JP7279898B2 - 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.

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 upper part of the water receives electrical signals of underwater sound waves received from the upper part of the water via a suspension cable, and the position information of the upper part of the water measured by a GPS (Global Positioning System) receiver provided in the upper part of the water. The information is transmitted to an information center on an aircraft, on the ground, or on the sea via the radio communication unit and radio antenna of the terminal.

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). The acoustic element receives an underwater sound wave emitted from an underwater object, converts the received sound wave into an electric signal, and transmits the electric signal to the upper part of the water via the signal line of the suspension cable. 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 above, converts the echo sound into an electric signal, and transmits the electric signal to the above water surface through the signal line (signal cable) of the suspension cable. .

FIG. 1(A) 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 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 upper water portion 2 and the underwater portion 3 from a plane parallel to the straight line connecting the upper water portion 2 and the underwater portion 3 in 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.

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 sea winds and waves.

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) that acts on the water section 2 and affects 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) of the upper part of the water 2 due to waves and the like. As the force (kinetic energy) that acts on the upper part of the water 2 and affects its movement, there are things other than wind power, such as tidal currents, ocean currents, and waves. , so it is not suitable for real-time operations.

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. As the kinetic energy that affects the movement of the underwater part 3, there is also an intermediate ocean current at a depth of 100 m. Intermediate ocean currents are not always constant in direction and velocity depending on the depth of the water, and may vary in direction and velocity depending on the depth of the water. not suitable for the operation of

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, there arises a problem that the position of the underwater part 3, which is the starting point, is not accurate with respect to the accuracy of the arrival direction and distance of the underwater sound waves detected by the hanging sonar.

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 influence of ocean currents, etc., the position of the hydrophone causes a positional error (positional deviation) with respect to the buoy position, and the positional error of these sonobuoys etc. causes a large error in the calculation of the position of underwater targets etc. from the buoy position. is stated. In Patent Document 1, the deviation distance γ is calculated from the measured values of the length a of the signal cable between the buoy portion and the hydrophone, the hydrophone azimuth angle α from the buoy portion, the hydrophone inclination β, and the hydrophone depth d. are doing. Patent Document 1 states that when it is desired to improve the positional accuracy of the hydrophone position, it is possible to correct and calculate the "sag" that occurs in the signal cable using the catenary equation. and the motion of the hydrophone, especially the rotational motion of the hydrophone.

Further, in Patent Document 2, a GPS-type motion measurement sensor mounted on the upper part of the spar buoy is used to measure motion displacement due to shaking of the upper part of the spar buoy in time series as 3D position data, and this 3D position data obtained in time series. The pitching amplitude angle φ and motion period Tw of the spar buoy caused by waves are obtained based on A configuration is disclosed in which an approximate value of the wave height Hw is obtained from the obtained numerical values of the pitching amplitude angle φ of the spar buoy and the movement period Tw, and the wave height of the ocean wave is estimated from the obtained numerical value. In Patent Document 2, the inclination direction and inclination angle of the upper part of the water are calculated from the moving trajectory of the upper part of the water, and the direction and velocity of the tidal current or the like are calculated.

JP-A-6-289132 JP 2007-327853 A

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, there is provided an upper part of the water, an underwater part that is suspended from the upper part of the water and has a sensor that detects its own posture, and an inclination of the underwater part that is detected by the sensor of the underwater part. Based on the direction and angle of inclination, the flow direction and flow velocity of the water flow acting on the underwater section are calculated, and based on the flow direction and flow velocity of the water flow acting on the underwater section, the displacement direction and position of the above water section and the underwater section. and position calculation means for calculating the displacement distance.

