JP2022075074A - Sonar system, method, and program - Google Patents

Abstract

To provide a sonar system that can estimate the shape of a towed array without using a sensor such as a compass.SOLUTION: A sonar system includes a reception processing device that calculates an arrival direction of a sound wave from reception data of the sound wave for each of a plurality of combinations different from each other of a plurality of receiving elements constituting an array, and estimates the shape of the array based on the arrival direction and an arrival time of the sound wave.SELECTED DRAWING: Figure 3

Description

The present invention relates to a receiving processing device, a sonar system, a method, and a program.

A sonar is a device that identifies the position of an object in the water using sound waves, includes an array in which a plurality of receiving elements that receive sound waves are arranged, and obtains acoustic information in the water. The receiving element converts the received sound wave into an electric signal. In tow-type sonar, a platform such as a ship tows an array of multiple receiving elements with a cable. Cables and arrays are deformed by receiving external force from platform movements and ocean currents. This deformation is difficult to predict. This makes it difficult to estimate the exact position of the array as seen from the platform. The position error of such an array affects signal processing and the like, and adversely affects the performance of the sonar itself.

For example, in Patent Document 1, a compass is set at the position of the receiver of the line array, and the coordinates of each receiver are obtained by using the output of each compass and the known distance between the receivers. We are looking for a shape when the line array is deformed. In this way, by attaching a plurality of sensors such as a gyro compass to a plurality of receivers constituting the array, the accuracy of estimating the position of the array as seen from the platform is improved. However, as many sensors (compasses) as the number of receivers that make up the array are required. In a tow-type sonar, since a large number of receivers are arranged, it is necessary to incorporate a large number of sensors (compasses) in the array, which makes it impractical in terms of manufacturing cost and the like. To solve this problem, Patent Document 2 provides a compass for the tow cable, and the signal processing device receives compass directional information (compass directional) from the compass and a received signal from each receiver of the line array through the tow cable. Is received, phase adjustment processing is performed using these compass directions and received signals, and the presence and direction of the target (for example, direction, depth, inclination, etc.) are detected using the phase adjustment output.

Japanese Unexamined Patent Publication No. 2008-261727 Japanese Unexamined Patent Publication No. 2011-158391

As described above, the tow-type sonar cannot accurately grasp the shape of the array underwater, which causes an error in signal processing and the like, which adversely affects the performance of the sonar.

The present invention has been devised in view of the above problems, and an object of the present invention is to provide a device, a method, and a program capable of estimating the shape of a towed array without using a sensor such as a compass. ..

According to one aspect of the present invention, the reception processing device of the sonar system calculates the arrival direction of the sound wave from the reception data of the sound wave for each of a plurality of different combinations of the plurality of receiving elements constituting the array. The shape of the array is estimated based on the arrival direction and the arrival time of the sound wave.

According to one aspect of the present invention, it is a method of estimating the shape of an array consisting of a plurality of receiving elements in a tow sonar system.
For each of the plurality of different combinations of the receiving elements, the arrival direction of the sound wave is calculated from the received data of the sound wave.
An array shape estimation method for estimating the shape of the array based on the arrival direction and the arrival time of the sound wave is provided.

According to one aspect of the present invention, it is a program that causes a computer to execute a process of estimating the shape of an array consisting of a plurality of receiving elements in a tow sonar system.
A program that calculates the arrival direction of the sound wave from the reception data of the sound wave for each of the plurality of different combinations of the receiving elements, and estimates the shape of the array based on the arrival direction and the arrival time of the sound wave. Provided. Further, according to the present invention, a semiconductor storage such as a computer-readable recording medium (for example, RAM (Random Access Memory), ROM (Read Only Memory), or EEPROM (Electrically Erasable and Programmable ROM)) that stores the above program. , HDD (Hard Disk Drive), CD (Compact Disc), DVD (Digital Versatile Disc)).

According to the present invention, the shape of the towed array can be estimated without using a sensor such as a compass.

It is a figure which schematically exemplifies the structure of the embodiment of this invention. It is a figure which schematically exemplifies the embodiment of this invention. It is a figure which schematically exemplifies the structure of the embodiment of this invention. It is a figure explaining the embodiment of this invention. It is a figure explaining the embodiment of this invention. It is a figure explaining the embodiment of this invention. It is a figure which schematically exemplifies the structure of the embodiment of this invention.

