JP7251875B2 - SONAR SYSTEM, POSITION DIFFERENCE DETECTION METHOD AND PROGRAM - Google Patents

Description

The present invention relates to a sonar system, positional deviation detection method, and program.

A suspended sonar is dropped from an aircraft or the like (for example, a fixed-wing anti-submarine patrol aircraft, an anti-submarine helicopter, etc.), and after landing on the sea surface, it is separated into an upper surface and an underwater portion. The upper part of the water has buoyancy against seawater and drifts on the sea surface. The above water surface receives electric signals of underwater sound waves received from the above water surface via a suspension cable, and positional information of the above water surface measured by a GPS (Global Positioning System) receiver provided above the water surface. It is transmitted to an information center on an aircraft, on the ground, or on the sea via a wireless communication device and a wireless antenna in the department.

Since the underwater part has a higher specific gravity than seawater, it sinks in the sea. The underwater part has an acoustic element (electrostrictive vibrator). In the underwater part, the acoustic element receives underwater sound waves emitted from an underwater object, converts the received sound waves into electric signals, and transmits the electric signals to the upper part of the water through the signal lines of the suspension cables. In the underwater part of the active sonar system, a transmission signal (electrical signal) amplified by an amplifier circuit powered by a built-in battery is converted into a sound wave by an acoustic element (electrostrictive transducer) and transmitted to detect underwater objects. The acoustic element (electrostrictive transducer) receives the echo sound reflected by the float, converts the echo sound into an electric signal, and transmits the electric signal to the upper part of the water via the signal line (signal cable) of the suspension cable. .

FIG. 1A is a plan view (xy plane) schematically showing an example of the water section 2 and the underwater section 3 when looking down on the sea surface from above. Although not particularly limited, the positive direction of the z-axis in FIG. Note that the x-axis may be the east-west direction, and the y-axis may be the north-south direction. In FIG. 1(A), the white arrow 5 represents the moving direction and moving speed of the upper part of the water 2 drifting on the sea surface 1 . In this specification, the moving speed is defined as the magnitude (speed) (scalar quantity) of the speed, and the moving direction and the moving speed are expressed as a vector, which is referred to as a "speed vector".

FIG. 1B is a schematic side view of the water section 2 and the underwater section 3 as seen from the side. Although not particularly limited, in FIG. 1B, the positive direction of the z-axis is the depth direction from the sea surface. FIG. 1(B) may be, for example, a view of the water section 2 and the underwater section 3 from a plane parallel to the yz plane. 1A may be a view of the side surfaces of the water section 2 and the water section 3 from a plane parallel to the straight line connecting the water section 2 and the water section 3 on the xy plane of FIG. 1A and perpendicular to the xy plane. In FIG. 1B, the aircraft 6 is a fixed-wing anti-submarine patrol aircraft, an anti-submarine helicopter, or the like that drops a suspended sonar.

As shown in FIGS. 1A and 1B, the underwater section 3 is not located directly below the underwater section 2, and there is a positional deviation between the underwater section 2 and the underwater section 3. FIG.

For example, in Patent Document 1, a sonobuoy dropped from an aircraft changes its position from moment to moment due to the effects of wind waves, sea currents, etc., and a positional error (positional deviation) occurs in the buoy position with respect to the dropped position. Due to the effects of wind waves, sea currents, etc., the position of the hydrophone will cause a positional error (positional deviation) with respect to the buoy position, and the positional error of these sonobuoys, etc. will cause a large error in calculating the position of underwater targets, etc. from the buoy position. It is stated that This problem will be explained below.

At present, the actual situation is that no technology has been established for detecting the positional deviation between the water section 2 and the underwater section 3 . In general, suspended sonars are used under the assumption that the underwater section 3 is directly below the underwater section 2 . In a model that simplifies the suspended sonar, it is assumed that the underwater section 3 is pulled by the above water section 2 in a form that is pulled by the movement of the above water section 2, which is affected by wind and waves on the sea.

2A and 2B are diagrams schematically illustrating an actual suspended sonar. In FIGS. 2A and 2B, the white arrow 7 represents the movement (moving direction, moving speed) of the water section 2 due to the wind force. Wind power is dominant as the force (kinetic energy) acting on the water section 2 and affecting its movement. Although it is not impossible to observe the wind direction and wind speed on the sea surface 1 that change from moment to moment with high accuracy, the cost is high and it takes a long time, so it is not suitable for real-time operation.

