RU95859U1 - WAVE FRONT CURVATION COMPENSATION DEVICE - Google Patents

Abstract

 1. A device for compensating curvature of the wave front, containing a multi-element cylindrical antenna, including N receiving channels formed by receiving elements consisting of N electro-acoustic transducers, N pre-amplifiers and N-2 delay lines, and in each receiving channel, the receiving elements are interconnected by a serial electric communication, in addition, the outputs of the respective receiving channels are connected to the corresponding inputs of the adder, the output of which is connected to the input of a three-dimensional indicator, characterized in that the device additionally includes an RF signal generator and an RF radiator with the possibility of switching the operation of each pre-amplifier to multiplier mode, respectively. ! 2. The device according to claim 1, characterized in that the N receiving channels include two identical extreme receiving channels and N-2 middle receiving channels. ! 3. The device according to claim 2, characterized in that each extreme receiving channel is formed by an electro-acoustic transducer and a pre-amplifier. ! 4. The device according to claim 2, characterized in that each middle receiving channel is formed by an electro-acoustic transducer, a pre-amplifier and a delay line. ! 5. The device according to claim 1 or 4, characterized in that the N-2 delay lines have linear dimensions due to the placement of a multi-element cylindrical antenna in the circle sector.

Description

The utility model relates to sonar technology, namely, sonar antenna arrays, and can be used in sonar tools with multi-element sonar antennas for the detection and direction finding of sonar radiation in the Fresnel zone.

When solving the problem of detecting marine objects, the specificity of hydroacoustic information received by hydroacoustic means from targets located in the near zone (Fresnel zone) should be attributed.

The specificity of sonar information when approaching sea targets is that the existing passive sonar tools are designed to detect targets in the far zone. The base of hydroacoustic antennas in these means is formed to receive a plane wave front. The signal from the sea target located in the sea waveguide, due to refractive and interference phenomena, forms a non-planar wave front from the target, which leads to unphased signal reception over the aperture of the receiving antenna. Therefore, when approaching a marine target due to the lack of formation of the directivity characteristics (CI) in the near zone, erosion occurs, loss of clarity of the mark from the target until it disappears completely on the hydroacoustic station indicator (GAS). The “collapse” of the mark in this case is due to the fact that the phase and amplitude distribution of acoustic pressure in space leads to unphased reception of the signal from the target along the antenna aperture.

One of the problems that must be solved when detecting a target is that there are no devices that track the curvature of the wave front when it changes rapidly over time.

This problem can be solved by creating an adaptive system that could optimize the antenna for phased signal reception with a non-planar wave front. The complexity of the problem lies in the fact that it is necessary to develop a device design that would have a high convergence rate with high reliability of the correct decision.

A device for cascading signal processing with interference compensation, in which the formation of the directivity occurs using phase shifters. The device contains a multi-element antenna, including N receiving elements, N (N-1) / 2 phase shifters and adders, interconnected cascadewise, so that the number of outputs in each stage is less than the number of inputs by 1, the output of the last stage is connected to the indicator input.

In this device, a useful signal is received by the receiving antenna array, and is processed in cascade. Due to the addition of signals from individual receivers with a certain phase shift, an NN of the desired shape is formed (K. Venskauskas, Compensation of interference in ship radio systems. - L .: Sudostroenie, 1989. - 264 p.)

The disadvantages of this known device are that for the cascade execution of the known device requires a large number of phase shifters and adders. This complicates the structural, technological and operational indicators. In addition, in the known device, signal processing occurs by iterations (stepwise approximation), which leads to a long convergence time of the signal processing algorithm.

Part of the disadvantages of the first analogue is absent in the second analogue.

There is another device for generating directivity characteristics due to the amplitude distribution of the signal over the antenna aperture. The device contains a multi-element antenna, including N receiving channels formed by receiving elements interconnected by serial electrical communication, in addition, the outputs of the respective receiving channels are connected to the corresponding inputs of the adder, the output of which is connected to the indicator input.

In this device, the useful signal is received by the receiving antenna array, amplified by preamplifiers with certain amplification factors, the signals of individual preamplifiers are then summed with a certain weight on the adder. Due to the addition of signals from individual receivers with a certain weight, an NN of the desired shape is formed (Monzingo R.A., Miller T.U. Adaptive antenna arrays. - M, Radio and communication, 1986.).

The disadvantage of the second analogue of the device:

- the known device is intended for the formation of CN in order to suppress local interference in the direction. This leads to low noise immunity when the interference signal is in one direction with the signal from the detected target and low noise immunity under the influence of near-field interference. In the known device, signal processing occurs by iterations (stepwise approximation), which is due to the long convergence time of the signal processing algorithm.

