unknown.

Known methods of active control of interference, in particular the method of coherent interference compensation described in [1 - Protection against radio interference / M.V. Maximov, M.P. Bobnev, B.Kh. Krivitsky et al .; Under. ed. M.V. Maksimova. - M .: Owls. radio. 1976. - S. 220, 234]. In accordance with the method, an interference signal is received by a highly directional antenna of the main channel and a weakly directional antenna of the compensation channel, the radiation pattern of which covers the side lobe region of the radiation pattern of the main channel, while at the outputs of the main and compensation channels by adjusting the interference level and phase shift in the compensation channel interference signals that are identical in intensity and opposite in phase, which, when summed, mutually cancel out, and pelengovogo nal direction passes through the adder with a minimum of distortion, since it ratio of amplitudes and phases required for suppression would not be observed. The method is implemented in the classical amplitude noise compensator, which is a two-channel system that includes two antennas: a directional one in the main channel and a weakly directional one in the compensation channel. The method allows to compensate for interference provided that the antenna pattern in the compensation channel and the antenna pattern in the main channel in the side lobe region are identical, and zero is formed in the directional pattern of the main channel antenna of the main channel in the antenna pattern of the compensation channel.

The disadvantage of this method is that in practice, zero is formed only in the direction of the maximum of the main lobe of the antenna of the main channel. If you deviate from this maximum due to overcompensation, a weakening of the useful signal appears, the source of which is located in the main lobe of the antenna pattern of the main channel.

To suppress interference in a wide sector of angles, this method is implemented in multi-channel interference compensators, where each radiation pattern in a particular compensation channel is responsible for its sector of angles. In this case, in each compensation channel in a certain sector of angles, a specified excess of the antenna radiation pattern of the compensation channel is provided over the level of the side lobes of the antenna pattern of the main channel [2 - Adaptive interference compensation in communication channels / Yu.I. Losev, A.G. Berdnikov, E.Sh. Goikhman, B.D. Sizov; Ed. Yu.I. Loseva. - M .: Radio and communication. 1988. S. 134-136].

The disadvantage of multi-channel interference cancellers is their significant complexity.

A number of methods are known for generating a radiation pattern of a phased antenna array with dips in the directions corresponding to interference sources.

So, there is a known method of forming a directivity pattern of a linear phased antenna array with dips in the directions corresponding to interference sources [3 - RU 2431222. A method of suppressing side lobes of a directivity pattern of a linear phased antenna array / Gavrilova S.E., Gribanov AN, Moseychuk G .F., Chubanova O.A. Class H01Q 3/26, published 10.10.2011], based on the assessment of the level of the initial radiation pattern of a phased array, the allocation of two M-element sublattices located at the edges of the source, and the introduction of phase corrections with a minus sign for elements of one sublattice and with a plus sign for elements of another sublattice, and the phase corrections for all elements of the sublattices are chosen equal in absolute value from the condition of a given suppression value and the width of the angular sector of suppression of the side lobes.

An analogue of the above method is the method described in [4 - RU 2123743. The method of forming a zero radiation pattern of a phased antenna array. / Manuylov B.D., Bashly P.N. Class H01Q 3/26, published December 20, 1998]

A disadvantage of the known methods is that the suppression of side radiation is guaranteed only in a certain angular sector.

There is a method of suppressing interference in the region of side lobes in antenna arrays with a decreasing amplitude distribution [5 - Voskresensky DI Antennas and microwave devices (design of phased antenna arrays). - 2nd ed., Ext. and reslave. - M: Radio and communications. 1994. S. 36]. The higher the decay rate of the amplitude distribution to the edges of the aperture, the lower the level of the side lobes of the antenna and the greater the attenuation of interference.

However, the use of a decreasing amplitude distribution leads to a decrease in the antenna energy, which limits the possibilities of this method and is a disadvantage of this method.

