RU2707985C2 - Automated multifunctional adaptive antenna array - Google Patents

Abstract

FIELD: physics.SUBSTANCE: invention relates to antenna engineering and can be used in radio communication, radiolocation and radio navigation systems when receiving signals under interference conditions. Essence of the invention is that the prototype further includes N band-pass filters, an operator panel, K adders by frequency component, as well as K keys K1 and K keys K2, the number of units for complex signal weighting increased by K times, in the adaptive processor additionally introduced are K-1 units for forming a weight coefficient vector, a unit for approximating the vector of weight coefficients, K keys K1 and K keys K2.EFFECT: similar design enables to simultaneously receive narrow-band and broadband signals coming from different directions from different radio devices in a complex signal-noise environment.1 cl, 6 dwg

Description

The invention relates to antenna technology and can be used in radio communication systems, radar and radio navigation when receiving signals in the presence of interference.

Known adaptive antenna array [1, p. 56, 2] containing N antenna elements. A device with quadrature channels is introduced into the channel of each antenna element, with the help of which the signal is divided into in-phase and quadrature components, and each of the components is subjected to the operation of multiplication by the weight coefficient. The signals obtained after such processing are added to the adder. The management of the values of weights is carried out using a signal processor.

However, this adaptive antenna array operates in a narrow frequency band, the shape of the radiation pattern will be constant, and the antenna itself can only perform one function.

Known adaptive antenna array [3], containing antenna elements, hybrid devices that provide separation of signals into in-phase and quadrature components, weight multipliers, a common adder, adaptive circuits, band-pass and barrage filters, power measurement units, a comparison unit and a control unit. Using filters, power measurement units, a comparison unit, and a control unit, the output power of the total adder is minimized and maximized in the modes of suppressing interference and extracting a useful signal.

The disadvantage of this adaptive antenna array is the complexity of the adaptive antenna array and the need for separate execution of the modes to minimize interference and maximize the power of the useful signal. It is also capable of receiving only one useful signal per unit of time.

Known adaptive antenna array [4] contains N antenna elements, the outputs of which are N bandpass filters, M × N blocks of complex signal weighting, M signal adders, a common adder and an adaptive processor. The adaptive processor is made in the form of a set of M blocks for the formation of weighting factors. The M outputs of each of the N band-pass filters are connected directly to the corresponding frequency component of the useful signal with the corresponding inputs of the M weighting units, and with the corresponding inputs of the M signal adders via the complex signal weighting units. This adaptive antenna array has high noise immunity when processing broadband signals in any signal-noise environment.

The main disadvantage of the adaptive antenna array under consideration is that it is capable of receiving only one useful signal per unit time. The second drawback is the lack of a universality function, that is, the adaptive antenna array can only be used for radio communication systems, or only for radio navigation systems, or only for radar systems.

The closest analogue (prototype) is a multifunctional adaptive antenna array [5], containing N antenna elements, N blocks of complex signal weighing, an adaptive processor and a common adder. The adaptive processor consists of a control vector generating unit responsible for phasing the antenna array in the direction of arrival of the useful signal and the shape of the main maximum of the radiation pattern, the generating unit of the covariance matrix of the interfering signals, the inverse unit of the covariance matrix of the interfering signals, and the generating unit of the weight vector. The outputs of the N antenna elements are connected to the inputs of the N blocks of the complex signal weighting and to the inputs of the block forming the covariance matrix of the interference signals, which are the corresponding inputs of the adaptive processor. The outputs of the unit for generating the covariance matrix of interfering signals through the unit for reversing the covariance matrix of interfering signals are connected to the inputs of the unit for generating the vector of weighting coefficients. The output of the control vector generation unit is connected to the control input of the weight vector forming unit. The outputs of the unit for generating the vector of weighting coefficients, which are the outputs of the adaptive processor, are connected to the control inputs of N blocks of complex weighing, the outputs of which are connected to a common adder.

The disadvantage of this multifunctional adaptive antenna array is that it operates in a narrow frequency band and is not able to simultaneously receive several useful signals coming from different directions.