An embodiment of the present invention will be described. According to the present invention, the shape of the array is estimated by numerical calculation such as signal processing based on the acoustic signal received by each receiving element of the array in the towed sonar. Here, as a tow-type sonar, an array (line array) in which a plurality of receiving elements (receivers) are arranged in a string (line) on a tow cable is assumed. In a platform such as a ship equipped with a tow-type sonar and a transmitter, the shape of the array is estimated from the received data of the receiving element of the array. That is, when a plurality of receiving elements arranged on a line array receive an acoustic signal (sound wave) emitted from a sound source, the phase difference is calculated from the received signals of adjacent receiving element pairs, and the middle of the receiving element pairs. Calculate the orientation of the sound wave as seen from the point. By calculating this sound source orientation between adjacent receiving element pairs in the line array, it is possible to draw a plurality of orientation lines of the sound source as seen from the line array. If the position of the sound source is known, the shape of the line array as seen from the sound source can be estimated.

The sonar system 100 according to the embodiment of the present invention will be described with reference to FIG. In FIG. 1, the transmission / reception control device 101, the transmission device 102, and the reception processing device 103 are arranged on a platform such as a ship. The plurality of (N) receiving elements 104 constituting the array (line array) 105 are towed by a cable (not shown) and electrically connected to the receiving processing device 103.

The transmission device 102 converts the transmission signal (electrical signal) supplied from the transmission / reception control device 101 into an acoustic signal (sound wave) and transmits the sound signal (sound wave).

Each receiving element 104 receives a sound wave, converts the sound wave into an electric signal, and sends data to the receiving processing device 103. In each receiving element 104, the electric signal converted from the sound wave is converted into digital signal data by an analog-digital converter (not shown) and transmitted to the receiving processing device 103 via the transmission line of the cable (not shown). May be good. The reception processing device 103 is configured to be able to determine which receiving element 104 the data transmitted from each receiving element 104 is from.

The transmission / reception control device 101 sends information (data) such as a transmission signal waveform and a transmission time to be transmitted from the transmission device 102 to the transmission device 102 and the reception processing device 103.

The reception processing device 103 estimates the shape of the array 105 by performing arithmetic processing on the data transmitted from the transmission / reception control device 101 and each reception element 104.

FIG. 2 is a diagram illustrating a system according to an embodiment of the present invention. In the ship 110 provided with the transmission / reception control device 101, the transmission device 102, and the reception processing device 103 of FIG. 1, a plurality of reception elements 104 (N reception elements 104 ₁ to 104 _N ) are connected by a cable 106 from the stern side. Tow the array 105 (also referred to as the "tow array"). The sound wave transmitted from the transmitting device 102 on the bottom side of the ship 110 is received by the plurality of receiving elements 104 of the array 105. The receiving element 104 is composed of a cylindrical hydrophone provided with a cylindrical sensing portion. The plurality of receiving elements 104 of the array 105 are electrically connected to the receiving processing device 103 in the ship 110 via the cable 106.

FIG. 3 is a diagram illustrating a process (function) executed by the reception processing device 103 of FIG. The received data 1031 includes data obtained by converting an acoustic signal (sound wave) received by each receiving element 104 into a digital signal. Further, the received data 1031 from each receiving element 104 may include the time information when the acoustic signal (sound wave) is received by each receiving element 104.

The azimuth calculation process 1032 calculates the arrival direction of the sound wave from the set of the received data 1031 from the adjacent receiving element 104 pairs by using the frequency of the received sound wave and the distance between the receiving elements.

FIG. 4 is a diagram illustrating the direction calculation process 1032. The arrival direction θ _i in FIG. 4 is the distance between the adjacent i-th and ( _i + 1) th receiving elements 104: di, the sound wave frequency: f, the speed of sound: C, and the adjacent i-th and (i + 1). The phase difference α between the) th receiving elements 104 is obtained by the following equation (1). sin ^-1 is an inverse trigonometric function.

…(1)

… (1)

However, the solution of Eq. (1) is that when the distance _{di between the receiving elements is larger than the wavelength of the sound wave: C / f, that is, when di> C / f, −π <θ i < π} . There is an area where the arrival direction cannot be determined.

