Positioning method suitable for acoustic subsurface buoy main floating body

Abstract

The invention provides a positioning method suitable for a main floating body of an acoustic subsurface buoy, and relates to the technical field of positioning of the main floating body of the acoustic subsurface buoy, and the positioning method specifically comprises the following steps: measuring the pressure of the position of the main floating body by using a pressure sensor, and further calculating the actual depth and settlement displacement of the main floating body; the sound velocity in seawater is indirectly calculated through CTD arranged on the cable system in a segmented mode, the distance between the main floating body and the anchored weight is calculated through the sound velocity, and therefore the offset of the main floating body in the horizontal direction is indirectly calculated; the seawater flow velocity vector of the water area where the main floating body is located is measured through ADCP; an incident flow tail fin is arranged at the tail of the main floating body, so that the main floating body always carries out incident flow, and the opposite direction of the seawater flow direction is the main floating body direction. According to the technical scheme, the problem that the main floating body of the acoustic subsurface buoy cannot be accurately positioned in the prior art is solved.

Description

Technical Field

[0001] The invention relates to the technical field of submerged buoy positioning, and in particular to a positioning method suitable for a main floating body of an acoustic submerged buoy. Background Art

[0002] Acoustic buoys can be used to detect abnormal sound signals in the deep sea. They have the advantages of long monitoring time, strong concealment, and no influence from sea surface weather conditions. With the rapid increase in the number of acoustic buoys, the amount of observation data is also gradually huge, and the data quality is also crucial.

[0003] Most of the various observation instruments carried by the acoustic buoy are on the main buoy, which is then connected to the anchored weight through a cable system. The cable system is usually arranged for a long time. When encountering a current, the acoustic buoy will tilt as a whole under the influence of the current, resulting in offset settlement and left and right swaying. As a result, the actual depth of the observation instrument attached to the main buoy is lower than the preset depth, and the monitored direction is offset. This longitudinal offset and the influence of the current cannot be predicted in advance. If the position of the main buoy cannot be accurately located, the data measured by some observation instruments will be deeper than the preset data depth. For example, the observation instrument is preset to be hung at a water depth of 1000m. Due to the offset settlement of the acoustic buoy, the overall cable system is tilted, resulting in the observation instrument actually being located at a water depth of 1100m. Then, the water depth at 1100m will be mistakenly assigned to 1000m, and the data quality measured by the observation instrument will be poor, and the left and right swaying will affect the judgment of the monitoring target direction. Therefore, it is particularly important to ensure that the acoustic buoy works normally and effectively underwater, accurately locate the buoy, and control the buoy's posture. In the prior art, IMU (Inertial Measurement Unit) can be used to determine the real-time rotation angle. However, the calculation of the rotation angle requires the integration of the angular acceleration measured by the IMU. The accuracy of the angle calculation algorithm cannot support the long-term use of the acoustic buoy underwater. In addition, high-precision IMUs are not only expensive, but also usually require the integration of satellites or long-baseline positioning systems to correct inertial navigation to improve the accuracy of the calculation, while underwater satellite systems do not work.

[0004] Therefore, a positioning method capable of accurately positioning the main floating body of an acoustic buoy is now needed. Summary of the invention

[0005] The main purpose of the present invention is to provide a positioning method suitable for the main floating body of an acoustic submerged buoy, so as to solve the problem that the main floating body of the acoustic submerged buoy cannot be accurately positioned in the prior art.

[0006] To achieve the above object, the present invention provides a positioning method for the main floating body of an acoustic buoy, which specifically includes the following steps:

[0007] S1, using the pressure sensor to measure the pressure at the location of the main floating body, and then calculating the actual depth and settlement displacement of the main floating body.

[0008] S2, uses CTD sensors arranged in sections on the cable system to indirectly calculate the speed of sound in the seawater, and uses the speed of sound to calculate the distance between the main buoy and the anchored weight, thereby indirectly calculating the horizontal displacement of the main buoy.

[0009] S3, using ADCP to measure the seawater velocity vector in the water area where the main buoy is located.

[0010] S4, a tail fin facing the flow is set at the tail of the main floating body so that the main floating body always faces the flow and the direction of the main floating body is the opposite direction of the sea water flow.