A white arrow 8 represents movement (moving direction, moving speed) due to tidal current or the like in the upper part of the water 2 . The force (kinetic energy) that acts on the upper part of the water 2 and affects its movement includes forces other than wind power, such as tidal currents, ocean currents, and waves. It is not impossible to observe all tidal currents, ocean currents, and waves other than wind power, but it is expensive and takes a long time, so it is not suitable for real-time operation.

A hollow arrow 9 represents the movement (moving direction, moving speed) of the suspension cable 4 due to the middle ocean current. As a force (kinetic energy) acting on the suspension cable 4, there is, for example, a middle ocean current at a depth of 100 m. Intermediate ocean currents are less affected by wind forces and waves on the sea surface, and act in a direction different from movement caused by waves on the sea surface. It is possible to observe all of them, but it is expensive and takes a long time, so it is not suitable for real-time operation.

A white arrow 10 represents traction (moving direction, moving speed) by the water section 2 . As the force (kinetic energy) that affects the movement of the underwater section 3, generally, the traction caused by the movement of the underwater section 2 is dominant.

A white arrow 11 represents the movement (moving direction, moving speed) of the underwater part 3 due to the intermediate ocean current. The force (kinetic energy) that affects the movement of the underwater part 3 includes, for example, a middle ocean current at a depth of 100 m. The direction and velocity of the intermediate ocean current are not always constant depending on the depth of the water, and the direction and velocity of the current may vary depending on the depth of the water. Therefore, it is not impossible to observe all of them, but it is costly and takes a long time, so it is not suitable for real-time operation.

The water section 2 is affected by movement due to wind power and movement due to factors other than wind power such as tidal currents. In addition, the suspension cable 4 is affected by intermediate ocean currents. The submerged part 3 is subject to traction by the submerged part 2 and the mid-level ocean currents. When observing the effects of complicated weather and sea conditions on and under the sea, the cost of observation equipment is high and observation takes a long time. For this reason, the positional deviation between the water section 2 and the underwater section 3 is treated as small enough to be ignored.

However, when the length of the suspension cable 4 reaches, for example, several 100 m, the distance of positional deviation between the above water section 2 and the underwater section 3 may also exceed 100 m. In this case, regarding the accuracy of the arrival azimuth and distance of underwater sound waves detected by the hanging sonar, the problem that the position of the underwater part 3 that is the starting point is not accurate becomes more obvious.

JP-A-6-289132

There is a tendency to improve the accuracy of position measurement above water, such as the spread of sonobuoys equipped with GPS receivers. For this reason, it is desired to put into practical use a technique for detecting the positional deviation between the upper part of the water and the underwater part at low cost and in a short period of time.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a system, method, and program for solving the above problems.

According to one aspect of the present invention, a sonar system comprises a water upper portion equipped with means for measuring its own position by suspending the underwater part, and a means for measuring its own position without suspending the underwater part. and a position calculation means. The position calculation means calculates a difference in moving direction and a difference in moving speed between the upper water portion and the upper water portion for comparison from respective positional information measured at the upper water portion and the upper water portion for comparison. Based on the difference in the direction of movement and the difference in speed of movement of the upper portion of the water for comparison, the direction and velocity of the water flow acting on the underwater portion are obtained, and the positions of the upper portion of the water and the underwater portion are determined based on the direction and velocity of the water flow. Calculate the displacement direction and position displacement distance.

According to another aspect of the present invention, there is provided a method for detecting misalignment of an underwater part in a sonar system having an upper part of the water equipped with means for suspending the underwater part and measuring its own position, comprising:
A comparison water upper portion having a structure that does not suspend the underwater portion and equipped with a means for measuring its own position is arranged on the water surface together with the above water portion,
Calculate a difference in moving direction and a difference in moving speed between the upper water portion and the upper water portion for comparison from the respective positional information measured at the upper water portion and the upper water portion for comparison,
Based on the difference in the moving direction and the difference in moving speed between the upper water portion and the upper water portion for comparison, determine the flow direction and flow velocity of the water flow acting on the underwater portion,
Based on the flow direction and flow velocity of the water flow, a positional displacement direction and a positional displacement distance between the above water portion and the above water portion are calculated.