A known method of coherent interference compensation, proposed in [1, p. 220]. It consists in the fact that they receive signals and interference using the receiving antenna of the main channel, orienting it in the direction of the signal, receive interference acting on the side lobes of the receiving antenna of the main channel, by one means or another form opposite at the outputs of the amplifiers of high or intermediate frequency in phase, the interference signals of the main and compensation receivers, the voltages of the main and compensation receivers, taking into account the weight coefficients, are summed up, while the coherent com the compensation of interference acting on the side lobes of the radiation pattern of the receiving antenna of the main receiver. The disadvantages of this method include the following. Considering that the omnidirectional antenna with a fixed zero position of the radiation pattern is most often used as the antenna of the compensation channel, weakening of the useful signal is possible. When using a directional antenna in the compensation channel, forming zero in the estimated direction of arrival of the signal, the possibility of the component of the useful signal entering the compensation channel when the signal arrives from another direction is not ruled out. In addition, the radiation pattern of the antenna of the compensation channel, as a rule, differs from the radiation pattern of the antenna of the main channel, which leads to a decrease in the efficiency of coherent interference compensation while suppressing several interference.

Closer in technical essence to the claimed method (prototype) is a method of forming a compensation radiation pattern [6 - patent 2395141 (RU). The method of forming a compensation radiation pattern in an antenna system with electronic beam control. / Alekseev O.S., Barinov N.N., Moseychuk G.F., Sinani A.I. Class H01Q 3/00, published July 20, 2010], based on the formation of a highly directional scanning radiation pattern of the antenna system of the main channel and a weakly directional non-scanning radiation pattern of the antenna of the compensation channel, which overlaps the lateral radiation of the directional radiation pattern, a part of the microwave signal received sharply directed radiation pattern of the antenna system of the main channel, as well as the regulation of the level and phase of the microwave signal so that in the subsequent m summing this branched microwave signal with a signal received by a weakly directional radiation pattern, a dip in the directional direction of the directional radiation pattern formed in the resulting radiation pattern of the weakly directional antenna, moreover, when the angular position of the beam of the scanning directional radiation pattern in the scanning sector and / or the operating frequency for formation the failure in the resulting radiation pattern of a weakly directed antenna further changes the amplitude dy and phase of the branched microwave signal.

The advantages of the method include a decrease in the direction of the signal level of the compensation radiation pattern in an antenna system with electronic beam control at any frequency in the operating frequency range, and the disadvantage of this method is the difficulty of generating a weakly directed non-scanning radiation pattern, which everywhere overlaps the level radiation of the directional scanning radiation patterns, from which it follows that this method can work in a limited area of the angle . In the presence of one antenna element, a weakly directed radiation pattern will be almost isotropic, but the level of the received signal will be the smallest. With an increase in the number of antenna elements in a non-scanning radiation pattern, its norm increases, however, when the beam narrows, the area of interference compensation is limited. Therefore, to expand the beam, it is necessary to increase the transmission coefficient in the compensation channel and reduce the sensitivity of the receiving system (when amplifying the signal in the compensation channel, noise amplification also occurs).

The problem to which the proposed method is aimed is to ensure the required excess of the level of the compensation radiation pattern over the level of the side lobes of the directional scanning radiation pattern of a flat antenna array in a wide sector of angles.

To solve this problem, a method for generating a compensating radiation pattern in a flat antenna array with electronic beam control is proposed, based on the formation of a highly directional scanning radiation pattern of a flat antenna array and a weakly directional radiation pattern that overlaps the lateral radiation level of a directional scanning radiation pattern of a flat antenna array.

According to the invention, the formation of a directional scanning radiation pattern of a flat antenna array is carried out using the selected complex amplitudes of the antenna elements, taking into account the required excess of the level of the compensation radiation pattern above the level of the side lobes of the directional scanning radiation pattern, the formation of a weakly directional radiation pattern is performed by summing the signals of the antenna elements located in the central orthogonal rulers a flat antenna array, with complex amplitudes corresponding to the complex amplitudes of the antenna elements of a flat antenna array in the direction to the source of the useful signal, and the compensation radiation pattern is obtained by subtracting the directional scanning radiation pattern from the weakly directional radiation pattern multiplied by a weight coefficient equal to the ratio of the rates of the directional scanning and weakly directed radiation patterns with the orientation of the beam of a flat antenna array direction normal to the plane of the aperture.

