JPH08160126A - Sonar receiver - Google Patents

Abstract

PURPOSE: To improve the target identifying ability of an active sonar receiver using a split beam receiving system. CONSTITUTION: Each split beam receiving signal 101 is generated by means of aligning circuits 8-9 by using a receiver element 1U for upper beam and 1D for lower beam in addition to a receiver 1L for left beam and receiver 1R for right beam of the receiver elements contained in a receiver array 1. By obtaining the phase difference signal 104 between upper and lower split beams in addition to the phase difference signal 103 between left and right split beams, variance value calculating circuits 16 and 17 respectively calculate the error variance values 105 and 106 of the phase difference signals. A variance value judgment circuit 18 compares the variance values with a threshold and, when both variance values become smaller than the threshold, a gate 19 is turned on and an amplitude signal 102 is outputted to a displaying section as a video signal 108.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sonar receiving device, and more particularly to an active sonar receiving device for emitting a sound wave into water to receive a reverberant sound from a target object, displaying the echo sound to detect a target. It is about.

[0002]

2. Description of the Related Art When a sonar target signal is received, a split beam having a plurality of electroacoustic transducers, that is, two outputs which are equal to each other in right and left directions with respect to an arbitrary azimuth is formed by phasing outputs of the receiver. A split beam receiving system in which a plurality of beams are formed and received is widely known.

An example of a conventional active sonar receiver of this type of split beam receiving system is disclosed in Japanese Examined Patent Publication No. 63-5.
2346, and its schematic configuration is shown in FIG.
Is shown in. In FIG. 4, LFM (Linear
When the target is discriminated by transmitting a Frequency Modulation (Signal Modulation) signal, for example, in the receiver 1 arranged in a cylindrical shape, the range where one beam is formed is divided into two groups of left and right element groups 1R and 1L. Received signals from the left and right element groups 1R and 1L are amplified by amplifier circuits 2 and 3, respectively, and input to phasing circuits 6 and 7, respectively.

In these phasing circuits 6 and 7, each element group 1
The amplified received signals from R and 1L are phased in the same direction to form left and right split beams 101. Then, with respect to these split beam reception signals 101, the LFM correlation circuits 10 and 11 perform correlation calculation with the replica signal and further perform pulse compression.

The outputs of the correlation circuits 10 and 11 are input to the split beam correlation circuit 14. The split beam correlation circuit 14 has a phase difference detection function and a detection function. The phase difference detection function calculates the phase difference 103 between the left and right reception beams, and the detection function detects the amplitude 102 based on the left and right reception beams. Is detected.

The phase difference signal 103 is input to the variance value calculation circuit 16. The dispersion value calculation circuit 16 has a sampling circuit, a dispersion calculation circuit, a correlation coefficient calculation circuit, and the like.
An error variance value of the phase difference 103 is calculated and output by each of these circuits.

In this case, the input phase difference signal 10
3 is sampled in a time section that can be arbitrarily specified from operating conditions such as the transmission pulse width of the sonar, and the error variance value of the section phase difference in each time section is calculated. The variance value determination circuit 18 compares this interval phase error variance value with a preset threshold value. When it is smaller than this threshold value, it is determined to be the target signal, and the gate 19 for sending the amplitude signal 102 to the video display unit (not shown) is on-controlled,
It is designed to display images.

[0008]

In the conventional method shown in FIG. 4, the target is discriminated only by the beams in the left and right directions. There is a drawback that even small things are judged as goals.

Therefore, the present invention has been made to solve the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a sonar receiving apparatus capable of further enhancing the target discriminating ability. It is in.

[0010]

A sonar receiver according to the present invention is a means for dividing a plurality of receiver groups into four element groups of upper, lower, left and right to generate a left and right split beam and an upper limit split beam, respectively. And a first correlation calculation means for performing the correlation calculation of the left and right split beams, a second correlation calculation means for performing the correlation calculation of the upper and lower split beams, and the first and second correlation calculation means. First and second steps of obtaining the phase difference of the target signal from the respective outputs
Phase difference detecting means, first and second phase error dispersion processing means for obtaining an error dispersion of each phase difference obtained by the first and second phase difference detecting means, and first and second phase error detecting means. And a control means for outputting a received video signal in accordance with each error dispersion value by the phase error dispersion processing means and performing video display control.