According to one aspect of the present invention, there is provided a method for detecting misalignment between an upper water portion and an underwater portion in a sonar system having an upper water portion and an underwater portion suspended from the upper water portion. The method comprises
A sensor for detecting the attitude of the underwater part is mounted on the underwater part,
based on the inclination direction and inclination angle of the underwater part detected by the sensor of the underwater part, calculating the flow direction and flow velocity of the water flow acting on the underwater part;
Based on the flow direction and flow velocity of the water flow acting on the underwater section, a displacement direction and a displacement distance between the above water section and the underwater section are calculated.

According to one aspect of the present invention, a sonar system having an upper water portion and an underwater portion that is suspended from the upper water portion and that is equipped with a sensor for detecting the posture of the sonar system detects a positional deviation between the upper water portion and the underwater portion. on the computer that performs the detection process,
Based on the inclination direction and inclination angle of the underwater section detected by the sensor of the underwater section, the flow direction and flow velocity of the water flow acting on the underwater section are calculated, and the flow direction and flow velocity of the water flow acting on the underwater section are calculated. Based on this, there is provided a program for executing a process of calculating the positional deviation direction and the positional deviation distance between the above water portion and the above water portion. 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. It is a figure explaining embodiment of this invention. It is a figure explaining the underwater part of embodiment of this invention. It is a figure explaining the underwater part of embodiment of this invention. It is a figure explaining embodiment of this invention. It is a figure explaining embodiment of this invention.

An embodiment of the present invention will be described. 3 and 4 are diagrams illustrating the underwater section 3 in one embodiment of the present invention. FIG. 3 schematically shows the underwater section 3 of the suspended sonar according to one embodiment of the present invention, and schematically shows a state in which the underwater section 3 is tilted by movement due to water flow or the like. In FIG. 3, the underwater section 3 is connected to the underwater section 2 (not shown) (see FIGS. 1, 2, etc.) by a suspension cable 4. As shown in FIG. FIG. 4 schematically shows a state in which the underwater part 3 rotates while performing a swinging motion (steady precession motion) in water.

Referring to FIG. 3, the underwater section 3 has a 3-axis attitude sensor 31 . The 3-axis posture sensor 31 is composed of, for example, a 3-axis acceleration sensor, and continuously detects the tilt angle (roll angle, pitch angle) with respect to the front/rear and left/right axes and the rotation angle (yaw angle) about the vertical axis. . A rotation angle (yaw angle) about the vertical axis detected by the three-axis posture sensor 31 is called a tilt direction (tilt azimuth). 3, the tilt angle (roll angle, pitch angle) and tilt direction (yaw angle) of the underwater section 3 detected by the three-axis attitude sensor 31 are represented by the tilt angle and tilt direction 15 of the underwater section 3. there is

Since the underwater portion 3 rotates underwater, the tilt angle and the tilt direction 15 of the underwater portion 3 are affected by the swinging motion accompanying the rotation of the underwater portion 3 . According to the present embodiment, when detecting the position of the underwater section 3, the average value obtained by arithmetically averaging the inclination angle and the inclination direction 15 of the underwater section 3 measured for a predetermined time (fixed time) by the three-axis attitude sensor 31 is calculated as the tilt angle and tilt direction of the underwater portion 3 (the average tilt angle (average tilt direction) 38 of the underwater portion in FIG. 4). Then, based on the calculated inclination angle and inclination direction of the underwater part 3, the moving direction and the moving speed of the underwater part 3 are calculated.

In the above water surface 2, the GPS receiver (24 in FIG. 5) continuously measures the position of the above water surface 2 as latitude and longitude, and from the trajectory, the moving direction and moving speed of the above water surface 2 (velocity vector in FIG. 1 5) is calculated. Further, the underwater part 2 receives the inclination angle and the inclination direction of the underwater part 3 from the three-axis posture sensor 31 of the underwater part 3 via the suspension cable 4 .

In the upper water part 2, the horizontal direction and horizontal distance to the underwater part 3 (direction and distance on the xy two-dimensional plane in FIG. 2) from the water upper part 2 to the underwater part 3 are calculated as the positional deviation between the water upper part 2 and the underwater part 3. .

