JP2020060482A - Underwater wave receiving device - Google Patents

Abstract

To provide an underwater wave receiving device capable of correcting deviation of orientation resulting from rotary motion of a hanging cable.SOLUTION: An underwater wave receiving device comprises a float part, a plurality of wave receivers, an underwater part, and a hanging cable connecting them, wherein the underwater part or the wave receiver is provided with an orientation sensor. The underwater wave receiving device comprises: an azimuth angle correction value storage unit that calculates the deviation of an angular velocity and angular acceleration of the orientation sensor and the deviation of an azimuth angle of each receiver, to store them in association with an azimuth correction value; and an azimuth angle correction unit that corrects the orientation deviation of a received signal of each wave receiver using the azimuth angle correction value corresponding to the angular velocity and angular acceleration obtained from the orientation sensor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an underwater wave receiving device, and particularly to an underwater wave receiving device used for azimuth measurement.

  The underwater wave receiving device is effective for detecting an underwater vehicle that is dropped from an aircraft into the water and dives underwater while the aircraft is flying in the air.

  An underwater wave receiving device with a wave receiver array consisting of multiple wave receivers suppresses the noise coming from the direction of the water surface and the bottom of the water by vertical directivity, and detects the horizontal direction of the underwater vehicle that is the sound source. It is a high-performance underwater wave receiving device that can perform.

  In the underwater wave receiving device described in Patent Document 1, as shown in FIG. 3 of the document, a plurality of wave receivers 102 are vertically and linearly attached to a cable 106 suspended from a fishing boat 105. Each output of 102 is added. Similarly, the azimuth detecting device of Patent Document 2 is a azimuth that forms a azimuth data of an incoming sound wave by analyzing a spatial frequency based on the output of each wave receiver and a wave receiver array in which N wave receivers are linearly arranged. The data forming unit is provided.

Japanese Patent Publication No. 57-019389 Patent No. 2580855

  Since the hanging cable is usually longer than 100 m, it is wound on a drum when it is not hanging, but the hanging cable is twisted when wound. When the suspension cable wound on the drum is paid out from the drum of the float section into the water, the suspension cable rotates in the water in order to release the twist. Since the receiver array also rotates as the suspension cable rotates, the direction of the received signal of the receiver shifts as compared with the case where there is no rotation. Therefore, the direction of the sound source calculated from the received signal is deviated. Moreover, since the hanging cable is twisted, the values of the direction deviations of the received signals of the respective wave receivers are different. Patent Documents 1 and 2 make no mention of the misalignment caused by the rotational movement of the suspension cable and its correction.

It is an object of the present invention to solve the above-mentioned problems and to provide an underwater wave receiving device capable of correcting the azimuth deviation caused by the rotational movement of the suspension cable.

The present invention comprises a float section, a plurality of wave receivers, an underwater section and a suspension cable connecting them,
An orientation sensor is provided in the underwater portion or the wave receiver,
An azimuth angle correction value storage unit that stores the angular velocities and angular accelerations of the azimuth sensors and the azimuth angles of the respective wave receivers, and stores the azimuth angle correction values in association with each other,
Underwater wave reception, comprising an azimuth angle correction unit for correcting the azimuth deviation of the received signal of each wave receiver by using the azimuth angle correction values corresponding to the angular velocity and the angular acceleration obtained from the azimuth sensor. It is a device.
The present invention also provides
A float part, a plurality of wave receivers, an underwater part is connected by a cable, an azimuth correction method for an underwater wave receiving device in which an azimuth sensor is provided in the underwater part or the wave receiver,
The angular velocity and angular acceleration of the azimuth sensor and the deviation of the azimuth angle of each of the wave receivers are calculated, and the azimuth angle correction values are stored in association with each other.
The azimuth angle correction method is characterized in that the azimuth angle correction values corresponding to the angular velocity and the angular acceleration obtained from the azimuth sensor are used to correct the azimuth deviation of the received signals of the respective wave receivers.

  ADVANTAGE OF THE INVENTION According to this invention, the underwater wave receiving apparatus which can correct | amend the misalignment of the direction resulting from the rotary motion of a suspension cable can be provided.

