A Riverbed Gradient Measurement System Based on Unmanned Vessel Positioning

Abstract

This invention proposes a riverbed gradient measurement system based on unmanned surface vessel (USV) positioning, comprising: an USV, a connecting rod, a GNSS positioning device, an acoustic automatic water level gauge, and a single-beam echo sounder. One end of the connecting rod is fixed to the hull of the USV, and the axis of the connecting rod is perpendicular to the plane of the USV hull. At least two connecting studs are provided along the axis of the connecting rod; one stud is connected to the GNSS positioning device, and the other stud is connected to the single-beam echo sounder. The axes of the GNSS positioning device and the single-beam echo sounder are both coincident with the axis of the connecting rod. The upper end of the connecting rod is connected to the acoustic automatic water level gauge via a first connecting stud, and the axis of the acoustic automatic water level gauge is perpendicular to the plane of the USV hull. The GNSS positioning device, the single-beam echo sounder, and the acoustic automatic water level gauge are all connected to their corresponding connecting studs on the connecting rod via nuts pre-embedded in the vessel body. This invention can automatically measure the riverbed gradient, effectively reducing measurement costs and improving the efficiency and accuracy of riverbed gradient measurement.

Description

Technical Field

[0001] This utility model relates to the field of water conservancy and waterway engineering surveying, specifically to a riverbed gradient measurement system based on unmanned vessel positioning. Background Technology

[0002] Riverbed gradient is the ratio of the elevation difference between two points on the longitudinal profile of the riverbed to the horizontal distance. Riverbed gradient is an important data point for determining the inundation range of reservoirs, water flow velocity, and design parameters of waterway regulation structures. In order to obtain riverbed gradient data and thus provide basic data support for the study of river hydrodynamic characteristics, it is usually necessary to measure the riverbed gradient on-site.

[0003] Currently, the main method for measuring riverbed gradient is to have surveyors travel by boat to a pre-defined river centerline, use a shipborne single-beam echo sounder combined with actual water level data from nearby stations to analyze and measure the riverbed elevation at the first measuring point, and then travel by boat to a pre-defined second measuring point to obtain the riverbed elevation at the second measuring point using the same method. At the same time, the horizontal distance between the two measuring points must be recorded. The riverbed gradient is then calculated based on the difference in riverbed elevation between the two measuring points and the horizontal distance.

[0004] However, the aforementioned riverbed gradient measurements have several significant shortcomings, primarily in three aspects: First, low safety. Surveyors must travel by boat to conduct measurements, facing considerable safety risks in adverse weather conditions and turbulent currents. Second, low measurement accuracy. Current methods do not measure water depth and water level simultaneously; water level measurements rely on data from nearby stations, while elevation is derived from both. This time lag between water level and depth measurements introduces errors in the elevation calculation of riverbed points. Third, low efficiency and high cost. Current survey vessels are typically large, resulting in slow speeds and high fuel and time consumption during measurements, leading to low efficiency and high manpower and material costs. Utility Model Content

[0005] To address the issues of low safety, accuracy, efficiency, and high cost in existing riverbed gradient measurement methods, this invention proposes a riverbed gradient measurement system based on unmanned surface vessel (USV) positioning. The system includes: an USV, a connecting rod, a GNSS positioning device, an acoustic automatic water level gauge, and a single-beam echo sounder. One end of the connecting rod is fixed to the hull of the USV, and the axis of the connecting rod is perpendicular to the plane of the USV hull. At least two connecting studs are provided along the axial direction of the connecting rod; one stud is connected to the GNSS positioning device, and the other stud is connected to the single-beam echo sounder, with the axes of both the GNSS positioning device and the single-beam echo sounder coinciding with the axis of the connecting rod. The upper end of the connecting rod is connected to the acoustic automatic water level gauge via a first connecting stud, and the axis of the acoustic automatic water level gauge is perpendicular to the plane of the USV hull. The GNSS positioning device, the single-beam echo sounder, and the acoustic automatic water level gauge are all connected to their corresponding connecting studs on the connecting rod via nuts pre-embedded in the vessel body.