3 and 4, the outline arrow 16 indicates the water flow acting on the underwater section 3. As shown in FIG. As exemplified in FIG. 2, the underwater section 3 tries to drift along the intermediate ocean current 11, but the suspension cable 4 suspended from the underwater section 2 (10 in FIG. Move against 2-11). Therefore, the underwater section 3 receives resistance from the water flow 16 . In the submerged section 3 that receives resistance from the water flow 16 , a deviation occurs between the fulcrum of the suspension cable 4 and the center of gravity 32 of the submerged section 3 . Therefore, the underwater part 3 is inclined in the direction opposite to the water flow 16 .

The direction of this water flow 16 is the combined vector of the traction vector by the upper water section 2 and the movement vector by the intermediate ocean current. That is, the direction opposite to the direction of the water flow 16 is generally the tilt direction of the underwater section 3 (15 in FIG. 3), and the magnitude of the water flow 16 is substantially proportional to the tilt angle of the underwater section 3 (15 in FIG. 3). influence in the way it does.

In FIG. 4, the underwater section (average posture) indicated by reference numeral 33 indicates the average posture of the underwater section 3 in FIG. After the suspension type sonar lands on the surface of the sea and is separated into an upper water part 2 and an underwater part 3, the underwater part 3 sinks while extending the suspension cable 4. - 特許庁At that time, since the suspension cable 4 is released from the twist, the underwater part 3 rotates in the water. At this time, the underwater part 2 rotates in the opposite direction to the underwater part 3 .

In FIG. 4, an underwater section (average posture) 33 indicates an average posture of the underwater section 3 rotating while swinging.

An underwater portion (minimum tilt angle) 34 shows a state in which the tilt angle of the underwater portion 3 rotating while swinging underwater is minimized. The tilt direction of the underwater portion (at the minimum tilt angle) 34 coincides with the average tilt direction of the underwater portion 3 .

An underwater portion (maximum tilt angle) 35 shows a state in which the underwater portion 3 rotating while swinging underwater has the maximum tilt angle. The tilt direction of the underwater portion (at maximum tilt angle) 35 coincides with the average tilt direction of the underwater portion 3 .

The minimum tilt angle (average tilt direction) 36 of the underwater section indicates the minimum tilt angle of the underwater section 3 in the underwater section (at the minimum tilt angle) 34 . The inclination direction of the minimum inclination angle (average inclination direction) 36 of the underwater part coincides with the average inclination direction of the underwater part 3 .

The maximum tilt angle (average tilt direction) 37 of the underwater portion indicates the maximum tilt angle of the underwater portion 3 in the underwater portion (maximum tilt angle) 35 . The inclination direction of the maximum inclination angle (average inclination direction) 37 of the underwater part coincides with the average inclination direction of the underwater part 3 .

The average inclination angle (average inclination direction) 38 of the underwater part indicates the inclination angle of the underwater part 3 in the underwater part (average posture) 33 . The inclination direction of the average inclination angle (average inclination direction) 38 of the underwater part coincides with the average inclination direction of the underwater part 3 .

A suspension cable (average posture) 41 indicates the average posture of the suspension cable 4 and indicates the state of the suspension cable 4 corresponding to the underwater section (average posture) 33 .

FIG. 5 is a diagram illustrating the water section 2 in one embodiment of the present invention. Referring to FIG. 5 , the water section 2 includes a GPS receiver 24 , a position calculator 25 , a radio communication section 26 and a radio antenna 27 . The GPS receiver 24 continuously outputs latitude and longitude information as the position of the above water surface 2 by GPS to the position calculator 25 at regular time intervals. The GPS receiver 24 may of course be read as GNSS (Global Navigation Satellite System), which is a general term for satellite positioning systems such as GPS and Quasi-Zenith Satellite System (QZSS (Quasi-Zenith Satellite System)). is.

