JP3527792B2 - Underwater probe - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater exploration device,
Particularly, the present invention relates to an underwater exploration device having a wide dynamic range while suppressing side lobes and narrowing a main lobe directional angle.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional receiving system circuit of this type. Reference numeral 1 is a transducer including N linear ultrasonic transducers, and 2 is a trap circuit for receiving a reception signal from the transducer 1. Reference numeral 3 denotes a variable gain preamplifier that amplifies the received signal from the trap circuit 2, and
A TVG (time variable gain) signal is input to the preamplifier 3 as a gain control signal so that the gain increases according to (distance). Reference numeral 4 is a filter that passes only a desired frequency band. 5 is
It is a carrier generation circuit that generates carriers for N channels. Reference numeral 6 denotes a multiplication circuit, which multiplies the N-channel received signal that has passed through the filter 4 and the carrier having the predetermined phase information from the carrier generation circuit 5.

Reference numeral 7 denotes an adder / detector circuit for mutually adding and detecting received signals from the right half (N / 2) of the transmitter / receiver 1, and 8 denotes the left half (N / 2) of the transmitter / receiver 1. It is an adder / detector circuit that adds each received signal (from / 2) and detects it. 9
Is an adder circuit for mutually adding signals from both adder / detector circuits 7 and 8, and 10 is a subtracter circuit for subtracting the signal from the other adder / detector circuit 8 from the signal from one adder / detector circuit 7. Is. Reference numerals 11 and 12 are filters that pass a signal of a desired frequency from the signals from the adder circuit 9 and the subtractor circuit 10. Reference numerals 13 and 14 denote variable-gain main amplifiers for amplifying the received signals from the filters 11 and 12, respectively.
The VG signal is input as the gain control signal.
Reference numeral 15 is a subtraction circuit 15 for subtracting the output signal from the other amplifier 14 from the output signal from one amplifier 13, and the signal obtained by this subtraction circuit 15 is supplied to the CRT display through a predetermined display control circuit. To be done.

The control operation of FIG. 1 will be described. Transducer 1
The echo signal due to the transmission performed through the same is received by the same transmitter / receiver 1, the signal is amplified by the preamplifier 3 through the trap circuit 3, and after passing through the filter 4, the multiplier circuit 6 As a result of multiplying the passed N-channel received signal by the carrier having the predetermined phase information from the carrier generation circuit 5 and giving a predetermined amount of delay between the N-channel received signals, the echo from the predetermined direction is obtained. The signals are incident on each ultrasonic transducer in the same phase, that is, the receiving direction of the wave transmitter / receiver 1 is directed in that direction.

Generally, the N received signals whose phases have been aligned are then simply added, or each signal is given a predetermined weight and mutually added to obtain a single received wave oriented in the predetermined direction. A beam is formed. By the way, due to the characteristics of the transmitter / receiver 1 itself, a low-level sub-beam (side lobe) is derived from the received beam, in addition to the main beam (main lobe). When such a side lobe occurs in fish school detection, a virtual image of the sea floor appears due to this side lobe, and when such a virtual image occurs, it is difficult to distinguish from the fish school, so suppression of the side lobe is essential, Further, in order to improve the detection resolution, it is necessary to make the main lobe sharp (to narrow the directional angle).
Then, for example, the beam forming is performed by two systems of circuits, the sum and difference signals are taken with respect to the outputs of both circuits, and the side difference lobe-suppressed beam forming circuit is formed based on these sum and difference signals. Has been adopted.

That is, the beam forming by the multiplication circuit 6 is N
The N / 2 channel signal R from the right half of the transmitter / receiver 1 is added / detected by the adding / detecting circuit 7 to the received signal of the channel, and N / 2 from the left half of the transmitter / receiver 1 is used. The channel signal L is also added / detected by the addition / detection circuit 8, and both detection signals are added / subtracted by the addition circuit 9 and the subtraction circuit 10 to obtain a sum beam (R + L) and a difference beam, respectively.
(RL) is obtained.

FIG. 2 shows the sum beam (R + L) and difference beam (RL) thereof. Sum beam (R + L) is simply N
It is the same as the beam obtained by combining the received signals of the channels, and in this figure, in the normal direction (0 °) of the transducer 1,
It shows the case where the main lobe M of the sum beam (R + L) is formed, and the side lobe S is derived in the left-right direction.
On the other hand, the difference beam (RL) has a level of 0 in the normal direction and peaks on the left and right sides.