[0006] The technical effects of the above system include: the system achieves precise matching of the measurement directions of each instrument, can simultaneously acquire the geographical location, water depth and water level data of the measurement point, solves the problem of asynchronous water level and water depth measurement in traditional measurement, and improves the accuracy of riverbed gradient measurement; at the same time, it eliminates the need for surveyors to accompany the vessel, improving the safety of field measurement, and the integrated system design improves measurement efficiency.

[0007] Furthermore, a support washer is provided on one side of the connecting rod. The support washer is fixedly connected to the connecting rod body and perpendicular to the rod body axis. The support washer has holes for connecting screws to pass through. The hull connecting plate of the unmanned surface vessel also has holes for connecting screws to pass through. The connecting rod is threadedly connected to the hull connecting plate. The technical effects include: ensuring the connection stability between the connecting rod and the hull of the unmanned surface vessel, while ensuring that the axis of the connecting rod is perpendicular to the hull plane, providing a structural foundation for accurate measurements by various instruments, and avoiding measurement deviations caused by loose connections.

[0008] Furthermore, the hull connecting piece of the unmanned vessel is a stainless steel rectangular piece, which is fixedly connected to the hull of the unmanned vessel by welding. Its technical advantages include: the welding of the stainless steel rectangular hull connecting piece enhances the connection strength and corrosion resistance between the connecting piece and the hull of the unmanned vessel, adapts to complex aquatic environments in the wild, and ensures stability for long-term use.

[0009] Furthermore, the support pad includes an upper pad and a lower pad, and the distance between the upper and lower pads is equal to the thickness of the unmanned vessel's hull connecting piece. The technical advantages include: the distance between the upper and lower support pads is equal to the thickness of the hull connecting piece, resulting in a tighter fit between the support pad and the hull connecting piece, improving the stability of the connection between the connecting rod and the unmanned vessel, and reducing errors caused by structural swaying during measurement.

[0010] Furthermore, the GNSS positioning device is screwed to a first connecting stud on the connecting rod along its own axis via a first pre-embedded nut embedded in its body, and the GNSS positioning device and the connecting rod are coaxially arranged. The technical advantages include: the coaxial arrangement of the GNSS positioning device and the connecting rod ensures that the measured geographical coordinates strictly correspond to the actual measuring points of the unmanned vessel, avoiding positioning errors caused by positional offsets and improving the accuracy of distance measurement between two points.

[0011] Furthermore, the single-beam echo sounder is screwed to a connecting stud on the connecting rod along its own axis via a second pre-embedded nut embedded in its body, and the single-beam echo sounder and the connecting rod are coaxially arranged. The technical advantages include: the coaxial arrangement of the single-beam echo sounder and the connecting rod ensures that the measured water depth data corresponds to the riverbed position directly below the measuring point, avoiding water depth errors caused by measurement direction deviations and ensuring the accuracy of riverbed bottom elevation calculations.

[0012] Furthermore, the acoustic automatic water level gauge is screwed to the second connecting stud on the connecting rod, which is set along a direction parallel to its own axis, via a third pre-embedded nut pre-embedded in its body, and the acoustic automatic water level gauge remains perpendicular to the plane of the unmanned vessel's hull. Its technical advantages include: the acoustic automatic water level gauge is perpendicular to the hull plane, making its measurement direction perpendicular to the water surface, enabling accurate acquisition of the real-time water level at the measuring point and reducing water level measurement deviation.

[0013] Furthermore, nut washers are provided between the first connecting stud, the second connecting stud, the first connecting stud, and the pre-embedded nuts of the corresponding instruments on the connecting rod. The technical benefits include: the nut washers prevent loosening when the GNSS positioning device, single-beam echo sounder, and acoustic automatic water level gauge are connected to the connecting rod, ensuring the positional stability of each instrument during measurement and avoiding fluctuations in measurement data caused by vibration or water flow impact.