The position calculation unit 25 of the above water part 2 receives the position information of the above water part 2 from the GPS receiver 24 . Further, the position calculation unit 25 of the upper water part 2 inputs the inclination angle and the inclination direction of the underwater part 3 from the 3-axis posture sensor 31 of the underwater part 3, The flow direction and flow velocity of the water flow 16 acting on are calculated.

The position calculator 25 of the upper water part 2 calculates the position of the upper water part 2 and the underwater part based on the flow direction and flow velocity of the water flow 16 acting on the underwater part 3 and the movement direction and movement speed of the water upper part 2 (velocity vector 5 in FIG. 1). 3, the displacement direction and the displacement distance are calculated.

The wireless communication unit 26 of the water section 2 is a communication device that performs wireless communication between the suspended sonar and the aircraft (6 in FIG. 1B). Transmit the location information of the central section 3 to the aircraft. A radio antenna 27 on the water section 2 transmits and receives radio waves.

Next, positional deviation detection of the underwater section 3 in this embodiment will be described with reference to FIG. 6 and the like. FIG. 6 is a diagram for explaining the water section 2 and the underwater section 3 of this embodiment.

The three-axis attitude sensor 31 of the underwater section 3 measures the inclination angle and the inclination direction of the underwater section 3 at a period of, for example, 20 to 50 milliseconds, and outputs them to the position calculation section 25 of the underwater section 2 via the suspension cable 4. do.

The position calculation unit 25 of the upper part of water 2 calculates the average value of the inclination angle and the inclination direction (15 in FIG. 3) of the underwater part 3 input from the 3-axis attitude sensor 31 of the underwater part 3, for example, for about 30 seconds. do. The average value of the inclination angle and the inclination direction of the underwater part 3 calculated by the position calculator 25 of the water part 2 corresponds to the average inclination angle (average inclination direction) 38 of the underwater part in FIG.

It is assumed that the maximum rotation speed of the underwater section 3 of the assumed suspension type sonar is 120 deg/sec, and one rotation is performed in about 3 seconds. In this case, by calculating the average value of the inclination angle and the inclination direction of the underwater part 3 for 30 seconds, the inclination direction and the inclination angle as the average posture of the underwater part 3 (the average inclination angle of the underwater part in FIG. 4 (average tilt direction) 38) can be obtained.

The position calculation unit 25 of the underwater part 2 calculates the position of the underwater part 3 based on the inclination angle as the average posture of the underwater part 3 (the average inclination angle of the average inclination angle (average inclination direction) 38 of the underwater part in FIG. 4). The flow velocity of the water stream 16 acting is calculated.

In calculating the flow velocity of the water flow 16 acting on the underwater part 3 from the inclination angle as the average posture of the underwater part 3, the position calculation unit 25 of the upper part of the water 2 performs, for example,
-Using a method of creating a fluid motion simulation model of the underwater part 3 and formulating it, or
By submerging and suspending the underwater part 3 in the water tank and moving the underwater part 3 in the horizontal direction or by causing a water flow in the water tank, when there is a water flow with a known flow rate, the underwater part 3 can be tilted by how many degrees A conversion table between the inclination angle of the underwater section 3 and the flow velocity of the water flow is created in advance, and the position calculation section 25 of the underwater section 2 stores and retains the conversion table in a storage section (not shown). Then, the flow velocity of the water flow 16 acting on the underwater section 3 may be obtained from the average inclination angle of the underwater section 3 by referring to the conversion table.

…（１）
で表される。 The position calculation unit 25 of the underwater part 2 determines the direction opposite to the inclination direction as the average posture of the underwater part 3 (the average inclination direction in the average inclination angle (average inclination direction) 38 of the underwater part in FIG. 4). 3 is the direction of the water flow 16 acting on the water. The flow direction and flow velocity of the water flow 16 acting on the underwater part 3 are the direction and velocity projected onto the xy two-dimensional plane (horizontal plane) such as FIG. 2(A). For example, if the north-south direction (y-axis) is the reference direction, the flow direction of the water flow 16 is β, and the flow velocity is V _b , the velocity vector of the water flow 16 ^→ V _b (two-dimensional vector) is

…(1)
is represented by

The GPS receiver 24 of the above water surface 2 outputs the position (latitude and longitude) of the above water surface 2 to the position calculation unit 25 of the above water surface 2, for example, at intervals of one second.