[0011] Furthermore, step S1 specifically includes the following steps:

[0012] S1.1, install CTD on the main buoy, after the main buoy settles and stabilizes, use the formula Measure the pressure value of the main buoy, where H is the actual depth of the main buoy measured by the pressure sensor, P is the pressure measured by CTD, ρ is the seawater density, g is the gravitational acceleration, and H1 is the water depth of the sea area where the main buoy is deployed.

[0013] S1.2, calculate the settlement Δh:

[0014] Δh=h+H-H1;

[0015] Wherein, h is the length of the main buoy cable.

[0016] Furthermore, step S2 specifically includes the following steps:

[0017] S2.1, the temperature, salinity and depth of the seawater are measured by CTD sensors arranged in sections on the cable system, and the speed of sound in the seawater is calculated:

[0018]

[0019] Among them, v i is the speed of sound in seawater; T i is the sea water temperature; S i is salinity; depth is D i .

[0020] S2.2, calculate the average speed of sound

[0021]

[0022] in, is the average speed of sound; v i and v i-1 The depth is D iand D i-1 The speed of sound at D 发 is the depth of the sonic wave transmitting probe; D 收 is the depth of the sound wave receiving probe; n is the number of underwater sound speed samples.

[0023] S2.3, the acoustic wave transmitting probe and the acoustic wave receiving probe are fixed on the anchor weight and the main floating body respectively, and the distance x between the main floating body and the anchor weight is calculated:

[0024]

[0025] Among them, Δt is the time difference between the sound wave transmitting probe transmitting the sound wave and the sound wave receiving probe receiving the sound wave.

[0026] S2.4, calculate the inclination angle θ of the main floating body relative to the initial position:

[0027]

[0028] S2.5, calculate the horizontal displacement ΔX of the main floating body:

[0029]

[0030] Furthermore, step S3 specifically includes the following steps:

[0031] S3.1, calculate the direction angle and tilt angle of ADCP:

[0032]

[0033] Where α is the direction angle of ADCP, β is the tilt angle of ADCP, and h heading , p, and r represent the yaw angle, pitch angle, and roll angle of ADCP, respectively.

[0034] S3.2, using the direction angle and inclination angle of ADCP, the velocity in the ADCP coordinate system is converted to the velocity in the earth coordinate system, where u is the east-west velocity, v is the north-south velocity, and w is the vertical velocity:

[0035]

[0036] in:

[0037] R = R(α)·R(β);

[0038] R represents the transformation matrix, R(α) represents the rotation matrix around the Z axis, and R(β) represents the rotation matrix around the Y axis; u0, v0 and w0 represent the east-west flow velocity, north-south flow velocity and vertical flow velocity in their own coordinate system respectively;

[0039]

[0040] S3.3, calculate the velocity vector V=u+v+w of seawater.

[0041] Furthermore, the main floating body in step S4 includes: an integrally formed ball head, a main body and a tail, one end of the main body is the ball head, and the other end is the tail, a flow-facing tail fin is arranged above the tail, and the longitudinal extension direction of the flow-facing tail fin is perpendicular to the horizontal plane, and two balancing tail fins are arranged below the tail, and the two balancing tail fins are symmetrically arranged along the transverse center axis of the main floating body.

[0042] Furthermore, a notch is provided on the flow-facing tail fin.

[0043] Furthermore, two balancing tail fins are arranged near the tail end surface.

[0044] Furthermore, the main body is cylindrical, the ball head is semi-spherical, the tail is a trapezoidal structure, and the diameter of the tail gradually decreases from the main body to the end face of the tail.

[0045] Furthermore, a side thrust motor is arranged on the side of the main body.

[0046] Furthermore, a torque measuring instrument is arranged below the main body.

[0047] The present invention has the following beneficial effects:

[0048] The present invention proposes a spatial positioning and attitude determination method applicable to the main floating body of a deep-sea acoustic buoy and performs yaw attitude correction on the main floating body of an acoustic buoy equipped with a hydrophone after encountering turbulence, thereby improving the accuracy of the acoustic buoy in monitoring the position and distance of underwater targets. The sensors used in the present invention are basically sensors commonly carried on the buoy observation system, making full use of the existing observation data in the buoy system, and having a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the specific implementation or the prior art description. Obviously, the drawings described below are some implementations of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0050] Figure 1 The main floating body structure diagram in step S4 of the present invention is shown.

