Hydrographic measurement method and hydrographic measurement device for shallow water environment

Abstract

The invention relates to a hydrographic measurement method and device for a shallow water environment, and the method comprises the steps: obtaining the propagation velocity ratio of light in a to-be-measured shallow water environment, and the propagation velocity ratio is the ratio of the propagation velocity of light in a to-be-measured water area to the propagation velocity of light in the air; measuring first water depth data of the to-be-measured area according to a laser range finder of the water depth measurement assembly, wherein the laser range finder is located above the water surface; and calibrating the first water depth data by using the propagation speed ratio to obtain second water depth data. Relates to the technical field of hydrographic survey. According to the invention, direct contact with the riverbed is not needed when the shallow water environment is measured, the influence on the riverbed is reduced, the measurement precision is high, and the method is very suitable for hydrographic survey in the shallow water environment.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrological measurement, and in particular to a hydrological measurement method and a measurement device in a shallow water environment. Background Art

[0002] In order to measure the hydrological data of the riverbed, the water depth of the riverbed is often measured. In deep water environments, an ultrasonic rangefinder is often extended underwater, and then the underwater ultrasonic rangefinder is used to obtain the water depth data of the riverbed.

[0003] However, in some shallow water environments, it is difficult to submerge the ultrasonic probe below the water surface due to the shallowness of the water. Or the distance between the underwater ultrasonic probe and the riverbed surface is too small, which does not meet the measurement requirements of the ultrasonic rangefinder (generally requiring a distance greater than 5-10 cm).

[0004] Currently, water depth measurement in shallow water environments still relies heavily on steel rulers, which require direct contact with the riverbed during measurement. This not only easily causes certain damage to the terrain, but also has low measurement accuracy and a large workload. Summary of the Invention

[0005] The present invention provides a hydrological measurement method and a measuring device for a shallow water environment, which are used to solve the problem of difficulty in measuring water depth in a shallow water environment and to improve the efficiency of hydrological measurement in a shallow water environment.

[0006] In a first aspect, the present invention provides a method for hydrological measurement in a shallow water environment, comprising:

[0007] Obtaining a light propagation speed ratio in a shallow water environment to be measured, wherein the light propagation speed ratio is a ratio of the light propagation speed in the water area to be measured to the light propagation speed in air;

[0008] Obtaining first water depth data of the area to be measured according to the laser rangefinder of the water depth measurement component, wherein the laser rangefinder is located above the water surface;

[0009] The first water depth data is calibrated using the propagation speed ratio to obtain second water depth data.

[0010] In one embodiment, obtaining the propagation speed ratio of light in the shallow water environment to be measured comprises the following steps:

[0011] Using a water depth measurement component to measure the laser measured water depth Y of a calibration area at a plurality of calibration points, wherein the water quality environment of the calibration area is the same as the water quality environment of the shallow water environment to be measured;

[0012] Obtain the actual water depth X of multiple corresponding rate fixed points;

[0013] Based on the laser-measured water depth Y and the corresponding actual water depth X at multiple calibration points, a linear regression function Y = a*X + b is obtained, where the slope a in the linear regression function is the propagation speed ratio.

[0014] In one embodiment, obtaining the actual water depth X at multiple corresponding calibration points includes the following steps:

[0015] Empty the water in the calibration area, and use the water depth measurement component to measure the actual depth at the corresponding calibration points;

[0016] Based on the actual depth at the calibration points after drainage and the water surface height before drainage, obtain the actual water depth X at the calibration points before drainage.

[0017] In one embodiment, the second water depth data is calibrated according to the following formula:

[0018] H2 = H1 / a, where H1 is the first water depth data, a is the propagation speed ratio, and H2 is the second water depth data.

[0019] In one embodiment, the water depth measurement component further includes an ultrasonic rangefinder located above the river surface;

[0020] The step of obtaining the first water depth data of the area to be measured by measuring with the laser rangefinder of the water depth measurement component includes the following steps:

[0021] Use the laser rangefinder above the water surface to emit laser light to the riverbed of the area to be measured to obtain the first elevation;

[0022] Use the ultrasonic rangefinder above the water surface to emit ultrasonic waves to the river surface of the area to be measured to obtain the second elevation;

[0023] Obtain the elevation difference between the laser rangefinder and the ultrasonic rangefinder, and based on the elevation difference, the first elevation, and the second elevation, obtain the first water depth data.

