A system and method for measuring water capacity of polar lakes

Abstract

The present invention provides a system and method for measuring the water capacity of polar lakes, which relates to the technical field of lake water capacity measurement. The system uses an ADRC algorithm to control a drone to move with an unmanned boat at a preset height directly above the unmanned boat; obtains lake surface point cloud data, lake shoreline point cloud data, and single-beam ranging data under the lake to construct a three-dimensional topographic map of the water surface, a three-dimensional topographic map of the lake coast, and a three-dimensional topographic map of the lake bottom in the same coordinate system, thereby determining the water capacity of the lake. The present invention realizes automatic measurement of lake elevation and underwater topographic data of the lake by setting an unmanned boat, an unmanned boat-mounted module, a drone, and an unmanned boat-mounted module, thereby improving the observation accuracy of polar lakes.

Description

Technical Field

[0001] The present invention relates to the technical field of lake water capacity measurement, and in particular to a system and method for measuring the water capacity of polar lakes. Background Art

[0002] At present, the speed of human exploration of the earth is gradually accelerating, and the exploration of the deep sea and the polar regions, two areas where human footprints are seldom seen, has gradually been valued. Among them, scientific expeditions to the Antarctic region are of great strategic significance. At present, surveys of polar lakes are mostly measured by macroscopic measurement methods based on remote sensing, but such lakes are covered with ice and snow all year round and are connected to the surface. It is difficult to measure the lake elevation and underwater topography data of the lake through aerial remote sensing, and then accurately assess its water content. The only method for assessing the water capacity of such lakes is to use a small boat to measure the depth with a plumb bob, and then make a rough estimate of the water capacity of the lake. The measured water content has a large error, and the harsh environment in the polar region makes it difficult for humans to conduct long-term measurements. Summary of the invention

[0003] The purpose of the present invention is to provide a system and method for measuring the water capacity of polar lakes, which can automatically measure the lake elevation and the underwater topography data of the lake, and then determine the water capacity of polar lakes, thereby improving the observation accuracy of polar lakes.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A polar lake water capacity measurement system, comprising:

[0006] Unmanned boats, unmanned boat-mounted modules, drones, drone-mounted modules and ground-operated modules;

[0007] The unmanned boat is used to carry an unmanned boat-mounted module; the unmanned boat-mounted module is connected to the unmanned boat-mounted module and the ground operation module; the unmanned boat-mounted module is used to measure lake shoreline point cloud data and single-beam ranging data under the lake;

[0008] The drone is used to carry the drone-mounted module; the drone-mounted module is also connected to the ground operation module; the ground operation module is also connected to the drone and the unmanned boat respectively; the ground operation module is used to obtain the path planned by the unmanned boat, and use the ADRC algorithm to control the drone to move with the unmanned boat at a preset height directly above the unmanned boat; the drone-mounted module is used to obtain lake surface point cloud data and attitude data of the unmanned boat-mounted module; the drone-mounted module is also used to determine the coordinate system conversion parameters of the unmanned boat and the drone according to the attitude data of the unmanned boat-mounted module;

[0009] The ground operation module is also used to determine the lake surface point cloud data in the geographic coordinate system, the lake shoreline point cloud data in the geographic coordinate system, and the single beam ranging data under the lake in the geographic coordinate system according to the coordinate system conversion parameters;

[0010] The ground operation module is also used to construct a three-dimensional topographic map on the water based on the lake surface point cloud data in the geographic coordinate system; the ground operation module is also used to construct a three-dimensional topographic map along the lake based on the lake shoreline point cloud data in the geographic coordinate system; the ground operation module is also used to construct a three-dimensional topographic map on the lake bottom based on the single-beam ranging data under the lake in the geographic coordinate system; the ground operation module is also used to determine the water capacity of the lake based on the three-dimensional topographic map on the water, the three-dimensional topographic map along the lake shore and the three-dimensional topographic map on the lake bottom.

[0011] Optionally, the unmanned boat module includes:

[0012] The first computer, underwater single beam sensor, linear array laser radar sensor and the first UWB data transmission unit;

[0013] The first computer is respectively connected to the underwater single beam sensor, the linear array laser radar sensor and the first UWB data transmission unit;

[0014] The first computer is used to control the underwater single-beam sensor to obtain single-beam ranging data under the lake;

[0015] The first computer is also used to control the linear array laser radar sensor to obtain lake shoreline point cloud data;

[0016] The first UWB data transmission unit is also connected to the ground operation module; the first computer is also used to control the first UWB data transmission unit to transmit the lakeside single-beam ranging data and the lakeshore point cloud data.

