CN115508579A - A Seawater Profile Velocity and Direction Observation Method - Google Patents

Abstract

The invention discloses a method for observing the flow velocity and the flow direction of a seawater profile, which comprises the following steps: an ADCP and an azimuth sensor are arranged on the buoy body; adjusting the Y-axis direction of the ADCP self coordinate system to be consistent with the north direction of the azimuth sensor; while controlling the ADCP to emit sound waves, collecting the azimuth data detected by the azimuth sensor, receiving the flow speed data collected and output by the ADCP, and calculating the north component of the flow speed in the earth coordinate system

And an east component

(ii) a Continuous collection of multiple streamsSpeed data and azimuth data, and calculating average value of north direction component

And average value of east component

(ii) a By using

And

and calculating the flow speed and the flow direction of the seawater profile. The invention adopts an external azimuth sensor to replace an internal magnetic compass of a current meter to detect the azimuth of the buoy body, and accurate azimuth data detected by the azimuth sensor and flow speed data detected by the ADCP are subjected to vector synthesis, so that accurate ocean current observation data under a terrestrial coordinate system can be obtained.

Description

A Seawater Profile Velocity and Direction Observation Method

technical field

The invention belongs to the technical field of marine environment observation, and in particular relates to an observation method for detecting the flow velocity and flow direction of a seawater profile.

Background technique

In marine surveys, current observation is an important element in marine hydrological observations. It can not only provide important basic parameters for marine scientific research, but also provide information for marine engineering construction, offshore oil development, marine aquaculture, maritime security and defense, etc. The important marine hydrological data that need to be based on. Therefore, how to improve the reliability of ocean current observation data is an important topic concerned by many oceanographers and engineers.

Acoustic Doppler Profiler Current Meter (ADCP) is a commonly used ocean current profile observation instrument. Based on the principle of Doppler frequency shift, it can observe the velocity and direction of seawater profile. The ocean current profile observation method based on buoys and ADCP current meters is currently a commonly used technical solution for fixed-point, long-term, continuous, on-site, and real-time observation of ocean currents. Compared with ship-borne surveys, it can provide all-weather and perennial real-time observation data; compared with satellite remote sensing Observation, the accuracy of the observation data is higher; compared with submersible buoy and seabed-based observation, the electricity required by the buoy can be supplied by natural energy such as solar energy in real time, and the observation time at sea is long. Therefore, the ocean current profile observation method based on buoys and ADCP current gauges has its unique advantages.

In the ocean current profile observation technology based on buoys and ADCP current meters, the ADCP current meter is usually used to directly measure the flow velocity and direction of the seawater profile. However, the current ADCP current meter uses its built-in magnetic compass to detect the azimuth of the current meter, and corrects the ocean current observation data according to the azimuth of the current meter. However, most of the existing buoy bodies are steel structures or steel skeletons. These steel materials will cause magnetic interference to the magnetic compass built in the current meter, resulting in inaccurate detection of the azimuth of the current meter, which in turn affects the accuracy of current observation results. .

At this stage, one of the methods to solve the above problems is to keep the ADCP current gauge as far away from the buoy body as possible, so as to reduce the influence of the ferromagnetism of the buoy body on the internal magnetic compass of the current gauge as much as possible. According to the previous research, the influence of ferromagnetism is basically negligible when the distance from the buoy body is more than one meter. Therefore, on many current buoys, a non-magnetic support 2 will be installed at the bottom of the steel instrument well 4 of the buoy body 1, as shown in FIG. 2 . The non-magnetic support 2 is located outside the instrument well 4 and extends vertically downward. The current meter 3 is installed on the bottom of the non-magnetic support 2, more than one meter away from the instrument well 4, so that the ferromagnetism of the buoy body 1 can effectively reduce the interference effect caused by the magnetic compass in the current meter 3. However, when the buoy body 1 with this structure is operating at sea, the current meter 3 is easily entangled and damaged by foreign objects such as fishing nets and drift ropes. In addition, the magnetic compass in the current gauge 3 is still magnetized by the buoy body 1 after being used for a long time, so there is still a problem affecting the quality of ocean current observation data.