…(2)
を用いて式（１）を解くようにしてもよい。このとき、到来方位は（２ｎ＋１）個求まるが、同じ方位から到来する複数の波長の音波に対して同様の計算をすることで、真の到来方位を求めることができる。 When the transmission device 102, which is a sound source, uses a sound wave having such a wavelength, instead of the phase difference α,

… (2)
May be used to solve equation (1). At this time, (2n + 1) arrival directions can be obtained, but the true arrival direction can be obtained by performing the same calculation for sound waves of a plurality of wavelengths arriving from the same direction.

By performing the direction calculation process 1032 on the received data 1031 from the adjacent receiving elements 104, as shown in FIG. 5, a plurality of sound wave arrival direction lines can be drawn. That is, the direction (arrival direction line) with respect to the transmission device 102, which is a sound source, can be obtained at each of the centers between adjacent receiving elements. From FIG. 5, the position coordinates of the sound source (transmitter 102) are derived from the arrival direction line (the arrival direction and the distance between the center between the adjacent receiving elements and the sound source) and the distance _di between the adjacent receiving elements. The positions of adjacent receiving elements can be obtained.

The shape estimation process 1033 estimates the shape of the array by using the arrival time of the sound wave calculated from the received data 1031 (the reception time of the sound wave by the receiving element 104), the result of the direction in the direction calculation process 1032, and the like. The distance between the receiving element 104 and the sound source can be obtained from the transmission time and arrival time of the sound wave from the transmission / reception control device 101. Specifically, for example, for the variable shown in FIG. 6, the coordinates of the i-th and (i + 1) -th receiving elements 104 adjacent to each other are set by using the following equations (3) to (6). demand.

In FIG. 6, the receiving element coordinates (x _i , y _i ) and (x _{i + 1} , y _{i + 1} ) are adjacent i-th and (i + 1) th receiving elements (reception element 104 _i in FIG. 2). , 104 _{i + 1} (i = 1, ..., N-1)), and (x ₀ , y ₀ ) are the two-dimensional position coordinates of the sound source (transmitter 102). In FIG. 6, the horizontal direction is the x-coordinate (x-axis) and the vertical direction is the y-coordinate (y-axis). In this embodiment, the coordinates of the receiving element 104 and the sound source are, for example, the coordinates projected onto a two-dimensional plane parallel to the sea surface. This is because the receiving element 104 of the array 105 is designed to be parallel to the sea surface by using, for example, a neutral buoyancy cable, and the error is small even if it is handled in a two-dimensional plane. That is, even if the Z-axis coordinates (depth) values are the same, the estimation error of the array shape is small. Therefore, the shape of the array estimated by the shape estimation process 1033 is a shape projected on a two-dimensional plane.

In FIG. 6, di is a distance (distance between receiving elements) (known) between adjacent receiving elements 104 _i and 104 _{i + 1} . The sound source distance l _i is the distance from the center of the adjacent receiving elements 104 _i and 104 _{i + 1} to the sound source (transmitting device 102 in FIG. 1). The sound source distance l _i may be a value obtained by arithmetically averaging the distances (calculated) to the sound source (transmitter 102 in FIG. 1) obtained by the receiving elements 104 _i and 104 _{i + 1} , respectively. The cable positive lateral direction φ _i with respect to the adjacent receiving elements 104 _i and 104 _{i + 1} is the true direction from true north. The arrival direction θ _i is the arrival direction (calculated) of the sound wave at the centers of the adjacent receiving elements 104 _i and 104 _{i + 1} . From FIG. 6, it can be seen that the following equations (3) to (6) hold.

…(3)

… (3)

…(4)

…(Four)

…(5)

…(Five)

…(6)

… (6)

If the cable forward / lateral direction φ _i (i = 1, .., N-1) for the adjacent receiving elements 104 _i , 104 _{i + 1} (i = 1, .., N-1) is known, the above equation ( From 3) to (6), the position coordinates (x _i , y _i ) and (x _{i + 1} , y _{i + 1} ) of the adjacent receiving elements 104 _i and 104 _{i + 1} can be obtained.

