A method for observing seawater profile flow velocity and flow direction

Abstract

The application discloses a kind of seawater profile flow velocity flow direction observation methods, comprising: installing ADCP and azimuth sensor on buoy body;Adjust the Y-axis direction of ADCP own coordinate system with the north direction of azimuth sensor consistent;While controlling ADCP emits sound wave, the azimuth data detected by azimuth sensor is collected, and the north component and east component of flow velocity under the earth coordinate system are calculated by receiving the flow velocity data collected and output by ADCP;Flow velocity data and azimuth data are collected continuously for multiple times, and the average value of north component and the average value of east component are calculated;The flow velocity and flow direction of seawater profile are calculated using and calculated.The application uses external azimuth sensor to replace the built-in magnetic compass of current meter to detect the azimuth of buoy body, and the accurate azimuth data detected by azimuth sensor and the flow velocity data detected by ADCP are vector synthesized, so that the accurate current observation data under the earth coordinate system can be obtained.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of marine environment observation, and particularly relates to a method for detecting seawater profile flow velocity and flow direction. BACKGROUND

[0002] In marine survey, sea current observation is an important element in marine hydrological observation, which can not only provide important basic parameters for marine scientific research, but also provide important marine hydrological data required by marine engineering construction, offshore oil development, marine aquaculture, maritime security and defense, etc. Therefore, how to improve the reliability of sea current observation data is an important issue concerned by many oceanographers and engineering technicians.

[0003] Acoustic Doppler Current Profiler (ADCP) is a commonly used sea current profile observation instrument, which can observe seawater profile flow velocity and flow direction based on the principle of Doppler shift. The sea current profile observation method based on a buoy and ADCP current meter is a commonly used technical solution for fixed-point, long-term, continuous, on-site and real-time observation of sea current, which can provide all-weather and real-time observation data all year round, has higher accuracy of observation data than satellite remote sensing observation, and has longer in-situ observation time on the sea than submersible and seabed-based observation, because the electricity required by the buoy can be supplied in real time by natural energy such as solar energy. Therefore, the sea current profile observation method based on a buoy and ADCP current meter has its unique advantages.

[0004] In the sea current profile observation technology based on a buoy and ADCP current meter, the flow velocity and flow direction of seawater profile are usually directly measured by ADCP current meter. However, the current ADCP current meter detects the orientation of the current meter by using the built-in magnetic compass, and corrects the sea current observation data according to the orientation of the current meter. However, the existing buoy body is usually made of steel or uses a steel skeleton, which can cause magnetic interference to the built-in magnetic compass of the current meter, resulting in inaccurate orientation detection of the current meter and affecting the accuracy of the sea current observation results.

[0005] At present, one of the methods to solve the above problems is to keep the ADCP current meter away from the buoy body as far as possible to reduce the influence of the ferromagnetic property of the buoy body on the internal magnetic compass of the current meter. It is found from the previous research that the influence of ferromagnetic property can be basically ignored when the distance is more than one meter. Therefore, on many current buoys, a non-magnetic bracket 2 is installed at the bottom of the steel instrument well 4 of the buoy body 1, as shown in Figure 2As shown, the non-magnetic support 2 is located outside the instrument well 4 and extends vertically downwards. The current meter 3 is installed at the bottom of the non-magnetic support 2, more than one meter away from the instrument well 4. This effectively reduces the interference caused by the ferromagnetism of the buoy body 1 on the magnetic compass in the current meter 3. However, with this structure, the current meter 3 is easily entangled and damaged by fishing nets, drift ropes, and other foreign objects during operation at sea. Furthermore, the magnetic compass in the current meter 3 can still be magnetized by the buoy body 1 after prolonged use, thus still affecting the quality of ocean current observation data.