Another method is to regularly calibrate the magnetic compass in the current meter, for example, periodically transfer the magnetic compass to a non-magnetic environment for self-difference calibration. However, this method is obviously difficult to realize for long-term unattended buoy equipment.

Contents of the invention

Aiming at the problem that the magnetic compass in the ADCP current meter is easily affected by the magnetization of the steel material on the buoy body, resulting in inaccurate azimuth detection, the invention proposes a combination of an external azimuth sensor and an ADCP current meter to measure seawater profiles The observation method of current velocity and direction, in order to improve the accuracy of ocean current observation data.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions to achieve:

A method for observing the flow velocity and direction of a seawater profile, comprising:

Install ADCP current meter and independent azimuth sensor on the buoy body;

Adjust the Y-axis direction of the ADCP current meter's own coordinate system to be consistent with the north direction of the azimuth sensor;

While controlling the ADCP sea current meter to emit sound waves, collect the azimuth data θ detected by the azimuth sensor, and receive the flow velocity data V _x and V _y collected and output by the ADCP sea current meter; where θ is used to indicate the Y axis of the ADCP sea current meter’s own coordinate system The deflection angle relative to the north direction of the earth coordinate system; V _x and V _y respectively represent the X-axis component and the Y-axis component of the current velocity data collected by the ADCP sea current meter in its own coordinate system;

Calculate the northward component V _N and eastward component V _E of the flow velocity in the earth coordinate system:

和东向分量的平均值

Using the ADCP sea current meter and azimuth sensor to continuously collect multiple flow velocity data and azimuth data, after calculating the northward component V _N and eastward component V _E of the flow velocity in multiple sets of earth coordinates, calculate the average value of the northward component of the flow velocity

and the mean of the eastward component

Calculate the velocity of the seawater profile:

Compute the flow direction of a seawater profile:

In some embodiments of the present application, in order to further improve the accuracy of ocean current observation data, after continuously collecting multiple current velocity data and azimuth data, firstly, the suspicious data collected during the drastic change of the attitude or azimuth of the buoy can be analyzed. Filter and eliminate, and then calculate the northward component V _N and eastward component _VE in the earth coordinate system, so as to avoid the impact of abnormal data on the calculation results.

In some embodiments of the present application, the ADCP sea current meter can be installed on the sea-going side of the instrument well of the buoy body to ensure that the ADCP sea current meter can fully contact with seawater; when installing the azimuth sensor, it can be erected on the deck of the buoy body Set up a non-magnetic upper platform, install the azimuth sensor on the upper platform, and make the azimuth sensor completely separated from the magnetic influence produced by the steel structure in the buoy body, so as to ensure that the azimuth sensor can accurately detect the current of the ADCP current meter. direction.

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

Form a bearing mark on the upper platform, and when the bearing sensor is installed on the upper platform, adjust the north direction of the bearing sensor to be in the same direction as the bearing marker;

According to the azimuth mark formed on the upper platform, the projection method is used to form the same direction azimuth mark on the deck of the buoy body, and point to the instrument well;

Install the instrument well flange on the deck, and arrange a positioning pin on the opposite sides of the instrument well flange. The connecting line of the two positioning pins is in the same direction as the azimuth mark. A mounting hole is respectively provided on both sides, and the line connecting the two mounting holes is perpendicular to the line connecting the two positioning pins;

The flange is installed on the upper part of the derrick of the instrument well, and two positioning pin holes and two assembly holes are formed on the flange, wherein the two positioning pin holes correspond to the positions of the two positioning pins on the flange of the instrument well and are assembled , the two assembly holes correspond to the positions of the two installation holes on the flange of the instrument well and are assembled;

Install the current meter installation plate on the derrick, and make the connection line between the installation plate and the two positioning pin holes vertical;

Positioning pins and sea current meter mounting clips are arranged on the mounting plate, the ADCP sea current meter is installed on the sea current meter mounting clips, and the positioning pins on the mounting plate are vertically inserted into the positioning holes of the ADCP sea current meter, so that Make the Y-axis direction of the ADCP sea current meter's own coordinate system consistent with the direction of the azimuth mark on the deck, and then realize that the north direction of the azimuth sensor is in the same direction as the Y-axis direction of the ADCP sea current meter's own coordinate system.