[0051] Figure 2 A schematic diagram of the equilibrium state of the anchor system under ideal conditions is shown.

[0052] Figure 3 A schematic diagram showing the equilibrium state of the anchor system when displacement and settlement occur is shown.

[0053] Figure 4 A position relationship analysis diagram of the anchor system is shown.

[0054] Figure 5 The velocity diagram of the main floating body being impacted by the current in a current field with a flow rate of 0.3 m / s is shown.

[0055] Figure 6 The figure shows the flow resistance coefficient of the main buoy in a 0.3 m / s sea current.

[0056] Figure 7 The main floating body is shown to be automatically corrected by the side thrust motor after being subjected to a large torque.

[0057] The reference numerals in the above drawings are:

[0058] 10. Ball head; 20. Main body; 30. Tail; 31. Tail end face; 40. Flow-incoming tail fin; 41. Notch; 50. Balance tail; 60. Side thrust motor; 70. Torque measuring instrument;

[0059] 1. Main buoy; 2. Cable mooring; 3. Anchored weight. DETAILED DESCRIPTION

[0060] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] like Figure 1 A positioning method applicable to the main floating body of an acoustic buoy is shown, which specifically includes the following steps:

[0062] S1, using the pressure sensor to measure the pressure at the location of the main floating body, and then calculating the actual depth and settlement displacement of the main floating body.

[0063] S2, uses the CTD (temperature, salinity and depth meter) sensors arranged in sections on the cable to indirectly calculate the sound speed in the seawater, and uses the sound speed to calculate the distance between the main floating body and the anchored weight, thereby indirectly calculating the displacement of the main floating body in the horizontal direction.

[0064] S3, using ADCP to measure the seawater velocity vector in the water area where the main buoy is located.

[0065] S4, a tail fin facing the flow is set at the tail of the main floating body so that the main floating body always faces the flow and the direction of the main floating body is the opposite direction of the sea water flow.

[0066] The present invention proposes a positioning method suitable for the main float of an acoustic buoy. When the main float is deployed in a sea area with currents, the impact force of the water flow, the gravity anchor resistance and the buoyancy will cause the entire anchor system to drift dynamically. The entire cable system will inevitably shift ΔX in the horizontal direction in three-dimensional space and produce a certain amount of settlement Δh in the vertical direction. The motion trajectory of the main float caused by the tide is roughly an ellipse. Therefore, in order to achieve precise positioning, it is necessary not only to locate the displacement of the main float's settlement, but also to determine the horizontal displacement of the main float relative to the initial position and the directional change relative to the initial position. The movement state of the main float underwater is as follows: Figure 1 and Figure 2 shown.

[0067] The main buoy 1, as a buoyancy platform, provides positive buoyancy for underwater sensors. The main buoy is equipped with a variety of sensors, hydrophones, and sound wave receiving probes. Since the alarm detected by the hydrophone needs to be transmitted in real time, the main buoy is designed to be horizontal to facilitate the release of real-time communication buoys.

[0068] The cable 2 is made of ultra-high molecular weight polyethylene material, which has the characteristics of ultra-high strength, low elongation, and slight positive buoyancy, and is used to connect the sinker and the main buoy. CTD sensors are arranged in sections on the cable.

[0069] The anchoring weight 3 is connected to the main floating body 1 through the cable 2. There is an acoustic wave transmitting probe on the anchoring weight 3, and the acoustic wave transmitting probe can transmit acoustic signals for acoustic distance measurement.

[0070] Specifically, Figure 4 The displacement of the main floating body is determined as shown in the figure. The present invention uses a pressure sensor for indirect measurement. A CTD is installed on the main floating body. After the floating body settles and stabilizes, its pressure value is measured. The formula The actual depth of the sensor can be obtained. The actual depth plus the mooring length minus the water depth of the sea area is the vertical settlement Δh.

[0071] Step S1 specifically includes the following steps:

[0072] S1.1, install CTD on the main buoy, after the main buoy settles and stabilizes, use the formula Measure the pressure value of the main buoy, where H is the actual depth of the main buoy measured by the pressure sensor, P is the pressure measured by CTD, ρ is the seawater density, g is the gravitational acceleration, and H1 is the water depth of the sea area where the main buoy is deployed.