[0006] Another approach is to periodically calibrate the magnetic compass in the current meter, for example, by periodically transferring the magnetic compass to a demagnetized environment for self-calibration. However, this method is clearly difficult to implement for buoy devices that are unattended for extended periods. Summary of the Invention

[0007] This invention addresses the problem that the magnetic compass in ADCP current meters is easily affected by the magnetization of the steel material on the buoy, leading to inaccurate orientation detection. It proposes an observation method that combines an external orientation sensor with an ADCP current meter to measure the velocity and direction of seawater profiles, thereby improving the accuracy of ocean current observation data.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A method for observing seawater profile velocity and direction includes:

[0010] An ADCP current meter and an independent orientation sensor are installed on the buoy.

[0011] Adjust the Y-axis direction of the ADCP current meter's own coordinate system to align with the north direction of the azimuth sensor;

[0012] While controlling the ADCP current meter to emit acoustic waves, the system collects azimuth data θ detected by the azimuth sensor and receives the current velocity data V output by the ADCP current meter. x V y ;wherein, θ indicates the northward deflection of the Y-axis of the ADCP current meter's own coordinate system relative to the Earth's coordinate system; V x V y These represent the X-axis and Y-axis components of the current velocity data collected by the ADCP current meter in its own coordinate system, respectively.

[0013] Calculate the northward component V of the flow velocity in the Earth coordinate system N and the eastward component V E :

[0014]

[0015] The ADCP current meter and the azimuth sensor are used to continuously collect multiple flow velocity data and azimuth data, and multiple sets of northward components V N and eastward components V E of the flow velocity in the earth coordinate system are calculated The average value of the northward components V and the average value of the eastward components V

[0016] of the flow velocity are calculated

[0017] The flow direction of the seawater profile is calculated

[0018] In some embodiments of the present application, in order to further improve the accuracy of the current observation data, after continuously collecting multiple flow velocity data and azimuth data, the suspicious data collected during the posture or azimuth of the buoy body changes dramatically are first screened and removed, and then the northward components V N and eastward components V E of the flow velocity in the earth coordinate system are calculated to avoid the influence of abnormal data on the calculation results.

[0019] In some embodiments of the present application, the ADCP current meter can be installed on the sea side of the instrument well of the buoy body to ensure that the ADCP current meter can be in full contact with seawater; when installing the azimuth sensor, a non-magnetic upper platform can be erected on the deck of the buoy body, the azimuth sensor is installed on the upper platform, and the azimuth sensor is completely separated from the magnetic influence of the steel structure in the buoy body to ensure that the azimuth sensor can accurately detect the direction of the ADCP current meter.

[0020] In some embodiments of the present application, in order to make the Y-axis direction of the ADCP current meter coordinate system consistent with the north direction of the azimuth sensor, the following positioning method can be used:

[0021] A direction mark is formed on the upper platform, and when the azimuth sensor is installed on the upper platform, the north direction of the azimuth sensor is adjusted to be the same direction as the direction mark;

[0022] According to the direction mark formed on the upper platform, a projection method is used to form a direction mark on the deck of the buoy body, which points to the instrument well.

[0023] An instrument well flange is installed on the deck, a positioning pin is arranged on each of the opposite sides of the instrument well flange, the connecting line of the two positioning pins is the same direction as the direction mark, an installation hole is formed on each of the other opposite sides of the instrument well flange, and the connecting line of the two installation holes is perpendicular to the connecting line of the two positioning pins.

[0024] A flange is installed on the upper part of the derrick of the instrument well, two positioning pin holes and two assembly holes are formed on the flange, wherein the two positioning pin holes correspond to and are assembled with the two positioning pin positions on the instrument well flange plate, and the two assembly holes correspond to and are assembled with the two mounting hole positions on the instrument well flange plate;

[0025] A current meter mounting plate is installed on the derrick, and the mounting plate is perpendicular to the line connecting the two positioning pin holes;

[0026] Positioning pins and current meter mounting clips are arranged on the mounting plate, the ADCP current meter is mounted on the current meter mounting clip, and the positioning pins on the mounting plate are vertically inserted into the positioning holes of the ADCP current meter, so that the Y-axis direction of the ADCP current meter coordinate system is consistent with the direction of the azimuth mark on the deck, and the north direction of the azimuth sensor is consistent with the Y-axis direction of the ADCP current meter coordinate system.

