JP4955345B2 - Underwater detection device and underwater detection method - Google Patents

Description

  The present invention relates to an underwater detection device such as a scanning sonar that detects underwater by transmitting and receiving ultrasonic waves.

  Scanning sonar is used to detect underwater targets. In the scanning sonar, as shown in FIG. 1, there are a horizontal mode in which detection is performed in a whole tilt direction at a predetermined tilt angle, and a vertical mode in which a tilt angle is increased to detect a fan-shaped cross section in a substantially vertical direction. The horizontal mode is mainly used to detect targets within a predetermined range around the ship, and the vertical mode is mainly used to detect targets within a range extending almost directly below the ship. Used for.

Either one of the horizontal mode and the vertical mode is normally set according to the detection purpose. However, there is a case where it is desired to simultaneously detect the vicinity of the ship along with the detection of the area around the ship. In order to meet such demands, there is a mode called a horizontal / vertical combined mode in which a detection image in the horizontal mode and a detection image in the vertical mode are simultaneously displayed on a single display screen. Patent Document 1 and Patent Document 2 disclose an underwater detection device for realizing a horizontal / vertical composite mode.
JP 2003-202370 A JP2004-347319

  In order to realize the horizontal / vertical combined mode, the underwater detection device forms a first transmission beam directed in the horizontal direction and a second transmission beam directed in the vertical direction. Further, in order to eliminate the time lag of the detection from these two transmission beams, it is necessary to make these transmission intervals as short as possible. However, when the transmission interval is shortened, the second transmission beam is formed with the voltage of the capacitor and the like after the first transmission beam is formed. Since the capacitor voltage drops to form a transmit beam, the second transmit beam will have a lower output than the first transmit beam. Even if echoes from the same target are received with respect to such a transmission beam, their reception intensities are different. This causes a difference in sensitivity when the target is displayed as an image, and is inconvenient for the user and the like because it is difficult to visually recognize the corresponding target in the image display in each mode.

  The present invention has been made in view of such a problem. Even when a plurality of transmission beams are continuously formed as in the horizontal / vertical combined mode, the sensitivity of the detection image obtained with respect to the transmission beams is improved. The aim is to reduce the difference. By extension, it is an object to provide an underwater detection device that is convenient for the user.

In order to solve the above-described problem, an underwater detection apparatus that performs underwater detection by transmitting and receiving beams according to the present invention includes an oscillator that sequentially transmits N (N is a natural number) transmission beams having different transmission frequencies, and the oscillator A transmission amplifier that amplifies a transmission signal for driving the power supply, a capacitor that stores power required for the transmission amplifier to amplify the transmission signal, and a frequency component corresponding to the transmission frequency of the N transmission beams. A filter for extracting a signal, a first voltage which is a voltage of the capacitor when transmitting the first transmission beam, and an M-th transmission beam (M is an integer of 2 to N) A gain correction unit that corrects the gain of the received signal corresponding to the Mth transmission beam based on the Mth voltage that is the voltage of the capacitor, and the Mth voltage is up to M−1th . The voltage is lower than the first voltage as the transmission beam is transmitted.

Furthermore, in the above-described underwater detection device, the gain correction unit corrects a gain of a reception signal corresponding to the Mth transmission beam based on a ratio between the first voltage and the Mth voltage . And

Further, the gain correction unit may determine the Mth based on the ratio of the average voltage of the capacitor when transmitting the first transmission beam and the average voltage of the capacitor when transmitting the Mth transmission beam. The gain of the received signal corresponding to the second transmission beam is corrected.