It is a figure which shows the structure of the underwater wave receiving apparatus of the 1st Embodiment of this invention. It is a figure which shows a mode that the receiver array and the underwater part suspended in the water by the suspension cable rotate in order to eliminate the twist of the suspension cable in the first embodiment of the present invention. In the 1st Embodiment of this invention, the time change of the angular velocity which a receiver array and an underwater part rotate by the rotational motion of a hanging cable is shown. It is a figure. It is a figure which shows the structure of the calculation process which correct | amends the direction gap of the received signal of the wave receiver in an underwater part in the 1st Embodiment of this invention. It is a table which calculated | required the angle (azimuth | direction angle correction value) which should correct | amend the received signal of each wave receiver S1-S5 when the angular velocity and angular acceleration of the underwater part fluctuate within a predetermined range. It is a figure which shows the structure of the underwater wave receiving apparatus of the 2nd Embodiment of this invention.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.
Configuration description)
In FIG. 1, (a) on the left side is the overall configuration of the underwater wave receiving device 100, (b) in the center is the configuration of the wave receiver array 4 and the underwater portion 5, and (c) on the right side is the wave receiver array 4. It is a perspective view which shows the structure of the wave receivers S1-S5 which do. The underwater wave receiving apparatus 100 of the present embodiment includes a float unit 2 floating on a water surface 1, a receiver array 4 and an underwater unit 5 submerged in water, and a suspension cable 3 connecting the float unit 2 and the underwater unit 5. Equipped with.

  The wave receiver array 4 includes five wave receivers S1 to S5 as shown in FIG. There is a fixed interval between the five wave receivers S1 to S5. The underwater portion 5 is connected to the lowermost wave receiver S5 by a suspension cable 3. The five wave receivers S1 to S5 and the underwater portion 5 which form the wave receiver array 4 are structured to be directed in the same direction by three cables.

  The float portion 2 has a buoyancy force larger than the total of the underwater weights of the suspension cable 3, the receiver array 4, and the underwater portion 5, and floats on the water surface 1.

The suspension cable 3 is an electric wire that connects the float unit 2, the receiver array 4 and the underwater unit 5, and prevents the receiver array 4 and the underwater unit 5 from sinking due to the buoyancy of the float unit 2. The tension due to the underwater weight of the suspension cable 3 itself, the receiver array 4 and the underwater portion 5 is applied. The suspension cable 3 from the wave receiver array 4 to the underwater portion 5 is composed of a plurality of cables, here three cables. Therefore, the suspension cable is not easily twisted even if tension due to underwater weight is applied, and the receiver array 4 and the underwater portion 5 have the same horizontal direction.

  Each of the wave receivers S1 to S5 has SIN (sine) directivity and COS (cosine) directivity that are orthogonal to the horizontal direction. Each of the wave receivers has a disk shape and includes an electrostrictive vibrator 12 which is an acoustic sensor that occupies an outer peripheral portion and detects underwater sound waves from the horizontal direction, and a resin mold portion 13 at a central portion. The resin mold portion 13 has a ring shape with three holes formed in the center and is molded with synthetic resin. In order to prevent vibrations from being transmitted to each other between the wave receivers S1 to S5 via the suspension cable 3 via the suspension cable 3, it is preferable that the resin mold portion is made of a soft material. The electrostrictive oscillator 12 is provided outside the resin mold portion 13.

  A hanging cable connection hole 14 is opened in the central portion of the resin mold portion 13. The hanging cable connection hole 14 is provided at the apex of an equilateral triangle.

  The underwater unit 5 includes an azimuth sensor 11 and an azimuth calculation circuit 300. In this embodiment, a geomagnetic sensor is used as the orientation sensor. As shown in FIG. 4, to the azimuth calculation circuit 300, the wave reception signals are input from the wave receivers S1 to S5 that form the wave receiver array 4, and the azimuth angle signal is input from the azimuth sensor 11. , Calculate the direction of the target underwater vehicle by digital signal processing them. The azimuth sensor 11 outputs the horizontal azimuth angle calculated based on the geomagnetism at a constant interval of 20 to 50 times per second.