[0014] Furthermore, the unmanned surface vessel (USV) is equipped with a remote control device that controls its navigation trajectory. The technical advantages include: the remote control device enables remote navigation control of the USV, eliminating the need for onboard personnel and improving the safety of the measurement operation.

[0015] Furthermore, it also includes a display terminal, which is connected to the GNSS positioning device, the acoustic automatic water level gauge, and the single-beam echo sounder via network communication. Its technical advantages include: the display terminal acquires and displays the geographical location, water level, and water depth data of the measurement point in real time through network communication, facilitating real-time monitoring of the measurement process by operators and further improving measurement efficiency.

[0016] The beneficial effects of this utility model include:

[0017] This invention features a high degree of automation in measuring riverbed gradient, greatly improving the safety of measurement personnel. It can measure the riverbed gradient between any two points in a river and is suitable for riverbed gradient measurement under various external environmental conditions. It effectively reduces measurement costs, greatly improves the efficiency and accuracy of riverbed gradient measurement, and can provide a large amount of original field measurement data for riverbed evolution analysis and other work. It will also greatly promote the study of river dynamics. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0019] Figure 2 This is a schematic diagram of the connecting rod of this utility model;

[0020] Figure 3 This is a schematic diagram of the structure of the unmanned vessel hull connecting piece and connecting rod after connection according to this utility model;

[0021] Figure 4 This is a schematic diagram of the structure of the connecting rod of this utility model after connecting various devices;

[0022] Figure 5 This is a top view of the GNSS positioning device of this utility model installed behind the connecting rod;

[0023] Figure 6 This is a top view of the single-beam depth sounder of this utility model installed behind the connecting rod;

[0024] Figure 7 This is a top view of the acoustic automatic water level gauge of this utility model installed behind the connecting rod;

[0025] The markings in the diagram are as follows: 1-Unmanned Surface Vessel, 2-Connecting Rod, 3-GNSS Positioning Device, 4-Single Beam Echo Sounder, 5-Acoustic Automatic Water Level Gauge, 6-Water Surface Line, 7-Underwater Topographic Longitudinal Profile Line, 8-Display Terminal, 10-Hull Connecting Plate, 20-Supporting Washer, 21-First Connecting Stud, 22-Second Connecting Stud, 23-Third Connecting Stud, 24-Connecting Screw, 25-Connecting Nut, 26-Transition Rod, 30-First Embedded Nut, 31-First Nut Washer, 40-Second Embedded Nut, 41-Second Nut Washer, 50-Third Embedded Nut, 51-Third Nut Washer. Detailed Implementation

[0026] The following detailed embodiments are provided to explain the technical solution of this utility model, so that those skilled in the art can understand this utility model. The protection scope of this utility model is not limited to the following specific embodiments. Any modifications or improvements made by those skilled in the art that incorporate the technical solution of this utility model but differ from the following detailed embodiments are also within the protection scope of this utility model.

[0027] A riverbed gradient measurement system based on unmanned vessel positioning, such as Figure 1 As shown, the system includes an unmanned surface vessel (USV) 1, a connecting rod 2, a GNSS positioning device 3, an acoustic automatic water level gauge 5, and a single-beam depth sounder 4. One end of the connecting rod 2 is fixed to the hull of the USV 1, and the axis of the connecting rod 2 is perpendicular to the plane of the USV 1. At least two connecting studs are provided along the axis of the connecting rod 2, one of which is connected to the GNSS positioning device 3, and the other is connected to the single-beam depth sounder 4. The axes of the GNSS positioning device 3 and the single-beam depth sounder 4 are both coincident with the axis of the connecting rod 2. The upper end of the connecting rod 2 is connected to the acoustic automatic water level gauge 5 through a first connecting stud 21, and the axis of the acoustic automatic water level gauge 5 is perpendicular to the plane of the USV 1. The GNSS positioning device 3, the single-beam depth sounder 4, and the acoustic automatic water level gauge 5 are all connected to the corresponding connecting studs of the connecting rod 2 through nuts pre-embedded in the vessel body.