Furthermore, the vibrator transmits N transmission beams having different transmission frequencies in a vertical direction and a horizontal direction.
In order to solve the above problem, an underwater detection method for detecting underwater by transmitting and receiving a beam in the present invention includes a step of sequentially transmitting N (N is a natural number) transmission beams having different transmission frequencies, and an oscillator. A step of amplifying a transmission signal for driving the transmission signal, a step of storing power required for the transmission amplifier to amplify the transmission signal, and a reception signal for each frequency component corresponding to the transmission frequency of the N transmission beams. A step of extracting, a first voltage which is a voltage of a capacitor when transmitting the first transmission beam, and a capacitor of the capacitor when transmitting the Mth transmission beam (M is an integer of 2 to N). Correcting the gain of the received signal corresponding to the Mth transmission beam based on the Mth voltage, which is a voltage, wherein the Mth voltage is the transmission of the M-1th transmission beam. With the first The voltage is lower than the voltage.
In order to solve the above-described problem, an underwater detection apparatus that performs underwater detection by transmitting and receiving a beam according to the present invention includes: a first transmission beam amplified by power accumulated in a capacitor; the first transmission beam; Is a transmitter for sequentially transmitting second transmission beams having different frequencies, a first reception signal corresponding to the frequency of the first transmission beam, and a second corresponding to the frequency of the second transmission beam. A reception unit that receives each of the reception signals; and a gain correction unit that corrects the gain of the second reception signal based on the voltage of the capacitor that has decreased due to the transmission of the first transmission beam. Features.
Furthermore, the transmission unit includes an amplifier that amplifies a transmission signal with the power accumulated in the capacitor, and a vibrator that transmits a transmission beam based on the amplified transmission signal.
In order to solve the above problem, an underwater detection method for detecting underwater by transmitting and receiving a beam according to the present invention includes a first transmission beam amplified by power accumulated in a capacitor, the first transmission beam, Sequentially transmits a second transmission beam having a different frequency, a first reception signal corresponding to the frequency of the first transmission beam, and a second reception corresponding to the frequency of the second transmission beam. Receiving each of the signals, and correcting the gain of the second received signal based on the voltage of the capacitor that has decreased with the transmission of the first transmission beam.
In order to solve the above-described problem, an underwater detection apparatus that performs underwater detection by transmitting and receiving a beam according to the present invention includes: a first transmission beam amplified by power accumulated in a capacitor; the first transmission beam; Is a transmitter for sequentially transmitting second transmission beams having different frequencies, a first reception signal corresponding to the frequency of the first transmission beam, and a second corresponding to the frequency of the second transmission beam. A receiving unit that respectively receives a reception signal, a storage unit that stores information on a gain to be corrected based on the voltage of the capacitor that decreases with transmission of the first transmission beam, and a gain that is to be corrected And a gain correction unit that corrects the gain of the second received signal based on the information.
In order to solve the above problem, an underwater detection method for detecting underwater by transmitting and receiving a beam according to the present invention includes a first transmission beam amplified by power accumulated in a capacitor, the first transmission beam, Sequentially transmits a second transmission beam having a different frequency, a first reception signal corresponding to the frequency of the first transmission beam, and a second reception corresponding to the frequency of the second transmission beam. Each of a signal, a step of storing gain information to be corrected based on a voltage of the capacitor that decreases with transmission of the first transmission beam, and a basis of the gain information to be corrected And a step of correcting the gain of the second received signal.

  According to the present invention, even if a plurality of transmission beams are continuously formed as in the horizontal / vertical composite mode, the difference in sensitivity of the detection image obtained with respect to the transmission beams can be reduced. As a result, an underwater detection device that is highly convenient for the user can be provided.

(Embodiment 1)
Hereinafter, the underwater detection device 100 according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 2 is a diagram showing an example of the configuration of the underwater detection device 100 according to Embodiment 1 of the present invention.

  The underwater detection device 100 includes a voltage monitoring unit 1, a gain correction unit 2, a transmission power source 10, a capacitor 11, a transmission amplifier 12, a reception amplifier 20, a first filter 21, a first amplifier 22, a second filter 23, and a second filter. The amplifier 24 includes a transmission / reception unit 30 and a transmission / reception switching unit 31.

  The transmission power supply 10 supplies power to the capacitor 11. The capacitor 11 stores the power supplied from the transmission power supply 10. At this time, by reducing the power per unit time that the transmission power supply 10 supplies to the capacitor 11, the size of the transmission power supply 10 itself can be reduced. Therefore, in order to reduce the size of the underwater detection device 100, it is preferable to reduce the power per unit time supplied by the transmission power supply 10. The power stored in the capacitor 11 is used to form a transmission beam.

  The transmission amplifier 12 amplifies a drive waveform (transmission signal) for driving each transducer provided in the transmission / reception unit 30. The transmission signal amplified by the transmission amplifier 12 drives a transducer provided in the transmission / reception unit 30 via the transmission / reception switching unit 31, and an ultrasonic signal (transmission beam) is transmitted into the water.

  Hereinafter, the operation of the underwater detection apparatus 100 during the transmission beam forming period will be described with reference to FIG. FIG. 3 is a diagram illustrating the relationship between the transmission signal, the accumulated power of the capacitor 11, and the transmission beam when two types of transmission beams are transmitted continuously, and FIG. ) Indicates the accumulated power of the capacitor 11, and FIG. 3 (c) indicates the transmission beam. The horizontal axis represents time, and the vertical axis represents amplitude in FIGS. 3A and 3B, and FIG. 3C represents voltage value.