The azimuth calculation circuit 300 will be described. The azimuth calculation circuit 300 corresponds to an azimuth angle correction unit.
Each of the wave receivers S1 to S5 has a SIN directivity 28 and a COS directivity 29 which are orthogonal to the horizontal direction. The electric signal generated by the electrostrictive vibrator 12 vibrating by the sound wave in the water is output to the preamplifier 30 incorporated in the underwater unit 5. The preamplifier 30 amplifies the input electric signal to a voltage suitable for the input range of the A / D (Analog / Digital) converter 31, and outputs the voltage to the A / D converter 31.

  The A / D conversion unit 31 converts the input electric signal into digital data and outputs the digital data to the azimuth correction calculation unit 34. The azimuth sensor 11 outputs the magnetic azimuth directed by the underwater portion to the angular velocity / angular acceleration calculation unit 32 at a constant cycle of 20 to 50 times per second.

The angular velocity / angular acceleration calculation unit 32 stores the azimuth angle of the past fixed time for the azimuth angle of the underwater portion input from the azimuth sensor 11, and stores the azimuth angle input last time, the latest azimuth angle and azimuth angle input this time. The angular velocity and the angular acceleration in the rotation of the underwater portion 5 are calculated from the input time interval, and output to the azimuth correction value acquisition unit 33. Specifically, it is calculated as follows.
Angular velocity (deg / sec) =
= (Current azimuth (deg) -previous azimuth (deg)) / time interval (seconds)
Angular acceleration (deg / sec ² ) =
= (Current angular velocity (deg / sec) -Previous angular velocity (deg / sec)) ÷ Time interval (sec)
Generally, the azimuth is shown from north to east, so if the angular velocity (deg / sec) is positive, it is clockwise (clockwise), and if the angular velocity (deg / sec) is negative, it is counterclockwise (counterclockwise). Clockwise).

  The azimuth correction value acquisition unit 33 determines which phase of the angular velocity time change 17 shown in FIG. 3 is in which the forward rotation motion or the reverse rotation motion of the wave receiver array and the underwater unit 5 is, and each wave receiver S1 to S1. The correction value of the azimuth angle of the received signal in S5 is determined by the method described in the following section (Description of operation) and output to the azimuth angle correction calculation unit 34. The azimuth correction calculation unit 34 corrects the digital data of the SIN directivity 28 or the COS directivity 29 input from the A / D conversion unit 31 with the azimuth correction value from the azimuth correction value acquisition unit 33. In this way, the corrected SIN directivity 35 (horizontal directivity in the north-south direction based on the magnetic north of the geomagnetic field) or the corrected COS directivity 36 (horizontal directivity in the east-west direction based on the magnetic north of the geomagnetic field) calculate. This makes it possible to calculate the arrival direction of sound waves.

(Explanation of operation)
<Rotating motion of hanging cable>
As described above, when the suspension cable 3 is unwound (stretched) from the drum of the float part 2 in order to eliminate the twist of the suspension cable 3 when wound around the drum, the suspension cable 3 Rotates. That is, as shown in FIG. 2 (c), it becomes a rotational motion of twisting the suspension cable 3 that suspends the wave receivers and the underwater portion 5 that form the wave receiver array 4. FIG. 2 shows a state in which the suspension cable 3 rotates in order to eliminate the twist, and the wave receivers S1 to S5 and the underwater portion 5 forming the wave receiver array 4 are directed in different directions.

  FIG. 2A is the same as FIG. 1B and shows the directions of the forward rotation movement 15 and the reverse rotation movement 16. FIG. 2B is a side view of the state where the suspension cable 3 is not rotating, and FIG. 2C is a side view of the state where the suspension cable 3 is rotating. FIG. 2D shows a state in which the wave receivers and the underwater portion 5 have different angles (θ1 to θ6) (twist) due to the twisting of the hanging cable due to the positive rotation motion of the wave receivers S1 to S5. Show. Similarly, in FIG. 2E, due to the twisting of the suspension cable due to the reverse rotational movement of the wave receivers S1 to S5, the respective wave receivers and the underwater portion 5 have different angles (θ1 ′ to θ6 ′) (twisting). The situation is shown. Underwater wave receiving device having a wave receiver array composed of a plurality of wave receivers, since the wave receiver has a horizontal directivity, it is desirable that each wave receiver and the underwater portion face the same direction, Twisting leads to different directions.