[0024] In one embodiment, the following steps are further included:

[0025] Move the water depth measurement component along the riverbed section to obtain the second water depth data at multiple measurement points on the riverbed section;

[0026] Combine the horizontal positions of multiple measurement points and the second water depth data of each measurement point to obtain the topographic model of the riverbed section.

[0027] In a second aspect, the present application further provides a measurement device, which includes:

[0028] In a second aspect, the present application further provides a measurement device, which includes:

[0029] A measurement platform is provided above the riverbed, and the measurement platform is above the water surface;

[0030] A main body is provided above the measurement platform;

[0031] A water depth measurement component is installed on the main body. The water depth measurement component includes a laser rangefinder and an ultrasonic rangefinder. The measurement directions of the laser rangefinder and the ultrasonic rangefinder are both in the vertical direction, and both the laser rangefinder and the ultrasonic rangefinder are above the water surface. Among them, the laser rangefinder is used to emit measurement laser to the riverbed to obtain a first elevation, and the ultrasonic rangefinder is used to emit ultrasonic waves to the river surface to obtain a second elevation; and

[0032] A controller is connected to the water depth measurement component.

[0033] In one embodiment, a reflecting vertical plate is further included;

[0034] A horizontal rangefinder connected to the controller is further installed on the main body. The horizontal rangefinder is used to emit a measurement signal towards the reflecting vertical plate to measure the horizontal distance between the main body and the reflecting vertical plate.

[0035] In one embodiment, the measurement platform extends along the riverbed cross-section, and the reflecting vertical plate is arranged on one side of the measurement platform along the extension direction of the riverbed cross-section;

[0036] Rollers are further installed on the main body, and the controller is connected to the rollers so that the main body can move along the extension direction of the riverbed cross-section.

[0037] In one embodiment, the measurement directions of the laser rangefinder and the ultrasonic rangefinder are both in the vertical direction, and the measurement direction of the horizontal rangefinder is in the horizontal direction.

[0038] In one embodiment, a vertically extending slide rail is provided on the main body, and the ultrasonic rangefinder is slidably installed on the slide rail.

[0039] In one embodiment, a marking ruler is installed on the slide rail. The scale lines of the marking ruler are arranged along the extension direction of the slide rail, and the zero scale line of the marking ruler is at the same height as the probe of the laser rangefinder.

[0040] In one embodiment, the marking ruler is slidably installed at the slide rail, and an indicating plate that slides horizontally is installed at the zero scale of the marking ruler. The indicating plate can slide below the laser rangefinder.

[0041] In one embodiment, the slide rail has a slide groove for installing the ultrasonic rangefinder, and a threaded hole connected to the slide groove is provided on the slide rail. A locking screw is threadedly connected to the threaded hole. The locking screw is used to abut the mounting seat of the ultrasonic rangefinder and to press the mounting seat into the slide groove to lock the ultrasonic rangefinder.

[0042] In one embodiment, the ultrasonic rangefinder is detachably slidably mounted on the slide rail.

[0043] Compared with existing technologies, the present invention has the advantage of using a water depth measurement assembly with a laser rangefinder to measure and obtain the first water depth data of the measured area. Because the laser rangefinder is located above the water surface, the measurement process does not require the laser rangefinder to be inserted underwater or directly contact the riverbed. The measurement process does not change the shallow riverbed environment, making measurement easier. Furthermore, the laser-measured water depth data can be calibrated using the light propagation speed ratio in the shallow water environment to be measured, avoiding laser ranging errors caused by the slower underwater light propagation speed compared to the light propagation speed in air, thereby improving the measurement accuracy of water depth measurements in shallow water environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Hereinafter, the present invention will be described in more detail based on embodiments with reference to the accompanying drawings.

[0045] Figure 1 is a flow chart of a hydrological measurement method according to an embodiment of the present invention;

[0046] Figure 2 1 is a schematic diagram of a measuring device in use according to an embodiment of the present invention;

[0047] Figure 3 is a schematic diagram of the three-dimensional structure of a measuring device in an embodiment of the present invention;

[0048] Figure 4 is a schematic diagram of the main structure of a measuring device in an embodiment of the present invention;

[0049] Figure 5 1 is a schematic diagram of the main structure of the measuring device in an embodiment of the present invention when adjusting the position of the marking ruler;

[0050] Figure 6 It is a scatter plot of measurement data from multiple rate points;

[0051] Figure 7 It is a riverbed cross-section model diagram drawn using the hydrological survey method of the present application.