From the subtraction circuit 15, (R + L)-(R-L)
Beam is output, and the beam waveform is shown in FIG. As can be seen from FIG. 3, the main beam M ′ has a narrower directional angle and the side lobes S ′ are suppressed.

[0009]

In a fish school search using such an apparatus, generally, a seafloor echo is detected larger than an echo from a school of fish. When the seafloor echo is extremely large, it will be saturated beyond the allowable level in the receiving system, and the seafloor echo will also be suppressed to a certain level, so that it will be at the same level as the fish school, and the fish school and the seabed will be distinguished. Will be difficult. In order to prevent such a problem from occurring, the preamplifier 3 and the main amplifiers 13 and 14 require cumbersome gain adjustment, and for that purpose, a gain adjustment circuit for N channels is required, which results in high cost and device Invites upsizing.

In the case of a normal amplifier circuit, a wide dynamic range can be easily achieved by using a log amplifier that outputs logarithmic values to the amplifier. However, FIG.
When the sum difference method is used for signal processing to suppress the generation of side lobes, the circuit is basically configured to function by adding and subtracting linear signals. Therefore, it cannot be used for circuits handling log signals due to the use of log amplifiers. That is, in the linear scale of FIG. 2, the level of the difference beam (RL) was 0 in the normal direction, but in the log scale, as shown in FIG.
It is not completely 0 and is only about 30 dB lower than the peak level of the sum beam (R + L). If the sum difference calculation is performed on the sum beam and the difference beam on such a log scale, the sum beam method will be used. The level in the line direction is reduced by 30 dB, and therefore the log amplifier cannot be used in the sum difference calculation circuit.

Therefore, it is an object of the present invention to provide an underwater exploration device which suppresses the generation of side lobes and narrows the width of a main lobe, and has a wide dynamic range.

[0012]

Underwater exploration apparatus of the present invention
(Claim 1) directs the received signal by applying a predetermined phase shift amount to each received signal from the ultrasonic transducer and the ultrasonic transducer. Direction control means for controlling, first beam forming means for forming a first beam by setting a predetermined weight with respect to a received signal from the direction control means, and reception by the direction control means Second beam forming means for forming a second beam by setting a predetermined weight for the signal; and a log amplifier for amplifying the first and second beams respectively and outputting them on a log scale, By performing addition and subtraction on both outputs from the log amp, or by selecting the lower level of both outputs, the main lobe has a narrow directivity angle and a beam with suppressed sidelobe level is obtained. Having beam shaping means And it features.

Underwater exploration device according to the first aspect of the present invention
(Claim 2) directs the received signal by providing a transducer comprising a plurality of ultrasonic transducers and giving a predetermined phase shift amount to each received signal from the ultrasonic transducers. And a first beam forming means for performing a control, a first beam forming means for lowering a side lobe level from a received signal from the directivity controlling means, and as a result, forming a main beam A having a wide directivity angle in the main lobe, Second beam forming means for forming a reference beam B having a wide directivity angle which is almost omnidirectional from the received signal, a log amplifier for amplifying each of the beams A and B, and outputting the log scale, and a reference beam. And subtracting the main beam A from B to obtain the beam C, and further subtracting the beam C from the main beam A to make the main lobe a narrow directional angle and to obtain a beam D with the sidelobe level suppressed. Characterize.

Underwater exploration device of the second invention according to the present invention
(Claim 3) is directed to the received and transmitted signals by applying a predetermined phase shift amount to each of the received and transmitted signals from the ultrasonic transducers and the ultrasonic transducers. Directivity control means for performing control, and first beam forming means for increasing the sidelobe level from the received signal from the directivity control means, and as a result, forming the beam X having a narrow directivity angle in the main lobe,
Second beam forming means for forming a beam Y whose side lobe has a wide directional angle by lowering the side lobe level from the received signal, and the beams X and Y are amplified respectively, and then, on a log scale. A log amplifier for outputting and a low level selecting means for selecting a lower level from both the beams X and Y to suppress the side lobe level and to obtain a beam Z having a narrow directional angle of the main lobe are provided. It is characterized by

[0015]

According to the present invention (Claim 1), two types of beams are formed from the same received signal, and both beams are added or subtracted by the beam shaping means, or both beams are added. By selecting the one with a lower level, the main lobe obtains the desired beam with the side lobe level suppressed with a narrow directivity angle.