According to yet another aspect of the present invention, a comparison comprising a water upper portion provided with means for suspending the underwater portion and measuring its own position, and a structure not suspending the underwater portion and provided with means for measuring its own position a sonar system computer having an upper water supply;
a process of calculating a difference in moving direction and a difference in moving speed between the upper water portion and the upper water portion for comparison from the respective positional information measured at the upper portion of water and the upper portion of water for comparison;
a process of determining the flow direction and flow velocity of the water flow acting on the underwater part based on the difference in the movement direction and the difference in the movement speed between the water upper part and the comparison water upper part;
A program is provided for executing a process of calculating a displacement direction and a displacement distance between the above water portion and the above water portion based on the direction and velocity of the water flow. Furthermore, 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)) storing the program , HDD (Hard Disk Drive), CD (Compact Disc), DVD (Digital Versatile Disc)).

According to the present invention, it is possible to detect the positional deviation between the upper part of the water and the underwater part at low cost and in a short period of time.

(A) and (B) are diagrams for explaining a related technology. (A) and (B) are diagrams for explaining a related technology. (A) and (B) are diagrams for explaining an embodiment of the present invention. It is a figure explaining embodiment of this invention. It is a figure explaining the water part of embodiment of this invention. It is a figure explaining the structural example of embodiment of this invention. It is a figure explaining embodiment of this invention.

An embodiment of the present invention will be described. 3A and 3B are diagrams illustrating an embodiment of the present invention. FIG. 3A is a plan view (xy plane) schematically showing an example of the water section 2 and the underwater section 3 when looking down on the sea surface from above. In FIG. 3A, the x-axis is the east-west direction 15 and the y-axis is the north-south direction 14 . FIG. 3(B) is a schematic side view of the upper water portion 12 for comparison, the upper water portion 2 and the underwater portion 3 as seen from the side. The xyz coordinate system in FIGS. 3A and 3B is the same as in FIGS. 1A and 1B.

According to the present embodiment, in the suspended sonar that is dropped onto the sea from an aircraft (not shown), the suspended sonar is divided into an upper surface 2 on the surface of the sea and an underwater portion 3 in the sea. In order to detect the displacement of the underwater section 3, the position calculation means monitors the position of the comparison upper water section 12 from which the underwater section 3 is not suspended. The position calculation means detects the difference in moving direction and moving speed between the upper water portion 12 for comparison and the upper water portion 2 and calculates the direction and speed of the water flow acting on the underwater portion 3 . The position calculation means calculates the direction and distance of positional displacement between the upper part of the water and the part of the water based on the direction and velocity of the water flow.

In FIGS. 3A and 3B, the white arrow 5 represents the moving direction and moving speed of the upper part of the water 2 drifting on the sea surface 1, that is, the speed vector. In FIG. 3B, the white arrow 13 represents the water flow acting on the underwater section 3.

As exemplified in FIGS. 3A and 3B, in addition to the suspended sonar composed of the underwater section 3, the suspension cable 4, and the underwater section 3, the comparative water section 12 composed only of the water section into the sea.

In this embodiment, the upper water portion 12 for comparison is used to measure the direction and speed of movement due to a force (kinetic energy such as wind force) acting only on the upper water portion 2 .

As described with reference to FIG. 2, the submersible section 3 tries to drift along the middle layer current, but it moves against the middle layer current by the suspension cable 4 suspended from the surface section 2 . Therefore, the underwater section 3 receives resistance from the water flow 13 . The submersible part 3, which receives resistance from the water stream 13, is swept away from directly below the submersible part 2. - 特許庁

The upper water portion 12 for comparison and the upper water portion 2 are each provided with a GPS receiver (not shown). The GPS receivers of the comparison upper water section 12 and the upper water section 2 continuously measure their respective positions as latitude and longitude, and calculate the moving direction and moving speed of the comparison upper water section 12 and the upper water section 2 from their trajectories.