The position calculation unit 25 of the upper part of water 2 stores position information of the upper part of water 2 from the latest position information up to 30 seconds ago, and converts the position information into latitude and longitude data that can be easily calculated by the following equations.

The position calculation unit 25 of the upper water section 2 stores position information from the latest position information to a predetermined time (for example, 30 seconds ago), and calculates the position information by the following equations (2) and (3) as latitude and longitude. Convert to 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
…(2)

Location information (longitude 1 to 30) → (degree value x 60 x 60 + minute value x 60 + second value) x cos (location information (latitude (deg)))
…(3)

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 25 of the water part 2, for example, the movement direction α (for example, the horizontal direction with the north-south direction (y-axis) as the reference direction) and the movement speed V _a is calculated by the following equations (4) and (5).

(i=1,…,30)
…（４）

(i=1,…,30)
…(4)

（ｍ／秒）
…（５）

(m/sec)
…(5)

…（６） The velocity vector of the upper part of the water 2 ^→ V _a (two-dimensional vector) is given below.

… (6)

The position calculation unit 25 of the upper part of the water 2 may calculate an average value of the moving direction and the moving speed (m/sec) of the upper part of the water 2 for 30 seconds, for example. Alternatively, the position calculation unit 25 calculates 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 position calculation unit 25 of the upper water part 2 calculates the position of the upper water part 2 and the underwater part 3 from the flow direction and flow velocity of the water flow 16 acting on the underwater part 3 and the movement direction and movement speed of the water upper part 2 by the following equation (7). An approximate value of the positional deviation direction (positional deviation direction on a two-dimensional plane (horizontal plane)) is calculated.

Direction of positional deviation ≈ Flow direction (β) of water flow 16 acting on underwater section 3 + 180 (deg)
… (7)

In the position calculation unit 25 of the upper water part 2, in order to calculate the positional deviation direction of the upper water part 2 and the underwater part 3 with high accuracy, for example, the suspension cable 4 having a length of several hundred meters is affected by the water flow, It is necessary to consider that when viewed from above, it does not form a straight line, but instead curves in the direction of the water flow due to the resistance of the water flow.

For the deviation angle in the positional deviation direction of the underwater section 3 due to the curving of the suspension cable 4, for example, either of the following methods (a) and (b) can be used.

(a) A fluid motion simulation model of the underwater section 3 and the suspension cable 4 is created, and a calculation formula for calculation from the velocity of the water flow and the length of the suspension cable 4 is obtained.

(b) By submerging and suspending the underwater part 3 in the water tank, moving the underwater part 3 horizontally or by generating a water flow in the water tank, the upper starting point of the suspension cable 4 in the case of a water flow with a known flow rate Measure the number of displacements between the upper water portion 2 and the underwater portion 3, and prepare a conversion table for the velocity of the water flow acting on the underwater portion 3 and the suspension cable 4 and the displacement angle in advance. The position calculator 25 of the water section 2 stores and retains the conversion table in a storage unit (not shown), and refers to the conversion table to determine the positional deviation from the flow velocity of the water flow 16 and the length of the suspension cable 4. ask for directions.

For the displacement distance between the water section 2 and the underwater section 3, for example, one of the following methods (c) and (d) can be used.