On the other hand, the cable forward / lateral directions φ ₁ for the adjacent first and second receiving elements 104 ₁ and 104 ₂ are known, but the adjacent receiving elements 104 _i , 104 _{i + 1} (i = 2, .., N). When the cable normal lateral direction φ _i regarding -1) is unknown, for example, the position coordinates (x ₁ , y ₁ ) of the first receiving element 104 ₁ are obtained from the following equations (7) and (8).

…(7)

… (7)

…(8)

… (8)

Then, from the position coordinates (x ₁ , y ₁ ) of the first receiving element 104 ₁ , the position coordinates (x ₂ ) of the second receiving element 104 ₂ are used by using the recurrence formulas (5) and (6) above. , y ₂ ) is obtained.

The cable forward / lateral orientation φ ₂ with respect to the adjacent second and third receiving elements 104 ₂ and 104 ₃ is the position coordinates (x ₂ , y ₂ ) and sound source coordinates (x ₀ ) of φ ₂ and the second receiving element 104 ₂ . , y ₀ ) and the relational expression (inverse trigonometric function) that holds between the distance d ₂ between the receiving elements and the sound source distance l ₂ is used to obtain φ ₂ , and the third receiving element is obtained from the equations (5) and (6). The position coordinates (x ₃ , y ₃ ) of 104 ₃ may be obtained recursively. For the cable forward / lateral direction φ _i (i = 3, .., N-1), the position coordinates (x _i , y _i ) and the sound source coordinates (x ₀ ) of φ _i and the i-th receiving element are the same as above. , Y ₀ ), the distance d _i between the receiving elements, and the relational expression (inverse trigonometric function relational expression) that holds for the sound source distance _{l i} . The position coordinates (x _{i + 1} , y _{i + 1} ) of the second receiving element 104 _{i + 1} may be recursively obtained.

According to the present embodiment, in the tow-type sonar system, the arrival direction of the acoustic signal is obtained from the reception signal in the array of the acoustic signal (sound wave) transmitted from the transmission device (sound wave), and the arrival direction, the sound source distance, and the sound source are obtained. Based on the position coordinates of, the position coordinates of a plurality of receiving elements constituting the array are calculated by arithmetic processing. Therefore, the shape of the array can be estimated without attaching a sensor such as a gyro to the receiving element of the array.

FIG. 7 is a diagram illustrating an embodiment of the present invention, and is a diagram illustrating a configuration when the reception processing apparatus 103 of FIG. 1 is mounted on a computer apparatus 200. Referring to FIG. 7, the computer device 200 includes a processor 201 and a semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), and an EEPROM (Electrically Erasable Programmable Read-Only Memory) (or an HDD (Hard)). It is provided with a storage device 202 (which may be a Disk Drive) or the like), a display device 203, and an interface 204 connected to the transmission / reception control device 101 and the reception element 104 of FIG. The processor 201 may be a DSP (Digital Signal Processor). By executing the program stored in the storage device 202, the processor 201 executes the processing of the reception processing device 103 of FIG.

Although FIG. 2 shows an example of a line array towed from a ship, the present embodiment can be widely used when it is desired to estimate the relative positions of a plurality of receiving elements.

Further, in FIG. 3, for the sake of simplification of the explanation, the orientation calculation process 1032 uses the reception data 1031 of the two adjacent receiving elements 104, but the reception data used in the orientation calculation process 1032 are not necessarily adjacent to each other. Of course, it does not have to be. For example, the direction calculation process 1032 may be calculated from three or more received data 1031.

Regarding the azimuth calculation process 1032, the process of using sound waves of a plurality of wavelengths when the distance d between the receiving elements is larger than the wavelength of the sound wave has been described. It is also possible to use a process such as obtaining.

In the present embodiment, the sound wave received by the receiving element 104 of the array 105 is not only a direct wave from the transmitting device 102 as illustrated in FIG. 2, but also a sound wave including time information such as a reflected wave from a target. May be. Among the sounds emitted by the target, there are sounds that are constantly generated from the engine and the like, and sounds that are generated only for a short time when the ship is steered. Transient sounds that occur only for a short time are called transient signals. The sound wave received by the receiving element 104 of the array 105 may be a transient signal from the target.