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, which can prevent the ADCP current meter from being caught by foreign objects such as fishing nets and current ropes in seawater. The winding damage plays a role in protecting the ADCP sea current meter.

Compared with the prior art, the advantages and positive effects of the present invention are: the present invention is aimed at the problem that the built-in magnetic compass of the ADCP current meter installed on the buoy body is easily affected by the magnetism of the buoy body, and an external azimuth sensor is used instead of the current meter The built-in magnetic compass is used to detect the azimuth of the buoy body. By vector synthesis of the accurate azimuth data detected by the azimuth sensor and the current velocity data detected by the ADCP sea current meter, the ocean current observation data in the earth coordinate system can be obtained to realize It improves the measurement of seawater profile velocity data and flow direction data, and solves the problem of inaccurate azimuth detection caused by the built-in magnetic compass of ADCP current meter which is easily affected by the buoy body.

Other features and advantages of the present invention will become more apparent after reading the detailed description of the embodiments of the present invention in conjunction with the accompanying drawings.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings that need to be used in the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. Those of ordinary skill in the art can also obtain other drawings based on these drawings without any creative effort.

Fig. 1 is the outline structure schematic diagram of a kind of embodiment of buoy body;

Fig. 2 is a schematic diagram of the installation method of the ADCP current meter on the buoy body in the prior art;

Fig. 3 is a structural representation of an embodiment in which the ADCP current meter is built into the instrument well;

Fig. 4 is a schematic diagram of the installation position of the external orientation sensor on the buoy body;

Figure 5 is a partially enlarged view of Figure 4;

Fig. 6 is a diagram of the corresponding position relationship between the instrument well flange and the azimuth mark;

Fig. 7 is a diagram of the corresponding positional relationship between the upper flange of the derrick and the azimuth mark;

Fig. 8 is a schematic diagram of an assembly structure of an embodiment of a derrick and a current meter mounting plate;

Fig. 9 is a schematic diagram of an assembly structure of an embodiment between the derrick, the current meter mounting plate and the ADCP current meter;

Figure 10 is a cross-sectional view of the installation structure of the ADCP current meter on the current meter mounting plate;

Fig. 11 is a coordinate system diagram used in the vector synthesis operation of the external azimuth data and velocity data;

Fig. 12 is the waveform diagram of the seawater profile velocity data collected and output by the ADCP flowmeter installed in a conventional manner;

Figure 13 is a waveform diagram of seawater profile velocity data collected and output by an external sensor and an ADCP flowmeter;

Fig. 14 is the waveform diagram of the seawater profile flow direction data collected and output by the ADCP flowmeter installed in a conventional way;

Fig. 15 is a waveform diagram of seawater profile flow direction data collected and output by external sensors and ADCP flowmeters.

detailed description

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

It should be noted that, in the description of the present invention, the terms "upper", "lower", "inner", "outer", "top", "bottom" and other terms indicating direction or positional relationship are based on the terms shown in the accompanying drawings. Orientation or positional relationship is only for convenience of description, and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore, should not be construed as limiting the present invention.

In addition, it should be noted that in the description of the present invention, the terms "installation", "connection" and "connection" should be interpreted in a broad sense unless otherwise specified and limited. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary; it can be the internal communication of two components . Those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

In this embodiment, the combination of external azimuth sensor and ADCP current meter is used to observe the flow velocity and flow direction of the seawater profile. The technical problems that need to be solved mainly include:

(1) Spatial alignment problem. The ADCP current meter and its built-in magnetic compass are installed in one piece, so the north direction of the built-in magnetic compass is easy to align with the direction of the current meter itself; when the external azimuth sensor is used, due to the relatively large space size of the buoy, the height and diameter Generally, it is about 10 meters. Therefore, it is necessary to solve the problem of spatial alignment between the direction of the ADCP current meter and the direction of the external azimuth sensor.