[0027] In some embodiments of the present application, the ADCP current meter is preferably installed inside the instrument well, and only the acoustic probe of the current meter is exposed to the wellhead, so that the ADCP current meter can be protected from being entangled and damaged by fishing nets, stream ropes and other external objects in the seawater.

[0028] Compared with the prior art, the advantages and positive effects of the present application are that: for the ADCP current meter installed on the buoy body, the built-in magnetic compass is easily affected by the magnetism of the buoy body, an external azimuth sensor is used to replace the built-in magnetic compass of the current meter to detect the azimuth of the buoy body, and the accurate azimuth data detected by the azimuth sensor and the flow rate data detected by the ADCP current meter are vector synthesized, so that the seawater current observation data in the earth coordinate system can be obtained, the measurement of the seawater profile flow rate data and the flow direction data is realized, and the problem of inaccurate azimuth detection caused by the built-in magnetic compass of the ADCP current meter being easily affected by the buoy body is solved.

[0029] Other features and advantages of the present application will become more apparent after reading the detailed description of the embodiments of the present application in combination with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below, and obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0031] Figure 1 An external structure schematic diagram of an embodiment of the buoy body;

[0032] Figure 2Fig. 1 is a schematic diagram of the installation of an ADCP current meter on a buoy body according to the prior art;

[0033] Figure 3 Fig. 2 is a schematic diagram of the structure of an embodiment of the instrument well in which the ADCP current meter is built-in;

[0034] Figure 4 Fig. 3 is a schematic diagram of the installation position of an external orientation sensor on a buoy body;

[0035] Figure 5 Fig. 4 is a schematic diagram of the installation of an external orientation sensor on a buoy body; Figure 4 Fig. 5 is an enlarged view of a part of Fig. 4;

[0036] Figure 6 Fig. 6 is a diagram of the corresponding position relationship between the instrument well flange and the orientation mark;

[0037] Figure 7 Fig. 7 is a diagram of the corresponding position relationship between the upper flange of the well head and the orientation mark;

[0038] Figure 8 Fig. 8 is a schematic diagram of the assembly structure of an embodiment of the well head, the current meter installation plate and the ADCP current meter;

[0039] Figure 9 Fig. 9 is a schematic diagram of the assembly structure of an embodiment of the well head, the current meter installation plate and the ADCP current meter;

[0040] Figure 10 Fig. 10 is a sectional view of the installation structure of the ADCP current meter on the current meter installation plate;

[0041] Figure 11 Fig. 11 is a diagram of the coordinate system used when performing vector synthesis operation on the external orientation data and the flow velocity data;

[0042] Figure 12 Fig. 12 is a waveform diagram of the seawater profile flow velocity data collected and output by the ADCP current meter installed in a conventional manner;

[0043] Figure 13 Fig. 13 is a waveform diagram of the seawater profile flow direction data collected and output by the ADCP current meter installed in a conventional manner;

[0044] Figure 14 Fig. 14 is a waveform diagram of the seawater profile flow direction data collected and output by the ADCP current meter installed in a conventional manner;

[0045] Figure 15 Fig. 15 is a waveform diagram of the seawater profile flow direction data collected and output by the ADCP current meter installed in a conventional manner. DETAILED DESCRIPTION

[0046] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0047] It should be noted that in the description of the present application, the terms "upper", "lower", "inner", "outer", "top", "bottom" and the like indicating the direction or positional relationship are based on the direction or positional relationship shown in the drawings, which is merely for the convenience of description, and does not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, cannot be understood as a limitation of the present application.

[0048] In addition, it should also be noted that in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly. For example, it can be fixedly connected, or it can be detachably connected or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0049] The embodiment adopts the mode of combining the external orientation sensor with the ADCP current meter to observe the flow velocity and flow direction of the seawater profile, and the main technical problems to be solved are:

[0050] (1) Spatial alignment problem. The ADCP current meter and its built-in magnetic compass are integrally installed, so the north direction of the built-in magnetic compass is easy to align with the direction of the current meter itself; when using the external orientation sensor mode, because the buoy space size is relatively large, the height and diameter are generally about 10 meters, therefore, the problem of spatial alignment of the direction of the ADCP current meter itself and the direction of the external orientation sensor needs to be solved.