According to the first invention (claim 2) of the present invention, the side lobe level is lowered, and as a result, the main beam A whose main lobe has a wide directional angle and the wide directional angle which is almost omnidirectional. The reference beam B is formed, these are log-scaled by a log amplifier, and the beams A and B having these log-scale values are subjected to subtraction processing as beam shaping to set a main lobe to a narrow directivity angle and a side lobe level. A beam D in which is suppressed is obtained.

In the second aspect of the present invention, the side lobe level is increased, and as a result, the beam X whose main lobe has a narrow directivity angle.
And the side lobe level is lowered, and as a result, a beam Y whose main lobe has a wide directivity angle is formed, and these are log-scaled by a log amplifier, and as beam shaping, beam X of these log-scale values, By selecting the lower level of Y, the main lobe has a narrow directivity angle, and the beam Z in which the side lobe level is suppressed is obtained.

A specific configuration based on the first invention is as follows.
Claims 4, 5 and 6 are shown, and as a concrete structure based on the second invention, it is shown in claim 7.
The following embodiments are disclosed in detail as the first, second, third embodiments of the first invention and one embodiment of the second invention.

[0019]

FIG. 5 shows a first embodiment of the first invention, and elements common to those of FIG. 1 are designated by the same reference numerals. Reference numeral 3'denotes a fixed gain preamplifier, and the adder circuits 7'and 8'reciprocally add the N-channel received signals from the multiplier circuit 6 based on the weights of weights A and B to form a beam. The output signals of both adder circuits 7'and 8'are input to gain-fixed log amplifiers 13 'and 14' through filters 11 and 12, respectively.

The beam A (referred to as the main beam) output from one of the log amplifiers 13 ′ is an addition input unit of the subtraction circuit 15.
Input to (+) and subtraction unit (-) of operational amplifier 16
Entered in. The beam B (referred to as a reference beam) output from the other log amplifier 14 ′ is input to the non-inverting input section (+) of the operational amplifier 16. The output C (= BA) of the operational amplifier 16 is the inverting input section of the subtraction circuit 15.
Input to (-). G is a gain adjusting resistor of the operational amplifier amplifier 16. Output D (= A-C) of the subtraction circuit 15
Are supplied to the CRT.

The operation of the above device will be described below. When the beam combining in adder circuit 7 ', as the main beam A in FIG. 6, the side lobe level S ₁ is set a wait A to be lower, as a result, the directivity angle of the main lobe M ₁ is slightly Get wider In addition, in the beam combining of the adder circuit 8 ', the weight B is set so as to have a wide directivity angle which is almost omnidirectional like the reference beam B.

These main beam A and reference beam B
Is output as a detection signal on the log scale by being amplified by the log amplifiers 13 ′ and 14 ′, and is input to the operational amplifier 16. As shown in FIG. 6, if the levels of both beams A and B are the same in the normal direction, the output C from this operational amplifier 16 becomes 0 in the normal direction, as shown in FIG. , A relatively high level side lobe S ₃ is generated in the left and right directions. Subtraction circuit 15
When the beams A and C as shown in FIG. 8 are input to the adder (+) and the subtractor (−) of FIG. 8, the output D = A−C of the subtractor 15 is shown in FIG. As described above, the main lobe M ₄ has a narrow directivity angle, and the side lobe S _{4 is}
Is suppressed to a fairly low level. By changing the level of the beam C by the adjusting resistor G as shown by the broken line C ′ in FIG. 8, it is possible to narrow the beam directivity angle and adjust the sidelobe level suppression as shown in FIG. Of course,
It goes without saying that the adoption of the log amp has a wide dynamic range characteristic that is free from gain adjustment and is not saturated even with an excessive level signal.

The output signals of the log amplifiers 13 'and 14' may be converted into digital signals, and the addition / subtraction calculation in the operational amplifier 16 and the subtraction circuit 15 may be performed using a DSP (digital signal processor).

The wave transmitter / receiver 1 of FIG. 5 may have N ultrasonic transducers arranged in a straight line, but may have an arc shape. That is, the transducers are arrayed on the circumference (on a cylindrical body because of the necessity of beam combining in the vertical direction when giving a depression angle), and N transducers on an arc among them are detected as one group to detect signals. In the case of a scanning sonar that sequentially retrieves all directions, the detection signals from N oscillators may be captured in the trap circuit 2 in FIG.