(2) Time synchronization problem. The ADCP current meter is based on the principle of Doppler frequency shift. When measuring the ocean current, the time when the ADCP current meter emits sound waves needs to be synchronized with the azimuth sampling time. When using the built-in magnetic compass of the ADCP current meter to measure the azimuth, the emission time of the sound wave and the azimuth sampling time of the magnetic compass can be uniformly processed by the ADCP current meter, so it is relatively easy to implement. When using the external azimuth sensor method, it is necessary to obtain the azimuth sampling value of the external azimuth sensor at the time corresponding to the sound wave emitted by the ADCP current meter in real time, and calculate it. Therefore, the problem of time synchronization needs to be solved.

(3) Data fusion problem. In order to obtain accurate ocean current observation data, it is necessary to vector-combine the accurate direction data output by the external azimuth sensor and the current velocity data output by the ADCP current meter relative to its own coordinate system, so as to obtain the seawater profile in the real space coordinate system. Velocity data and flow direction data, therefore, it is necessary to design a vector synthesis algorithm.

This embodiment proposes the following solutions for the spatial alignment problem between the external orientation sensor and the ADCP current meter.

As shown in FIG. 1 , an upper platform 20 is erected on the deck 10 of the buoy body for installing an orientation sensor. The upper platform 20 should be made of non-magnetic material, and the height of its top surface from the buoy body deck 10 should ensure that when the azimuth sensor is installed on the top surface of the upper platform 20, the azimuth sensor can completely get rid of the steel in the buoy body. The influence of ferromagnetism produced by the control structure. In this embodiment, the height of the upper platform 20 can be designed at about 10 meters or more, so that the orientation sensor can be far away from the deck 10 of the buoy body, so as to ensure the accuracy of the direction data detected by the orientation sensor.

As shown in FIG. 4 and FIG. 5 , an orientation mark 21 is set 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 coincides with or is in the same direction as the arrow direction of the orientation mark 21, thereby completing the positioning of the orientation sensor 22 on the upper platform 20.

According to the azimuth mark 21 formed on the upper platform 20, adopt the projection method to form the same direction azimuth mark 11 on the deck 10 of the buoy body. The specific method is: a straight rod is placed on the upper platform 20, and the straight rod and the orientation mark 21 are collinear; heavy hammers are hung at the two ends of the straight rod respectively, and they hang down towards the deck 10 directions; Form two projection points on the deck 10, connect the two projection points to form a straight line; form a bearing mark 11 that coincides with the straight line on the deck 10, for example, draw an arrow, and the direction of the arrow is directed to the arrow of the bearing marker 21 on the upper platform 20 Pointing to the same direction, it can be ensured that the orientation mark 21 on the upper platform 20 is in the same direction as the orientation mark 11 on the deck 10 .

In order to facilitate the precise positioning of the installation direction of the ADCP current meter according to the azimuth mark 11 on the deck 10, when the azimuth marks 11 and 21 are respectively formed on the deck 10 and the upper platform 20, it is preferable to make the azimuth mark 11 point to the position of the instrument well 12 ,As shown in Figure 4.

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

When the ADCP current meter is installed in the instrument well 12, in order to make the Y-axis direction of the ADCP current meter's own coordinate system be in the same direction as the orientation mark 11 on the deck 10, the present embodiment designs the following positioning method:

On the one hand, as shown in Figure 6, the instrument well flange 13 is installed at the position where the instrument well 12 is set on the deck 10, and a positioning pin 131, 132 is respectively installed on the opposite sides of the instrument well flange 13. The connecting line of the pins 131, 132 should be collinear or in the same direction as the orientation mark 11 formed on the deck 10 . A mounting hole 133 , 134 is provided on the other opposite sides of the instrument well flange 13 , and the connecting line of the two mounting holes 133 , 134 is perpendicular to the connecting line of the two positioning pins 131 , 132 . The welding direction of the instrument well flange 13 on the deck 10 is fixed, and the installation direction of the derrick 14 installed in the instrument well 12 can be fixed.