[0073] S1.2, calculate the settlement Δh:

[0074] Δh=h+H-H1;

[0075] Wherein, h is the length of the main buoy cable.

[0076] Specifically, to determine the horizontal distance of the main buoy displacement, the present invention uses the acoustic ranging principle to measure the time difference between the transmitted sound wave signal and the received reflected signal to calculate the distance between the main buoy and the anchored weight, and then indirectly calculates the horizontal distance ΔX of the displacement by solving the triangle. The specific operation process is to fix the sound wave transmitting probe and the receiving probe on the anchored weight and the main buoy respectively, and record the initial position of the buoy when it is deployed. This position is the position of the sound wave transmitting probe. After the transmitting probe transmits the sound wave signal, the time difference Δt when the receiving probe receives the sound wave signal is calculated, and then the horizontal distance ΔX is calculated by The distance can be calculated by the calculation formula. The relative distance x between the two can be obtained by the principle of acoustic ranging.

[0077] When calculating x, the underwater sound speed error becomes the main factor restricting high-precision positioning. Different depths and different temperatures will affect the underwater sound speed. If the change of sound speed is not considered, the obtained x error is large, which affects the positioning of the buoy. Therefore, the present invention uses a method for reducing the sound speed error suitable for buoy positioning and ranging.

[0078] Step S2 specifically includes the following steps:

[0079] S2.1, in order to improve the measurement accuracy, the present invention integrates the underwater sound velocity and obtains the underwater average sound velocity. This method can significantly reduce the sound velocity gradient change caused by the sound sounding error. Using the indirect measurement method, the temperature, salinity and depth of the seawater are measured by the CTD sensors arranged in sections on the cable system, and the sound velocity in the seawater is calculated:

[0080]

[0081] Among them, v i is the speed of sound in seawater; T i is the sea water temperature; S i is salinity; depth is D i .

[0082] S2.2, calculate the average speed of sound

[0083]

[0084] in, is the average speed of sound; v i and v i-1 The depth is D i and D i-1 The speed of sound at D 发 is the depth of the sonic wave transmitting probe; D 收 is the depth of the sound wave receiving probe; n is the number of underwater sound speed samples.

[0085] S2.3, the acoustic wave transmitting probe and the acoustic wave receiving probe are fixed on the anchor weight and the main floating body respectively, and the distance x between the main floating body and the anchor weight is calculated:

[0086]

[0087] Among them, Δt is the time difference between the sound wave transmitting probe transmitting the sound wave and the sound wave receiving probe receiving the sound wave.

[0088] S2.4, calculate the inclination angle θ of the main floating body relative to the initial position:

[0089]

[0090] S2.5, calculate the horizontal displacement ΔX of the main floating body:

[0091]

[0092] Specifically, for the determination of the direction of the main buoy of the submerged buoy, the present invention uses the ADCP carried by the submerged buoy for indirect measurement. The ADCP is installed under the main buoy. Since the submerged buoy body and the ADCP have the same underwater direction, as long as the main buoy is always in a flow-facing posture, the opposite direction of the current measured by the ADCP is the direction of the main buoy.

[0093] Since ADCP can measure the frequency shift information of the scattered signal of the layered water medium through the acoustic Doppler frequency shift, and use the vector synthesis method to obtain the current velocity, the current direction can be determined by the vector direction of the three-dimensional flow velocity. When in use, ADCP transmits a sound wave signal into the water, and compares the frequency of the transmitted signal with the frequency of the echo signal reflected by the particles in the water to calculate the particle movement speed, that is, the water flow speed. Among them, the calculation formula between the transmitted sound wave frequency and the echo frequency is as follows

[0094] F d =2F0V / C, V=CF d / 2F0

[0095] Among them, F d is the acoustic Doppler shift; F0 is the frequency of the transmitted wave; V is the moving speed of the suspended matter along the direction of the sound beam (flow velocity m / s); C is the propagation speed of the sound wave in water.