In FIG. 5, predetermined weights A and B are set in the adder circuits 7'and 8'for forming the main beam A and the reference beam B (FIG. 2), but beam forming is performed by another method. A circuit to be executed is shown in FIG. 10 as a second embodiment of the first invention. By adding signals for all N channels to the adder circuit 7 ', and for example, signals for 3 channels to the adder circuit 8', by changing the substantial length of the transmitter / receiver 1, the adder circuit 7'can be used to The main beam A as shown in 6 is outputted, and the reference beam B is outputted from the adding circuit 8 '. In FIG. 10, a predetermined weight can be set for the adder circuits 7'and 8'to obtain a more preferable beam shape.

As can be seen from the flow of FIGS. 6 to 9, the main lobe M ₂ of the reference beam B needs to have a broad directivity angle. However, in the circuit configurations shown in FIG. 5 and FIG. 10, when received signals arrive from multiple directions at the same time, a level dip may occur in a certain direction in the main lobe M ₂ of the reference beam B in FIG. In that case, the level reduction cannot be expected in the side lobe S corresponding to the depressed portion. Therefore, even if a level drop occurs in the main lobe M ₂ of the reference beam B, it is necessary to devise a device that does not adversely affect the suppression of the side lobe. A circuit configuration therefor is shown in FIG. 11 as the third embodiment of the first invention. Is shown in.

The difference from FIG. 10 is that, in order to obtain the reference beams B ₁ and B ₂ of two systems, apart from the processing circuits of 8 ′, 12 and 14 ′, they are composed of 8 ″, 12 ′ and 14 ″. Two processing circuits are provided, and the output sections of both processing circuits are respectively connected to the non-inverting input section (+) of the operational amplifier 16 via the diode D.
Further, since it is necessary to specify the channels to be taken in by the first and second processing circuits, the number N of transducers of the transceiver 1 is set to 12 here. Similar to FIG. 11, all 12 channels of signals are input to the adder circuit 7 ', but three channels 5, 6, and 7 are input to the adder circuit 8', and channels are input to the adder circuit 8 ". 4, 5, 6, 7 4
The channel is input.

It is desirable that the adder circuit 8'acquires the three channels (CH5, 6, 7) located at the center of all 12 channels, and the other adder circuit 8 "takes in the channels. Any series of channels adjacent to each other, such as CH4 to CH7, may be used.

Now, as shown in FIG. 12, the reference beam B2 based on the channels 5, 6, 7 has a different level dip in a certain direction, but the reference beams B2 generated by the channels 4, 5, 6, 7 are different. As shown in the figure, the level drop is unlikely to occur in the same direction as described above. Therefore, if the OR sum is obtained by the diode D, a uniform sublobe B without level dip can be obtained as shown in FIG. 13, and the reference beam B is added to the addition section (+) of the operational amplifier 16.
Input to the sublobe S _{4 as} shown in FIG.
Is sufficiently suppressed, and the main lobe M ₄ has a narrow directivity angle.

In FIG. 5 and FIG. 11, the sum / difference operation is performed for narrowing the main lobe and suppressing the side lobe.
This can also be achieved by forming two different beams, extracting the lower sidelobe from both beams, and extracting the narrower mainlobe.
An embodiment of the invention is shown in FIG. This FIG.
In FIG. 5, elements common to those in FIG. 5 are denoted by common reference numerals.

In beam combining in the adder circuit 7 ', as shown by the beam X in FIG. 15, the side lobe S ₅ has a high level but the main lobe M ₅ has a narrow directivity angle.
Weight X is set, whereas, in the beam combining in adder circuit 8 ', as shown by the beam Y, so that the main lobe M ₆ is a wide directivity angle sidelobe levels S ₆ decreases, weight Y is set.

The beam X from the log amplifier 13 'is input to the non-inverting input section (+) of the operational amplifier 16'. Between the inverting input (-) and the output of this operational amplifier 16 ',
The diode D is connected with the cathode on the output side.
On the other hand, the beam Y from the log amplifier 14 ′ is input to the non-inverting input section (+) of the operational amplifier 16 and the operational amplifier 1
A diode D is connected between the inverting input section (-) of 6 and the output section with the cathode on the output side. The anodes of both diodes D are connected to each other, and their interconnection point is further connected to the line of the DC voltage V via the resistor R. The interconnection point becomes the output terminal of the device.