[0051] (2) Time synchronization problem. The ADCP current meter is based on the principle of Doppler shift, and when measuring the sea current, the time of ADCP current meter emitting sound wave needs to be synchronized with the time of orientation sampling. When using the built-in magnetic compass of ADCP current meter to measure the orientation, the emission time of sound wave and the orientation sampling time of magnetic compass can be processed by ADCP current meter, so it is relatively easy to realize. When using the external orientation sensor mode, the orientation sampling value of the external orientation sensor at the corresponding time of ADCP current meter emitting measurement sound wave needs to be obtained in real time and calculated, therefore, the problem of time synchronization needs to be solved.

[0052] (3) Data fusion problem. In order to obtain accurate sea current observation data, the accurate direction data output by the external orientation sensor and the flow velocity data relative to the coordinate system of ADCP current meter need to be vector synthesized to obtain the flow velocity data and flow direction data of the seawater profile in the real space coordinate system, therefore, a vector synthesis algorithm needs to be designed.

[0053] The embodiment is directed to the spatial alignment of the external orientation sensor and the ADCP current meter, and the following solution is provided.

[0054] As shown in Figure 1 , an upper platform 20 is erected on the deck 10 of the buoy body for installing the orientation sensor. The upper platform 20 should be made of non-magnetic material, and the height of the top surface of the upper platform 20 from the deck 10 of the buoy body should be ensured to be able to completely eliminate the ferromagnetic influence of the steel structure in the buoy body when the orientation sensor is installed on the top surface of the upper platform 20. In the embodiment, the height of the upper platform 20 can be designed to be about 10 meters or more than 10 meters, so that the orientation sensor can be away from the deck 10 of the buoy body to ensure the accuracy of the direction data detected by the orientation sensor.

[0055] As shown in Figure 4 , Figure 5 , a direction mark 21 is arranged on the upper platform 20, for example, an arrow is drawn on the top surface of the upper platform 20 to indicate the north direction of the orientation sensor 22. When the orientation sensor 22 is installed on the upper platform 20, the north direction of the orientation sensor 22 is made to coincide with or be in the same direction as the arrow direction of the direction mark 21, thereby completing the positioning of the orientation sensor 22 on the upper platform 20.

[0056] According to the direction mark 21 formed on the upper platform 20, a direction mark 11 in the same direction is formed on the deck 10 of the buoy body by using the projection method. The specific method is as follows: a straight rod is placed on the upper platform 20 and made to be collinear with the direction mark 21; heavy weights are hung on both ends of the straight rod and allowed to fall towards the deck 10; two projection points are formed on the deck 10 by the two heavy weights, and a straight line is formed by connecting the two projection points; a direction mark 11 is formed on the deck 10 which coincides with the straight line, for example, an arrow is drawn, and the pointing direction of the arrow is the same as that of the arrow on the upper platform 20, thereby ensuring that the direction mark 21 on the upper platform 20 is in the same direction as the direction mark 11 on the deck 10.

[0057] In order to facilitate accurate positioning of the installation direction of the ADCP current meter according to the direction mark 11 on the deck 10, when the direction marks 11 and 21 are formed on the deck 10 and the upper platform 20 respectively, it is preferred that the direction mark 11 points to the position of the instrument well 12, as shown in Figure 4 .

[0058] The instrument well 12 is an instrument installation well for carrying environmental element sensors and other sensors on the buoy, which is opened on the buoy body 1 and penetrates the buoy body 1 up and down, as shown in Figure 3 . A derrick 14 is installed in the instrument well 12, and the ADCP current meter can be carried on the derrick 14.