The proposed automated multifunctional adaptive antenna array is aimed at achieving a technical result consisting in the ability of the antenna array to simultaneously generate more than one radiation pattern for different frequency ranges in different directions and quickly change the shapes of the main maxima of radiation patterns due to changes in the amplitude-phase distribution of currents in the antenna emitters gratings in a complex signal-noise environment. This allows you to simultaneously use the same antenna array for various purposes, for example, for radio communications or for radar, or for radio navigation, etc., which makes it universal for various systems.

To achieve the specified technical result, a multifunctional adaptive antenna array, which is the closest analogue (prototype), containing N antenna elements, N blocks of complex signal weighing, a common adder, an adaptive processor, consisting of a unit for generating a vector of weight coefficients, which includes a unit for generating control vector, covariance matrix generation block of interfering signals, covariance matrix reversal block of interfering signals, multiplication block, additional Additionally, N bandpass filters, an operator panel, K totalizers in the frequency component, as well as K keys K1 and K keys K2, were added, the number of blocks for complex signal weighting was increased K times, K-1 blocks for generating the vector of weighting factors were additionally introduced into the adaptive processor, block approximations of the vector of weights, K keys K1 and K keys K2, and the outputs of N antenna elements through N bandpass filters are connected to the corresponding information inputs of N × K blocks of complex signal weighting, as well as to and to the information inputs of the covariance matrix matrix of the interference signals of each of K adaptive processor weight coefficients vector generation blocks, the control panel operator outputs are connected to the control vector of each of the K adaptive processor weight vector formation blocks, the outputs of the covariance matrix of interference signals are connected to the corresponding the inputs of the block of treatment of the covariance matrix of interference signals, the outputs of which are connected are connected to the first inputs of the multiplication unit, the second input of the multiplication unit is connected to the output of the control vector generation unit, the outputs of each of the K multiplication unit, which are the outputs of the K units of the formation of the weight vector through K keys K1, are connected to the inputs of the approximation unit of the weight vector, the output of which is control output of the adaptive processor connected to the corresponding control inputs of N × K blocks of complex signal weighing, and through K keys K2 are connected to the corresponding control inputs of N × K blocks of complex signal weighing, outputs of N × K blocks of complex signal weighing are connected to the corresponding K adders in the frequency component, outputs of K adders in the frequency component through K keys K1 are connected to a common adder, the output of which is the output of the device, and through K keys K2 to the outputs of the device.

A comparative analysis of the claimed device and prototype shows that the claimed device is characterized in that:

- N band-pass filters, an operator console, K totalizers for the frequency component, 2K keys K1 and 2K keys K2 were introduced, the number of blocks for complex signal weighting increased K times;

- Changed the relationship between the elements;

- K-1 blocks of the formation of the vector of weight coefficients and an approximation block of the vector of weight coefficients are additionally introduced into the adaptive processor.

The invention is illustrated by drawings, where in FIG. 1 is a structural diagram of an automated multifunctional adaptive antenna array.

In FIG. 2 shows a block diagram of an adaptive processor.

In FIG. 3 is a structural diagram of a weighting unit.

In FIG. Figure 4 shows the frequency range of functioning of an automated multifunctional adaptive antenna array, divided into K private processing channels.

In FIG. Figure 5 shows the optimal (1) and approximated (2) frequency dependence of the real part of the vector of weight coefficients.

In FIG. Figure 6 shows the optimal (1) and approximated (2) frequency dependence of the imaginary part of the vector of weight coefficients

The structure of an automated multifunctional adaptive antenna array (Fig. 1) includes antenna elements 1 forming an N-element antenna array and connected to N bandpass filters 2. The operator console 3 is connected to the adaptive processor 4, the outputs of the N bandpass filters 2 are connected to the adaptive processor 4 and to the inputs of N × K blocks 5 of the integrated signal weighting. The outputs of the adaptive processor 4 are connected to the inputs of the N × K blocks 5 of the complex signal weighting, the outputs of the N × K blocks 5 of the complex signal weighting are connected to the corresponding K adders in the frequency component 6, the outputs of which through K keys K1 are connected to the common adder 7, and through K K2 keys are device outputs.