It is assumed that the movement direction and movement speed of the comparison upper water section 12 are due to the kinetic energy due to wind force or the like acting only on the comparison upper water section 12 . Therefore, according to the present embodiment, the difference between the moving direction and moving speed of the upper water portion 12 for comparison and the moving direction and moving speed of the upper water portion 2 is calculated, and the difference in the moving direction and moving speed is calculated as The moving direction and moving speed of the lower cable 4 due to the water flow or the like. That is, although the upper water portion 2 receives the action of kinetic energy due to wind power and the like in the same way as the upper water portion 12 for comparison, since the underwater portion 3 receives the action of the water current, etc., the moving direction and A difference occurs between the moving speed and the moving direction and moving speed of the comparative water upper part 12 which does not suspend the underwater part. This difference (difference) is used as the moving direction and moving speed of the water flow or the like acting on the underwater section 3 .

As the positional deviation between the underwater part 2 and the underwater part 3 of the suspended sonar, for example, the horizontal direction (direction projected in the same plane (horizontal plane)) and the horizontal distance ( Calculate the distance between two points projected on the same horizontal plane (xy plane).

FIG. 4 is a diagram for explaining this embodiment, and corresponds to FIG. 3(A). In FIG. 4, an arrow 16 represents the moving direction and moving speed (velocity vector ^→ V _a ) of the water section 2 . The moving direction and moving speed of the above water portion 2 are synonymous with the moving direction and moving speed (velocity vector) of the above water portion 2 of the suspended sonar, and their values are the same.

An arrow 17 represents the moving direction and moving speed (velocity vector ^→ V _b ) of the upper water portion 12 for comparison.

An angle 18 represents a deviation angle θ (horizontal direction of deviation) between the moving direction of the water upper part 12 for comparison and the water upper part 2 . It is considered that the displacement angle between the moving direction of the upper water portion 12 for comparison and the upper water portion 2 is caused by the water flow or the like acting on the underwater portion 3 of the suspension type sonar.

FIG. 5 is a diagram for explaining the configuration of the water section 2. As shown in FIG. It should be noted that the upper water portion 12 for comparison is not connected to the suspension cable 4 in FIG. signal transmission is not performed), the physical configuration is preferably the same as that of the water section 2 . In FIG. 5, reference number 19 indicates the vertical direction, and reference number 23 indicates the inclination angle of the water section 2. As shown in FIG. The water section 2 is equipped with a GPS receiver 20 . GPS receivers 20 are installed in the upper water section 12 for comparison and the upper water section 2, respectively, and transmit latitude and longitude information as the respective positions of the upper water section 2 and the upper water section 12 for comparison at fixed time intervals to wireless communication devices 21. Output to The radio communication device 21 is installed in each of the water section 2 and the comparison water section 12, and performs radio communication with the aircraft 6 (see FIG. 6).

The wireless communication devices 21 of the upper water portion 2 and the comparison upper water portion 12 compare the position information of the upper water portion 2 and the comparison upper water portion 12 measured by the GPS receivers 20 of the upper water portion 2 and the comparison upper water portion 12 with the upper water portion 2. The information is transmitted to the aircraft 6 (see FIG. 6) via the radio antennas 22 respectively equipped on the water upper parts 12 .

FIG. 6 is a diagram for explaining the functional configuration of the aircraft 6 and the water section 2. As shown in FIG. In FIG. 6, the upper water portion 12 for comparison does not receive electrical signals (received acoustic signals) from the underwater portion 3 via the suspension cable 4 and does not transmit signals to the underwater portion 3. 2 is the same as the functional configuration.

The aircraft 6 has an on-board radio antenna 62 , an on-board radio communication device 61 and a position calculator 60 . The on-board radio communication device 61 demodulates the position information of the comparison water section 12 and the water section 2 received by the on-board radio antenna 62 and outputs the information to the position calculation section 60 . The position calculation unit 60 calculates the displacement horizontal azimuth and position displacement horizontal distance of the water section 2 and the underwater section 3 from the position information of the comparison water section 12 and the water section 2 input from the on-board wireless communication device 61 .

An example of positional deviation detection of the underwater section 3 of the suspension type sonar according to the present embodiment will be described.

The GPS receiver 20 on the water section 2 measures the position (latitude and longitude) of the water section 2, for example, at a cycle of 1 second, and transmits the position (latitude and longitude) of the water section 2 by radio from the radio antenna 22 by the radio communication device 21. It is received by the antenna 62 and output from the on-board wireless communication device 61 to the position calculation section 60 .