On the other hand, as shown in Figure 7, a flange 15 is installed on the top of the derrick 14, a positioning pin hole 151, 152 is respectively provided on opposite sides of the flange 15, and an assembly pin hole 151, 152 is respectively provided on the other opposite sides of the flange 15. Holes 153,154. When the flange 15 is installed on the instrument well flange 13, the positions of the two positioning pin holes 151, 152 on the flange 15 and the two positioning pins 131, 132 on the instrument well flange 13 correspond to each other and Assembling, thus just can guarantee that the connecting line of two positioning pin holes 151, 152 on the flange 15 is in the same direction as the direction mark 11 formed on the deck 10. Simultaneously, the positions of the two mounting holes 153, 154 on the flange 15 and the two mounting holes 133, 134 on the instrument well flange 13 correspond to each other, and screws and nuts can be utilized to assemble and fix the two, thus ensuring 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 .

In three aspects, install the current meter mounting plate 16 on the derrick 14, and make the mounting surface of the current meter mounting plate 16 perpendicular to the line connecting the two positioning pin holes 151, 152 on the flange 15. In some embodiments, the derrick 14 can be designed as a triangular prism frame structure, as shown in Figure 7, when the flange 15 is installed on the top of the derrick 14, one of the facets 141 of the triangular prism frame should be aligned with the The line connecting the two positioning pin holes 151, 152 on the flange 15 is vertical. In this way, when the current meter mounting plate 16 is installed on the face 141 , it can be ensured that the mounting 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 .

Since the current meter needs to be in contact with seawater when in use, it is preferable to install the current meter at the bottom of the instrument well. For this installation position requirement of the sea current meter, in this embodiment, the sea current meter installation plate 16 is preferably installed at the bottom position of the derrick 14, as shown in FIG. When , the ADCP sea current meter 17 can be fully contacted with sea water, and then meet the sea current observation requirements.

Fourthly, as shown in FIG. 8 , a positioning pin 161 perpendicular to its mounting surface is installed on the current meter mounting plate 16 , and a mounting hole 162 is provided. Two pairs of mounting holes 162 may be provided on the upper part of the current meter mounting plate 16, and one pair may be provided on the lower part of the current meter mounting plate 16 for assembling the current meter mounting clip 163, as shown in FIG. 9 and FIG. 10 .

Two pairs of mounting holes 162 are provided on the top 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, select a pair of mounting holes 162 on the top of the current meter mounting plate 16 to assemble a current meter mounting clip 163, and assemble a current meter on the mounting hole 162 at the bottom of the current meter mounting plate 16 Install clip 164. Mount the upper and lower ends of the ADCP sea current meter 17 on the sea current meter mounting clips 163 and 164 respectively, adjust the angle of the ADCP sea current meter 17 so that its positioning hole is aligned with the positioning pin 161 on the mounting plate and inserted, so that The Y-axis direction of the self-coordinate system of the ADCP current meter 17 is perpendicular to the installation surface of the current meter installation plate 16 . Because the mounting surface of the current meter mounting plate 16 is perpendicular to the connection line of the two positioning pin holes 151,152 on the flange 15, and the connection line of the two positioning pin holes 151,152 on the flange 15 is connected to the connection line on the deck 10. The formed azimuth marks 11 are in the same direction. Therefore, as long as the ADCP current meter 17 is assembled in place on the mounting plate 16, the Y-axis direction of the ADCP current meter 17's own coordinate system and the direction of the azimuth marks 11 formed on the deck 10 can be guaranteed. The same direction.