In the circuit of FIG. 14, the operational amplifier 16 '
The beam X shown in FIG. 15 is input to the non-inverting input section (+) of the above, and the beam Y is input to the non-inverting input section (+) of the operational amplifier 16. Saburobu S5, S6, as shown in Figure 15, when towards the beam Y is lower level than the beam X, only the diode D of the subtractor circuit 16 is switched on, the side lobes S ₆ of the beam Y is output to the output terminal, and , When the level of the beam X is lower than that of the beam Y like the main lobes M5 and M6, only the diode D of the operational amplifier 16 'is switched on, and the main lobe M ₅ of the beam X is output to the output terminal. Therefore, as shown in FIG. 16, a beam Z composed of a main lobe M ₅ having a narrow directivity angle and a side lobe S ₆ whose level is suppressed is output to the output terminal.

[0034]

According to the present invention, two types of beams are formed from the same received signal, and the beam shaping means performs addition and subtraction on both beams, or a beam having a lower level from both beams is detected. By selecting, the desired beam with the main lobe suppressing the side lobe level with a narrow directional angle is obtained. In the first aspect of the present invention, the side lobe level is lowered, and as a result, the main beam A whose main lobe has a wide directional angle and the reference beam B having a wide directional angle which is almost omnidirectional are formed. By making log-scale and performing subtraction processing on these beams A and B as beam shaping, a beam D in which the main lobe is set to a narrow directivity angle and the side lobe level is suppressed is obtained. The display of the virtual image of the seabed due to the side lobes can be suppressed, and a wide dynamic range that does not saturate even high level signals can be achieved. A second invention according to the present invention increases the sidelobe level, and as a result,
A beam X whose main lobe has a narrow directional angle and a beam Y whose side lobe level is low and whose main lobe has a wide directional angle are formed into a log scale for beam shaping. , Y, the lower level is selected to obtain a beam Z in which the main lobe has a narrow directivity angle and the sidelobe level is suppressed.
Although it has a simple structure, the same effect as the first invention can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a receiving circuit system of a conventional underwater exploration device.

2 is a waveform diagram showing a sum beam and a difference beam in FIG.

FIG. 3 is a waveform diagram when a difference beam is subtracted from the sum beam of FIG.

FIG. 4 is a waveform diagram showing a sum beam and a difference beam on a log scale.

FIG. 5 is a block diagram showing a receiving system of a first embodiment of the first invention.

6 is a main beam A and a reference beam B in FIG.
Waveform diagram showing

7 is a waveform diagram of beam C when main beam A is subtracted from reference beam B in FIG.

FIG. 8 is a waveform diagram showing the main beam A and the beam C of FIG. 7.

FIG. 9: Beam waveform diagram when beam C is subtracted from main beam A

FIG. 10 is a block diagram showing a receiving system of a second embodiment of the first invention.

FIG. 11 is a block diagram showing a receiving system of a third embodiment of the first invention.

FIG. 12 is a waveform diagram of reference beams B1 and B2 in FIG.

FIG. 13 is a waveform diagram of the OR sum of the reference beam B1 and the reference beam B2.

FIG. 14 is a block diagram showing a receiving system according to an embodiment of the second invention.

FIG. 15 is a waveform diagram of beam X and beam Y in FIG.

16 is a waveform diagram of a beam Z output from the device of FIG.

[Explanation of symbols]

1 Transceiver 2 trap circuit 3'preamp 4 filters 5 Carrier generation circuit 6 Multiplier circuit 7'adder circuit 8'addition circuit 11 filters 12 filters 13 'log amplifier 14 'log amplifier 15 Subtraction circuit 16 operational amplifier

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-2-209135 (JP, A) JP-A-3-15455 (JP, A) JP-A-52-127024 (JP, A) JP-A-6- 94827 (JP, A) JP-A-54-111372 (JP, A) Fukukaihei 4-85284 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01S 3/80-3 / 86 G01S 5/18-5/30 G01S 7/52-7/64 G01S 15/00-15/96 A61B 8/00

Claims (7)