[0096] The ADCP used in the present invention integrates four transducers, and the axes of all transducers can represent the coordinates of a sound beam. ADCP measures the flow velocity components in different beam directions, and any three transducer axes form a set of independent spatial beam coordinate systems.

[0097] ADCP first measures the velocity component along each beam direction, and then uses the conversion relationship between the beam coordinates and its own coordinate system (XYZ, local coordinate system, the Z direction is consistent with the ADCP axis direction) to convert the velocity in the beam coordinate system into the three-dimensional velocity u0, v0, w0 of its own coordinate system, which represents the velocity in the east-west, north-south and vertical directions respectively. Then, using the direction provided by the compass and the pitch and roll data provided by the inclinometer, the velocity in its own coordinate system is converted into the velocity u, v, w in the earth coordinate system. The conversion formula involves matrix calculation, and the direction angle and tilt angle of the ADCP also need to be obtained.

[0098] Step S3 specifically includes the following steps:

[0099] S3.1, calculate the direction angle and tilt angle of ADCP:

[0100]

[0101] Where α is the horizontal direction angle of ADCP, β is the tilt angle of ADCP, and h heading , p, and r represent the yaw angle, pitch angle, and roll angle of ADCP, respectively.

[0102] S3.2, using the direction angle and inclination angle of ADCP, the velocity in the ADCP coordinate system is converted to the velocity in the earth coordinate system, where u is the east-west velocity, v is the north-south velocity, and w is the vertical velocity:

[0103]

[0104] in:

[0105] R = R(α)·R(β);

[0106] R represents the transformation matrix, R(α) represents the rotation matrix around the Z axis, and R(β) represents the rotation matrix around the Y axis; u0, v0 and w0 represent the east-west flow velocity, north-south flow velocity and vertical flow velocity in their own coordinate system respectively;

[0107]

[0108] S3.3, calculate the velocity vector V=u+v+w of seawater.

[0109] Specifically, since the method for determining the direction of the main float requires that the main float always faces the flow, the present invention optimizes and improves the structure of the main float so that it can always be in a facing flow posture and verifies the effectiveness of the structure through simulation. In addition, a main float roll attitude correction system is designed to address potential underwater turbulence impacts, including a roll attitude sensing device, a roll attitude information processing device, and a roll attitude adjustment device, which are used to correct the roll attitude of the main float. The specific structure of the main float is as follows: Figure 1 shown.

[0110] The main floating body in step S4 includes: an integrally formed ball head 10, a main body 20 and a tail 30, one end of the main body 20 is the ball head 10, and the other end is the tail 30, a flow-facing tail fin 40 is arranged above the tail 30, and the longitudinal extension direction of the flow-facing tail fin 40 is perpendicular to the horizontal plane, and two balancing tail wings 50 are arranged below the tail 30, and the two balancing tail wings are symmetrically arranged along the transverse central axis of the main floating body. The ball head can reduce the flow resistance. The two balancing tail wings can maintain balance and resist rolling. The flow-facing tail fin can put the main floating body in a flow-facing posture, thereby improving its ability to resist the impact of water flow. The shell material of the main floating body adopts rust-proof aluminum alloy 5A06 with good corrosion resistance and mature processing technology. The shape of the main floating body shell is designed by fluid dynamics theory, which is a low-resistance winged slender water drop shape and a horizontal single-point mooring method. The main floating body is loaded with an acoustic vector hydrophone, a depth sensor, an underwater winch module, a connecting cable group, a data acquisition and processing module, a power module, an integrated control center, etc. The mooring cable is connected to the special mooring lug under the main buoy to ensure the horizontal posture of the main buoy in the ocean current.

[0111] Specifically, there is a notch 41 on the incoming tail fin 40. The notch can effectively reduce the roll tendency of the floating body under the interference of turbulent flow and maintain its balance and stability.

[0112] Specifically, two balancing fins 50 are disposed near the tail end surface 31 .

[0113] Specifically, the main body 20 is cylindrical, the ball head 10 is semi-spherical, and the tail 30 is a trapezoidal structure, and the diameter of the tail 30 gradually decreases from the main body 20 to the tail end face 31. The tail of the trapezoidal structure can better and smoothly guide the water flow, effectively reduce the generation of wake vortex, and improve the stability of the floating body.