The position calculation unit 60 of the aircraft 6 stores the position information of the above water portion 2 from the latest position information of the above water portion 2 to a predetermined time (for example, 30 seconds before), and calculates the position information by the following equations (1) and (2 ) into latitude and longitude data (in seconds). Longitude and latitude are expressed in degrees, minutes, and seconds.

Location information (latitude 1 to 30) → value of degrees x 60 x 60 + value of minutes x 60 + value of seconds
…(1)

Location information (longitude 1 to 30) → (degree value x 60 x 60 + minute value x 60 + second value) x cos (location information (latitude (deg)))
…(2)

Here, position information (longitudes 1 to 30) and position information (latitudes 1 to 30) are represented by arrays X[i], Y[i] (i=1, . . . , 30).

In the position calculation unit 60 of the aircraft 6, for example, from the position information every second, the direction of movement of the water section 2 in one second (for example, the angle α in FIG. 4: for example, the horizontal Azimuth) and moving speed _Va are calculated by the following equations (3) and (4).

(i=1,…,30)
…（３）

(i=1,…,30)
…(3)

α takes −π/2<α<π/2 (radian) as the principal value of the arctangent function tan ⁻¹ .

Here, when calculating the value of α as an integer azimuth from 0 to 359 degrees (deg), α←INT(α×180/π) (INT( x) corresponds to the Gaussian symbol [x] and returns the largest integer that does not exceed x), convert from radian to degree (integer), and then perform the following operations.
If (X[i+1]−X[i])/(Y[i+1]−Y[i])≧0, then
If X[i+1]≧X[i] and Y[i+1]>Y[i], α←0deg+αdeg
If X[i+1]<X[i] and Y[i+1]<Y[i], α←180deg+αdeg
If (X[i+1]-X[i])/(Y[i+1]-Y[i])<0, then
If X[i+1]>X[i] and Y[i+1]<Y[i], α←180deg+αdeg
If X[i+1]<X[i] and Y[i+1]>Y[i], α←360deg+αdeg

（ｍ／秒）
…（４）

(m/sec)
…(4)

The azimuth-based velocity vector ^→ V _a (see FIG. 4) regarding the movement of the upper part of the water 2 is defined by the following equation (5).

…（５）

…(5)

The position calculator 60 of the aircraft 6 may calculate an average value of the moving direction and moving speed (m/sec) of the water section 2 for 30 seconds, for example. Alternatively, in the position calculation unit 60, position information (latitude 1) X[1], position information 30 seconds ago (latitude 30) X[30], position information (longitude 1) Y[1] and 30 seconds ago With respect to the position information Y [30] (longitude 30), the moving direction of the water part 2 and the moving distance of the water part 2 for 30 seconds (also referred to as the moving speed for 30 seconds) are calculated by Equation (1). The movement distance of the water section 2 may be multiplied by 1/30 to obtain the movement distance of the water section 2 per unit time (1 second), that is, the movement speed (m/second).

The GPS receiver 20 of the comparison upper water section 12 measures the position (latitude and longitude) of the comparison upper water section 12 at a cycle of, for example, one second, and transmits the position information of the comparison upper water section 12 via the wireless communication device 21 and the wireless antenna 22. The positional information of the comparison water section 12 is supplied to the position calculation unit 60.

The position calculation unit 60 performs the same processing as the calculation of the moving direction and moving speed of the upper water portion 2 described above, and calculates the average value of the moving direction and moving speed (m/sec) of the comparative upper water portion 12. calculate.

In the position calculation unit 60 of the aircraft 6, from the movement direction β and the movement speed V _b (m/sec) (see FIG. 4) of the comparison upper water section 12, the azimuth-based velocity vector relating to the movement of the comparison upper water section 12 ^→ V _b ( 4), the east-west direction component (x component) V _b−x and the north-south direction (y component) V _b−y are calculated. Although not particularly limited, the east-west direction and north-south direction correspond to the x-axis and the y-axis, respectively.

…（６）

… (6)

…（７）

… (7)

The position calculation unit 60 of the aircraft 6 calculates the velocity vector of the underwater section 3 ^→ _Vc (moving direction, moving speed) based on the azimuth-based velocity vectors (moving direction, moving speed) of the above water section 2 and the comparison upper water section 12. calculate.