  As shown in FIG. 3A, when two types of transmission beams are to be transmitted continuously, transmission signals having two types of frequencies (f1 and f2) are formed. For example, when realizing a horizontal / vertical combined mode, a transmission beam formed based on a transmission signal of one frequency f1 (for example, 23 kHz) is used for a horizontal mode for detecting the surrounding direction of the ship, The transmission beam formed based on the transmission signal of the other frequency f2 (for example, 25 kHz) is used for the vertical mode in which detection is performed directly below the ship.

  When the transmission signal having the frequency f1 is input to the transmission amplifier 12, the transmission amplifier 12 amplifies the transmission signal using the power accumulated in the capacitor 11. The transducer provided in the transmission / reception unit 30 is driven by the amplified transmission signal, and a transmission beam having a frequency f1 as shown in FIG. 3C is transmitted into the water. At this time, the voltage of the capacitor 11 decreases from V1 to V2 as shown in FIG. 3B (between AB in FIG. 3).

  Subsequently, when the transmission signal having the frequency f <b> 2 is input to the transmission amplifier 12, the transmission amplifier 12 amplifies the transmission signal by using the remaining power accumulated in the capacitor 11. The transducer provided in the transmission / reception unit 30 is driven by the amplified transmission signal, and a transmission beam having a frequency f2 as shown in FIG. 3C is transmitted into the water. At this time (t = C), the voltage of the capacitor 11 is substantially the same as V2 after the voltage drop because the transmission interval of the transmission signals of the frequencies f1 and f2 is extremely short. For this reason, as shown in FIG. 3C, the amplitude of the transmission beam having the frequency f2 is smaller than the amplitude of the transmission beam having the frequency f1.

  Here, FIG. 4 shows in detail the displacement of the voltage of the capacitor 11 when the transmission beam is formed (between AD in FIG. 4). As shown in FIG. 4, the voltage of the capacitor 11 is kept at V1 until the start of the first transmission (t = A). This V1 is equal to the capacity of the capacitor 11. Then, at the end of the first transmission (t = B), the voltage of the capacitor 11 decreases to V2 '. Subsequently, by the time power is stored in the capacitor 11 from the transmission power supply 10 by the start of the second transmission (t = C), the voltage rises to V2. Then, at the end of the second transmission (t = D), the voltage of the capacitor 11 decreases to V3.

  Thus, the voltage rises as power is stored in the capacitor 11 from the transmission power source 10 until the transmission beam of the frequency f2 is transmitted (between BCs in FIG. 4) after the transmission of the transmission beam of the frequency f1. However, since the capacity of the transmission power supply 10 is small and the interval between BCs is short, the increase in the voltage may be ignored (V2 ′ = V2).

  Next, the operation of the underwater detection device 100 during the reception beam forming period will be described. The voltage of the capacitor 11 that has dropped to form the transmission beam rises during the reception beam formation period (between DF) as shown in FIG. The voltage of the capacitor 11 is constant between the EFs, but the voltage rise can be configured more gently as the E point can be brought closer to the F point. That is, the capacity of the transmission power source 10 can be reduced, and the size of the underwater detection device can be reduced.

  The transmission / reception unit 30 forms a reception beam for receiving an echo of the transmission beam during the reception beam forming period. The reception beam is formed with a predetermined directivity angle, and its irradiation direction is sequentially rotated. Thus, the direction in which the target exists can be specified by performing the detection in all directions sequentially.

  The transmission / reception switching unit 31 guides the transmission signal output from the transmission amplifier 12 to the transmission / reception unit 30 during the transmission beam forming period. Further, the reception signal output from the transmission / reception unit 30 is guided to the reception amplifier 20 during the reception beam forming period.

  The first filter 21 and the second filter 23 separate the reception signal amplified by the reception amplifier 20 into desired frequency components. The first filter 21 removes a band other than the frequency f1 as a noise component. Therefore, only the echo corresponding to the transmission beam formed at the frequency f1 can be extracted, and a reception signal for drawing the horizontal mode can be obtained. Similarly, the second filter 23 removes a band other than the frequency f2 as a noise component. Therefore, only the echo corresponding to the transmission beam formed at the frequency f2 can be extracted, and a reception signal for drawing the vertical mode can be obtained.

  The first amplifier 22 amplifies the reception signal output from the first filter 21. The reception signal amplified by the first amplifier 22 is subjected to a drawing process and drawn as a horizontal mode image.