[0052] Reference numerals:

[0053] 1. Main body; 11. Slide rail; 12. Marking ruler; 13. Roller; 14. Locking screw; 15. Indicator plate;

[0054] 2. Laser rangefinder;

[0055] 3. Ultrasonic rangefinder;

[0056] 4. Controller;

[0057] 5. Reflective vertical board;

[0058] 6. Measuring platform;

[0059] 7. Horizontal rangefinder. DETAILED DESCRIPTION

[0060] The present invention will be further described below with reference to the accompanying drawings.

[0061] In river model testing, it is often necessary to measure the impact of different fluid environments on the river channel model. This allows us to simulate the flow structure, riverbed evolution, and engineering solution effects of natural rivers under specific conditions. By measuring the riverbed information of river models under different conditions, we can reflect the actual evolution of the river channel under natural conditions.

[0062] However, river models are scaled down from natural rivers, resulting in shallow channels. This makes it difficult to extend ultrasonic probes below the water surface. Consequently, each depth measurement requires a steel ruler to be placed against the bottom of the river model to measure the riverbed depth. This inevitably alters the model's riverbed surface, damaging it and interfering with subsequent testing.

[0063] In other words, previous topographic survey methods are difficult to adapt to hydrological measurements in shallow water environments such as river engineering models.

[0064] See also Figures 1 to 3 As shown, in order to solve the difficulty of hydrological measurement in shallow water environment, this application provides a hydrological measurement method in shallow water terrain, which includes the following steps:

[0065] S100: Obtaining a propagation speed ratio of light in a shallow water environment to be measured, where the propagation speed ratio is a ratio of the propagation speed of light in the water to be measured to the propagation speed of light in air;

[0066] S200: Obtaining first water depth data of the area to be measured according to the laser rangefinder 2 of the water depth measurement component, where the laser rangefinder 2 is located above the water surface;

[0067] S300: calibrating the first water depth data using the propagation speed ratio to obtain second water depth data.

[0068] In this application, a laser rangefinder 2 above the water surface is used to measure the water depth of the area to be measured, obtaining the first water depth data. Compared with an ultrasonic measuring instrument, the laser rangefinder 2 can emit laser towards the riverbed above the water surface and obtain the distance between the laser rangefinder 2 and the riverbed surface according to the laser signal reflected by the riverbed, that is, the first water depth data.

[0069] Since in this application, the first water depth data is also calibrated through the light propagation speed ratio in the shallow water environment to be measured to obtain the second water depth data, it can avoid large deviations in measurement conclusions caused by the speed difference of light propagation in different media. And it can eliminate the measurement error caused by the light speed gap under different turbid water qualities, improving the measurement accuracy of the laser rangefinder 2 in water depth measurement.

[0070] A laser rangefinder refers to an instrument that uses a certain parameter of modulated laser to measure the distance to a target. The measurement range of the laser rangefinder is 3.5 - 5000 meters.

[0071] According to the ranging method, it is divided into a phase method rangefinder and a pulse method rangefinder. The pulsed laser rangefinder emits a beam or a series of short pulsed laser beams towards the target during operation. The photoelectric element receives the laser beam reflected by the target, and the timer measures the time from the emission to the reception of the laser beam to calculate the distance from the observer to the target.

[0072] It can be understood that the light propagation speed ratio in the shallow water environment to be measured can first measure the light propagation speed in the air and the light propagation speed under the water area to be measured, and then calculate the ratio of the light propagation speeds in the two propagation media to obtain the light propagation speed ratio in the shallow water environment to be measured.

[0073] In some implementation manners, step S100 of obtaining the light propagation speed ratio in the shallow water environment to be measured may further include the following steps:

[0074] S101: Use the water depth measurement component to measure the laser-measured water depth Y at multiple calibration points in the calibration area, where the water quality environment in the calibration area is the same as the water quality environment in the shallow water environment to be measured;

[0075] S102: Obtain the actual water depth X at multiple corresponding calibration points;

[0076] S103: Obtain the linear regression function Y = a*X + b according to the laser-measured water depth Y and the corresponding actual water depth X at multiple calibration points, where the slope a in the linear regression function is the propagation speed ratio.