If the velocity vectors of the upper water portion 2, the upper water portion 12 for comparison, and the underwater portion 3 are ^→ _Va , ^→ _Vb , and ^→ _Vc respectively, the following holds. That is, although the upper water portion 2 suspends the underwater portion 3 that is affected by the water flow, etc., the upper water portion 12 for comparison is not affected by the water flow, etc. because the underwater portion is not suspended. A vector obtained by subtracting the velocity vector of the upper part 2 ^→ V _a from the velocity vector of the upper part ^→ V _b becomes the velocity vector of the underwater part 3 ^→ V _c .

…（８）

... (8)

V _c−x and V _c−y are the east-west direction component (x component) and the north-south direction component (y component) (m/sec) of the velocity vector ^→ V _c of the underwater section 3 .

The position calculation unit 60 of the aircraft 6 calculates the shift angle θ (18 in FIG. 4) between the moving directions of the water section 2 and the underwater section 3 from the velocity vector of the underwater section 3 by the following equation (9).

…（９）

... (9)

When calculating the deviation angle θ from 0 to 359 deg (integer), the calculation for the principal value θ obtained by Equation (9): θ ← INT (θ × 180/π) (INT (x) does not exceed x returns the largest integer) to convert from radian to degree (integer) and then perform the following operations.
If V _c−x /V _c−y ≧0, then
If V _c−x ≧0 and V _c−y >0, then θ←0deg+θdeg
If V _c−x <0 and V _c−y <0, then θ←180deg+θdeg
If V _{c - x} /V _{c - y} < 0, then
If V _c−x >0 and V _c−y <0, then θ←180deg+θdeg
If V _c−x <0 and V _c−y >0, then θ←360deg+θdeg

The deviation angle θ is an angle in the xy plane of FIG. 4, and is also called a position deviation angle (horizontal direction of position deviation) between the underwater part 2 and the underwater part 3 .

The displacement horizontal direction of the underwater part 3 is substantially the same direction as the flow direction of the water flow 13 (FIG. 3).

However, in order to calculate the misalignment horizontal direction with higher accuracy, for example, the suspension cable 4 having a length of several hundred meters is affected by water flow, and the suspension cable 4 does not become straight when viewed from the sky. , it is necessary to consider that the curve is curved in the direction of the water flow due to the resistance of the water flow.

In this case, regarding the deviation angle in the positional deviation direction of the underwater section 3 due to the curving of the suspension cable 4, for example, a fluid motion simulation model of the underwater section 3 and the suspension cable 4 is created, and the flow velocity of the water flow 13 and the suspension It may be calculated from the length of the cable 4 . Alternatively, by submerging and suspending the underwater part 3 in the water tank and moving the underwater part 3 in the horizontal direction or by generating a water flow in the water tank, in the case of a water flow 13 with a known flow rate, the upper starting point of the suspension cable 4 By measuring the degree of displacement between the upper water portion 2 and the underwater portion 3, at least the flow velocity of the water flow acting on the underwater portion 3 and the displacement angle between the upper water portion 2 and the underwater portion 3 (displacement horizontal direction ) may be used to create a conversion table in advance.

The position calculator 60 calculates the moving speed Vc (m/sec) of the underwater section 3 with respect to the displacement distance of the underwater section 3 using the following equation (10). The moving speed (m/sec) of the underwater part 3 is the same as the flow speed (m/sec) of the water flow 13 shown in FIG. 3B and the like. The flow velocity V _c (m/sec) of the water flow 13 acting on the underwater section 3 is obtained by the following equation.

…（１０）

... (10)

The position calculator 60 calculates the positional displacement distance between the upper water portion 2 and the underwater portion 3 from the flow velocity (m/sec) of the water flow 13 acting on the underwater portion 3 . As the calculation method, for example, the following method can be used.

A fluid motion simulation model of the underwater section 3 and the suspension cable 4 is created, and the displacement distance between the underwater section 2 and the underwater section 3 is calculated from the water flow (m/sec) and the length of the suspension cable 4 .

In the case of a water flow 13 with a known flow velocity, the underwater part 3 is submerged in a water tank and suspended, and the water flow 13 with a known flow velocity is suspended by moving the underwater part 3 in the horizontal direction or by generating a water flow (m/sec) in the water tank. Measure how many meters the displacement occurs between the upper water portion 2 and the underwater portion 3, which are the upper starting point of the lower cable 4, and prepare in advance a conversion table of at least the flow velocity of the water flow 13 acting on the underwater portion 3 and the displacement distance. . The position calculation unit 60 calculates the displacement distance between the upper part of water 2 and the part of water 3 by referring to the conversion table from the flow velocity (m/sec) of the water flow 13 acting on the part of water 3 .