  FIG. 3 shows the initial part of the rotational movement that occurs in order to eliminate the twist of the suspension cable when the suspension cable is unrolled from the drum of the float portion when the suspension cable 3 is extended. The vertical axis in FIG. 3 is the angular velocity of the underwater portion or the wave receiver, and the horizontal axis is the time elapsed from the start of the expansion. Whether the forward rotation movement 15 is clockwise or counterclockwise depends on the direction of twist when the hanging cable is wound around the drum. The first rotational movement of the rotation is defined as a forward rotational movement 15 (clockwise in this case).

The first forward rotation movement is divided into two phases. First, since the hanging cable eliminates the initial twist immediately after the extension, the angular acceleration of the forward rotation motion is accelerated (forward rotation motion acceleration phase 24 in FIG. 3). Even after the initial twist of the suspension cable is eliminated, the suspension cable continues to rotate forward due to the moment of inertia due to the weight of the suspension cable, the receiver array, and the underwater weight of the underwater portion.As a result, the suspension cable is twisted in the opposite direction. The kinetic energy accumulated is accumulated, and the angular acceleration of the forward rotation movement is decelerated (forward rotation movement deceleration phase 25 in FIG. 3).

Next, in the hanging cable 3, the energy of the reverse rotation motion that eliminates the twist caused by the secondary inertia moment becomes larger than the energy of the normal rotation motion due to the initial moment of inertia, and the rotation direction is reversed. The angular acceleration of the reverse rotational movement is accelerated (reverse rotational movement deceleration phase 26 in FIG. 3).

  After the secondary twisting of the suspension cable is eliminated by the reverse rotation motion, the suspension cable continues the reverse rotation motion due to the secondary inertia moment due to the underwater weight of the suspension cable, the receiver array and the underwater part, The energy of the forward rotational motion due to the tertiary twist of the hanging cable is accumulated, and the angular acceleration of the reverse rotational motion is decelerated (reverse rotational motion deceleration phase 27 in FIG. 3).

  Further, due to the frictional resistance in water, the change cycle of the rotation direction becomes longer with the passage of time, and the maximum angular velocity becomes smaller. In FIG. 3, the first rotation direction change cycle 21 becomes longer than the rotation direction change cycle 22 in the fourth cycle, and a difference (23 in FIG. 3) occurs in the maximum rotation speed angular velocity time change. It is considered that the rotational movement to eliminate the twist is continued for several tens of minutes.

  In addition, the twist of the suspension cable 3 is converted into a moment of inertia for rotating the suspension cable 3, the receiver array 4, and the underwater portion 5 and potential energy for lifting against gravity, and the distance between them is from L1 to L5 to L1. It becomes shorter as shown by '~ L5'.

  In FIG. 2B and FIG. 2C, L1 to L5 indicate the intervals between the wave receivers S1 to S5 and the underwater portion 5 in the state where the forward rotation motion or the reverse rotation motion is not performed. Further, in FIG. 2, L1 'to L5' indicate the intervals between the wave receivers S1 to S5 and the underwater portion 5 in the state where the wave receiver array and the underwater portion are performing the normal rotation motion or the reverse rotation motion. Since the three hanging cables are twisted by the forward rotation movement or the reverse rotation movement, the wave receivers S1 to S5 and the underwater portion 5 are pulled upward against the gravity and rise. In FIG. 2, L1 to L5 and L1 ′ to L5 ′ are displayed with the same length (same spacing), but the moment of inertia applied to the suspension cable 3 between the wave receivers S1 to S5 and the underwater portion 5 is shown. And the intervals are different.

  In FIG. 2 (d), θ1 to θ6 indicate the pointing directions of the wave receivers S1 to S5 and the underwater portion 5 at a certain moment in the state of performing the positive rotation motion. Immediately after the suspension cable is stretched, the initial positive rotational movement is transmitted from top to bottom, so θ1 at the highest rank is the largest and θ6 at the lowest rank is the smallest.