[0077] Among them, in step S101, the water depth measurement component is moved to the calibration point, and the ranging laser is emitted by the laser rangefinder 2 to the riverbed at the calibration point. The height difference L1 between the laser rangefinder 2 and the riverbed bottom is obtained according to the time when the laser is reflected back to the laser rangefinder 2 by the riverbed. Combining the height difference L2 between the laser measuring instrument and the water surface, the laser-measured water depth Y can be obtained, Y = L1 - L2.

[0078] In some implementation manners, in step S102, when obtaining the actual water depths X of multiple corresponding calibration points, the following steps are further included:

[0079] Empty the water in the calibration area, and use the water depth measurement component to measure the actual depth of the corresponding calibration point;

[0080] According to the actual depth of the calibration point after drainage and the water surface height before drainage, the actual water depth X of the calibration point before drainage is obtained.

[0081] That is to say, in the present application, after emptying the water in the calibration area, there is no water in the calibration area at this time. The propagation speed during the laser measurement process is constantly equal to the propagation speed in the air. The height difference L3 between the calibration point and the laser rangefinder 2 can be measured by using the laser rangefinder 2. Combining the height difference L2 between the laser rangefinder 2 and the water surface measured in step S102 again, X = L3 - L2 can be obtained.

[0082] Since the laser-measured water depths Y of multiple calibration points are measured, and the actual water depths X of the corresponding calibration points can be plotted to obtain Figure 6 the scatter plot shown, and then the linear regression function Y = a*X + b can be obtained. For example Figure 6 for the multiple groups of measurement data shown in, the linear regression function can be obtained as Y = *X, that is, the propagation speed ratio a is 0.7341 and b is 0.

[0083] Compared with obtaining the propagation speed ratio by measuring the light propagation speed in water and combining the light propagation speed in air, the step of measuring the light propagation speed is omitted, and the measurement is simpler.

[0084] It can be understood that the calibration area here can be selected as a hydraulic model with the same water quality, and can also be measured in a water basin or a water bucket with the same water quality.

[0085] It can be understood that in some cases, if the water depth in the calibration area is relatively deep, the underwater ultrasonic measuring instrument is allowed to measure, and the underwater ultrasonic measuring instrument can also be used to directly measure the actual water depth X of the calibration point. If the riverbed bottom of the calibration area is made of hard materials (such as plastic, metal, etc.), the contact water depth measurement method such as the steel tape method can be used to measure the actual water depth X.

[0086] In some implementation manners, the second water depth data is calibrated according to the following formula:

[0087] H2 = H1 / a, where H1 is the first water depth data, a is the propagation speed ratio, and H2 is the second water depth data.

[0088] Calibrating through the propagation speed ratio to obtain the second water depth data makes it more consistent with the actual water depth situation.

[0089] In some implementation manners, the water depth measurement component further includes an ultrasonic rangefinder 3 located above the river surface;

[0090] In step S200, obtaining the first water depth data of the area to be measured according to the laser rangefinder 2 of the water depth measurement component includes the following steps:

[0091] Using the laser rangefinder 2 above the water surface to emit laser towards the riverbed of the area to be measured to obtain the first elevation (i.e., the height difference between the laser rangefinder 2 and the riverbed), D1;

[0092] Using the ultrasonic rangefinder 3 above the water surface to emit ultrasonic towards the river surface of the area to be measured to obtain the second elevation, D2 (i.e., the height difference between the ultrasonic rangefinder 3 and the river surface); obtaining the elevation difference D3 between the laser rangefinder 2 and the ultrasonic rangefinder 3, and obtaining the first water depth data H1 according to the elevation difference D3, the first elevation D1, and the second elevation D2.

[0093] Wherein, if the laser rangefinder 2 is above the ultrasonic rangefinder 3, then H1 = D1 - D2 - D3; if the laser rangefinder 2 is below the ultrasonic rangefinder 3, then H1 = D1 + D3 - D2.

[0094] In some implementation manners, the hydrological measurement method further includes the following steps: moving the water depth measurement component along the riverbed cross-section to obtain the second water depth data of multiple measurement points on the riverbed cross-section;

[0095] Combining the horizontal positions of multiple measurement points and the second water depth data of each measurement point to obtain the topographic model of the riverbed cross-section.