  The second amplifier 24 amplifies the reception signal output from the first filter 21 based on a correction coefficient from the gain correction unit 2 described later. The reception signal amplified by the second amplifier 24 is subjected to a drawing process and drawn as an image for the vertical mode.

  The voltage monitoring unit 1 monitors the displacement of the voltage of the capacitor 11 shown in FIG. Then, the voltage monitoring unit 1 outputs to the gain correction unit 2 the voltage value (transmission voltage) of the capacitor 11 when the transmission beam having the frequency f1 and the frequency f2 is formed.

  The gain correction unit 2 corrects the gain of the second amplifier 24 based on the voltage of the capacitor 11 monitored by the voltage monitoring unit 1. Specifically, the ratio of the voltage of the capacitor 11 at the start of transmission of the transmission beam having the frequency f1 and the transmission beam having the frequency f2 is used as a correction coefficient. That is, the gain of the second amplifier 24 is multiplied by a value calculated from V1 / V2 shown in FIG. Therefore, when the gain of the first amplifier 22 is G1, the corrected gain G2 of the second amplifier 24 is G2 = G1 × (V1 / V2). As a result, the gain of the received signal extracted based on the transmission frequency of each transmission beam does not differ due to the magnitude of the transmission voltage.

  Further, the correction performed by the gain correction unit 2 may be a ratio of the average value of the voltage of the capacitor 11 that is displaced when transmitting the transmission beam having the frequency f1 and the transmission beam having the frequency f2. That is, when the time between AB and CD shown in FIG. 3B is equal, the gain of the second amplifier 24 may be multiplied by a value calculated from (V1 + V2) / (V2 + V3).

  Furthermore, the correction performed by the gain correction unit 2 may be a ratio of the average value of the voltage of the capacitor 11 immediately after transmission of the transmission beam having the frequency f1 and the transmission beam having the frequency f2. That is, the gain of the second amplifier 24 may be multiplied by a value calculated from V2 / V3 shown in FIG.

  Further, the correction performed by the gain correction unit 2 uses a ratio of a value obtained by integrating the voltage of the capacitor 11 that is displaced when transmitting the transmission beam having the frequency f1 and the transmission beam having the frequency f2 for each transmission time as a correction coefficient. Also good. That is, it may be a ratio of the area surrounded by abcd and the area surrounded by efgh shown in FIG. By using this area ratio, the correction coefficient can be brought close to the transmission power ratio of the transmission beam, and the sensitivity difference in the detected image can be further reduced.

  When a correction coefficient such as V1 / V2 is equal in each transmission beam forming period, the gain correction unit 2 uses a predetermined correction value set in advance without monitoring the voltage by the voltage monitoring unit 1. Can do. For example, a table 3 can be used instead of the voltage monitoring unit 1 as shown in FIG.

  Table 3 has information on the gain to be corrected by the second amplifier 24 by the gain correction unit 2. This information is, for example, a matrix composed of transmission frequencies and detection ranges of transmission beams and correction coefficients corresponding to them. Here, if the transmission frequency is different, the gain of the transmission signal to be amplified is different, so that the power required to amplify the transmission signal is different. Also, if the detection range is different, since the transmission time of the transmission signal is different, similarly, the required power is different. In particular, the detection range can be arbitrarily changed by the user, but appropriate gain correction can be performed by using such a matrix prepared in advance.

  With the configuration as described above, the gain of the reception signal corresponding to the transmission signal can be corrected based on the voltage corresponding to each transmission signal, and the sensitivity error generated when displaying the image of the same target can be improved. it can.

(Embodiment 2)
Hereinafter, an underwater detection device 200 according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 7 is a diagram showing an example of the configuration of the underwater detection apparatus 200 according to Embodiment 2 of the present invention. The description of the same configuration as that of the first embodiment is omitted.

  In the first embodiment, the underwater detection device 100 that performs detection in two modes, the vertical mode and the horizontal mode, has been described. However, the present invention performs detection simultaneously for a plurality of cross sections having different tilt angles only in the horizontal mode. The same applies to the case.

  For example, FIG. 6 shows an example in which three lateral transmission beams having different tilt angles are transmitted simultaneously. These three transmission beams H1, H2, and H3 have different transmission frequencies and detection ranges. When receiving beams are formed, frequency components corresponding to the transmission frequencies of the three transmission beams H1, H2, and H3 are used as reception signals, respectively. Extract.