  Further, in FIG. 2 (e), θ1 ′ to θ6 ′ indicate the directional directions of the wave receivers S1 to S5 and the underwater portion 5 at a certain moment while performing the reverse rotation motion. Since the rotational movement is transmitted from the bottom to the top in the reverse rotational movement, the lowest .theta.6 'is the largest and the highest .theta.1' is the smallest.

  The energy of the forward rotation motion 15 and the reverse rotation motion 16 for eliminating the twist of the hanging cable 3 is transmitted as a force for twisting the three hanging cables 3 connecting the receiver array 4 and the underwater portion 5. There is a time difference in the propagation of the rotational energy. Therefore, each wave receiver and the underwater part at a certain moment point in a direction slightly shifted.

  For example, when the first forward rotation motion 15 is clockwise, the rotation motion is transmitted in order from top to bottom as shown by θ1 to θ6 in FIG. 2, so the angles θ1 to θ6 generated by the normal rotation motion 15 are the maximum. Θ1 of the wave receiver S1 located at the upper part is the largest, θ2, θ3 ... Are gradually smaller, and θ6 of the underwater part 5 located at the lowermost part is the smallest. That is, θ1 to θ6 have different values.

Further, for example, when the reverse rotation motion 16 is counterclockwise, the reverse rotation motion 16 is transmitted in order from bottom to top as shown in θ1 ′ to θ6 ′ of FIG. Θ6 ′ of the underwater portion 5 located at the bottom is the largest, θ5 ′, θ4 ′ ... Are gradually smaller, and θ1 ′ of the wave receiver S1 located at the top is the smallest. That is, θ1 ′ to θ6 ′ take different values.
<Azimuth correction value table creation by water tank experiment>
As described above, the angle (θ1 to θ5) of each of the wave receivers S1 to S5 and the angle (θ6) of the underwater portion 5 deviate due to the rotational movement that occurs when the suspension cable 3 tries to eliminate the twist. To correct this deviation, verify the azimuth deviation of the received signals of the individual wave receivers for each angular velocity and angular acceleration of the underwater in advance in a tank test, and obtain the correction value (angle) to correct the azimuth deviation. Remember in the form of a table. The correction value table is referred to by the measured values of the angular velocity and the angular acceleration when the underwater wave receiving device is actually dropped into the water, and the correction value is extracted and corrected. In other words, from the angular velocity and the angular acceleration of the underwater portion, it can be known where the underwater portion is on the curve of the angular velocity change in FIG. Since the correction value table stores the angle for correcting the azimuth deviation of the received signal of each wave receiver for each angular velocity and angular acceleration of the underwater portion, the correction value of each wave receiver can be known.

  The reason for using both the angular velocity and the angular acceleration is as follows. As shown in FIG. 3, the underwater portion (and each wave receiver) rotates many times while being attenuated. Therefore, there is no one-to-one correspondence between the azimuth angle of the underwater portion 5 indicated by the azimuth sensor 11 of the underwater portion 5 and how much each of the wave receivers is twisted (how much the angle is deviated). That is, even if the directivity azimuth angle of the underwater portion 5 is one value, there are a plurality of azimuth angle correction values corresponding to the respective wave receivers. Therefore, even if a directional azimuth of the underwater portion 5 and an azimuth correction value of each wave receiver corresponding to the azimuth correction value of the underwater portion 5 are obtained by a water tank experiment, it is not known which of the plurality of azimuth correction values should be applied. However, considering both the angular velocity and the angular acceleration, there is no same combination (the angular velocity is the same including the sign but the angular acceleration is different), so that it is possible to specify where the underwater portion is on the curve in FIG. 3. Therefore, if both the angular velocity and the angular acceleration are measured in the water tank experiment and they are associated with the azimuth correction values that match them, correct correction becomes possible.

FIG. 5 shows the angles to be corrected (azimuth angle correction) of each of the wave receivers S1 to S5 when the angular velocity of the underwater portion 5 changes within the range of 0.0 to 10.0 deg / sec and the angular acceleration within the range of 0 to 10.0 deg / sec ^2. Is a azimuth correction value table obtained in the water tank experiment.