Because the north direction of the azimuth sensor 22 is consistent with the direction of the azimuth mark 21 on the upper platform 20, the direction of the azimuth mark 21 on the upper platform 20 is consistent with the direction of the azimuth mark 11 on the deck 10, and the Y axis of the ADCP current meter 17 self coordinate system The direction is consistent with the direction of the azimuth mark 11 on the deck 10 , therefore, the Y-axis direction of the ADCP current meter 17's own coordinate system is consistent with the north direction of the azimuth sensor 22 . Thus, the external azimuth sensor 22 can be used instead of the built-in magnetic compass of the ADCP current meter 17 to detect the azimuth of the buoy body, and then be fused with the current velocity data detected by the ADCP current meter 17 to calculate the ocean current in the earth coordinate system data observation.

In the present embodiment, in conjunction with Fig. 3, shown in Fig. 10, ADCP sea current meter 17 is preferably installed in the inside of instrument well 12, and only the acoustic probe 171 of ADCP sea current meter 17 exposes wellhead, can not only guarantee that ADCP sea current meter 17 is normal like this It emits sound waves and receives reflected waves, which meets the measurement requirements, and can effectively solve the problem that the ADCP current meter 17 is easily entangled and damaged by foreign objects such as fishing nets and drift ropes due to its complete exposure to seawater, effectively ensuring that the ADCP current meter 17 is in seawater. Long-term, continuous and safe operation, it is very suitable for long-term unattended buoy equipment.

For the problem of synchronous acquisition of the flow velocity data of the ADCP current meter 17 and the orientation data of the orientation sensor 22, the present embodiment preferably configures a high-speed data processor with a CPU main frequency above 72MHz in the control system of the buoy, such as a single-chip microcomputer of the STM32 series, to Realize high-speed and high-precision collection of velocity data and azimuth data.

Aiming at the vector synthesis problem between the velocity data collected and output by the ADCP sea current meter 17 and the azimuth data output by the azimuth sensor 22, the present embodiment proposes the following vector synthesis algorithm:

Step 1: Use the control system on the buoy to control the ADCP sea current meter 17 to emit sound waves, and at the same time collect the azimuth data θ detected by the azimuth sensor 22 through the high-speed data processor, and receive the flow velocity data V _x , which are collected and output by the ADCP sea current meter 17 V _y , shielding the azimuth data collected and output by the built-in magnetic compass of the ADCP current meter 17, and thus obtaining a set of vector data {θ, V _x , V _y } that are synchronized in sampling time. Among them, V _x represents the X-axis component of the current velocity data collected by the ADCP sea current meter 17 in its own coordinate system; V _y represents the Y-axis component of the flow velocity data collected by the ADCP sea current meter 17 in its own coordinate system.

FIG. 11 shows the positional relationship between the ADCP sea current meter 17's own coordinate system and the earth coordinate system. Among them, YOX represents the own coordinate system of the ADCP current meter 17; 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 detected by the azimuth sensor 22 and the earth north. Since the Y-axis direction of the self-coordinate system of the ADCP current meter 17 is consistent with the north direction of the azimuth sensor 22 , θ also represents the deflection angle between the Y-axis of the self-coordinate system of the ADCP current meter 17 and the north direction of the earth.

Step 2: Periodically control the ADCP current meter 17 to emit sound waves, and repeat step 1 in each cycle to obtain multiple sets of flow velocity data and azimuth data.

Step 3: After collecting multiple times of flow velocity data and azimuth data continuously, filter and eliminate the doubtful data collected during the drastic change of the attitude or azimuth of the buoy.

In this embodiment, two methods can be used to determine the suspicious data: one is to judge the adjacent data whose variation exceeds the limit as suspicious data and eliminate it, that is, to regard the data collected before and after with drastic changes as suspicious data The other is to sort the multiple sets of azimuth data collected, and determine the azimuth data corresponding to the maximum value and the minimum value and the flow velocity data synchronously collected with the azimuth data as doubtful data to be eliminated.

Step 4: Project the flow velocity data V _x and V _y outputted by the ADCP sea current meter 17 each time (the flow velocity data V _x and V _y here are flow velocity data after removing doubtful data) into the earth coordinate system, and calculate the earth coordinates The northward component V _N and eastward component V _E of the flow velocity in the system are calculated as follows:

Thus, the northward component V _N and the eastward component V _E of the flow velocity in multiple sets of earth coordinate systems can be obtained.