  The first filter 21, the second filter 23, and the third filter 25 separate the reception signal amplified by the reception amplifier 20 into desired frequency components. The first filter 21 removes a band other than the transmission frequency of the transmission beam H1 as a noise component, and obtains a reception signal for rendering the horizontal mode 1. Similarly, the second filter 23 and the third filter 25 remove bands other than the transmission frequencies of the transmission beam H2 and the transmission beam H3 as noise components, respectively, and receive reception signals for drawing the horizontal mode 2 and the horizontal mode 3. obtain.

  The first amplifier 22 amplifies the reception signal output from the first filter 21. The reception signal amplified by the first amplifier 22 is subjected to drawing processing and drawn as an image for horizontal mode 1 (H1).

  The second amplifier 24 and the third amplifier 26 amplify the reception signals output from the second filter 23 and the third filter 25, respectively, based on the correction coefficient from the gain correction unit 2. The reception signals amplified by the second amplifier 24 and the third amplifier 26 are subjected to drawing processing, and are drawn as images for horizontal mode 2 (H2) and horizontal mode 3 (H3).

  The voltage monitoring unit 4 monitors the displacement of the voltage of the capacitor 11. Then, the voltage monitoring unit 4 outputs the voltage value (transmission voltage) of the capacitor 11 when transmitting the transmission beams H1, H2, and H3 to the gain correction unit 2.

  The gain correction unit 5 corrects the gains of the second amplifier 24 and the third amplifier 26 based on the voltage of the capacitor 11 monitored by the voltage monitoring unit 4. Specifically, the gain of the second amplifier 24 is multiplied by the ratio of the voltage of the capacitor 11 at the start of transmission of the transmission beam H1 and the transmission beam H2. Further, the gain of the third amplifier 26 is multiplied by the ratio of the voltage of the capacitor 11 at the start of each transmission of the transmission beam H1 and the transmission beam H3. As a result, the gain of the received signal extracted based on the transmission frequency of each transmission beam does not differ due to the magnitude of the transmission voltage.

  In addition, when a plurality of vertical transmission beams having different azimuth angles are formed, a plurality of vertical transmission beams having different azimuth angles and a plurality of horizontal transmission beams having different tilt angles may be formed. The present invention can be applied similarly to the above example. In the first and second embodiments, the gain obtained from the second and subsequent transmission beams is corrected with reference to the gain obtained from the first transmission beam. Not lost.

  Furthermore, although the above example showed the case where the detection image in the cross section by a transmission beam was obtained by scanning the inside of the transmission beam with a certain breadth with a reception beam, this invention is such a detection image. It is not limited to transmission / reception of ultrasonic signals for formation. For example, it is also effective in the case where transmission / reception of tidal current measurement ultrasonic signals and transmission / reception of fish detection ultrasonic signals are performed in parallel with the detection operation as a scanning sonar. In other words, transmission / reception of tidal current measurement ultrasonic signals, transmission / reception of fish detection ultrasonic signals, and transmission / reception for scanning sonar detection are performed by using different ultrasonic signal frequencies. You may make it carry out simultaneously.

  In addition, for example, when receiving a signal from another ultrasonic signal transmission device such as a netsonde or a net recorder, a signal transmitted from the ultrasonic signal transmission device is used as the frequency of the transmission / reception signal for target detection. By changing the frequency, the detection can be performed without interference.

It is a conceptual diagram showing the detection area | region in an underwater detection apparatus. It is a figure showing the structure of the underwater detection apparatus by Embodiment 1 of this invention. It is a figure showing the voltage of the transmission signal and capacitor | condenser in an underwater detection apparatus. It is a figure showing the voltage of the capacitor | condenser in an underwater detection apparatus. It is a figure showing the structure of the underwater detection apparatus by Embodiment 1 of this invention. It is a conceptual diagram showing the detection area | region in an underwater detection apparatus. It is a figure showing the processing structure of the received signal of the underwater detection apparatus by Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Voltage monitoring part 2 Gain correction part 3 Table 4 Voltage monitoring part 5 Gain correction part 10 Transmission power supply 11 Capacitor 12 Transmission amplifier 20 Reception amplifier 21 First filter 22 First amplifier 23 Second filter 24 Second amplifier 25 Third filter 26 Third amplifier 30 Transmission / reception switching unit 31 Transmission / reception unit 100 Underwater detection device 200 Underwater detection device

Claims (10)