(c) Create a fluid motion simulation model of the underwater section 3 and the suspension cable 4, and obtain a calculation formula for calculation from the flow velocity of the water flow and the length of the suspension cable.
(d) By submerging and suspending the underwater part 3 in the water tank, moving the underwater part 3 in the horizontal direction or by generating a water flow in the water tank, the upper starting point of the suspension cable 4 in the case of a water flow with a known flow rate Measure how many meters the displacement between the upper water portion 2 and the underwater portion 3 is, and create a conversion table for the velocity of the water flow acting on the underwater portion 3 and the suspension cable 4 and the displacement distance. The position calculation unit 25 of the water section 2 stores the conversion table in a storage unit (not shown), refers to the conversion table, and calculates the displacement distance from the flow velocity of the water flow 16 and the length of the suspension cable 4. Ask for

The position calculation unit 25 of ^the upper water part 2 calculates the displacement direction of the upper water part 2 and the underwater part 3 and The displacement distance may be corrected so as to reflect the influence of the movement of the upper part of the water 2 due to wind power (7 in FIG. 2) or movement due to tidal currents (8 in FIG. 2).

The position calculation unit 25 of the upper water part 2 includes information on the positional deviation direction and the positional deviation distance from the underwater part 3 calculated, for example, at a one-second cycle, and the latest positional information of the upper water part 2 input from the GPS receiver 24 ( latitude and longitude) to the wireless communication unit 26.

The wireless communication unit 26 receives information on the positional deviation direction and positional deviation distance from the underwater unit 3 from the wireless antenna 27 and the latest positional information (latitude and longitude) of the underwater unit 2 input from the GPS receiver 24. Send sonar to a fixed-wing or rotary-wing aircraft (6 in FIG. 1B) monitoring underwater acoustic waves. Note that the GPS receiver 24 and the wireless communication unit 26 are well known to those skilled in the art, and detailed descriptions of their operations will be omitted.

According to this embodiment, the displacement direction and displacement distance between the underwater section 2 and the underwater section 3 of the suspended sonar can be determined from the inclination angle and the inclination direction of the underwater section 3 detected by the three-axis posture sensor 31 of the underwater section. By estimating, it is possible to improve the positional accuracy of the underwater section 3 (which is the starting point of the direction of arrival of underwater sound waves received by the suspended sonar).

According to this embodiment, the inclination of the underwater section 3 caused by the water flow acting on the underwater section 3 can be achieved without observing weather and sea conditions that cause misalignment between the underwater section 2 and the underwater section 3 of the suspended sonar. By arithmetically processing the measurement result of the physical phenomenon, the positional deviation between the water section 2 and the underwater section 3 can be estimated in real time without 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 25 is implemented in the computer device 200. As shown in FIG. Referring to FIG. 7, the computer device 200 includes a processor 201, semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory) (or HDD (Hard Disk Drive)). disk drive), the display device 203, the GPS receiver 24 in FIG. It has an interface 204 (bus interface) for connection. 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 25 in FIG.

The disclosures of Patent Documents 1 and 2 mentioned above are 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 Aircraft 7 Movement by wind power 8 Movement by tidal currents 9 Movement by intermediate currents 10 Traction by upper water level 11 Movement by intermediate currents 14 Vertical direction 15 Inclination angle and direction of inclination 16 Water current 23 Inclination angle above water 24 GPS receiver 25 Position calculation unit 26 Wireless communication unit 27 Wireless antenna 31 3-axis attitude sensor 32 Underwater center of gravity 33 Underwater area (average attitude)
34 Underwater part (at minimum tilt angle)
35 Underwater part (at maximum tilt angle)
36 Minimum Inclination Angle of Underwater Section (Average Inclination Direction)
37 maximum angle of inclination of underwater part (average direction of inclination)
38 Average inclination angle of underwater part (average inclination direction)
41 suspension cable (average posture)
61 on-board wireless communication unit 62 on-board wireless antenna 200 computer device 201 processor 202 memory 203 display device 204 interface 205 program