[0059] When installing the ADCP current meter into the instrument well 12, in order to ensure that the Y-axis direction of the ADCP current meter's own coordinate system is aligned with the orientation mark 11 on the deck 10, the following positioning method is designed in this embodiment:

[0060] On the one hand, such as Figure 6 As shown, an instrument well flange 13 is installed at the location of the instrument well 12 on the deck 10. A locating pin 131 and a locating pin 132 are installed on opposite sides of the instrument well flange 13, respectively. The line connecting the two locating pins 131 and 132 should be collinear or in the same direction as the orientation mark 11 formed on the deck 10. A mounting hole 133 and a locating hole 134 are respectively opened on the other opposite sides of the instrument well flange 13, and the line connecting the two mounting holes 133 and 134 is perpendicular to the line connecting the two locating pins 131 and 132. By fixing the welding direction of the instrument well flange 13 on the deck 10, the installation direction of the derrick 14 installed in the instrument well 12 can be fixed.

[0061] Second, such as Figure 7 As shown, a flange 15 is installed on the upper part of the derrick 14. A locating pin hole 151 and 152 are respectively opened on opposite sides of the flange 15, and an assembly hole 153 and 154 are respectively opened on the other opposite sides of the flange 15. When the flange 15 is installed onto the instrument well flange 13, the two locating pin holes 151 and 152 on the flange 15 correspond to and are assembled with the two locating pins 131 and 132 on the instrument well flange 13. This ensures that the line connecting the two locating pin holes 151 and 152 on the flange 15 is in the same direction as the orientation mark 11 formed on the deck 10. Simultaneously, the two assembly holes 153 and 154 on the flange 15 correspond to the two mounting holes 133 and 134 on the instrument well flange 13. They can be assembled and fixed using screws and nuts, thus ensuring that the line connecting the two assembly holes 153 and 154 on the flange 15 is perpendicular to the orientation mark 11 formed on the deck 10.

[0062] Thirdly, a current meter mounting plate 16 is installed on the derrick 14, and the mounting surface of the current meter mounting plate 16 is perpendicular to the line connecting the two locating pin holes 151 and 152 on the flange 15. In some embodiments, the derrick 14 can be designed as a triangular prism frame structure, such as... Figure 7 As shown, when installing flange 15 onto the top of derrick 14, one facet 141 of the triangular prism frame should be perpendicular to the line connecting the two locating pin holes 151 and 152 on flange 15. This ensures that when the current meter mounting plate 16 is installed onto facet 141, the mounting surface of the current meter mounting plate 16 is perpendicular to the line connecting the two locating pin holes 151 and 152 on flange 15.

[0063] Since the current meter needs to be in contact with seawater when in use, it is preferred to install the current meter at the bottom of the instrument well. In view of the requirement of the installation position of the current meter, the embodiment preferably installs the current meter mounting plate 16 at the bottom of the well frame 14, as shown in Figure 9 so as to enable the ADCP current meter 17 to be in full contact with seawater when the ADCP current meter 17 is installed on the current meter mounting plate 16, thereby meeting the requirement of current observation.

[0064] Four aspects, as shown in Figure 8 , a positioning pin 161 perpendicular to the installation surface of the current meter mounting plate 16 is installed on the current meter mounting plate 16, and a mounting hole 162 is formed. The mounting hole 162 can be formed in two pairs on the upper part of the current meter mounting plate 16 and one pair on the lower part of the current meter mounting plate 16 for assembling a current meter mounting clip 163, in combination with Figure 9 , Figure 10 .

[0065] Two pairs of mounting holes 162 are formed on the upper part of the current meter mounting plate 16 to accommodate current meters of different lengths. According to the actual length of the ADCP current meter 17, one pair of mounting holes 162 on the upper part of the current meter mounting plate 16 is selected to assemble a current meter mounting clip 163, and a current meter mounting clip 164 is assembled on the mounting hole 162 on the lower part of the current meter mounting plate 16. The upper and lower ends of the ADCP current meter 17 are respectively clamped on the current meter mounting clips 163, 164, the angle of the ADCP current meter 17 is adjusted, the positioning hole is aligned with the positioning pin 161 on the mounting plate and is inserted, and thus the Y-axis direction of the coordinate system of the ADCP current meter 17 is perpendicular to the installation surface of the current meter mounting plate 16. Since the installation surface of the current meter mounting plate 16 is perpendicular to the line connecting the two positioning pin holes 151, 152 on the flange 15, and the line connecting the two positioning pin holes 151, 152 on the flange 15 is in the same direction as the azimuth mark 11 formed on the deck 10, as long as the ADCP current meter 17 is assembled in place on the mounting plate 16, the Y-axis direction of the coordinate system of the ADCP current meter 17 is consistent with the direction of the azimuth mark 11 formed on the deck 10.