Adaptive processor 4 (Fig. 2) consists of a set of K blocks 8 forming a vector of weight coefficients, the control inputs of which are connected to the operator panel 3, and the information inputs are connected to the outputs of bandpass filters 2. The outputs of K blocks 8 of forming a vector of weight coefficients through K keys K1 connected to the block 9 approximation of the vector of weights, the output of which is the control output of the adaptive processor, and through K keys K2 are the control outputs of the adaptive processor.

Each of the K blocks 8 of the formation of the vector of weight coefficients (Fig. 3) consists of a block 10 of the formation of the control vector, the control input of which is connected to the operator panel 3, and the output with the input of the block 13 multiplication, block 11 of the formation of the covariance matrix of the interference signals, the inputs of which are connected to the outputs of the bandpass filters 2. The N outputs of the block 11 for generating a covariance matrix of interference signals are connected to the N inputs of the block 12 of the inverse of the covariance matrix of interference signals, the outputs of which are connected to the inputs of the block 13 multiplication. The output of the multiplication block 13 is the output of the weighting vector unit 8.

Before considering the operation of the proposed automated multifunctional adaptive antenna array, we carry out a theoretical justification for the reception of a narrowband useful signal or part of a wideband useful signal for each of the K frequency processing channels.

Consider an N-element antenna array with known emitting aperture geometry, which receives a useful signal from the direction θ _0, ϕ ₀ and suppresses noise coming from unknown directions θ _l , ϕ _l, (l = 1, ..., L). It is required to determine and implement a set of weighting coefficients in the channels of the adaptive antenna array, providing a maximum signal / (noise + noise) ratio at the output of the adaptive antenna array.

We write the criterion for the maximum signal / (noise + noise) ratio:

where R _ss is the covariance matrix of the useful signal;

R _nn is the covariance matrix of interference signals;

W is the vector of weights;

T, * - symbols of transpose and complex conjugation operations, respectively.

The optimal dependence of the vector of weight coefficients has the form [1]:

- обратная ковариационная матрица помеховых сигналов;Where

- inverse covariance matrix of interfering signals;

S ₀ = А _n exp (-ik (x _n sinθ ₀ cosϕ ₀ + for _n sinθ ₀ sinϕ ₀ )) is a control vector that provides the construction of a given radiation pattern (in a given direction θ ₀ , ϕ ₀ with a given shape of the main maximum);

And _n is the vector of the amplitude-phase distribution of currents in the emitters of the antenna array;

k is the wave number;

θ ₀ , ϕ ₀ are the angles of the direction of arrival of the useful signal;

x _n , y _n - coordinates of the nth element of the antenna array.

The covariance matrix of interfering signals with an arbitrary number of interfering signals is determined by a ratio of the form:

where σ ² is the thermal noise power of the antenna array;

E is the identity matrix of dimension N × N;

ν is the power of the interfering signal;

- вектор-столбец, элементами которого являются комплексные сомножители, учитывающие фазовый набег на каждом элементе антенной решетки при приеме

-го (

) помехового сигнала.

- a column vector whose elements are complex factors that take into account the phase incursion at each element of the antenna array when receiving

th (

) interference signal.

Then the inverse covariance matrix using expression (2) is written as follows:

where U _p = exp (-ik (x _n sinθ _p cosϕ _p + y _n sinθ _p sinϕ _p )) is a column vector whose elements are complex factors that take into account the phase incursion at each element of the antenna array when receiving r (p = 1, ..., L) of the interfering signal.