[0028] The connecting rod is called connecting rod 2. Connecting rod 2 is made of stainless steel and has rust resistance and good tensile and compressive strength. The main body of connecting rod 2 is 100cm long and 8cm in diameter.

[0029] The hull connecting piece 10 of the unmanned vessel 1 is made of stainless steel rectangular sheet and is fixedly connected to the hull of the unmanned vessel 1 by welding.

[0030] The hull connecting piece 10 of the unmanned vessel 1 is welded to be parallel to the plane of the hull of the unmanned vessel 1.

[0031] The unmanned vessel 1 is equipped with a remote control device, which can control the navigation trajectory of the unmanned vessel 1.

[0032] The connecting rod 2 is specifically as follows: Figure 2 As shown, a support washer 20 is welded to the left end of the connecting rod 2, and the support washer 20 is perpendicular to the axis of the connecting rod 2; a first connecting stud 21 is welded to the upper end, and the first connecting stud 21 is on the same axis as the connecting rod 2; a second connecting stud 22 is welded to the lower end, and the second connecting stud 22 is also on the same axis as the connecting rod 2; a transition rod 26 is welded to the right end, and a third connecting stud 23 is welded below the transition rod 26, and the third connecting stud 23 is parallel to the axis of the connecting rod 2.

[0033] One end of the transition rod 26 is welded to one end of the connecting rod, and the other end extends downward. A third connecting stud 23 is welded below the transition rod 26. The axis of the third connecting stud 23 is parallel to the axis of the connecting rod 2 and is used to connect the third pre-embedded nut 50 at the top of the acoustic automatic water level gauge 5, thereby fixing the acoustic automatic water level gauge to the connecting rod.

[0034] The support pad 20 is divided into an upper pad and a lower pad. The distance between the upper pad and the lower pad is equal to the thickness of the hull connecting piece 10, which is 2cm.

[0035] The connection between the connecting rod 2 and the unmanned vessel 1 is as follows: Figure 3 As shown, the hull connecting piece 10 of the unmanned boat 1 and the support pad 20 are fixedly connected by connecting screws 24 and connecting nuts 25. Since the hull connecting piece 10 of the unmanned boat 1 is parallel to the plane of the hull of the unmanned boat 1 after welding, and the support pad 20 is perpendicular to the axis of the connecting rod 2, the axis of the connecting rod 2 is perpendicular to the plane of the hull of the unmanned boat 1 after connection.

[0036] In use, the GNSS positioning device 3, single-beam echo sounder 4, and acoustic automatic water level gauge 5 can be connected to the connecting rod 2 respectively, as follows: Figure 4 As shown.

[0037] like Figure 5 As shown, the bottom of the GNSS positioning device 3 is equipped with a first pre-embedded nut 30, and a first nut washer 31 is placed between the first pre-embedded nut 30 and the first connecting stud 21. The first pre-embedded nut 30 is screwed into the first connecting stud 21 of the connecting rod 2. Since the first connecting stud 21 and the connecting rod 2 are on the same axis, the GNSS positioning device 3 is connected to the connecting rod 2, and the GNSS positioning device 3 and the connecting rod 2 are also kept on the same axis.

[0038] The GNSS positioning device 3 can record the coordinates of each measuring point reached by the unmanned vessel 1 and the distance between the measuring points.

[0039] like Figure 6 As shown, the top of the single-beam depth sounder 4 is equipped with a second pre-embedded nut 40. A second nut washer 41 is placed between the second pre-embedded nut 40 and the second connecting stud 22. The second pre-embedded nut 40 is screwed into the second connecting stud 22 of the connecting rod 2. Since the second connecting stud 22 and the connecting rod 2 are on the same axis, the single-beam depth sounder 4 is connected to the connecting rod 2, and the single-beam depth sounder 4 and the connecting rod 2 are also kept on the same axis.