[0114] Specifically, a side thrust motor 60 is provided on the side of the main body 20. The side thrust motor is a yaw attitude adjustment device, which is a core component for yaw attitude correction of the floating body. After receiving the signal from the torque sensor, the side thrust motor can respond quickly, actively apply thrust according to actual needs to offset the torque of the main floating body, so that it quickly returns to the predetermined attitude, ensuring the stability of the main floating body of the submerged buoy.

[0115] Specifically, a torque meter 70 is provided below the main body 20. The torque meter is a device for sensing the lateral attitude of the main floating body, which can monitor and measure the torque change on the cable caused by the rotation of the main floating body under the flow in real time. When a large torque is detected, the information is immediately transmitted to the control system.

[0116] Next, simulation was used to verify that the improved main floating structure was in a head-on posture in the ocean current basin.

[0117] In ANSYS Fluent, we simulated the deep sea environment, built the sea current basin, and designed the sea current field with a flow rate of 0.3m / s. We placed the main floating structure in the flow field for simulation tests and observed the changes in the posture of the main floating structure in the flow field.

[0118] like Figure 5 As shown, through simulation experiments, it can be observed that after the main buoy is placed in the sea area, the main buoy will actively face the direction of the ocean current and actively face the current. In the ocean current basin, velocity concentration will occur at the front end of the main buoy. This is because the pressure exerted by the ocean current on the main structure is relatively large, and facing the current causes the front end area to bear greater stress. The design of the ball head shape can reduce the impact force of the fluid at the front end, making the stress distribution of the main buoy structure more uniform. As the streamlined main buoy structure gradually extends, the velocity concentration will disappear, and the design of the facing tail fin guides the water flow to converge at the tail, optimizes the flow pattern of the ocean current, and reduces the probability of ocean current separation. It has been verified that the main buoy structure provided by the present invention can effectively face the current and reduce the impact of water flow, improve the fluidity of the main buoy, and reduce the problem of stress concentration.

[0119] like Figure 6 As shown in the figure, the simulation generates a main float flow resistance coefficient diagram. For a conventional spherical main float, its resistance coefficient c in seawater is approximately 0.47, while the main float flow resistance coefficient is only about 0.372 after simulation, which can better reduce the ocean current resistance and make the main float face the current.

[0120] When the submerged buoy is displaced and rotated by the impact of turbulence, the torque of the cable connected to the main buoy is collected to approximate the torque of the main buoy at this time, and the force condition of the main buoy is further obtained. The side thrust motor designed on the side of the main buoy is then used to actively apply thrust to correct the yaw posture of the main buoy.

[0121] Assuming that the mooring cable is rigid and can transmit torque, a torque meter is installed on the cable at the connection to measure the torque of the cable at the connection. This torque is given to the main buoy, and the impulse force on the main buoy is calculated as follows:

[0122]

[0123] Where F is the force of the ocean current, T is the torque measured by the torque flow meter, and r is the horizontal distance from the thruster motor to the torque meter.

[0124] When the torque monitored by the torque meter is small, the thrust motor does not work, and self-correction is performed through the optimized main floating body structure. When the torque meter monitors a larger torque, it transmits a signal to the yaw attitude information processing device in the main floating body. After calculating the impulse exerted on the main floating body, it transmits a signal to the thrust motor, and the thrust motor actively applies a thrust of -F. After that, the thrust motors on both sides of the main floating body interact with each other to gradually offset the turbulent impulse and realize the correction of the yaw attitude. After simulation, when the torque meter monitors a torque of approximately 160N·m after the main floating body encounters turbulence, the torque curve after correction by the thrust motor is as follows Figure 7 shown.

[0125] from Figure 7 It can be seen from the figure that the thrust motor can offset the large torque on the main floating body. The yaw attitude correction system proposed in the present invention has a certain effect and improves the ability of the main floating body to resist turbulence.

[0126] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A positioning method for the main floating body of an acoustic buoy, characterized in that: The specific steps include: S1, using the pressure sensor to measure the pressure at the location of the main floating body, and then calculating the actual depth and settlement displacement of the main floating body; S2, using CTD sensors arranged in sections on the cable system to indirectly calculate the speed of sound in the seawater, and using the speed of sound to calculate the distance between the main buoy and the anchored weight, thereby indirectly calculating the horizontal displacement of the main buoy; S3, using ADCP to measure the seawater velocity vector in the water area where the main buoy is located; S4, a tail fin is set at the tail of the main floating body to make the main floating body always face the flow, and the opposite direction of the sea water flow is the direction of the main floating body.