A comparative analysis of the claimed method and prototype shows that the claimed method differs in that the set of actions is changed, namely: modes of performing three operations:

the mode of execution of the action associated with the formation of a directional scanning radiation pattern has been changed: a directional scanning radiation pattern of a flat antenna array is formed using the selected complex amplitudes of the antenna elements, taking into account the required excess of the level of the compensation radiation pattern over the level of the side lobes of the directional scanning radiation pattern;

the mode of execution of the action associated with the formation of a weakly directed radiation pattern is changed: a weakly directed radiation pattern is formed by summing the signals of the antenna elements located in the central orthogonal lines of the flat antenna array with complex amplitudes corresponding to the complex amplitudes of the antenna elements of the flat antenna array in the direction of the source of the useful signal;

the mode of execution of the action associated with the formation of the compensation radiation pattern has been changed: the compensation radiation pattern is obtained by subtracting the highly directional scanning radiation pattern from a weakly directed radiation pattern multiplied by a weight coefficient equal to the ratio of the norms of the highly directional scanning and weakly directional radiation patterns when the beam of a flat antenna array is oriented in the normal direction to the aperture plane.

The technical result of the proposed method is the preservation of the sensitivity of the receiving system when scanning in a wide sector of angles, as well as the formation of a zero compensation radiation pattern with a constant ratio of the norms of highly directional scanning and weakly directional radiation patterns.

Changing the modes of the three operations allows, in comparison with the prototype method, to ensure the required excess of the level of the compensation radiation pattern over the level of the side lobes of the directional scanning radiation pattern of a flat antenna array in a wide sector of angles while maintaining the sensitivity of the receiving system when scanning in a wide sector of angles, as well as the formation zero compensation radiation pattern with a constant ratio of sharply directed scanning and slightly directed th radiation patterns.

The present invention is not known from the prior art, and information sources containing information about similar technical solutions having features similar to those distinguishing the claimed solution from the prototype, as well as properties that match the properties of the proposed solution, are therefore not known, therefore, we can assume that it has significant differences, follows from them in an unobvious way and, therefore, meets the criteria of “novelty” and “inventive step”.

The figure 1 presents a functional diagram of a device that implements the proposed method.

The figure 2 shows a rectangular grid of coordinates and a flat antenna array.

The figure 3 shows the non-deviated three-dimensional radiation pattern of a planar antenna array (highly directional scanning radiation pattern of a planar antenna array of the main channel).

The figure 4 presents the non-deviated volume slightly directional radiation pattern (weak directional radiation pattern of the compensation channel).

The figure 5 shows the non-deviated volumetric compensation radiation pattern.

Figure 6 shows the main sections of a three-dimensional sharply directed scanning radiation pattern of a flat antenna array (dashed curve), a three-dimensional weakly directed beam pattern (dash-dot curve) and a three-dimensional compensated radiation pattern (solid curve) with an unbent beam.

The figure 7 shows a three-dimensional sharply directed scanning radiation pattern of a flat antenna array (deflected beam θ ₀ = 40 °, φ ₀ = 20 °).

The figure 8 presents the volumetric compensation radiation pattern (deviated zero θ ₀ = 40 °, (φ ₀ = 20 °).

Figures 9-10 show the main sections of the volumetric radiation pattern of a flat antenna array (dashed curve), volumetric weakly directional radiation pattern (dash-dotted curve) and volumetric compensation radiation pattern (solid curve) when the beam is deflected (θ ₀ = 40 °, (φ ₀ = 20 °).

In figures 11-12 shows the area of the angles in which the required excess of the level of the compensation radiation pattern is achieved above the level of the side lobes of the highly directional scanning radiation pattern of a flat antenna array (dark areas).

When implementing the method of forming a compensation radiation pattern in a flat antenna array with electronic beam control, the following sequence of operations is performed:

- receive signals of the antenna elements of a flat antenna array with electron beam scanning and summarize them, forming a highly directional scanning radiation pattern of the flat antenna array using the selected complex amplitudes of the antenna elements, taking into account the required excess of the level of the compensation radiation pattern over the level of the side lobes of the directional scanning radiation pattern;

- produce a weakly directed radiation pattern by summing the signals of the antenna elements located in the central orthogonal lines of the flat antenna array with complex amplitudes corresponding to the complex amplitudes of the antenna elements of the flat antenna array in the direction to the source of the useful signal;

- receive a compensating radiation pattern by subtracting the directional scanning radiation pattern from the weakly directional radiation pattern multiplied by a weight coefficient equal to the ratio of the norms of the directional scanning and weakly directional radiation patterns when the beam of the flat antenna array is oriented normal to the aperture plane.

The use of a digital antenna array as a flat antenna array with electronic beam control allows combining the antennas of the main and compensation channels in one opening [7 - EM Dobychina, PA Shmachilin The construction of digital antenna arrays for modern electronic systems // Antennas. 2011. No3. S. 36-46].