[0040] The single-beam echo sounder 4 can measure and record the real-time water depth at each measuring point reached by the unmanned vessel 1.

[0041] like Figure 7As shown, the top of the acoustic automatic water level gauge 5 is equipped with a third pre-embedded nut 50. A third nut washer 51 is placed between the third pre-embedded nut 50 and the third connecting stud 23. The third pre-embedded nut 50 is screwed into the third connecting stud 23 of the connecting rod 2. Since the third connecting stud 23 is parallel to the axis of the connecting rod 2, the acoustic automatic water level gauge 5 is connected to the connecting rod 2, and the acoustic automatic water level gauge 5 is parallel to the axis of the connecting rod 2.

[0042] The acoustic automatic water level gauge 5 can measure and record the real-time water level at each measuring point reached by the unmanned vessel 1.

[0043] The system also includes a display terminal 8, which is equipped with a wireless communication module. The display terminal 8 is connected to the GNSS positioning device 3, the single-beam echo sounder 4, and the acoustic automatic water level gauge 5 via a wireless network. The wireless communication method is that the GNSS positioning device 3, the single-beam echo sounder 4, and the acoustic automatic water level gauge 5 are all equipped with wireless communication modules, which can communicate wirelessly with the display terminal 8 to transmit back the real-time geographical location, water level, and water depth of the measurement point where the unmanned vessel 1 is located.

[0044] The specific working method of the riverbed gradient measurement system based on unmanned vessel positioning is as follows: After the measurement device is connected and assembled, the unmanned vessel 1 is placed on the riverbank, and the surveyors operate the measurement system from the bank. The specific operation procedure is as follows:

[0045] ① Before the test begins, the surveyor places the first nut washer 31 onto the first connecting stud 21 of the connecting rod 2, and then screws in the first pre-embedded nut 30 at the bottom of the GNSS positioning device 3 and tightens it to the first connecting stud 21; places the second nut washer 41 onto the second connecting stud 22 of the connecting rod 2, and then screws in the second pre-embedded nut 40 at the bottom of the single-beam depth sounder 4 and tightens it to the second connecting stud 22; places the third nut washer 51 onto the third connecting stud 23 of the connecting rod 2, and then screws in the third pre-embedded nut 50 at the bottom of the acoustic automatic water level gauge 5 and tightens it to the third connecting stud 24. After the GNSS positioning device 3, the single-beam depth sounder 4, and the acoustic automatic water level gauge 5 are all connected to the connecting rod 2, the unmanned vessel 1 and the connecting rod 2 are fixedly connected by the hull connecting piece 10 and the support washer 20 through the connecting screw 24 and the connecting nut 25. At this time, the bottom of the single-beam depth sounder 4 is flush with the bottom of the unmanned vessel 1. The assembled measurement system was placed on the riverbank, and the draft ∆ of the unmanned boat after the measurement device was installed was recorded. c Before starting the unmanned vessel, check whether the geographic coordinates, water depth and water level data measured by the GNSS positioning device 3, single beam depth sounder 4 and acoustic automatic water level gauge 5 can be displayed in real time by the display terminal, and whether the unmanned vessel's lithium battery, remote control and other indicators are normal.

[0046] ② After the experiment began, the surveyors used the GNSS positioning device on the unmanned vessel 1 to remotely guide the unmanned vessel 1 to directly above the first measuring point on the upstream riverbed surface, and recorded the real-time water depth displayed by the single-beam echo sounder 4 when the unmanned vessel 1 was directly above the first measuring point. h 1. Real-time water level measured by acoustic automatic water level gauge 5 w 1. Control the unmanned vessel 1 to travel in a straight line to directly above the second measuring point on the downstream riverbed surface, and record the straight-line distance ∆ from the first measuring point to the second measuring point. d Simultaneously, the real-time water depth displayed by the single-beam echo sounder 4 is recorded when the unmanned vessel 1 is directly above the second measuring point. h 2 and the real-time water level measured by the acoustic automatic water level gauge 5 w 2.