2. A positioning method for an acoustic buoy main float according to claim 1, characterized in that: Step S1 specifically includes the following steps: S1.1, install CTD on the main buoy, after the main buoy settles and stabilizes, use the formula Measure the pressure value of the main buoy, where H is the actual depth of the main buoy measured by the pressure sensor, P is the pressure measured by the CTD, ρ is the seawater density, g is the gravitational acceleration, and H1 is the water depth of the main buoy deployment area; S1.2, calculate the settlement Δh: Δh=h+H-H1; Wherein, h is the length of the main buoy cable.

3. A positioning method for an acoustic buoy main float according to claim 1, characterized in that: Step S2 specifically includes the following steps: S2.1, the temperature, salinity and depth of the seawater are measured by CTD sensors arranged in sections on the cable system, and the speed of sound in the seawater is calculated: Among them, v i is the speed of sound in seawater; T i is the sea water temperature; S i is salinity; depth is D i ; S2.2, calculate the average speed of sound in, is the average speed of sound; v i and v i-1 The depth is D i and D i-1 The speed of sound at D 发 is the depth of the sonic wave transmitting probe; D 收 is the depth of the sound wave receiving probe; n is the number of underwater sound speed samples; S2.3, the acoustic wave transmitting probe and the acoustic wave receiving probe are fixed on the anchor weight and the main floating body respectively, and the distance x between the main floating body and the anchor weight is calculated: Wherein, Δt is the time difference between the sound wave transmitting probe transmitting the sound wave and the sound wave receiving probe receiving the sound wave; S2.4, calculate the inclination angle θ of the main floating body relative to the initial position: S2.5, calculate the horizontal displacement ΔX of the main floating body:

4. A positioning method for an acoustic buoy main float according to claim 1, characterized in that: Step S3 specifically includes the following steps: S3.1, calculate the direction angle and tilt angle of ADCP: Where α is the direction angle of ADCP, β is the tilt angle of ADCP, and h heading , p, r represent the yaw angle, pitch angle, and roll angle of ADCP, respectively; S3.2, using the direction angle and inclination angle of ADCP, the velocity in the ADCP coordinate system is converted to the velocity in the earth coordinate system, where u is the east-west velocity, v is the north-south velocity, and w is the vertical velocity: in: R = R(α)·R(β); R represents the transformation matrix, R(α) represents the rotation matrix around the Z axis, and R(β) represents the rotation matrix around the Y axis; u0, v0 and w0 represent the east-west flow velocity, north-south flow velocity and vertical flow velocity in their own coordinate system respectively; S3.3, calculate the velocity vector V=u+v+w of seawater.

5. A positioning method for an acoustic buoy main float according to claim 1, characterized in that: The main floating body in step S4 includes: an integrally formed ball head, a main body and a tail, one end of the main body is the ball head, and the other end is the tail, a flow-facing tail fin is arranged above the tail, and the longitudinal extension direction of the flow-facing tail fin is perpendicular to the horizontal plane, and two balancing tail fins are arranged below the tail, and the two balancing tail fins are symmetrically arranged along the transverse center axis of the main floating body.

6. A positioning method for the main floating body of an acoustic buoy according to claim 5, characterized in that: The upstream tail fin is provided with a notch.

7. A positioning method for the main floating body of an acoustic buoy according to claim 6, characterized in that: Two balancing tail wings are arranged near the tail end surface.

8. A positioning method for an acoustic buoy main float according to claim 7, characterized in that: The main body is cylindrical, the ball head is semi-spherical, the tail is a trapezoidal structure, and the diameter of the tail gradually decreases from the main body to the end face of the tail.

9. A positioning method applicable to the main floating body of an acoustic buoy according to claim 8, characterized in that: A side thrust motor is arranged on the side of the main body.

10. A positioning method for the main floating body of an acoustic buoy according to claim 9, characterized in that: A torque measuring instrument is arranged below the main body.

Images