(57) [Claims] 1. A wave transmitter / receiver comprising a plurality of ultrasonic transducers, and by giving a predetermined phase shift amount to each received signal from the ultrasonic transducers, directivity control of the received signal is performed. Direction control means for performing, first beam forming means for forming a first beam by setting a predetermined weight on the received signal from the direction control means, and the received signal from the direction control means Second beam forming means for forming a second beam by setting a predetermined weight, a log amplifier for amplifying the first and second beams, and outputting the log scale with a log scale; and a log amplifier. By performing addition and subtraction on both outputs, or by selecting the lower level of both outputs, the main lobe has a narrow directivity angle and beam shaping that obtains a beam with suppressed sidelobe levels Having means Underwater exploration device featuring. 2. A direction control of a received signal is performed by giving a predetermined phase shift amount to each received signal from the ultrasonic transducer and a plurality of ultrasonic transducers. The directing control means for performing the first beam forming means for lowering the sidelobe level from the received signal from the directivity controlling means, and as a result, forming the main beam A having a wide directivity angle in the main lobe; From the reference beam B, the second beam forming means for forming the reference beam B having a wide directional angle which is almost omnidirectional from the signal, the log amplifier for amplifying the beams A and B, and outputting the amplified beams at the log scale, A subtracting means for subtracting the main beam A to obtain the beam C, and further subtracting the beam C from the main beam A to make the main lobe a narrow directional angle and obtaining the beam D in which the side lobe level is suppressed. Underwater exploration device. 3. A wave transmitter / receiver comprising a plurality of ultrasonic transducers, and by giving a predetermined phase shift amount to each received signal from the ultrasonic transducers, directivity control of the received signal is performed. Directing control means for performing, and a first beam forming means for increasing the side lobe level from the received signal from the directing control means, and as a result, forming a beam X whose main lobe has a narrow directivity angle,
Second beam forming means for forming a beam Y whose side lobe has a wide directional angle by lowering the side lobe level from the received signal, and the beams X and Y are amplified respectively, and then, on a log scale. A log amplifier for outputting and a low level selecting means for selecting a lower level from both the beams X and Y to suppress the side lobe level and to obtain a beam Z having a narrow directional angle of the main lobe are provided. An underwater exploration device characterized in that 4. A handset comprising a plurality of N ultrasonic transducers.
(1), and pointing control means (5, 6) for performing pointing control of the received signal by giving a predetermined phase shift amount to each received signal from the ultrasonic transducer, and pointing control means The first beam forming means (7) for forming the main beam A whose main lobe has a wide directivity angle and the sidelobe level for the received signal is substantially omnidirectional. Second beam forming means (8) for forming a reference beam B having a wide directivity angle close to, and log amplifiers (13 ', 14') for amplifying the beams A, B respectively and outputting them on a log scale, Subtraction means for subtracting the main beam A from the reference beam B having a log scale value to obtain the beam C, and further subtracting the beam C from the main beam A to obtain a beam D having a low sidelobe level and a narrow directivity angle as the main lobe. An underwater exploration device comprising (15, 16). 5. The transmitter / receiver (1) for weighting a received signal and / or limiting the number of channels to be referred to among received signals of N channels by said beam forming means (7, 8). 5. The underwater exploration device according to claim 4, wherein the actual length is changed. 6. When the beam forming means (7, 8) changes the substantial length of the wave transmitter / receiver (1) among the received signals of N channels by limiting the number of channels to be referred to, different channel configurations are performed. The reference beams B ₁ and B ₂ are formed on the basis of the two groups, and the OR sum of the two beams B ₁ and B ₂ is added to the reference beam B.
The underwater exploration device according to claim 4, which is adopted as. 7. A handset comprising a plurality of N ultrasonic transducers.
(1), and pointing control means (5, 6) for performing pointing control of the received signal by giving a predetermined phase shift amount to each received signal from the ultrasonic transducer, and pointing control means The first beam forming means (7) for increasing the side lobe level from the received signal and forming the beam X whose main lobe has a narrow directivity angle, and the lower side lobe level from the received signal. As a result, a second beam forming means (8) for forming a beam Y whose main lobe has a wide directional angle and a log amplifier (13 'for amplifying the beams X and Y respectively and outputting them on a log scale. , 14 ') and a lower level from both the beams to lower the side lobe level and obtain a beam Z having a narrow directional angle of the main lobe.
(16, 16 ', D, R) is provided with the underwater exploration device.