和东向分量的平均值

Step 5: According to the obtained northward component V _N and eastward component V _E of the flow velocity in the earth coordinate system, calculate the average value of the northward component of the flow velocity

and the mean of the eastward component

和东向分量的平均值

计算海水剖面的流速值V，计算公式如下：Step 6: Using the mean value of the north component of the flow velocity

and the mean of the eastward component

To calculate the velocity value V of the seawater profile, the calculation formula is as follows:

和东向分量的平均值

计算海水剖面的流向A，计算公式如下：Step 7: Using the mean value of the north component of the flow velocity

and the mean of the eastward component

To calculate the flow direction A of the seawater profile, the calculation formula is as follows:

Among them, arccot() represents the inverse cotangent function.

In this embodiment, a new installation structure of the current meter is designed for the defects of the current installation method of the ADCP current meter, and the current meter is placed inside the steel instrument well of the buoy body, and only the acoustic probe of the current meter is slightly exposed from the wellhead, thereby solving the problem The current meter is easily damaged by external forces such as fishing nets. At the same time, by shielding the built-in magnetic compass of the ADCP current meter, the real-time orientation of the buoy body is detected by means of an external orientation sensor, and the orientation sensor is installed on the upper platform far away from the steel material in the buoy body. Accurate detection of data. In addition, through data fusion of the accurate azimuth data collected and output by the external azimuth sensor and the flow velocity data collected and output by the ADCP current meter relative to its own coordinate system, the current data in the real space coordinate system are obtained, thereby solving the problem of the ADCP current meter. Its built-in magnetic compass is easily affected by the buoy body, which leads to inaccurate azimuth detection, and then cannot obtain accurate ocean current observation data.

Specific examples:

An ADCP current meter is installed on the buoy according to the conventional method in the prior art, as shown in Fig. 2, and it has been continuously operated at sea for nearly one year. Then, an ADCP sea current meter and an external orientation sensor are arranged on the same buoy according to the improved method proposed in this embodiment.

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

The consistency of the seawater profile velocity data obtained by using the conventional method and the observation method proposed in this embodiment is good, as shown in Fig. 12 and Fig. 13 . Among them, Fig. 12 shows the flow velocity data of the first five layers collected and output by the ADCP flowmeter installed in a conventional way; Fig. 13 shows the flow velocity data of the first five layers of the seawater profile obtained by using the observation method proposed in this embodiment.

The seawater profile flow direction data obtained by the conventional method and the observation method proposed in this example have the same basic trend, the flow direction has an obvious sinusoidal trend, and there are two flow reversal processes in one day, which is in line with the characteristics of the local semi-diurnal tidal current in the measured sea area, such as Shown in Figure 14 and Figure 15. Among them, Fig. 14 shows the flow direction of the first five layers collected and output by the ADCP flowmeter installed in a conventional way; Fig. 15 shows the flow direction data of the first five layers of the seawater profile obtained by using the observation method proposed in this embodiment.

However, the direction difference between the incoming and outgoing semi-diurnal tides observed by the observation method proposed in this embodiment is basically 180°, as shown in Figure 15, which is more in line with the local tidal current characteristics. However, the direction difference between the incoming and outgoing semi-diurnal tides observed by conventional methods is basically 120°, as shown in Figure 14, and there is a large observation error. This proves the effectiveness of the observation method proposed in this embodiment.

Of course, the above description is only a preferred embodiment of the present invention, and it should be pointed out that for those skilled in the art, some improvements and modifications can be made without departing from the principle of the present invention. Improvements and retouches should also be considered within the protection scope of the present invention.

