RU2308048C1 - Interference compensator - Google Patents

Abstract

FIELD: suppression devices used in radio engineering systems of suppression of signals (interference) supplied via the side lobes of the directivity pattern.

SUBSTANCE: the interference compensator of the interference received via the side lobes of the antenna directivity pattern has series-connected second auxiliary antenna, second computer, first device of complex conjugation, first multiplier, first sample adder, divider, second multiplier, first subtracter, first and second adders and second device of complex conjugation connected in a definite way and providing for elimination of the influence of correlation between the components of the useful signal from the output of the main antenna and the interference signal from the output of the second computer to the level of the interference suppression.

EFFECT: eliminated influence of correlation of signals.

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Description

The present invention relates to suppression devices used in radio engineering systems for suppressing signals (interference) coming from the side lobes of the antenna radiation pattern (BOTTOM), and can be used in other systems that eliminate unwanted signals.

Of the known interference suppression devices received along the side lobes of the BOTTOM, the closest in technical essence is the device described in patent RU 2247407 C2 of 02.27.05, the structural diagram of which is shown in figure 1. This device contains a second auxiliary antenna 11 connected in series, the second a subtractor 12, a complex conjugation device 2, a first multiplier 3, a first adder of samples 4, a divider 5, a second multiplier 6 and a first subtractor 7, the second input of which is connected to the output mainly antennas 8, and in series the main antenna 8, the third multiplier 9, the second adder 10, the output of which is connected to the second input of the divider 5, the second inputs of the first 3 and second 6 multipliers connected to the output of the second subtractor 12, the second input of the third multiplier 9 is connected to the output of the complex coupler 2, and the second input of the second subtractor 12 is connected to the output of the first auxiliary antenna 1. The output of the first subtractor 7 is the output of the interference suppression device.

The signal V _M from the output of the main antenna 8, which is the sum of the radar signal S reflected from the target, received by the main lobe of the BOTTOM, and the interference U received by the side lobes of the BOTTOM, is fed to the subtractor 7. The signal V _O from the output of the second subtractor 12, representing a difference of the signals output from the first 1 and the second auxiliary antenna 11 V _O = V _a -V _B, is used in the second multiplier 6, to obtain a weighted WV _O signal, which is subtracted from the signal V _M main antenna 8 in the first subtractor 7 to obtain a residual signal V _R. In addition, the signal from the output of the second subtractor 12 is fed to the inputs of the first multiplier 3 and the complex coupler 2. The complex conjugate signal V _O ^* from the output of the complex coupler 2 is fed to the inputs of the first 3 and third 9 multipliers, with another input the third multiplier 9 is fed a signal from the output of the main antenna 8. The signals from the outputs of the first 3 and third 9 multipliers, passing through the first 4 and second 10 adders respectively, are fed to the divider 5, from the output of which the signal is fed to the W swarm multiplier 6. In divider 5, a weight coefficient value W is generated that is optimal according to the criterion of minimum cross-correlation between the output signal of the suppressor V _R and the signal of the second subtractor Vo.

The disadvantage of this device is the low level of interference suppression due to fluctuations in the weight coefficient W relative to the optimal value due to the correlation between the components of the useful signal from the output of the main antenna 8 and the interference signal from the output of the second subtractor 12.

The technical result of the invention is to increase the level of noise suppression with the help of a noise compensation device.

The essence of the invention lies in the fact that in the interference suppression device containing a second auxiliary antenna, a second subtractor, a complex coupler, a first multiplier, a first adder of samples, a divider, a second multiplier and a first subtractor, the second input of which is connected to the main output antennas, and series-connected main antenna, third multiplier, second adder samples, the output of which is connected to the second input of the divider, while the second inputs the first and second multipliers are connected to the output of the second subtractor, the second input of the third multiplier is connected to the output of the complex conjugation device, the second input of the second subtractor is connected to the output of the first auxiliary antenna, the first and second summing devices and the second complex conjugation device are additionally introduced, and the input of the third the multiplier is disconnected from the main antenna and connected to the output of the first auxiliary antenna, the output of the second multiplier is disconnected from the input of the first about the subtracting device and connected to the input of the first summing device, the second input of which is connected to the output of the main antenna, the inputs of the first subtracting device are connected to the outputs of the first and second summing devices, the inputs of the second summing device are connected to the outputs of the first auxiliary antenna and the second subtracting device, the second multiplier disconnected from the output of the divider and connected to the output of the second complex interface device, the input of which is connected to the output of the divider.

The figure 2 presents a structural diagram of the proposed device to compensate for interference received on the side lobes.

The device for compensating for interference received along the side lobes of the BOTTOM contains serially connected devices: a second auxiliary antenna 11, a second subtractor 12, a first complex coupler 2, a first multiplier 3, a first adder of samples 4, a divider 5, a second complex coupler 13, and a second the multiplier 6, the first adder 14 and the first subtractor 7, the second input of which is connected to the output of the second adder 15, and the first auxiliary in series the antenna 1, the third multiplier 9, the second adder 10, the output of which is connected to the second input of the divider 5, while the second inputs of the first 3 and second 6 multipliers and the input of the second adder 15 are connected to the output of the second subtractor 12, the second input of the first adder device 14 is connected to the output of the main antenna 8, the second input of the second summing device 15 is connected to the output of the first auxiliary antenna 1. The output of the first subtractor 7 is the output of the interference suppression device.