Consider the implementation of the method using the device shown in FIG. one.

The device consists of: 1 - antenna elements (AE) of a digital antenna array, 2 - a multi-channel amplification and frequency conversion unit (BCH), 3 - a multi-channel analog-to-digital converter (ADC), 4 - a summing unit (BS), at the output of which a signal is generated that corresponds to an omnidirectional scanning radiation pattern of a flat antenna array, 5 is a summing unit (BS), which ensures the formation of a signal corresponding to a weakly directional radiation pattern, 6 is a weight generation and storage unit that (BVK), which is equal to the ratio of the norms of the directional scanning and weakly directed radiation patterns of a flat antenna array when the beam of a flat antenna array is oriented in the direction normal to the aperture plane, 7 is a multiplication unit (BU), 8 is a subtraction unit (BV) that provides signal generation, corresponding compensation radiation pattern.

, размерность которого N=M_x×M_y соответствует числу антенных элементов цифровой антенной решетки (M_x и M_y - число антенных элементов цифровой антенной решетки в центральных горизонтальной и вертикальной линейках соответственно). В БС 4 вектор отсчетов u(t) скалярно умножается на вектор комплексных весовых коэффициентов $$w_o={\left(w_{on}\right)}_{n=1}^N$$

, обеспечивающий установку луча в направлении источника сигнала (θ₀, φ₀), и производится формирование остронаправленной сканирующей диаграммы направленности плоской антенной решетки заданной ширины луча и уровня боковых лепестков (фигура 3). Следовательно, вектор w_o определяет форму остронаправленной сканирующей диаграммы направленности плоской антенной решетки F_o(θ, φ). В БС 5 параллельно во времени принятый вектор отсчетов умножается скалярно на векторы комплексных весовых коэффициентов $$w_{к1}={\left(w_{к1n}\right)}_{n=1}^N$$

и $$w_{к2}={\left(w_{к2n}\right)}_{n=1}^N$$

. При этом M_x комплексных коэффициентов $$w_{к1m_x}$$

, соответствующих антенным элементам цифровой антенной решетки в центральной горизонтальной линейке, совпадают с коэффициентами $$w_{0m_x}$$

, а остальные коэффициенты равны нулю; M_y комплексных коэффициентов $$w_{к2m_y}$$

, соответствующих антенным элементам цифровой антенной решетки в центральной вертикальной линейке, совпадают с коэффициентами $$w_{0m_y}$$

, а остальные коэффициенты равны нулю. Выбор комплексных весовых коэффициентов обеспечивает независимое формирование двух диаграмм направленности F₁(θ, φ) и F₂(θ, φ), одномерно расширенных в ортогональных плоскостях (вдоль ортогональных линеек антенной решетки), с нормами /F₁(θ₀, φ₀)/, /F₂(θ₀, φ₀)/ и максимумами, ориентированными в направлении источника сигнала (θ₀, φ₀). При этом в одной из главных плоскостей каждая из диаграмм направленности F₁(θ, φ) и F₂(θ, φ) совпадает с диаграммой направленности плоской антенной решетки F_o(θ, φ), а в другой - приближается к диаграмме направленности одиночного антенного элемента плоской антенной решетки. На выходе БС 5 образуется сигнал, соответствующий слабонаправленной диаграмме направленности, F₁(θ,φ)/|F₁(θ₀,φ₀)|+F₂(θ,φ)/|F₂(θ₀,φ₀)| (фигура 4).The set of signals and interference received by AE 1 of a digital antenna array, after performing the necessary actions related to amplification and frequency conversion in BUPCH 2, is digitized in ADC 3 and arrives at the time of input t of a specialized computer in the form of a sample vector $$u\left(t\right)={\left(u_n\left(t\right)\right)}_{n=\mathrm{one}}^N$$

whose dimension N = M _x × M _y corresponds to the number of antenna elements of the digital antenna array (M _x and M _y are the number of antenna elements of the digital antenna array in the central horizontal and vertical bars, respectively). In BS 4, the sample vector u (t) is scalarly multiplied by the vector of complex weighting factors $$w_o={\left(w_{on}\right)}_{n=\mathrm{one}}^N$$