[0047] ③ Calculate the riverbed gradient J Because the single-beam echo sounder 4 is positioned below the water surface during measurement, the measured water depth is the depth from the instrument to the riverbed. The actual water depth at the measurement point should also include the water depth from the instrument to the water surface. Since the bottom of the single-beam echo sounder 4 is flush with the bottom of the unmanned vessel 1, the water depth from the instrument to the water surface is the vessel's draft ∆. c Actual water depth at the first measuring point h 1 '=h 1+∆ c The actual water depth at the second measuring point h 2 '=h 2+∆ c Since the water level and depth differ at each measuring point, the bed elevation at each measuring point is calculated using the water level and depth values ​​at that point. In other words, the bed elevation at each measuring point is the difference between the water level at the time of measurement and the actual water depth. The bed elevation at the first measuring point... h a = w 1 - ( h 1+∆ c ), second measuring point bed surface elevation h b = w 2-( h 2+∆ c Since the unmanned vessel 1 travels in a straight line between the two measuring points, the distance traveled by the unmanned vessel on the water surface is ∆. d =Submarine straight-line distance between two measuring points ∆ d' Due to the riverbed gradient J It is the elevation difference ∆ between two points on the longitudinal section of the riverbed. h (Right now h a - h b ) and horizontal distance ∆ d The ratio can be calculated. J= ∆ h / ∆d= ( h a - h b ) / ∆ d= ( w 1- h 1- w 2+ h 2) / ∆ d .

[0048] The working principle of the unmanned surface vessel 1 during the entire riverbed gradient measurement process is as follows:

[0049] The hull connecting plate 10 of the unmanned surface vessel (USV) 1 is parallel to the plane on which the USV 1 hull lies. This ensures that after the hull connecting plate 10 is connected to the support pad 20 of the connecting rod 2, the axis of the USV 1 hull is perpendicular to the axis of the connecting rod 2. This ensures that the data measured by the equipment mounted on the connecting rod 2 are all data from the measuring points of the USV 1, improving data accuracy and establishing conditions for calculating the relationship between the bed surface elevation difference and distance. In addition, the bottom of the USV 1 remains flush with the bottom of the single-beam echo sounder 4 after it is connected to the lower end of the connecting rod 2. This ensures that the distance from the single-beam echo sounder 4 to the water surface is always equal to the draft of the USV after the measuring equipment is mounted.

[0050] The working principle of connecting rod 2 during the entire riverbed gradient measurement process is as follows:

[0051] The plane of the support pad 20 at the left end of the connecting rod 2 is perpendicular to the axis of the connecting rod 2, which is to establish the conditions for subsequent calculation of the bed surface elevation difference and distance relationship; the GNSS positioning device 3 installed at its upper end is kept on the same axis as the connecting rod 2, in order to ensure that the plane position coordinates of the unmanned vessel 1 measured by the GNSS positioning device 3 are accurate, thus improving the accuracy of the data; the single-beam depth sounder 4 installed at its lower end is also kept on the same axis as the connecting rod 2, in order to ensure that the single-beam depth sounder 4 measures the plane position coordinates of the unmanned vessel 1. The point refers to the water depth measured by the GNSS positioning device 3; the acoustic automatic water level gauge 5 installed at its right end is parallel to the axis of the connecting rod 2, which means that the axis of the single-beam depth sounder 4 is parallel to the axis of the acoustic automatic water level gauge 5. This is to ensure that after obtaining the water level measured by the acoustic automatic water level gauge 5 and the water depth measured by the single-beam depth sounder 4, they can be regarded as values ​​on the same measuring line or within a small plane range. By processing the water level and water depth values, the relationship between the bed surface elevation is established, and a high-precision bed surface elevation value is obtained.