How to obtain the azimuth correction value table will be described below.
(1) In advance, write a line (mark) as a direction mark on the wave receivers S1 to S5.
(2) Put an underwater wave receiving device in a water tank, and use a motor or the like to generate a rotational motion of angular velocity and angular acceleration that simulates a predetermined amount of twist in a hanging cable in the water tank. (If the angular velocity and the angular acceleration are the same, the rotational angles of the wave receivers S1 to S5 are the same whether the rotational movement to release the twist or the rotational movement to rotate the suspension cable with a motor or the like. You can simulate the rotation by releasing the twist.)
(3) The rotation of the wave receivers S1 to S5 is photographed by an underwater video camera, and the angle of the mark line of the wave receivers S1 to S5 is measured at predetermined time intervals. The angle of the mark line is, for example, the angle of deviation from magnetic north. In parallel with this, the angle of the underwater portion 5 at the same time is measured by the azimuth sensor 11. The measurement of the angle of the mark line and the measurement of the azimuth of the azimuth sensor 11 may be performed at the same timing.
(4) If there are multiple torsional magnitudes (magnitudes of rotational movement caused by them), such as multiple types of drums around which the underwater wave receiving device is wound, change the number of rotations of the motor, Rotational motion of angular velocity and angular acceleration simulating a twist of a different magnitude from (2) is generated, and the measurement of (3) is performed.

An azimuth angle correction value for estimating the pointing azimuth angles of the wave receivers S1 to S5 from the azimuth angle, the angular velocity (deg / sec) and the angular acceleration (deg / sec ² ) of the underwater portion 5 after performing the measurement as described above. (Deg) is determined.

  In addition, the rotational movement generated to eliminate the twist of the suspension cable is the type of the underwater receiving device, for example, the length of the suspension cable, the weight of the device, the number of wave receivers, the distance between each other, etc. Since it depends on the parameter of, the correction table as shown in FIG. 5 is created for each model. This correction table is stored in the table holding memory 40. The table holding memory 40 corresponds to an azimuth angle correction value storage unit, and corresponds the azimuth angle correction value, which is the deviation of the azimuth angle of the received signal of each wave receiver, from the angular velocity and angular acceleration of the azimuth sensor. It is something I remember.

  When the initial angular velocity (deg / sec) of the underwater portion 5 is a positive value, it is determined that the positive rotational movement 15 is clockwise, and when the angular velocity is negative, the positive rotational movement 15 is counterclockwise, and the reverse rotational movement 16 is positive. It is determined that the rotational movement is in the opposite direction of the rotational movement 15.

In the correction table of FIG. 5, only the case where the angular acceleration (deg / sec ² ) of the azimuth sensor has a positive value is described. The reason is that the azimuth angle correction value due to the forward rotation motion and the azimuth angle correction value due to the reverse rotation motion are close to each other in absolute value although the signs of plus and minus are different. This is because the case was omitted.
<Calculation of azimuth>
The uncorrected SIN directivity 28 and the uncorrected COS directivity 29 output from the wave receivers S1 to S5 are corrected by the angular velocity and angular acceleration data obtained from the azimuth sensor 11. A signal processing method for obtaining the corrected SIN directivity 35 and the corrected COS directivity 36 will be described with reference to FIG.