, providing the installation of the beam in the direction of the signal source (θ ₀ , φ ₀ ), and the formation of a sharply directed scanning radiation pattern of a flat antenna array of a given beam width and level of the side lobes (figure 3). Therefore, the vector w _o determines the shape of the directional scanning radiation pattern of the planar antenna array F _o (θ, φ). In BS 5, in parallel, the received sample vector is scalarly multiplied by the vectors of the complex weighting coefficients $$w_{\mathrm{to}\mathrm{one}}={\left(w_{\mathrm{to}\mathrm{one}n}\right)}_{n=\mathrm{one}}^N$$

and $$w_{\mathrm{to}2}={\left(w_{\mathrm{to}2n}\right)}_{n=\mathrm{one}}^N$$

. Moreover, M _x complex coefficients $$w_{\mathrm{to}\mathrm{one}{m}_x}$$

corresponding to the antenna elements of the digital antenna array in the central horizontal ruler, coincide with the coefficients $$w_{0m_x}$$

, and the remaining coefficients are zero; M _y complex coefficients $$w_{\mathrm{to}2m_y}$$

corresponding to the antenna elements of the digital antenna array in the central vertical ruler, coincide with the coefficients $$w_{0m_y}$$

, and the remaining coefficients are zero. The choice of complex weighting coefficients ensures the independent formation of two radiation patterns F ₁ (θ, φ) and F ₂ (θ, φ), one-dimensionally expanded in orthogonal planes (along the orthogonal lines of the antenna array), with the norms / F ₁ (θ ₀ , φ ₀ ) /, / F ₂ (θ ₀ , φ ₀ ) / and the maxima oriented in the direction of the signal source (θ ₀ , φ ₀ ). Moreover, in one of the main planes, each of the radiation patterns F ₁ (θ, φ) and F ₂ (θ, φ) coincides with the radiation pattern of a flat antenna array F _o (θ, φ), and in the other it approaches the radiation pattern of a single antenna element of a flat antenna array. At the output of BS 5, a signal is generated corresponding to a weakly directed radiation pattern, F ₁ (θ, φ) / | F ₁ (θ ₀ , φ ₀ ) | + F ₂ (θ, φ) / | F ₂ (θ ₀ , φ ₀ ) | (figure 4).

In BVK 6, at the stage of tuning and debugging the flat antenna array in the absence of interference, a weight coefficient is formed that corresponds to the ratio of the norms of the highly directional scanning and weakly directed radiation patterns when the beam of the flat antenna array is oriented in the direction normal to the aperture plane. This weight coefficient remains constant during operation and can only be changed when reconfiguring a flat antenna array.

The signal from the output of BS 5 is supplied to the first input of the control unit 7, and the signal from the output of the control unit 6 is supplied to the second input of the control unit 7. At the output of the control unit 7, a signal is generated, the level corresponds to the level of a weakly directed radiation pattern times the weight coefficient. To generate a signal corresponding to the compensation radiation pattern, in BV 8 at each moment of time, the signal from the output of BS 4 is subtracted from the signal from the output of BU 7. As a result of algebraic summation, a signal is generated corresponding to the compensation radiation pattern (figure 5), which is in the angular region corresponding to the main beam of a sharply directed scanning radiation pattern of a planar antenna array has a region of “zeros”. The main sections of the three specified radiation patterns are shown in figure 6.

Let us evaluate the possibility of forming a weakly directed antenna pattern of the compensation channel with a specified excess of the flat antenna array of the main channel in the region of the side lobes over the highly directional scanning radiation pattern.

Consider N = M _x × M _y - an elementary flat digital antenna array with a rectangular aperture shape. AE 1 are placed in nodes of a rectangular grid with a step of d _x and d _y along the corresponding coordinate direction (figure 2).

Let a directional scanning radiation pattern of a planar antenna array of the main channel be described by the expression:

where f ₀ (u, ν) is the radiation pattern of a single antenna element of a flat antenna array;

и $$B_{m_y}$$

- амплитуды антенных элементов в центральных ортогональных линейках плоской антенной решетки с координатами фазовых центров (x_mx, 0) и (0, y_mx) соответственно; $$A_{m_x}$$

and $$B_{m_y}$$

- the amplitudes of the antenna elements in the central orthogonal lines of the flat antenna array with the coordinates of the phase centers (x _mx , 0) and (0, y _mx ), respectively;

и $${\gamma }_{m_y}$$

- фазы антенных элементов в центральных ортогональных линейках плоской антенной решетки. $${\psi }_{m_x}$$

and $${\gamma }_{m_y}$$

- phases of the antenna elements in the central orthogonal lines of the flat antenna array.