In an underwater detection device that detects underwater by transmitting and receiving beams,
An oscillator for sequentially transmitting N (N is a natural number) transmission beams having different transmission frequencies;
A transmission amplifier for amplifying a transmission signal for driving the vibrator;
A capacitor for storing power required for the transmission amplifier to amplify the transmission signal;
A filter for extracting a reception signal for each frequency component corresponding to the transmission frequency of the N transmission beams;
The first voltage, which is the voltage of the capacitor when transmitting the first transmission beam, and the first voltage, which is the voltage of the capacitor when transmitting the Mth transmission beam (M is an integer of 2 to N). A gain correction unit that corrects the gain of the reception signal corresponding to the Mth transmission beam based on the M voltage,
The underwater detection device, wherein the Mth voltage is lower than the first voltage with the transmission of M-1th transmission beams. The underwater detection device according to claim 1,
The underwater detection device, wherein the gain correction unit corrects a gain of a reception signal corresponding to the Mth transmission beam based on a ratio between the first voltage and the Mth voltage. The underwater detection device according to claim 1,
The gain correction unit is configured to determine the Mth-th order based on a ratio between the average voltage of the capacitor when transmitting the first transmission beam and the average voltage of the capacitor when transmitting the Mth transmission beam. An underwater detection apparatus that corrects a gain of a reception signal corresponding to a transmission beam. The underwater detection device according to any one of claims 1 to 3,
The underwater detection device, wherein the vibrator transmits N transmission beams having different transmission frequencies in a vertical direction and a horizontal direction. In the underwater detection method that detects underwater by transmitting and receiving beams,
Sequentially transmitting N (N is a natural number) transmission beams having different transmission frequencies;
Amplifying a transmission signal for driving the vibrator ;
Storing power required for a transmission amplifier to amplify the transmission signal;
Extracting a received signal for each frequency component corresponding to the transmission frequency of the N transmission beams;
The first voltage, which is the voltage of the capacitor when transmitting the first transmission beam, and the Mth voltage, which is the voltage of the capacitor when transmitting the Mth transmission beam (M is an integer of 2 to N). Correcting the gain of the received signal corresponding to the Mth transmit beam based on the voltage,
The underwater detection method, wherein the Mth voltage is lower than the first voltage with transmission of M-1th transmission beams. In an underwater detection device that detects underwater by transmitting and receiving beams,
A transmitter that sequentially transmits a first transmission beam and a second transmission beam having a frequency different from that of the first transmission beam, amplified by the power accumulated in the capacitor;
A receiving unit for receiving a first reception signal corresponding to the frequency of the first transmission beam and a second reception signal corresponding to the frequency of the second transmission beam;
An underwater detection device comprising: a gain correction unit that corrects the gain of the second reception signal based on the voltage of the capacitor that has decreased as a result of transmission of the first transmission beam. The underwater detection device according to claim 6,
The transmitter is
An amplifier that amplifies the transmission signal by the electric power stored in the capacitor;
An underwater detection device comprising: a vibrator that transmits a transmission beam based on the amplified transmission signal. In the underwater detection method that detects underwater by transmitting and receiving beams,
A step of sequentially transmitting a first transmission beam and a second transmission beam having different frequencies from the first transmission beam amplified by the power stored in the capacitor;
Receiving a first reception signal corresponding to the frequency of the first transmission beam and a second reception signal corresponding to the frequency of the second transmission beam;
And a step of correcting the gain of the second received signal based on the voltage of the capacitor that has decreased with the transmission of the first transmission beam. In an underwater detection device that detects underwater by transmitting and receiving beams,
A transmitter that sequentially transmits a first transmission beam and a second transmission beam having a frequency different from that of the first transmission beam, amplified by the power accumulated in the capacitor;
A receiving unit for receiving a first reception signal corresponding to the frequency of the first transmission beam and a second reception signal corresponding to the frequency of the second transmission beam;
A storage unit that stores information on gain to be corrected based on the voltage of the capacitor that decreases with transmission of the first transmission beam;
An underwater detection device comprising: a gain correction unit that corrects the gain of the second reception signal based on the information on the gain to be corrected. In the underwater detection method that detects underwater by transmitting and receiving beams,
A step of sequentially transmitting a first transmission beam and a second transmission beam having different frequencies from the first transmission beam amplified by the power stored in the capacitor;
Receiving a first reception signal corresponding to the frequency of the first transmission beam and a second reception signal corresponding to the frequency of the second transmission beam;
Storing information on gain to be corrected based on the voltage of the capacitor that decreases with transmission of the first transmission beam;
And a step of correcting the gain of the second received signal based on the information on the gain to be corrected.

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