, которые можно найти из выражения (3) и (4), учитывая условие:In relation (4), all terms are known except for the coefficients

which can be found from expressions (3) and (4), given the condition:

определяется в виде:In the particular case of a single interference coefficient

defined as:

and the inverse covariance matrix of interfering signals after substituting (5) in (4) is determined by the formula:

The expression for the vector of weights in this case has the form:

After carrying out mathematical transformations of expression (7), taking into account the relations for S ₀ and U ₁ , we obtain the analytical dependence of the vector of weight coefficients. The resulting vector of weighting coefficients allows you to phase the antenna array in the direction of arrival of the useful signal, to form the desired shape of the main maximum of the radiation pattern, as well as the "zeros" of the radiation pattern in the direction of the interfering signals.

In the case when the useful signal is characterized not by a single frequency, but by a frequency spectrum, it becomes necessary to form a vector of weighting coefficients for the entire frequency range, which is impossible in practice. Therefore, it is proposed for each k-th frequency channel of processing to optimally determine the vector of weighting coefficients for the k-th frequency. For the remaining frequencies of the continuous spectrum of the signal, approximate the vector of weights by various functions, for example, piecewise constant or piecewise linear (Fig. 4-6).

Thus, the expression (7) will take the form:

- оптимальный вектор весовых коэффициентов для k-ой частоты;Where

- the optimal vector of weights for the k-th frequency;

- аппроксимирующая функция (фиг. 5-6).

- approximating function (Fig. 5-6).

The proposed automated multi-functional adaptive antenna array operates as follows.

An additive mixture of useful signals coming from different directions at different frequencies, noise and interference signals is received by N antenna elements 1. N bandpass filters 2 divide the received additive mixture of signals into K frequency ranges (Fig. 4). Part of the divided additive signal mixture is fed to the inputs of the blocks 5 complex signal weighting. Similarly, the second part of the additive signals is fed to the corresponding information inputs of the adaptive processor 4, namely, to the corresponding information inputs of the weight vector generation blocks 8, and in each of them to the inputs of the interference covariance matrix generation block 11.

Let us consider in more detail the functioning of the adaptive processor 4. An additive signal mixture, divided into K frequency ranges, is fed to the inputs of the corresponding kth block 8 of the formation of the vector of weight coefficients, and in each of them to the inputs of the block 11 of the formation of the covariance matrix of the interference signals, in which, in accordance With the given relations, the elements of the covariance matrix of the interfering signals for the k-th frequency channel of processing are formed. The signals corresponding to the elements of the covariance matrix of the interfering signals are fed to the inputs of the block 12 of the covariance matrix of the interfering signals. Next, the signals from the block 12 of the treatment of the covariance matrix of the interference signals are supplied to the first inputs of the block 13 multiplication. The second input of the multiplication unit 13 receives a control signal from the control vector generating unit 10 (S ₀ = А _n exp (-ik (x _n sinθ ₀ cosϕ ₀ + y _n sinθ ₀ sinϕ ₀ ))) containing information about the direction of arrival of the useful signal and the shape of the desired main beam maximum. The shape of the main maximum of the radiation pattern directly depends on the tasks performed by the antenna array, and is capable of changing in real time. The signal about the direction of arrival of the useful signal and the change in the amplitude-phase distribution of currents in the emitters of the antenna array, and therefore the shape of the main maximum of the radiation pattern, is issued by the control vector generation unit 10 upon command from the operator panel 3. In the multiplication block 13, signals are generated to control the corresponding blocks 5 integrated signal weighting. The formation of these signals is based on the rules of matrix multiplication, which are easily implemented using multipliers and adders of low-frequency signals. The output signals K of the blocks 8 of the formation of the vector of weights through the keys K2 closed by the command from the operator’s console 3 are the output signals of the adaptive processor. If the keys K1 are closed by a command from the operator’s console, then the output signals K of the blocks 8 for generating the vector of weight coefficients are fed to the inputs of the block 9 for approximating the vector of weight coefficients, where the formation of the vector of weight coefficients is performed in accordance with expression (8). As a result, at the output of the adaptive processor, control actions are generated that arrive at the corresponding control inputs of the integrated signal weighing units 5. The signals from the outputs of the blocks 5 complex signal weighing are fed to the inputs of the respective adders in the frequency component 6. The outputs of the adders in the frequency component 6 through closed by the command from the operator console 3, the keys K1 are the outputs of the device. In this case, the signals received at the output of the device are narrowband signals received simultaneously from different directions. Through the keys K2, closed by the command received from the operator’s control panel 3, the signals from the outputs of the adders with respect to the frequency component 6 are fed to the common adder 7, in which the signals are summed over the frequency. The output of the total adder 7 is the output of the device. In this case, the signal coming from the output of the device is a broadband signal received from a certain direction. If it is necessary to combine several frequency ranges from the operator panel 3, a command is issued to close the corresponding keys K1. For the remaining frequency processing channels, the corresponding keys K2 are closed by a command from the operator panel 3. The keys K1 and K2 by the same command are closed in all elements of the device. Thus, an automated multifunctional adaptive antenna array can simultaneously receive signals coming from different directions with different spectral widths from different radio systems.