Then, to describe a weakly directed radiation pattern, the expression can be used:

Suppose that C _o is the norm of a sharply directed scanning radiation pattern of a planar antenna array of the main channel. Then C _c is the norm of a weakly directed radiation pattern. Obviously, for the generated radiation patterns, the relation C _c <C _o is fulfilled, which is due to the different number of antenna elements in the aperture. However, in the region of the side lobes Ω, the _{side of the} directional scanning radiation pattern, as can be seen from the above formulas, a relation can be fulfilled showing that the level of the irregular compensated radiation pattern exceeds the level of the irregularized directional scanning radiation pattern in the region of the side lobes θ, φ∈Ω _side :

Inequality (3) is satisfied in a wide sector of angles with a decrease in the norm of C _o , i.e. in the case when the beam of the main channel becomes wider, and the level of the side lobes in the orthogonal rulers is lower. As a result, one can choose such an amplitude distribution in the aperture of a planar antenna array in which the required excess of the level of the compensation radiation pattern over the level of the side lobes of the highly directional scanning radiation pattern of the planar antenna array of the main channel will be achieved in the entire observation area (excluding the main beam area). Therefore, the fulfillment of inequality (3) can be related to the directional coefficient of the planar antenna array of the main channel.

The compensation radiation pattern of a flat antenna array is formed as a difference

The peculiarity of the generated compensation radiation pattern (figures 5, 6, 8-10) is that the radiation pattern F _to (θ, φ) has the form of two intersecting one-dimensionally extended rays with zero in the direction of the signal source F _to (θ ₀ , φ ₀ ) = 0, that is, in the region occupied by the main lobe of the directional scanning radiation pattern of the flat antenna array of the main channel F ₀ (θ, φ), a failure is formed.

At the outputs of the linear paths after summing the signals from AE 1 in BS 4, 5, there are, respectively, signal components, noise and noise associated with weakly and strongly directional beams, respectively.

In BVK 6, the weight coefficient C is stored, which corresponds to the ratio of the signal values of the sharply directional scanning and weakly directional radiation patterns of a flat antenna array when the beam of a flat antenna array is oriented in the direction normal to the aperture plane, which is described by an expression of the form:

As mentioned above, it is determined during debugging and tuning of a flat antenna array and remains constant during operation. The signal corresponding to the weight coefficient C is fed to the input of the control unit 7, in which a signal is formed equal to the product F _c (θ, φ) · С ₀ / C _c .

In accordance with expression (4), a signal corresponding to the compensation radiation pattern is formed at the output of the BV 8 as the difference of the signals: a signal corresponding to the level of a weakly directional radiation pattern multiplied by a weight coefficient and a signal corresponding to the level of a sharply directed scanning radiation pattern.

The sensitivity of the receiving system decreases the more, the higher the value of C. Indeed, when the compensation beam is formed, the factor C affects the amplitude of the noise in the compensation channel. Therefore, at C> 1 there is an increase in the noise level and, accordingly, a decrease in the sensitivity of the receiving system with an interference compensator.

A reduction in transmission coefficient C can be achieved by increasing the directional coefficient of a weakly directed antenna. However, this approach limits the use of the receiving system only to that region of angles into which the beam of a weakly directed antenna is oriented. As a result, in the theory and practice of such systems there was a contradiction between the desire to deal with an arbitrarily oriented noise and maintaining the sensitivity of the receiving system. Therefore, the problem arises of limiting the transmission coefficient C or of forming an excess of a weakly directed radiation pattern over the level of the side lobes of a sharply directed scanning radiation pattern of the antenna array W:

The choice of the amplitude distribution for the antenna elements of the antenna array is related to the value W. The larger the value of W, the lower should be the level of the side lobes in the directional scanning radiation pattern. This requirement is associated with the value of the threshold of the detected signal above the interference level for a given probability of correct detection and the probability of false alarm.

The ability to compensate for interference in the entire sector of the angles with the required excess of the level of the compensation radiation pattern over the level of the side lobes of the directional scanning radiation pattern was tested on the example of a flat antenna array. As a given value of W, W = 10 dB was selected.