The signals of the SIN directivity 28 and the COS directivity 29, which are the received signals including the azimuth error, are input to the preamplifier 30 and amplified to a voltage suitable for the input range of the A / D converter 31 in the subsequent stage. The A / D conversion unit 31 converts the input electric signal into digital data and outputs the digital data to the azimuth correction calculation unit 34. On the other hand, the azimuth sensor 11 outputs the data of the magnetic azimuth directed by the underwater portion 5 to the angular velocity / angular acceleration calculation unit 32 at a constant cycle of 20 to 50 times per second. The angular velocity / angular acceleration calculation unit 32 receives this data and calculates the angular velocity and the angular acceleration as described above in (Signal processing circuit). Based on the calculated angular velocity and angular acceleration, the azimuth angle correction value acquisition unit 33 determines which phase in the angular velocity time change 17 shown in FIG. 3, the normal rotational movement (or the reverse rotational movement) of the wave receiver array 4 and the underwater portion 5. (Which point on the curve of change in angular velocity with time)? After the determination, the azimuth correction value acquisition unit 33 calls the azimuth correction values of the wave receivers S1 to S5 corresponding to the combination of the angular velocity and the angular acceleration from the table holding memory 40. Since the azimuth angle correction value differs for each wave receiver, the azimuth angle correction value acquisition unit 33 outputs the azimuth angle correction value for each of the wave receivers S1 to S5 to the azimuth angle correction calculation unit 34. The azimuth correction calculation unit 34 corrects the digital data of the received signal level of the SIN directivity 28 or the COS directivity 29 input from the A / D conversion unit 31 with the azimuth correction value from the azimuth correction value acquisition unit 33. To do. In this way, the corrected SIN directivity 35 and the corrected COS directivity 36 are calculated. Specifically, the following calculation is performed (only S1 is shown).
SIN directivity after correction of receiver S1 =
= Digital data of received signal level of S1 x COS (Underwater azimuth (deg) + S1 azimuth correction value (deg))
Corrected COS directivity of receiver S1 =
Digital data of received signal level of S1 x SIN (underwater azimuth (deg) + azimuth correction value of S1 (deg))
The above calculation formula is for the wave receiver S1, but in the case of the wave receivers S2 to S5, the azimuth correction value is replaced with the corresponding wave receiver for calculation.

The corrected SIN directivity 35 is digital data indicating directivity in the north-south direction with the magnetic north of the geomagnetism as a reference. Similarly, the corrected COS directivity 36 is digital data indicating the directivity in the east-west direction with reference to the magnetic north of the geomagnetism. From the corrected SIN directivity 35 and the corrected COS directivity 36, it is possible to calculate the accurate direction in which the sound wave comes, excluding the influence of the twist of the hanging cable.

(Effects of the embodiment)
As described above, the present embodiment has the following effects.

  Due to the rotational movement due to the twisting of the suspension cable, the azimuth angle measured by the azimuth sensor and the azimuth angle calculated from the received signals measured by the multiple wave receivers that make up the wave receiver array may deviate. Can be corrected, and the deviation of the horizontal azimuth angle in the direction of arrival of the sound waves received by the underwater receiver can be improved.

  Regarding the vertical directivity of the wave receiver array in which the wave receivers are arranged in the vertical direction, the deviation of the horizontal directionality of the wave receivers is improved, and The directivity in the vertical direction, which is calculated in, can also be improved.

Furthermore, the azimuth angle deviation between the azimuth sensor and the plurality of wave receivers can be corrected by providing only one azimuth sensor in the underwater portion.
(Second embodiment)
FIG. 6 is a diagram showing an underwater wave receiving device 600 according to a second embodiment of the present invention.

  The float portion 62, the plurality of wave receivers S61 to S65, and the underwater portion 65 are connected by a suspension cable 63. The direction sensor 66 is provided in the underwater portion 65 or the wave receiver. The azimuth angle correction value storage unit 70 calculates the azimuth deviation of the received signals of the wave receivers S61 to S65 from the angular velocity and the angular acceleration obtained from the azimuth angle of the azimuth sensor 66, and calculates the azimuth of each wave receiver. The angle correction value is stored. The azimuth angle correction unit 80 corrects the azimuth angle of each wave receiver using the azimuth angle correction values corresponding to the angular velocity and the angular acceleration obtained from the azimuth sensor 66.

By doing so, even if the azimuths of the wave receiver and the underwater portion are deviated due to the rotational movement of the wave receiver and the underwater portion, which are generated in an attempt to eliminate the twist of the cable, it is possible to correct the deviation.
(Other embodiments)
In the first embodiment, the orientation sensor 11 is provided in the underwater section 5. However, the wave receivers S1 to S5 may be installed instead of the underwater unit 5.
Although the geomagnetic sensor is used as the orientation sensor in the first embodiment, it is obvious that other types of orientation sensors such as a gyro sensor may be used.