Claims

1. A riverbed gradient measurement system based on unmanned surface vessel positioning, characterized in that, include: The unmanned surface vessel (1), connecting rod (2), GNSS positioning device (3), acoustic automatic water level gauge (5), and single-beam depth sounder (4) are provided. One end of the connecting rod (2) is fixed to the hull of the unmanned surface vessel (1), and the axis of the connecting rod (2) is perpendicular to the plane of the hull of the unmanned surface vessel (1). At least two connecting studs are provided on the connecting rod (2) along its axial direction, one of which is connected to the GNSS positioning device (3), and the other is connected to the single-beam depth sounder (4). The axes of the GNSS positioning device (3) and the single-beam depth sounder (4) are both coincident with the axis of the connecting rod (2); the upper end of the connecting rod (2) is connected to the acoustic automatic water level gauge (5) through the first connecting stud (21), and the axis of the acoustic automatic water level gauge (5) is perpendicular to the hull plane of the unmanned vessel (1); the GNSS positioning device (3), the single-beam depth sounder (4) and the acoustic automatic water level gauge (5) are all connected to the corresponding connecting stud of the connecting rod (2) through nuts pre-embedded in the vessel body.

2. The riverbed gradient measurement system based on unmanned vessel positioning as described in claim 1, characterized in that, The connecting rod (2) has a support pad (20) on one side. The support pad (20) is fixedly connected to the rod body of the connecting rod (2) and is perpendicular to the axis of the rod body. The support pad (20) has a hole for the connecting screw (24) to pass through. The hull connecting piece (10) of the unmanned boat (1) has a hole for the connecting screw (24) to pass through. The connecting rod (2) is threadedly connected to the hull connecting piece (10).

3. The riverbed gradient measurement system based on unmanned vessel positioning as described in claim 2, characterized in that, The hull connecting piece (10) of the unmanned vessel (1) is a stainless steel rectangular piece, which is fixedly connected to the hull of the unmanned vessel (1) by welding.

4. The riverbed gradient measurement system based on unmanned vessel positioning as described in claim 2 or 3, characterized in that, The support pad (20) includes an upper pad and a lower pad, and the distance between the upper pad and the lower pad is equal to the thickness of the hull connecting piece (10) of the unmanned vessel (1).

5. The riverbed gradient measurement system based on unmanned vessel positioning as described in claim 1, characterized in that, The GNSS positioning device (3) is screwed to the first connecting stud (21) on the connecting rod (2) along its own axis by the first pre-embedded nut (30) pre-embedded in its body, and the GNSS positioning device (3) and the connecting rod (2) are coaxially arranged.

6. The riverbed gradient measurement system based on unmanned vessel positioning as described in claim 5, characterized in that, The single-beam depth sounder (4) is screwed to the connecting stud (22) set along its own axis on the connecting rod (2) by the second pre-embedded nut (40) pre-embedded in its body, and the single-beam depth sounder (4) and the connecting rod (2) are set coaxially.

7. The riverbed gradient measurement system based on unmanned vessel positioning as described in claim 6, characterized in that, The acoustic automatic water level gauge (5) is screwed to the third connecting stud (23) on the connecting rod (2) along the direction parallel to its own axis by the third pre-embedded nut (50) pre-embedded in its body, and the acoustic automatic water level gauge (5) is perpendicular to the hull plane of the unmanned vessel (1).

8. The riverbed gradient measurement system based on unmanned vessel positioning as described in claim 7, characterized in that, Nut washers are provided between the first connecting stud (21), the second connecting stud (22), the third connecting stud (23) on the connecting rod (2) and the pre-embedded nuts of the corresponding instruments.

9. The riverbed gradient measurement system based on unmanned vessel positioning as described in claim 1, characterized in that, The unmanned vessel (1) is equipped with a remote control device.

10. The riverbed gradient measurement system based on unmanned vessel positioning as described in claim 1, characterized in that, It also includes a display terminal (8), which is connected to the GNSS positioning device (3), the acoustic automatic water level gauge (5) and the single beam depth sounder (4) via network communication.

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