The disclosures of Patent Documents 1 and 2 described above shall be incorporated into this document by citation. Within the framework of the entire disclosure (including the scope of claims) of the present invention, it is possible to change or adjust the embodiments or examples based on the basic technical idea thereof. Further, various combinations or selections of various disclosure elements (including each element of each claim, each element of each embodiment, each element of each drawing, etc.) are possible within the scope of the claims of the present invention. .. That is, it goes without saying that the present invention includes all disclosure including claims, various modifications and modifications that can be made by those skilled in the art in accordance with the technical idea.

100 Sonner system 101 Transmission / reception control device 102 Transmission device 103 Reception processing device 104, 104 ₁ to 104 _N Reception element 105 Line array 106 Cable 110 Ship 200 Computer device 201 Processor 202 Storage device 203 Display device 204 Interface 1031 Received data 1032 Direction calculation processing 1033 Shape estimation process

Claims (10)

It is a reception processing device of the sonar system.
For each of a plurality of different combinations of the plurality of receiving elements constituting the array, the arrival direction of the sound wave is calculated from the reception data of the sound wave, and the shape of the array is determined based on the arrival direction and the arrival time of the sound wave. A reception processing device characterized in that it estimates. For each of the pair of two adjacent receiving elements for the plurality of receiving elements constituting the array, the arrival direction of the sound wave is calculated from the received data of the sound wave.
The position coordinates of the sound source of the sound wave and
For each set of two adjacent receiver elements,
The arrival direction, the distance between the receiving elements, the distance to the sound source, and the cable forward / horizontal direction.
Based on
The reception processing device according to claim 1, wherein the position coordinates of each receiving element are calculated. The position coordinates of each receiving element and the sound source are calculated on the two-dimensional coordinates obtained by projecting the receiving element and the sound source on the two-dimensional plane, and the shape of the array is estimated on the two-dimensional plane. The reception processing device according to claim 2, wherein the reception processing device is characterized. Multiple receiving elements that make up the array,
The reception processing device according to any one of claims 1 to 3.
A transmitter that transmits sound waves, and
A control device that gives a transmission waveform and a transmission time to the transmission device,
Equipped with
The control device gives the reception processing device at least the transmission time of the sound wave.
The reception processing device is a sonar system characterized in that the distance from the transmission time of the sound wave and the reception time of the sound wave by the receiving element to the sound source of the sound wave is obtained. The plurality of receiving elements constituting the array are
Direct wave from the transmitter,
Reflected wave from the target,
Receive one of the transient signals from the target and
The sonar system according to claim 4, wherein the reception processing device estimates the shape of the array from the reception data of the plurality of receiving elements constituting the array. The sonar system according to claim 4 or 5, wherein the receiving element includes a cylindrical sensing portion and is towed from a platform by a cable. A method of estimating the shape of an array consisting of multiple receiving elements in a tow sonar system.
For each of the plurality of different combinations of the receiving elements, the arrival direction of the sound wave is calculated from the reception data of the sound wave, and the shape of the array is estimated based on the arrival direction and the arrival time of the sound wave. A featured array shape estimation method. With respect to the receiving elements constituting the array, the arrival direction of the sound waves is calculated from the received data of the sound waves for each of two pairs of adjacent receiving elements.
Position coordinates of each receiving element based on the position coordinates of the sound source of the sound wave, the arrival direction of each set of two adjacent receiving elements, the distance between the receiving elements, the distance to the sound source, and the cable normal lateral direction. 7. The array shape estimation method according to claim 7, wherein the method is calculated. A program that causes a computer to execute the process of estimating the shape of an array consisting of multiple receiving elements in a tow sonar system.
A program that calculates the arrival direction of the sound wave from the reception data of the sound wave for each of a plurality of different combinations of the receiving elements, and estimates the shape of the array based on the arrival direction and the arrival time of the sound wave. For the receiving element constituting the array, the arrival direction of the sound wave is calculated from the reception data of the sound wave for each pair of two adjacent receiving elements.
Position coordinates of each receiving element based on the position coordinates of the sound source of the sound source, the arrival direction of each set of two adjacent receiving elements, the distance between the receiving elements, the distance to the sound source, and the cable normal lateral direction. 9. The program according to claim 9, wherein the computer is made to execute the process of calculating the above.

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