There is another, closest in technical essence and selected as a prototype, a device for generating a response of a cylindrical antenna with a uniform amplitude-phase distribution at the input of the shaper HN. The device contains a multi-element cylindrical antenna, including N receiving channels formed by receiving elements consisting of N electro-acoustic transducers, N pre-amplifiers and N-2 frequency-dependent delay lines, and in each receiving channel, the receiving elements are interconnected by serial electric communication, in addition, the outputs corresponding receiving channels are connected to the corresponding inputs of the sum transformer, which is connected through an amplifier to the input of the circular indicator ora.

In this device, a useful signal is received at the receivers of a multi-element cylindrical antenna, amplified, delayed by an amount that takes into account the curvature of the antenna. The antenna response is generated by summing the signals from each elementary channel. (Orientation of acoustic antennas // Hydroacoustic Textbook. - M.: Military. Publishing House, 1993. - p.23-29)

Despite the fact that in the third known device, unlike the first and second analogs, the signal received by the antenna array, without spending time on adaptation algorithms, is immediately displayed on the indicator, the prototype has the following disadvantages:

- low noise immunity for a signal having a non-flat wave front;

- low noise immunity when receiving a signal from a detectable target located in the same direction as the interference signal.

From the above-mentioned drawbacks of the first and second analogues and the prototype, the “Wavefront curvature compensation device” freely declared as a utility model, the technical task of which is to create an adaptive system that optimizes an antenna for phased signal reception with a non-planar wave front, for detecting and detecting hydroacoustic signals in the Fresnel zone.

The implementation of the technical task allows to achieve the following technical result:

- created a new technical tool for the detection and direction finding of hydroacoustic radiation in the aquatic environment in the Fresnel zone.

To achieve the technical result, a “Wavefront curvature compensation device” is proposed, comprising a multi-element cylindrical antenna including N receiving channels formed by receiving elements consisting of N electro-acoustic transducers, N pre-amplifiers and N-2 delay lines. Moreover, in each receiving channel, the receiving elements are interconnected by a serial electrical connection, in addition, the outputs of the respective receiving channels are connected to the corresponding inputs of the adder, the output of which is connected to the input of a three-dimensional indicator.

The fundamental difference of the proposed device is that the RF generator and the RF radiator are additionally included in the device, with the possibility of switching the operation of each preliminary amplifier to the frequency multiplier mode, respectively.

It is these fundamental differences that make it possible to heterodyne the received useful signal by an RF signal to optimize the antenna for phased reception of a signal with a nonplanar wavefront.

Other qualifying features are:

- N receive channels include two identical extreme receive channels and N-2 middle receive channels;

- each extreme receiving channel is formed by an electro-acoustic transducer and a preliminary amplifier;

- each middle receiving channel is formed by an electro-acoustic transducer, a preliminary amplifier and a delay line;

- N-2 delay lines have linear dimensions due to the placement of a multi-element cylindrical antenna in the circle sector.

It is these clarifying features that are necessary for the formation of a multi-element cylindrical antenna capable of scanning space in a circle.

The invention is illustrated by drawings:

Figure 1. Device for compensating the curvature of the wave front. Structural and functional diagram.

Figa. Device for compensating the curvature of the wave front. Receiving channels (extreme and middle). Structural and functional diagram.

Figure 1 presents the structural-functional diagram of a device for compensating the curvature of the wave front, including:

1. Multi-element cylindrical antenna;

1.1.1. Electro-acoustic transducer (EAP), the number of EAP - N from 1.1.1 to 1.1.N;

1.2.1. Preliminary amplifier (PU), the number of PUs is N from 1.2.1 to 1.2.N;

1.3.1. Delay line (LZ), the number of LZ-K from 1.3.1 to 1.3.K, K = N-2;

2. The adder;

3. RF radiator (high-frequency radiator);

4. RF signal generator;

5. Three-dimensional indicator.

A multi-element cylindrical antenna is made in the form of a discrete antenna array located in space along the circle sector. The structural-functional diagram includes N receiving channels (two extreme and N-2 middle). The output of each Nth receiving channel is connected to one of the corresponding inputs of the adder. In each receiving channel, the receiving elements, consisting of an electro-acoustic transducer, a pre-amplifier and a delay line, are interconnected by a serial electrical connection.

All the outputs of the receiving channels of the multi-element cylindrical antenna are connected to the corresponding inputs of the adder, the output of which is connected by electrical communication with the input of a three-dimensional indicator. In addition, the indicator is configured to visually display linear parameters of time and frequency of the input signal in combination with the signal voltage level.

At high radiation levels of the RF signal emitted by the RF emitter 3 of FIG. 1, namely: 20-50 Pa, each of the preliminary amplifiers (PU) 1.2.1-1.2.N of FIG. 1 can switch to the low-frequency (LF) multiplier mode and RF signals received by a multi-element cylindrical antenna. To this end, an RF signal generator 4 of FIG. 1 is included in the device, to the output of which an RF emitter 3 of FIG. 1 is connected.