The device operates as follows. The signal from the output of the main antenna 8 V _M = S + U, which is the sum of the radar signal S received by the main lobe of the BOTTOM and the interference U received by the side lobes of the BOTTOM, is fed to the first adder 14, to the other input of which a weighted signal W ^* V _O from the output of the second multiplier 6.

The first auxiliary antenna 1 is omnidirectional with a directional coefficient determined by the level of the side lobes of the beam of the main antenna 8. The first auxiliary antenna 1 is offset relative to the main antenna 8 by a distance d, which leads to a phase shift of the interference signal received by this antenna relative to the interference signal received the main antenna 8, by the quantity φ = 2π (d / λ) sinα, where α is the direction of arrival of the interfering signal, counted from the normal to the base of the antennas - the line connecting the main 8 and the first auxiliary 1 antenna. Based on the foregoing, the signal at the output of the first auxiliary antenna 1 can be written in the form:

V _A = S _OSL + Uexp {jφ},

where S _OSL is the attenuated useful signal at the output of the first auxiliary antenna 1. The presence of the attenuated useful signal is due to the fact that the first auxiliary antenna 1 has a certain directional coefficient in the direction of arrival of the useful signal. In this case, we believe that the useful signal comes from the direction perpendicular to the base of the antennas.

The second auxiliary antenna 11 is offset from the first auxiliary antenna 1, along the base of the antennas, by a distance d and has a directional coefficient determined by the level of the side lobes of the main antenna 8. The signal at the output of the second auxiliary antenna 11 has the form:

V _A = S _OSL + Uexp {j2φ}.

This signal is fed to a second subtractor 12, to the other input of which a signal is output from the output of the first auxiliary antenna 1.

Given the introduced notation, the signal at the output of the second subtractor 12 has the form: V _O = Uexp {jφ} (1-exp {jφ}). This signal is fed to the device, complex pairing 2, as well as the first 3, second 6 multipliers and the second adder 15. From the output of the complex pairing device 2, the signal goes to the inputs of the first 3 and third 9 multipliers. The second input of the third multiplier 9 receives a signal from the output of the first auxiliary antenna 1. The signals from the outputs of the first 3 and third 9 multipliers are supplied to the first 4 and second 10 adders respectively and further to the inputs of the divider 5.

The weight coefficient obtained at the output of the divider 5 is determined by the expression:

W1 = M {V _O V _O ^* } / M {V _A V _O ^* },

where the sign * - means a complex conjugate, M {} - the operation of mathematical averaging. Taking into account the introduced notation, we obtain:

W1 = 1-exp (jφ).

At the output of the second complex interface device 13, we obtain the optimal weight coefficient for effective noise suppression:

W1 = 1-exp (-jφ)

The signal from the output of the first auxiliary antenna 1, in addition, enters the second summing device 15, the output of which the signal enters the second input of the first subtracting device. The output signal of the compensator is determined by the expression: V _R = V _M + W · V _O + V _A -V _O.

The value of the weight coefficient obtained in the prototype is:

,

,

,

- дисперсии полезного и помехового сигналов. Анализ последнего выражения показывает, что наличие корреляции между полезным и помеховым сигналами приводит к флуктуации весового коэффициента относительно оптимального значения, что снижает уровень подавления помех.where ρ is the cross-correlation coefficient of the useful and interference signals,

,

- dispersion of useful and interference signals. An analysis of the latter expression shows that the presence of a correlation between the useful and interfering signals leads to fluctuations in the weight coefficient relative to the optimal value, which reduces the level of noise suppression.

In the proposed device, the formation of the weight coefficient does not involve the components of the useful signal from the output of the main antenna 8.

Thus, the proposed device eliminates the influence of the correlation between the components of the useful signal from the output of the main antenna and the interfering signal from the output of the second subtractor, on the level of noise suppression.

All elements of the proposed device can be implemented on a modern element base.

The use of the invention in this regard allows to increase the efficiency of the device for suppressing interference received on the side lobes of the bottom.

Claims (1)

A device for compensating for interference received along the side lobes of the radiation pattern of the main antenna, which contains the second auxiliary antenna, the second subtractor, the first complex conjugation device, the first multiplier, the first adder of the samples and the divider, as well as the first auxiliary antenna, the third multiplier, and the second the adder samples, the output of which is connected to the second input of the divider, while the second input of the third multiplier is connected to the output of the first triple complex conjugation, and the second inputs of the first and second multipliers are connected to the output of the second subtracting device, characterized in that it additionally introduced the first and second summing devices and the second complex conjugation device, the input of the second complex conjugation device connected to the output of the divider, and the output with the first input of the second multiplier, the inputs of the first summing device are connected to the outputs of the main antenna and the second multiplier, and the inputs of the second summing device are connected Nena output from the first auxiliary antenna and a second subtractor, the inputs of the first subtractor connected to the outputs of the first and second adders, the output of the first subtractor is an output noise compensation device.

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