[0066] Since the north direction of the orientation sensor 22 aligns with the direction of the orientation marker 21 on the upper platform 20, and the orientation marker 21 on the upper platform 20 aligns with the direction of the orientation marker 11 on the deck 10, and the Y-axis of the ADCP current meter 17's own coordinate system aligns with the direction of the orientation marker 11 on the deck 10, the Y-axis of the ADCP current meter 17's own coordinate system is aligned with the north direction of the orientation sensor 22. Therefore, the external orientation sensor 22 can be used to replace the built-in magnetic compass of the ADCP current meter 17 to detect the buoy's orientation, and then fused with the current velocity data detected by the ADCP current meter 17 to calculate the ocean current observation data in the Earth coordinate system.

[0067] In this embodiment, combined with Figure 3 , Figure 10 As shown, the ADCP current meter 17 is preferably installed inside the instrument well 12, with only the acoustic probe 171 of the ADCP current meter 17 protruding from the well opening. This not only ensures that the ADCP current meter 17 can normally emit sound waves and receive reflected waves to meet the measurement requirements, but also effectively solves the problem that the ADCP current meter 17 is easily damaged by fishing nets, drift ropes and other foreign objects because it is completely exposed to seawater. This ensures that the ADCP current meter 17 can operate safely and continuously in seawater for a long time, making it very suitable for use in long-term unattended buoy equipment.

[0068] To address the issue of synchronously acquiring current velocity data from ADCP current meter 17 and azimuth data from azimuth sensor 22, this embodiment preferably configures a high-speed data processor with a CPU clock speed of 72MHz or higher, such as an STM32 series microcontroller, in the buoy's control system to achieve high-speed and high-precision acquisition of current velocity and azimuth data.

[0069] To address the vector synthesis problem between the current velocity data acquired and output by ADCP current meter 17 and the azimuth data detected and output by azimuth sensor 22, this embodiment proposes the following vector synthesis algorithm:

[0070] Step 1: Using the control system on the buoy, while controlling the ADCP current meter 17 to emit sound waves, the high-speed data processor acquires the azimuth data θ detected by the azimuth sensor 22, and receives the current velocity data V collected and output by the ADCP current meter 17. x V y The azimuth data acquired and output by the built-in magnetic compass of the ADCP current meter 17 is shielded, thereby obtaining a set of vector data {θ, V} with synchronized sampling time. x V y}. Among them, V x This represents the X-axis component of the velocity data collected by ADCP current meter 17 in its own coordinate system; V yrepresents the Y-axis component of the flow velocity data collected by the ADCP current meter 17 in its own coordinate system.

[0071] Figure 11 The positional relationship between the ADCP current meter 17 own coordinate system and the earth coordinate system is shown. Wherein, YOX represents the ADCP current meter 17 own coordinate system; NOE represents the earth coordinate system, and N represents the geographic north, and E represents the geographic east; θ is the deflection angle between the buoy body and the earth north detected by the azimuth sensor 22. Since the Y-axis direction of the ADCP current meter 17 own coordinate system is consistent with the north of the azimuth sensor 22, θ also represents the deflection angle between the Y-axis of the ADCP current meter 17 own coordinate system and the earth north.

[0072] Step 2: periodically control the ADCP current meter 17 to emit sound waves, and repeatedly execute step 1 every cycle to obtain multiple sets of flow velocity data and azimuth data.

[0073] Step 3: after continuously collecting multiple flow velocity data and azimuth data, the suspicious data collected during the process of the attitude or azimuth of the buoy body changing dramatically is screened and removed.