Claims (6)

1. A method for observing the flow velocity and the flow direction of a seawater section is characterized in that,

an ADCP current meter and an independent azimuth sensor are arranged on the buoy body;

adjusting the Y-axis direction of the ADCP current meter self coordinate system to be consistent with the north direction of the azimuth sensor;

while controlling the ADCP current meter to emit sound waves, collecting azimuth data theta detected by an azimuth sensor, and receiving flow speed data V collected and output by the ADCP current meter _x 、V _y (ii) a Indicating the north deflection angle of the Y axis of the coordinate system of the ADCP current meter relative to the earth coordinate system by utilizing theta; v _x 、V _y Respectively representing an X-axis component and a Y-axis component of flow speed data acquired by the ADCP current meter under a self coordinate system;

calculating the north component V of the flow velocity in the earth coordinate system _N And an east component V _E ：

Continuously acquiring multiple times of flow velocity data and orientation data by using the ADCP current meter and the orientation sensor, and calculating the north component V of the flow velocity under multiple groups of earth coordinate systems _N And an east component V _E Then, the average value of the north component of the flow velocity is calculated

And average value of east component

Calculating the flow velocity of the seawater profile:

calculating the flow direction of the seawater profile:

2. the method for observing flow velocity and flow direction of sea water profile according to claim 1, wherein after continuously collecting flow velocity data and orientation data for a plurality of times, firstly screening and removing suspicious data collected in the process of drastic change of the attitude or orientation of the buoy body, and then calculating the northbound component V under the plurality of groups of terrestrial coordinate systems _N And an east component V _E 。

3. The method for observing sea water profile, flow velocity and flow direction according to claim 1 or 2,

installing the ADCP current meter on the sea-entering side of the instrument well of the buoy body;

a nonmagnetic upper layer platform is erected on a deck of the buoy body, the azimuth sensor is installed on the upper layer platform, and the azimuth sensor is completely separated from magnetic influence generated by a steel structure in the buoy body.

4. The method for observing sea water profile flow velocity and flow direction according to claim 3, wherein the process of adjusting the Y-axis direction of the ADCP current meter coordinate system to be consistent with the north direction of the azimuth sensor comprises:

forming equidirectional azimuth marks on the deck and the upper-layer platform of the buoy body respectively;

installing the azimuth sensor on the upper-layer platform, and adjusting the north direction of the azimuth sensor to be in the same direction as the azimuth identifier;

installing an instrument well flange plate at the instrument well position of the deck, respectively arranging a positioning pin at two opposite sides of the instrument well flange plate, wherein the connecting line of the two positioning pins is in the same direction as the azimuth mark, respectively arranging a mounting hole at the other two opposite sides of the instrument well flange plate, and the connecting line of the two mounting holes is vertical to the connecting line of the two positioning pins;

installing a flange on the upper part of a derrick of an instrument well, wherein two positioning pin holes and two assembling holes are formed in the flange, the two positioning pin holes correspond to and are assembled with two positioning pins on a flange plate of the instrument well, and the two assembling holes correspond to and are assembled with two installing holes on the flange plate of the instrument well;

installing a current meter installation plate on the derrick, and enabling the installation plate to be perpendicular to a connecting line of the two positioning pin holes;

set up locating pin and current meter installation checkpost on the mounting panel, will ADCP current meter is installed on current meter installation checkpost, and the angle of adjustment ADCP current meter makes the perpendicular cartridge of locating pin on its locating hole and the mounting panel, and the Y axle direction of ADCP current meter self coordinate system is unanimous with the on-board position sign direction this moment, realizes orientation sensor's northward and the Y axle direction syntropy of ADCP current meter self coordinate system.

5. The method for observing sea water profile, flow velocity and flow direction according to claim 4, wherein the process of forming the equidirectional orientation marks on the deck and the upper platform of the buoy body respectively comprises the following steps:

forming an orientation mark on the upper platform;

and forming the equidirectional azimuth mark on the deck of the buoy body by adopting a projection method according to the azimuth mark formed on the upper platform, and pointing to the instrument well.

6. The method of observing sea water profile flow velocity flow direction according to claim 3, wherein the ADCP current meter is installed inside an instrument well, and only the acoustic probe is exposed out of a wellhead.

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