1 Water surface 2, 62 Float part 3, 63 Suspended cable 4, 64 Wave receiver array S1, S2, S3, S4, S5, S61, S62, S63, S64, S65 Wave receiver 5 Underwater part 11 Direction sensor 12 Electricity Strain oscillator 13 Resin mold part 14 Suspended cable connection hole 15 Forward rotation motion 16 Reverse rotation motion 17 Angular velocity time change 21, 22 Rotation direction change cycle 24 Forward rotation motion acceleration phase 25 Forward rotation motion deceleration phase 26 Reverse rotation motion deceleration phase 28 SIN directivity before correction 29 COS directivity before correction 30 Preamplifier 31 A / D conversion unit 32 Angular velocity / angular acceleration calculation unit 33 Azimuth correction value acquisition unit 34 Azimuth correction calculation unit 35 SIN directivity after correction 36 COS directivity after correction 40 Table holding memory 66 Azimuth sensor 70 Azimuth angle correction value storage unit 80 Azimuth angle correction unit 100, 60 Underwater reception device 300 orientation calculation circuit

Claims (9)

It is connected with a float part, multiple wave receivers, an underwater part, and a hanging cable connecting them,
An orientation sensor is provided in the underwater portion or the wave receiver,
An azimuth angle correction value storage unit that stores the angular velocity and angular acceleration of the azimuth sensor and the azimuth angle correction value indicating the azimuth angle correction value of the received signal of each of the wave receivers in association with each other,
Underwater wave reception, comprising an azimuth angle correction unit for correcting the azimuth deviation of the received signal of each wave receiver by using the azimuth angle correction values corresponding to the angular velocity and the angular acceleration obtained from the azimuth sensor. apparatus.   The azimuth correction value storage unit stores an angular velocity and an angular acceleration that change due to a rotational movement of the azimuth sensor due to a twist of the suspension cable, and an azimuth deviation of a received signal of each of the receivers caused by the rotational movement. The underwater wave receiving apparatus according to claim 1, wherein the azimuth correction values shown are associated with each other. The azimuth correction value storage unit,
In the correction table for the angular velocity and the angular acceleration obtained by measuring the angle of each of the wave receiver and the underwater part by causing the rotational motion of the angular velocity and the angular acceleration simulating the twist in the suspension cable in the water tank. The underwater wave receiving device according to claim 1 or 2. The underwater section is
An angular velocity / angular acceleration calculation unit that calculates the angular velocity of the azimuth sensor from the temporal change of the azimuth angle of the azimuth sensor, and calculates the angular acceleration from the temporal change of the angular velocity.
An azimuth angle correction value acquisition unit that obtains from the azimuth angle correction value storage unit the azimuth angle and angular acceleration output from the angular velocity / angular acceleration calculation unit, and the azimuth angle correction value corresponding to each of the receivers,
An azimuth angle correction calculation unit that corrects the received signal output from each of the wave receivers with the azimuth angle correction value output from the azimuth angle correction value acquisition unit,
The underwater wave receiving device according to claim 3, further comprising: Each of the wave receivers has a SIN directivity and a COS directivity orthogonal to the horizontal direction,
The underwater receiving wave according to claim 4, wherein the azimuth correction calculation unit corrects the SIN directivity and the COS directivity including the azimuth error due to the azimuth deviation with the azimuth angle correction value of each corresponding wave receiver. apparatus.   The underwater wave receiving device according to claim 1, wherein the suspension cables between the plurality of wave receivers and between the wave receiver and the underwater portion are connected by a plurality of cables. .   The underwater wave receiving device according to claim 6, wherein the wave receiver is disk-shaped, has a hole through which the plurality of cables pass, and has an acoustic sensor outside the center portion.   The underwater wave receiving device according to claim 1, wherein the direction sensor is a geomagnetic sensor. A float part, a plurality of wave receivers, an underwater part is connected by a cable, an azimuth correction method for an underwater wave receiving device in which an azimuth sensor is provided in the underwater part or the wave receiver,
The angular velocity and angular acceleration of the azimuth sensor and the deviation of the azimuth angle of each of the wave receivers are calculated, and the azimuth angle correction values are stored in association with each other.
An azimuth angle correction method characterized in that the azimuth angle correction values corresponding to the angular velocity and the angular acceleration obtained from the azimuth sensor are used to correct the azimuth deviation of the received signal of each wave receiver.

Images