[0074] In this embodiment, two ways can be used to determine the suspicious data: one is to determine the adjacent data with the change amount exceeding the limit as suspicious data to be removed, that is, the data collected before and after the change is considered as suspicious data; the other is to sort the multiple sets of azimuth data, and determine the azimuth data corresponding to the maximum value and the minimum value and the flow velocity data collected synchronously with the azimuth data as suspicious data to be removed.

[0075] Step 4: project the flow velocity data V x , V y output by the ADCP current meter 17 each time (here, the flow velocity data V x , V y is the flow velocity data after removing the suspicious data) to the earth coordinate system, calculate the north component V N and the east component V E of the flow velocity in the earth coordinate system, and the calculation formula is as follows:

[0076]

[0077] Thus, multiple sets of north component V N and east component V E of the flow velocity in the earth coordinate system can be obtained.

[0078] Step 5: according to the obtained multiple sets of north component V N and east component V E of the flow velocity in the earth coordinate system, the average value of the north component of the flow velocity is calculated respectively and the average of the east component

[0079] Step 6: using the average of the north component of the flow velocity and the average of the east component The flow velocity value V of the seawater profile is calculated as follows:

[0080]

[0081] Step 7: using the average of the north component of the flow velocity and the average of the east component The flow direction A of the seawater profile is calculated as follows:

[0082]

[0083] where arccot() represents the inverse cotangent function.

[0084] The present embodiment aims at the defects of the current installation mode of ADCP current meter, designs a new installation structure of current meter, and places the current meter in the internal of the steel instrument well of the buoy body, only the acoustic probe of the current meter slightly exposes the well mouth, thereby solving the problem that the current meter is easily damaged by external force such as fishing net. At the same time, by shielding the magnetic compass built-in the ADCP current meter, the real-time orientation of the buoy body is detected by using the external orientation sensor, and the orientation sensor is installed on the upper platform far away from the steel material in the buoy body, thereby realizing accurate detection of the orientation data. In addition, by fusing the accurate orientation data collected and output by the external orientation sensor and the flow velocity data collected and output by the ADCP current meter relative to the self coordinate system, the seawater flow data in the real space coordinate system is obtained, thereby solving the problem that the ADCP current meter is easily affected by the buoy body due to the built-in magnetic compass, thereby leading to inaccurate orientation detection, and then accurate seawater flow observation data cannot be obtained.

[0085] Specific example:

[0086] An ADCP current meter is installed on the buoy in the conventional manner in the prior art, as shown in Figure 2 , and continuously operated at sea for nearly 1 year. Then, an ADCP current meter and an external orientation sensor are arranged on the same buoy in the improved manner proposed in the present embodiment.

[0087] In the same time period, the seawater flow observation data output by the ADCP current meter installed in the conventional manner and the seawater flow observation data calculated by the observation method proposed in the present embodiment are collected respectively. After 2 days of observation, by comparing the seawater profile flow velocity data and flow direction data obtained by the two methods, it can be found that:

[0088] The consistency of the seawater profile flow velocity data obtained by the conventional method and the observation method proposed in the embodiment is good, as shown in Figure 12 、 Figure 13 Among them, Figure 12 shows the first five layers of flow velocity collected and output by the ADCP flow meter installed in the conventional way; Figure 13 shows the first five layers of flow velocity data obtained by the observation method proposed in the embodiment.

[0089] The basic trend of the seawater profile flow direction data obtained by the conventional method and the observation method proposed in the embodiment is consistent, and the flow direction has a clear sinusoidal trend, with two flow reversal processes in a day, which is in line with the characteristics of the local semidiurnal tidal current in the measured sea area, as shown in Figure 14 、 Figure 15 Among them, Figure 14 shows the first five layers of flow direction collected and output by the ADCP flow meter installed in the conventional way; Figure 15 shows the first five layers of flow direction data obtained by the observation method proposed in the embodiment.