[0011]

In addition to the phase error dispersion processing by the left and right split beams, the phase error dispersion processing by the upper and lower split beams is further added, and the target signal is discriminated by using the two phase error dispersion values having different representations. High target discriminating ability is obtained.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, and the same parts as those in FIG. 4 are designated by the same reference numerals. FIG.
In the array type receiver 1, the receiving element groups that form one beam corresponding to image display are grouped into four blocks 1L, 1R and 1U, 1D on the left, right, top and bottom while allowing overlapping. The beam reception signal 1 is generated by the rectifying circuit 6 through the amplifiers 2 to 5 and is formed by the phasing circuits 6 to 9 on the lower right and upper left, respectively.
01 is output.

The two sets of split beam signals are multiplied by the LFM correlator circuits 10 to 13 corresponding to the LFM replica signals to perform pulse compression, and further split beam correlator circuits 14 to 1 corresponding to the left, right, up and down directions.
5, the amplitude signals 102, the left and right beam phase difference signals 103, and the upper and lower beam phase difference signals 104 are output after being multiplied by each other. The amplitude signal 102 is the gate circuit 1
9 is input.

On the other hand, the phase difference signals 103 and 104 are given to dispersion value calculation circuits 16 and 17, and phase error dispersion values 105 and 106 between the left and right beams and between the upper and lower beams are obtained. The variance value determination circuit 18 compares these two phase error variance values with respective preset threshold values as shown in FIG. A judgment is made, the gate circuit 19 is opened, the amplitude signal 102 is passed, and a video image is displayed as a target video signal 108.

As a second method, as shown in FIG. 3 (B), in addition to the first method of FIG. 3 (A), two phase error variance values within a certain section, for example, a time corresponding to the transmission pulse width, are used. , And compare it with a pre-stored pattern,
If the correlation is high, it is determined that the signal is a target signal, the gate circuit 19 is opened, the amplitude signal 102 is passed, and a video image is displayed as a target video signal 108.

FIG. 2 shows an example of the state of the signals of the respective parts of the block of FIG. 1. The amplitude signals after left-right and up-and-down split beam correlation by LFM correlation processing with respect to the respective received beam signals 101 on the lower right and left sides. 102 and the phase difference signals 103 and 104 are output after being delayed by a time corresponding to the transmission pulse width. Also, each phase error variance value 10
5, 106, the variance is large in the state of the noise signal and small in the state of the target signal.

Although the wave receiver 1 is shown as having a cylindrical array structure, it is obvious that the same can be applied to a plane array or an array surface having a certain curvature.

[0019]

As described above, according to the present invention, in addition to the phase error dispersion processing by the left and right split beams, the phase error dispersion processing by the upper and lower split beams is used to use two phase error dispersion values of different phenotypes. By doing
There is an effect that a high-level target signal can be judged.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing an example of signal waveforms of respective parts of the block of FIG.

FIG. 3 is a diagram showing pattern examples of phase error dispersion of left and right split beams and upper and lower split beams, respectively.

FIG. 4 is a block diagram of a conventional sonar receiver.

[Explanation of symbols]

 1 Array receiver 1L, 1R Left and right beam receiving element 1U, 1D Upper and lower beam receiving element 2-5 Amplifying circuit 6-9 Phase adjusting circuit 10-13 LFM correlation circuit 14,15 Split beam correlation circuit 16,17 Variance value calculation circuit 18 Variance value determination circuit 19 Gate circuit

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Claims (3)

[Claims] 1. A means for dividing a plurality of wave receiver groups into four element groups of upper, lower, left and right to respectively generate a left and right split beam and an upper limit split beam, and performing a correlation calculation of the left and right split beams. A first correlation calculating means, a second correlation calculating means for performing a correlation calculation of the upper and lower split beams, and a phase difference of the target signal from each output obtained by the first and second correlation calculating means. A first and a second phase difference detecting means, and a first to obtain an error variance of each phase difference obtained by the first and the second phase difference detecting means.
And a second phase error dispersion processing means, and a control means for outputting a received video signal in accordance with each error dispersion value by the first and second phase error dispersion processing means and performing video display control. Sonar receiver. 2. The control means determines whether or not each of the error variance values is within a predetermined threshold value, and the determination means determines that both are within the predetermined threshold value. The sonar receiving apparatus according to claim 1, further comprising means for forming the image display. 3. The control means obtains a change pattern of each of the error variance values in a preset time interval, and obtains a two-dimensional correlation between the change pattern and a predetermined pattern to obtain the correlation. 3. The sonar receiving apparatus according to claim 1, further comprising means for performing the video display control according to sex.