Automated multifunctional adaptive antenna array can be implemented on a modern element base. The implementation of the entered blocks is straightforward.

It follows from the foregoing that the proposed automated multifunctional adaptive antenna array, depending on the type of tasks performed, on which the shape of the main maximum of the radiation pattern depends, provides the selection of the useful signal from the received set of useful and interference signals with unknown parameters, and allows you to receive useful signals coming from various directions at different frequencies, quickly change the shape of the main maximum of the radiation pattern. Automated multifunctional adaptive antenna array can be implemented using existing electronic means and elements.

Thus, the introduction of a totality of new elements allows us to obtain a technical result consisting in the possibility of an antenna array to simultaneously generate more than one radiation pattern at different frequency ranges in different directions and to quickly change the shapes of the main maxima of radiation patterns due to changes in the amplitude-phase distribution of currents in the antenna emitters gratings in a complex signal-noise environment. This allows you to simultaneously use the same antenna array for various purposes, for example, for radio communications or for radar, or for radio navigation, etc., which makes it universal for various systems.

Literature

1. Monzingo R.A., Miller T.U. Adaptive Antenna Arrays: Introduction to Theory: Per. from English - M .: Radio and communications, 1986. - S. 56.

2. AS of the USSR, No. 1506569, 1987

3. AS of the USSR, No. 1548820, 1990

4. RU, No. 2466482, 2012

5. RU, No. 2579996, 2016.

Claims (1)

An automated multifunctional adaptive antenna array containing N antenna elements, N blocks of complex signal weighting, a common adder, an adaptive processor, consisting of a weight vector vector generating unit, which includes a control vector generating unit, a covariance matrix generating unit for interfering signals, a covariance reversing unit interference signal matrices, a multiplication unit, characterized in that N band-pass filters, an operator console, K sum frequency components, as well as K keys K1 and K keys K2, the number of blocks of complex signal weighting is increased K times, the adaptive processor has additionally introduced K-1 blocks for generating vector weights, an approximation block for vector weights, K keys K1 and K K2 keys, and the outputs of N antenna elements through N bandpass filters are connected to the corresponding information inputs of N × K blocks of complex signal weighing, as well as to the information inputs of the covariance matrix forming the interfering signals of each of K adaptive processor weight coefficient vector generation blocks, the control panel operator outputs are connected to the control vector control unit of each adaptive processor weight vector K blocks, the covariance matrix generation unit of the interference signals are connected to the corresponding inputs of the covariance matrix reversing unit interfering signals, the outputs of which are connected to the first inputs of the multiplication block, the second input of the block the knives are connected to the output of the control vector forming unit, the outputs of each of the K multiplication units, which are the outputs of the K weight vector forming units, are connected via K keys K1 to the inputs of the approximation unit of the weight vector, the output of which is the control output of the adaptive processor connected to the corresponding control inputs of N × K blocks of complex signal weighting, and through K keys K2 are connected to the corresponding control inputs of N × K blocks of complex weighting s signals, the outputs of N × K blocks of complex signal weighting are connected to the corresponding K adders in the frequency component, the outputs of K adders in the frequency component through K keys K1 are connected to a common adder, the output of which is the output of the device, and through K keys K2 to the outputs of the device.

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