Volume radiation patterns were calculated for a 32 × 32-element flat antenna array with antenna elements placed in nodes of a rectangular grid with a step of 0.5λ. The radiation patterns of a sharply directed scanning and compensation radiation patterns of a flat antenna array, obtained as a result of numerical studies, are shown in figures 3-9.

For a non-deflected beam, figure 3 shows a three-dimensional sharply directional scanning radiation pattern of a flat antenna array with an amplitude distribution of "cosine on the pedestal 0.1", figure 4 shows a three-dimensional weakly directional radiation pattern, figure 5 shows a volume compensation radiation pattern, and figure 6 main sections of a three-dimensional sharply directed scanning radiation pattern of a flat antenna array (dashed curve), a three-dimensional weakly directional radiation pattern (dash-dot cr Wai) and the volume compensating directivity pattern (solid line).

The deviation of the beam in the direction (θ ₀ = 40 °, φ ₀ = 20 °) corresponds to the graphs shown in figures 7-9: in figure 7, 8 - three-dimensional sharply directed scanning and compensation radiation patterns of a flat antenna array, respectively, in figures 9, 10 cross-sections in the main planes of the volumetric radiation pattern of a flat antenna array (dashed curve), volumetric weakly directed radiation pattern (dash-dotted curve) and volume compensation radiation pattern (solid curve).

In figures 11, 12 marked spatial (dark) areas in which there is a required excess of 10 dB of the level of the compensation antenna radiation pattern over the level of the side lobes of a sharply directed scanning radiation pattern of a flat antenna array.

From the analysis of the results shown in figures 11, 12, it follows that the required excess of the compensation radiation pattern over the level of the side lobes of the directional scanning radiation pattern is provided throughout the scanning sector.

The implementation of the proposed method in the radar system for detecting and tracking targets, where one of the conditions for obtaining the specified accuracy characteristics of the system was the suppression of the interfering signal in the receiving path to a certain (required) technical task, is considered. The use of a digital antenna array as a receiving antenna made it possible to realize highly directional scanning and weakly directional radiation patterns using a single aperture, which led to a decrease in the mass and overall dimensions of the antenna array and increased the operational efficiency of the complex. The use of a multi-channel digital signal processing module, which simultaneously forms an interference canceller channel and radar information processing channels, made it possible to achieve the required level of exceeding the level of the compensation radiation pattern over the level of the side lobes of the highly directional scanning radiation pattern of the flat antenna array of the main channel and to suppress spatial interference in an arbitrary direction. The aforesaid is confirmed by the results of a full-scale experiment using a fragment of an S-band antenna array with a size of 24 by 8 antenna elements.

The above-described possibility of implementing this method based on a fragment of the antenna array of the radar system for detecting and tracking targets provides him with the criterion of "industrial applicability".

An analysis of the obtained results confirms the correctness of the ideas laid down, that is, the possibility of implementing a method of generating a compensation radiation pattern in a flat antenna array with electronic beam control, which ensures the required excess of the level of the compensation radiation pattern over the level of the side lobes of the directional scanning radiation pattern of a flat antenna array, in a wide sector angles, as well as the formation of a zero compensation radiation pattern at n a constant relation to the norms of sharply directed scanning and weakly directed radiation patterns.

Claims (1)

A method of generating a compensation radiation pattern in a planar antenna array with electronic beam control, wherein a directional scanning radiation pattern of a planar antenna array and a weakly directional radiation pattern are formed that overlap the lateral radiation of a directional scanning radiation pattern of a planar antenna array, characterized in that the formation of a directional scanning pattern directivity of a flat antenna array is carried out using By calling the selected complex amplitudes of the antenna elements, taking into account the required excess of the level of the compensation radiation pattern over the level of the side lobes of the sharply directed scanning radiation pattern, the formation of a weakly directed radiation pattern is performed by summing the signals of the antenna elements located in the central orthogonal arrays of the flat antenna array with complex amplitudes corresponding to complex amplitudes antenna elements of a flat antenna array in the direction to the source of the useful signal, and the compensation radiation pattern is obtained by subtracting the highly directional scanning radiation pattern from the weakly directional radiation pattern multiplied by the weight coefficient equal to the ratio of the norms of the directional scanning and weakly directional radiation patterns when the beam of the flat antenna array is oriented normal to the aperture plane.

Images