[0096] That is to say, in this application, the topographic model of the riverbed cross-section can be drawn by measuring the water depth data of multiple measurement points (such as Figure 7 the "corrected" topographic curve). It is almost equivalent to the topographic curve measured in an "almost waterless" environment. The "almost waterless" corresponding topographic curve is the topographic curve obtained after draining the water in the shallow water area to be measured. Compared with the "water measurement" topographic curve directly measured by laser, it can more accurately display the actual shape of the riverbed and does not require draining the water.

[0097] In a second aspect, the present application further provides a measuring device. The measuring device includes a main body 1, a water depth measuring component, the water depth measuring component is installed on the main body 1, the water depth measuring component includes a laser rangefinder 2 and an ultrasonic rangefinder 3, both the laser rangefinder 2 and the ultrasonic rangefinder 3 are located above the water surface, the laser rangefinder 2 is used to emit a measuring beam towards the riverbed to measure the first elevation, the ultrasonic rangefinder 3 is used to emit ultrasonic waves towards the river surface to measure the second elevation, and a controller 4, the controller 4 is connected to the water depth measuring component to obtain the first water depth data according to the first elevation and the second elevation.

[0098] It is possible to measure the water depth data of the riverbed without contacting the riverbed surface, and there is no need to extend the probe underwater, which is very suitable for measuring the water depth in a shallow water environment.

[0099] In some cases, the above hydrological measurement method may be stored in the controller 4, and the controller 4 is used to calibrate the first water depth data according to the propagation speed ratio of the to-be-measured shallow water environment to obtain the second water depth data.

[0100] Among them, the propagation speed ratio can be pre-stored in the controller 4, or the propagation speed ratio can be measured by using the above hydrological measurement method.

[0101] When using the measuring device provided in the present application to measure the water depth, the laser rangefinder 2 can first emit laser towards the riverbed to obtain the first elevation, and send the first elevation D1 to the controller 4 installed on the main body 1.

[0102] Then, the ultrasonic rangefinder 3 is used to emit ultrasonic waves towards the water surface to obtain the second elevation D2, and the second elevation D2 is sent to the controller 4. The controller 4 obtains the first water depth data H1 according to D1, D2 and the height difference D3 between the laser rangefinder 2 and the ultrasonic rangefinder 3.

[0103] Then the controller 4 calibrates the first water depth data H1 by using the stored propagation speed ratio a to obtain the second water depth data H2. Thus, it is possible to measure the water depth in a shallow water environment, avoiding the damage to the riverbed environment caused by measuring the water depth with a steel tape.

[0104] In some implementation manners, the measuring device further includes a reflecting vertical plate 5, and a horizontal rangefinder connected to the controller 4 is further installed on the main body 1. The horizontal rangefinder is used to emit a measuring signal towards the reflecting vertical plate 5 to measure the horizontal distance between the main body 1 and the reflecting vertical plate 5.

[0105] According to the horizontal distance measured by the horizontal rangefinder, the current horizontal position of the measuring device can be determined, so that the coordinates of a point on the riverbed can be obtained by combining the second water depth data measured at the current horizontal position.

[0106] It can be understood that the horizontal rangefinder can be a device that uses laser or ultrasonic waves to achieve ranging.

[0107] See Figures 2 to 5 As shown, in some implementation manners, the measuring device further includes a measuring platform 6 extending along the riverbed section. The reflector is arranged on one side of the measuring platform 6 along the extension direction of the riverbed section. A roller 13 is also installed on the main body 1 so that the main body 1 can move along the extension direction of the riverbed section. The controller is connected to the roller 13 and can drive the roller to roll on the measuring platform, thereby realizing the movement of the main body on the measuring platform 6. Specifically, a driving motor connected to the roller is arranged on the main body, and the controller is connected to the driving motor. By controlling the driving motor, the rotation of the roller is controlled, and further the movement of the main body on the measuring platform is realized.

[0108] During the process of hydrological measurement using the measuring device provided by the present application, each time the main body 1 moves along the riverbed section, a second water depth data of a measurement point can be obtained by using the water depth measurement component and the controller 4. Combining the horizontal distance between the main body 1 and the reflection vertical plate 5 measured by the horizontal rangefinder on the main body 1 at this time, the horizontal position of the measurement point on the riverbed section can be obtained.

[0109] Then move the main body 1 at a specific step size, and a model of the riverbed section can be obtained by combining the measurement data of multiple measurement points.