Claims (10)

above the water;
an underwater section suspended above the water section and equipped with a sensor for detecting its own posture;
based on the inclination direction and inclination angle of the underwater part detected by the sensor of the underwater part, calculating the flow direction and flow velocity of the water flow acting on the underwater part;
position calculation means for calculating a positional deviation direction and a positional deviation distance between the water section and the underwater section based on the flow direction and flow velocity of the water flow acting on the underwater section;
A sonar system comprising: The position calculation means is
Obtaining a flow velocity of the water flow acting on the underwater section based on an angle obtained by averaging inclination angles of the underwater section detected by the sensor of the underwater section;
2. The sonar system according to claim 1, wherein a direction opposite to a direction obtained by averaging inclination directions of said underwater section detected by said sensor of said underwater section is set as a flow direction of said water current acting on said underwater section. . The position calculation means is
approximating the positional deviation direction between the above water portion and the above water portion by the flow direction of the water flow acting on the above water portion, or
Based on the relationship between the flow velocity of the water flow and the displacement direction and displacement distance between the water upper portion and the underwater portion obtained in advance by a fluid motion simulation of the underwater portion and the suspension cable or a water flow experiment in a water tank. 3. The sonar system according to claim 1, wherein the displacement direction and the displacement distance between the above water portion and the above water portion are calculated. 4. A sonar system according to any one of claims 1 to 3, wherein said position calculating means is provided above said water. A method for detecting positional deviation between an upper water portion and an underwater portion in a sonar system having an upper water portion and an underwater portion suspended from the upper water portion, the method comprising:
A sensor for detecting the attitude of the underwater part is mounted on the underwater part,
based on the inclination direction and inclination angle of the underwater part detected by the sensor of the underwater part, calculating the flow direction and flow velocity of the water flow acting on the underwater part;
A positional deviation detection method, comprising: calculating a positional deviation direction and a positional deviation distance between the water section and the underwater section based on a flow direction and flow velocity of the water flow acting on the underwater section. Obtaining a flow velocity of the water flow acting on the underwater section based on an angle obtained by averaging inclination angles of the underwater section detected by the sensor of the underwater section;
6. The displacement according to claim 5, wherein a direction opposite to a direction obtained by averaging inclination directions of the underwater section detected by the sensor of the underwater section is set as a flow direction of the water flow acting on the underwater section. Detection method. In calculating the positional deviation direction and the positional deviation distance between the above water portion and the above water portion,
approximating the positional deviation direction between the above water portion and the above water portion by the flow direction of the water flow acting on the above water portion, or
Relationship between the flow velocity of the water flow, the direction of displacement between the upper part of the water and the underwater part, and the distance of the positional displacement obtained in advance from 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 the positional deviation direction and the positional deviation distance between the above water portion and the above water portion are calculated based on the above. A computer that executes processing for detecting a positional deviation between the above water portion and the above water portion of a sonar system that has an above water portion and an underwater portion that is suspended from the above water portion and has a sensor that detects its own posture,
based on the inclination direction and inclination angle of the underwater part detected by the sensor of the underwater part, calculating the flow direction and flow velocity of the water flow acting on the underwater part;
A program for executing a process of calculating a positional deviation direction and a positional deviation distance between the water upper part and the underwater part based on the flow direction and flow velocity of the water flow acting on the underwater part. Obtaining a flow velocity of the water flow acting on the underwater section based on an angle obtained by averaging inclination angles of the underwater section detected by the sensor of the underwater section;
9. The program according to claim 8, causing the computer to execute a process of setting a direction opposite to a direction obtained by averaging inclination directions of the underwater part detected by the sensor of the underwater part as a flow direction of the water flow acting on the underwater part. . In calculating the positional deviation direction and the positional deviation distance between the above water portion and the above water portion,
approximating the positional deviation direction between the above water portion and the above water portion by the flow direction of the water flow acting on the above water portion, or
Relationship between the flow velocity of the water flow, the direction of displacement between the upper part of the water and the underwater part, and the distance of the positional displacement obtained in advance from 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, causing the computer to execute 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.

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