[0090] However, the flow direction difference of the semidiurnal tidal inflow and outflow observed by the observation method proposed in the embodiment is basically 180°, as shown in Figure 15 , which is more in line with the local tidal current characteristics. The flow direction difference of the semidiurnal tidal inflow and outflow observed by the conventional method is basically 120°, as shown in Figure 14 , which has a large observation error. Thus, the effectiveness of the observation method proposed in the embodiment is proved.

[0091] Of course, the above only describes one preferred embodiment of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, several improvements and refinements can be made, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A method for observing the flow velocity and direction of seawater profile, characterized in that, a non-magnetic superstructure is erected on the deck of a buoy body, an independent azimuth sensor is installed on the superstructure, and the azimuth sensor is completely separated from the magnetic influence of the steel structure in the buoy body; the same direction azimuth marks are formed on the deck and the superstructure of the buoy body; the azimuth sensor is installed on the superstructure, and the north direction of the azimuth sensor is adjusted to be the same direction as the azimuth mark; an instrument well flange is installed at the instrument well position of the deck, two positioning pins are arranged on the opposite sides of the instrument well flange, the connecting line of the two positioning pins is the same direction as the azimuth mark, two mounting holes are opened on the other opposite sides of the instrument well flange, and the connecting line of the two mounting holes is perpendicular to the connecting line of the two positioning pins; a flange is installed on the upper part of the derrick of the instrument well, two positioning pin holes and two assembly holes are formed on the flange, the two positioning pin holes correspond to and are assembled with the two positioning pins on the instrument well flange, and the two assembly holes correspond to and are assembled with the two mounting holes on the instrument well flange; a current meter mounting plate is installed on the derrick, and the connecting line of the two positioning pin holes is perpendicular to the mounting plate; a positioning pin and a current meter mounting clip are arranged on the mounting plate, an ADCP current meter is installed on the current meter mounting clip, the angle of the ADCP current meter is adjusted, the positioning hole of the ADCP current meter is vertically inserted into the positioning pin on the mounting plate, at this time, the Y-axis direction of the ADCP current meter coordinate system is consistent with the direction of the azimuth mark on the deck, the north direction of the azimuth sensor is the same direction as the Y-axis direction of the ADCP current meter coordinate system, and the azimuth sensor is adjusted to be the same direction as the Y-axis direction of the ADCP current meter coordinate system; Collect azimuth data θ detected by the azimuth sensor and receive flow velocity data V output by the ADCP current meter while controlling the ADCP current meter to emit sound waves x , y ; wherein θ indicates the deflection angle of the Y-axis of the ADCP current meter's own coordinate system relative to the north direction of the earth coordinate system; V x , y respectively represent the X-axis component and the Y-axis component of the flow velocity data collected by the ADCP current meter in the own coordinate system. calculating the northward component V N and the eastward component V E of the flow velocity in the earth coordinate system By continuously acquiring multiple sets of current velocity and azimuth data using the ADCP current meter and azimuth sensor, the northward component V of the current velocity in multiple Earth coordinate systems was calculated. N and the eastward component V E Then, the average value of the northward component of the flow velocity was calculated. and the average value of the eastward component Calculating the flow rate of a seawater profile: Computing the flow direction of the seawater profile:

2. The seawater profile velocity flow direction observation method according to claim 1, characterized by, After continuously collecting multiple flow rate data and orientation data, firstly, suspicious data collected in the process of dramatic change of the attitude or orientation of the buoy body is screened and removed, and then the north component V N and the east component V E in the multiple sets of earth coordinate systems are calculated.

3. The seawater profile velocity and flow direction observation method according to claim 1, characterized by, the process of forming the same direction azimuth marks on the deck and the superstructure of the buoy body comprises: forming the azimuth mark on the superstructure; forming the same direction azimuth mark on the deck of the buoy body by projection method according to the azimuth mark formed on the superstructure, and pointing to the instrument well.

4. The seawater profile velocity flow direction observation method according to any one of claims 1 to 3, characterized by, The ADCP current meter is installed on the seaward side of the instrument well of the buoy body.

5. The seawater profile velocity and flow direction observation method according to claim 4, characterized by, The ADCP current meter is installed inside the instrument well, and only the acoustic probe is exposed to the wellhead.

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