[0110] As shown in the figure, in some implementation manners, the measuring platform 6 is a bridge across the riverbed. It can be understood that in some other implementation manners, the measuring platform 6 can also be a hull floating on the water surface, or a pier or support assumed in the river.

[0111] See Figure 4 And Figure 5 As shown, in some implementation manners, the measuring directions of both the laser rangefinder 2 and the ultrasonic rangefinder 3 are along the vertical direction, and the measuring direction of the horizontal rangefinder is along the horizontal direction.

[0112] In some implementation manners, a vertically extending slide rail 11 is arranged on the main body 1, and the ultrasonic rangefinder 3 is slidably mounted on the slide rail 11. During use, the height between the ultrasonic rangefinder 3 and the water surface can be adjusted by sliding the ultrasonic rangefinder 3 vertically. This can avoid excessive ultrasonic measurement errors caused by the ultrasonic rangefinder 3 being too close to the water surface.

[0113] See Figures 3 to 5 As shown, in some implementation manners, a marking scale 12 is installed on the slide rail 11. The scale lines of the marking scale 12 are arranged along the extension direction of the slide rail 11, and the zero scale line of the marking scale 12 is at the same height as the probe of the laser rangefinder 2.

[0114] When making a measurement, the height difference D3 between the ultrasonic rangefinder 3 and the laser rangefinder 2 can be measured by the marking ruler 12, so as to obtain the first water depth data H1 based on the first elevation D1 measured by the laser rangefinder 2 and the second elevation D2 measured by the ultrasonic rangefinder 3.

[0115] In some implementation manners, the marking ruler 12 is slidably mounted on the slide rail 11, and an indicating plate that slides horizontally is mounted at the zero scale of the marking ruler 12, and the indicating plate can slide horizontally to the lower side of the laser rangefinder.

[0116] That is to say, the height of the marking ruler 12 can be vertically adjusted along the slide rail 11. During the process of adjusting the marking ruler 12 up and down, the indicating plate 15 of the marking ruler 12 can be horizontally extended, so that the indicating plate 15 is located below the laser rangefinder. When the marking ruler 12 is adjusted up and down so that the indicating plate 15 fits with the probe of the laser rangefinder, it means that the height of the marking ruler 12 has been adjusted accurately. By fixing the marking ruler 12 and then sliding the indicating plate 15 back, it shows that the indicating plate 15 blocks the laser of the laser rangefinder. It can be understood that the locking or unlocking of the marking ruler 12 can be achieved by inserting screws into the guide rail, so as to prevent the marking ruler 12 from moving up and down after being locked.

[0117] Among them, in some implementation manners, the controller 4 further includes an input device, and the elevation difference D3 measured according to the marking ruler 12 can be input into the controller 4 through the input device, so that the controller 4 performs relevant operations to calculate the first water depth data H1.

[0118] It can be understood that in some implementation manners, a ranging probe facing the laser rangefinder 2 can also be installed on the ultrasonic rangefinder 3, and the height difference D3 between the ultrasonic rangefinder 3 and the laser rangefinder 2 can be directly measured by the ranging probe. The ranging probe can be electrically connected to the controller 4 to transmit the measured height difference D3 to the controller 4.

[0119] In some implementation manners, the slide rail 11 has a chute for installing the ultrasonic rangefinder 3, and a threaded hole communicating with the chute is provided on the slide rail 11. A locking screw 14 is threadedly connected to the threaded hole. The locking screw 14 is used to abut against the mounting seat of the ultrasonic rangefinder 3 and is used to press the mounting seat in the chute to lock the ultrasonic rangefinder 3.

[0120] See Figures 3 to 5As shown, in some implementations, the ultrasonic rangefinder 3 is detachably and slidably mounted on the slide rail 11. Specifically, the ultrasonic rangefinder 3 can be detached from the slide rail 11 by unscrewing the locking screw 14 from the threaded hole and then sliding the ultrasonic rangefinder 3 out of the chute. When the ultrasonic rangefinder 3 is damaged, the ultrasonic rangefinder 3 can be first slid out of the slide rail 11, and then a new ultrasonic rangefinder 3 can be inserted into the chute to realize the replacement of the ultrasonic rangefinder 3.