On figa presents an enlarged structural-functional diagram of the extreme and middle channels of a multi-element cylindrical antenna, including:

6. Extreme receiving channels (identical):

1.1.1. Electro-acoustic transducer (EAP) (first extreme receiving channel);

1.1.N. Electro-acoustic transducer (EAP) (second extreme receiving channel);

1.2.1. Preamplifier (first receive channel);

1.2.N. Preamplifier (second end receive channel).

7. Middle receiving channel:

1.1.2.-1.1.N-1. Electro-acoustic transducer (EAP);

1.2.2.-1.2.N-1. Pre-amplifier (PU);

1.3.1.-1.3.K. Delay line.

The extreme and middle channels are made in accordance with the widely known, prior to the priority date of the claimed technical solutions, the requirements of science and technology in the field of sonar technology and described in (Textbook sonar. - M .: Voen. Publ., 1993. - P.232). In this case, the extreme channels are identical, and the middle channels differ in the linear dimensions of the corresponding delay lines due to the placement of a multi-element cylindrical antenna in the circle sector.

The device operates as follows.

The device for compensating the curvature of the wave front is part of hydroacoustic means.

A useful sonar signal from the target is received by a multi-element cylindrical antenna 1 of FIG. 1, including N receiving channels 6 and 7 of FIG. 1 a. In each receiving channel, a corresponding electro-acoustic transducer from 1.1.1 to 1.1.N of FIG. 1. converts the hydroacoustic signal from the target to electric with a frequency corresponding to the received signal. Simultaneously with the useful hydroacoustic signal from the target, a hydroacoustic RF signal generated by the RF signal generator 4 of FIG. 1 and emitted by the RF emitter 3 of FIG. 1 is supplied to each receiving channel. In each receiving channel, a corresponding electro-acoustic transducer from 1.1.1 to 1.1.N of FIG. 1. converts the hydroacoustic RF signal into an electric signal with an appropriate frequency.

From the output of each respective electro-acoustic transducer (EAP 1.1.1-1.1.N of Fig. 1), the converted electrical signals are fed to the corresponding inputs of the pre-amplifiers (PU 1.2.1-1.2.N of Fig. 1) In each pre-amplifier, the converted signal from the target is multiplied with converted RF signal - heterodyne.

From the outputs of the pre-amplifiers, PU 1.2.2-1.2.N-1 of FIG. 1, the prorated signal arrives at the corresponding delay lines (LZ 1.3.1-1.3. To FIG. 1), which are part of the middle receiving channels 7 of FIG. 1a. In frequency-dependent delay lines, a signal is delayed for a predetermined time interval due to the placement of the receiving elements of the cylindrical antenna in the circle sector. The time-delayed signals are supplied to the corresponding inputs of the adder 2 of figure 1. Simultaneously with them at the corresponding inputs of the adder 2 of Fig.1, proheroded signals from the outputs of PU 1.2.1 and PU 1.2.N of Figure 1 of the extreme receiving channels 6 of Figure 1a, which do not contain delay lines, are received.

All signals received and processed in the extreme 6 of FIG. 1a and the middle receiving channels 7 of FIG. 1a are added up in the adder 2 of FIG. 1, forming the resulting signal, which is fed to the input of the three-dimensional indicator 5 of FIG. 1. The three-dimensional indicator 5 of FIG. 1 visually displays the spectrum of the low-frequency signal proherodenoded into various RF regions in the format: frequency, time, level.

Analyzing the visual information displayed by the indicator, the operator makes a conclusion about the presence or absence of the target in the fresnel zone.

The advantage of the proposed utility model is that the claimed device allows you to optimize the antenna for phased signal reception with a non-planar wave front, thereby increasing search performance, reducing time costs.

Thus, the claimed “Device for compensating the curvature of the wave front” is a new device - an adaptive system that allows you to optimize the antenna for phased reception of hydroacoustic signals in the Fresnel zone.

The claimed device is industrially applicable, since its implementation uses widespread components and products of the radio industry.

Claims (5)

1. A device for compensating curvature of the wave front, containing a multi-element cylindrical antenna, including N receiving channels formed by receiving elements consisting of N electro-acoustic transducers, N pre-amplifiers and N-2 delay lines, and in each receiving channel, the receiving elements are interconnected by a serial electric communication, in addition, the outputs of the respective receiving channels are connected to the corresponding inputs of the adder, the output of which is connected to the input of a three-dimensional indicator, characterized in that the device additionally includes an RF signal generator and an RF radiator with the possibility of switching the operation of each pre-amplifier to multiplier mode, respectively. 2. The device according to claim 1, characterized in that the N receiving channels include two identical extreme receiving channels and N-2 middle receiving channels. 3. The device according to claim 2, characterized in that each extreme receiving channel is formed by an electro-acoustic transducer and a pre-amplifier. 4. The device according to claim 2, characterized in that each middle receiving channel is formed by an electro-acoustic transducer, a pre-amplifier and a delay line. 5. The device according to claim 1 or 4, characterized in that the N-2 delay lines have linear dimensions due to the placement of a multi-element cylindrical antenna in the circle sector.