The position calculation unit 60 of the aircraft 6 calculates the position of the suspended sonar from the misalignment direction (horizontal direction) and misalignment distance (horizontal distance) of the underwater part 2 and the underwater part 3 of the suspended sonar. The corrected position of the underwater section 3 (the position projected onto the xy two-dimensional coordinates in FIG. 4), which is the starting point of the direction and distance of the received underwater sound wave, is calculated by the following equations (11) and (12), for example.

Corrected position of underwater section 3 (north-south direction) = [position of underwater section 2] + [horizontal distance of displacement of underwater section 3 (m)] x cos ([horizontal direction of displacement of underwater section 3 (deg)])
…(11)

Corrected position of underwater part 3 (east-west direction) = [position of underwater part 2] + [horizontal distance of displacement of underwater part 3 (m)] x sin ([horizontal direction of displacement of underwater part 3 (deg)])
…(12)

GPS receivers and wireless communication devices are well known to those skilled in the art, and detailed descriptions of their operations will be omitted. It goes without saying that the GPS receiver may be read as GNSS (Global Navigation Satellite System), which is a general term for satellite positioning systems such as GPS and Quasi-Zenith Satellite (QZSS).

According to the present embodiment, the positions of the comparison water section 12 dropped from the aircraft 6 and the positions of the water section 2 are observed with respect to the horizontal direction of positional deviation and the horizontal distance of positional deviation between the water section 2 and the underwater section 3 of the suspended sonar. and calculate the correction. Therefore, it is possible to improve the calculation accuracy of the position of the underwater section 3 which is the starting point of the reception position of the underwater sound waves received by the hanging sonar. According to this embodiment, it is possible to cope with a suspension type sonar having a length of the suspension cable 4 of about several hundred meters.

According to this embodiment, the kinetic energy that acts only on the upper water portion is used by using the upper water portion for comparison without observing weather and sea conditions that cause positional deviation between the upper water portion and the underwater portion of the suspended sonar. is observed and corrected. Therefore, it is possible to estimate the positional deviation between the underwater part 2 and the underwater part 3 in real time without any delay time.

FIG. 7 is a diagram for explaining the embodiment of the present invention, and is a diagram for explaining the configuration when the position calculation section 60 of FIG. Referring to FIG. 7, the computer device 200 includes a processor 201, a semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory) (or HDD (Hard Drive)). A disk drive or the like) memory 202, a display device 203, and an interface 204 (bus interface) connected to the on-board wireless communication device 61 in FIG. The processor 201 may be a DSP (Digital Signal Processor). By executing the program 205 stored in the memory 202, the processor 201 executes the processing of the position calculator 60 in FIG.

The disclosure of Patent Document 1 above is incorporated herein by reference. Within the framework of the full disclosure of the present invention (including the scope of claims), modifications and adjustments of the embodiments and examples are possible based on the basic technical concept thereof. Also, various combinations and 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, the present invention naturally includes various variations and modifications that can be made by those skilled in the art according to the entire disclosure including claims and technical ideas.

1 Sea surface 2 Above water 3 Underwater 4 Suspension cable 5 Velocity vector (moving direction, moving speed)
6 Airplane 7 Movement by wind force 8 Movement by tidal current 9 Movement by intermediate current 10 Traction by upper water 11 Movement by intermediate current 12 Upper water for comparison 13 Water flow 14 North-south direction 15 East-west direction 16 Velocity vector above water 17 Velocity above water for comparison vector (moving direction, moving speed)
18 Misalignment angle between moving direction above water and above water for comparison 19 Vertical direction 20 GPS receiver 21 Radio communication device 22 Radio antenna 23 Inclination angle above water 60 Position calculator 61 On-board radio communication device 62 On-board radio antenna 200 Computer device 201 processor 202 memory 203 display device 204 interface 205 program