[0121] Although the present invention has been described with reference to the preferred embodiments, various modifications can be made thereto and components thereof can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any manner. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A hydrographic measurement method for shallow water environments, characterized in that, It includes: Obtaining the propagation speed ratio of light in the shallow water environment to be measured, where the propagation speed ratio is the ratio of the propagation speed of light in the water area to be measured to the propagation speed of light in the air; Measuring the first water depth data of the area to be measured by the laser rangefinder of the water depth measurement component, where the laser rangefinder is located above the water surface; Calibrating the first water depth data with the propagation speed ratio to obtain the second water depth data.

2. The hydrographic survey method for a shallow water environment according to claim 1, characterized in that, The obtaining of the propagation speed ratio of light in the shallow water environment to be measured includes the following steps: Measuring the laser-measured water depth Y at multiple rate points in the rate calibration area by using the water depth measurement component, where the water quality environment of the rate calibration area is the same as that of the shallow water environment to be measured; Obtaining the actual water depth X at multiple corresponding rate points; Obtaining the linear regression function Y = a*X + b based on the laser-measured water depth Y and the corresponding actual water depth X at multiple rate points, where the slope a in the linear regression function is the propagation speed ratio.

3. The hydrological measurement method for the shallow water environment according to claim 2, characterized in that The obtaining of the actual water depth X at multiple corresponding rate points includes the following steps: Emptying the water in the rate calibration area and measuring the actual depth at the corresponding rate points by using the water depth measurement component; Obtaining the actual water depth X at the rate points before drainage based on the actual depth at the rate points after drainage and the water surface height before drainage.

4. The hydrological measurement method for the shallow water environment according to claim 1, characterized in that Calibrating to obtain the second water depth data according to the following formula: H2 = H1 / a, where H1 is the first water depth data, a is the propagation speed ratio, and H2 is the second water depth data.

5. The hydrological measurement method for the shallow water environment according to claim 1, characterized in that The water depth measurement component further includes an ultrasonic rangefinder located above the river surface; The measuring of the first water depth data of the area to be measured by the laser rangefinder of the water depth measurement component includes the following steps: Emitting laser from the laser rangefinder above the water surface to the riverbed of the area to be measured to obtain the first elevation; Emitting ultrasonic from the ultrasonic rangefinder above the water surface to the river surface of the area to be measured to obtain the second elevation; Obtaining the elevation difference between the laser rangefinder and the ultrasonic rangefinder, and obtaining the first water depth data based on the elevation difference, the first elevation, and the second elevation.

6. The hydrographic survey method for a shallow water environment according to any one of claims 1-5, characterized in that, It further includes the following steps: Moving the water depth measurement component along the riverbed cross-section to obtain the second water depth data at multiple measurement points on the riverbed cross-section; Combining the horizontal positions of multiple measurement points and the second water depth data of each measurement point to obtain the topographic model of the riverbed cross-section.

7. A measuring device, characterized in that, It includes: A measurement platform arranged above the riverbed, where the measurement platform is located above the water surface; A main body, which is arranged above the measurement platform; A water depth measurement component, which is installed on the main body. The water depth measurement component includes a laser rangefinder and an ultrasonic rangefinder. The measurement directions of the laser rangefinder and the ultrasonic rangefinder are both along the vertical direction, and both the laser rangefinder and the ultrasonic rangefinder are located above the water surface. Among them, the laser rangefinder is used to emit measurement laser to the riverbed to obtain the first elevation, and the ultrasonic rangefinder is used to emit ultrasonic to the river surface to obtain the second elevation; and A controller, which is connected to the water depth measurement component.

8. The measuring device according to claim 7, characterized in that, It further includes A reflecting vertical plate; A horizontal rangefinder connected to the controller is further installed on the main body. The horizontal rangefinder is used to emit a measurement signal towards the reflecting vertical plate to measure the horizontal distance between the main body and the reflecting vertical plate.

9. The measuring device according to claim 8, characterized in that, It further includes The measurement platform is arranged to extend along the riverbed cross-section, and the reflecting vertical plate is arranged on one side of the measurement platform along the extension direction of the riverbed cross-section; Rollers are further installed on the main body, and the controller is connected to the rollers so that the main body can move along the extension direction of the riverbed cross-section.

10. The measuring device according to any one of claims 7-9, characterized in that It further includes A vertically extending slide rail is arranged on the main body, and the ultrasonic rangefinder is slidably installed on the slide rail. A marking scale is installed on the slide rail. The scale lines of the marking scale are arranged along the extension direction of the slide rail, and the zero scale line of the marking scale is at the same height as the probe of the laser rangefinder.

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