Claims (10)

a water part equipped with a means for suspending the water part and measuring its own position;
a comparison water upper portion having a structure that does not suspend the underwater portion and equipped with a means for measuring its own position;
a position calculation means;
with
The position calculation means calculates a difference in moving direction and a difference in moving speed between the upper water portion and the upper water portion for comparison from respective position information measured at the upper portion of water and the upper portion of water for comparison, and
Based on the difference in the moving direction and the difference in moving speed between the upper water portion and the upper water portion for comparison, determine the flow direction and flow velocity of the water flow acting on the underwater portion,
A sonar system for calculating a positional deviation direction and a positional deviation distance between the above water portion and the underwater portion based on the direction and velocity of the water flow. The position calculation means uses the position of the upper part of the water and the positional deviation distance and the positional deviation direction of the underwater part to calculate the direction of arrival of the underwater sound wave received in the underwater part and the distance from the water. 3. The sonar system of claim 1, wherein the midsection position is corrected. When the position calculation means calculates the direction and distance of positional displacement between the above water portion and the underwater portion based on the direction and velocity of the water flow,
making the direction of positional deviation between the above water portion and the above water portion the flow direction of the water flow, or
Based on the relationship between the flow velocity of the water flow and the displacement direction and displacement distance between the water upper part and the underwater part, which are obtained in advance by a fluid motion simulation of the underwater part and the suspension cable or a water flow experiment in a water tank, 3. The sonar system according to claim 1, wherein a displacement direction and a displacement distance between said above water portion and said underwater portion are calculated. 4. A sonar system according to any preceding claim, wherein said position calculating means is provided on an aircraft. A method for detecting displacement of an underwater part in a suspended sonar system having an upper part of the water and means for measuring the position of the underwater part by suspending the underwater part, comprising:
A comparison water upper portion having a structure that does not suspend the underwater portion and equipped with a means for measuring its own position is arranged on the water surface together with the above water portion,
Calculate a difference in moving direction and a difference in moving speed between the upper water portion and the upper water portion for comparison from the respective positional information measured at the upper water portion and the upper water portion for comparison,
Based on the difference in the moving direction and the difference in moving speed between the upper water portion and the upper water portion for comparison, determine the flow direction and flow velocity of the water flow acting on the underwater portion,
A positional deviation detection method for calculating a positional deviation direction and a positional deviation distance between the above water portion and the underwater portion based on the flow direction and flow velocity of the water flow. 6. The positional deviation detection method according to claim 5, wherein the position of the underwater part is corrected using the position of the above water part and the positional deviation distance and the positional deviation direction of the underwater part. In calculating the positional displacement direction and positional displacement distance between the above water portion and the above water portion based on the flow direction and flow velocity of the water flow,
making the direction of positional deviation between the above water portion and the above water portion the flow direction of the water flow, or
Based on the relationship between the flow velocity of the water flow and the displacement direction and displacement distance between the water upper part and the underwater part, which are obtained in advance by a fluid motion simulation of the underwater part and the suspension cable or a water flow experiment in a water tank, 7. The positional deviation detection method according to claim 5, wherein a positional deviation direction and a positional deviation distance between said water portion and said underwater portion are calculated. a water part equipped with a means for suspending the water part and measuring its own position;
a sonar system computer having a comparison water top configured to not suspend the water portion and provided with means for measuring its own position;
a process of calculating a difference in moving direction and a difference in moving speed between the upper water portion and the upper water portion for comparison from the respective positional information measured at the upper portion of water and the upper portion of water for comparison;
a process of determining the flow direction and flow velocity of the water flow acting on the underwater part based on the difference in the movement direction and the difference in the movement speed between the water upper part and the comparison water upper part;
a process of calculating a positional deviation direction and a positional deviation distance between the above water portion and the above water portion based on the flow direction and flow velocity of the water flow;
program to run. 9. The program according to claim 8, which executes a process of correcting the position of the underwater section using the position of the above water section and the displacement distance and the displacement direction of the underwater section. In calculating the positional displacement direction and positional displacement distance between the above water portion and the above water portion based on the flow direction and flow velocity of the water flow,
making the direction of positional deviation between the above water portion and the above water portion the flow direction of the water flow, or
Based on the relationship between the flow velocity of the water flow and the displacement direction and displacement distance between the water upper part and the underwater part, which are obtained in advance by a fluid motion simulation of the underwater part and the suspension cable or a water flow experiment in a water tank, 10. The program according to claim 8 or 9, which calculates a positional deviation direction and a positional deviation distance between the above water portion and the underwater portion.

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