[0017] Optionally, the model of the underwater single-beam sensor is PSA-916;

[0018] The model of the linear array laser radar sensor is a 128-line laser radar.

[0019] Optionally, the unmanned boat-borne module is also provided with a posture cube and an infrared beacon positioning light array.

[0020] Optionally, the unmanned aerial vehicle onboard module includes:

[0021] a second computer, a downward-looking camera, an area array laser radar sensor, and a second UWB data transmission unit;

[0022] The second computer is respectively connected to the downward-looking camera, the area array laser radar sensor and the second UWB data transmission unit;

[0023] The downward-looking camera is used to photograph the posture cube and the infrared beacon positioning light array;

[0024] The second computer is used to determine the posture data of the unmanned boat module according to the image of the posture cube and the image of the infrared beacon positioning light array, and determine the coordinate system conversion parameters of the unmanned boat and the unmanned aerial vehicle according to the posture data of the unmanned boat module;

[0025] The second computer is used to control the area array laser radar sensor to obtain lake surface point cloud data;

[0026] The second UWB data transmission unit is connected to the ground operation module; the second computer is used to control the second UWB data transmission unit to transmit the lake surface point cloud data and the coordinate system conversion parameters.

[0027] Optionally, the area array laser radar sensor is a 128-line area array laser radar sensor.

[0028] Optionally, the drone-mounted module also includes:

[0029] PTZ;

[0030] The gimbal is used to carry the downward-looking camera and the area array laser radar sensor.

[0031] A method for measuring the water capacity of polar lakes, the method being applied to the above-mentioned polar lake water capacity measurement system, the method comprising:

[0032] Obtain the path planned by the unmanned boat, and use the ADRC algorithm to control the drone to move with the unmanned boat at a preset height directly above the unmanned boat;

[0033] Obtain lake shoreline point cloud data and lake bottom single beam ranging data;

[0034] Obtain lake surface point cloud data and attitude data of the unmanned boat module;

[0035] Determining coordinate system conversion parameters of the unmanned boat and the unmanned aerial vehicle according to the posture data of the unmanned boat-borne module;

[0036] Determine lake surface point cloud data in a geographic coordinate system, lake shoreline point cloud data in a geographic coordinate system, and single-beam ranging data under the lake in a geographic coordinate system according to the coordinate system conversion parameters;

[0037] Constructing a three-dimensional topographic map on water based on the lake surface point cloud data in the geographic coordinate system;

[0038] Constructing a three-dimensional topographic map of the lake coast based on the lake coastline point cloud data in the geographic coordinate system;

[0039] constructing a three-dimensional topographic map of the lake bottom according to the single-beam ranging data under the lake in the geographic coordinate system;

[0040] The water capacity of the lake is determined based on the three-dimensional topographic map above the water, the three-dimensional topographic map of the lake coast and the three-dimensional topographic map of the lake bottom.

[0041] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0042] The present invention provides a system and method for measuring the water capacity of polar lakes. The system uses an ADRC algorithm to control a drone to move with the unmanned boat at a preset height directly above the unmanned boat. The lake surface point cloud data, lake shoreline point cloud data, and single-beam ranging data under the lake are obtained to construct a three-dimensional topographic map of the water surface, a three-dimensional topographic map of the lake shore, and a three-dimensional topographic map of the lake bottom in the same coordinate system, thereby determining the water capacity of the lake. The present invention automatically measures the elevation of the lake and the underwater topographic data of the lake by setting an unmanned boat, an unmanned boat-mounted module, a drone, and an unmanned boat-mounted module, thereby improving the observation accuracy of polar lakes. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0044] Figure 1 This is a schematic diagram of the structure of the polar lake water capacity measurement system in Example 1 of the present invention;

[0045] Figure 2 This is a schematic diagram of the system operation in Example 2 of the present invention;

[0046] Figure 3 This is a schematic diagram of data collection types in Example 2 of the present invention;

[0047] Figure 4 Schematic diagram of system information flow in Example 2 of the present invention

[0048] Figure 5 This is a schematic diagram of a cross-domain UAV-UAV collaborative positioning module in Example 2 of the present invention;

[0049] Figure 6 This is a diagram of the collaborative operation of the infrared beacon positioning light array, posture cube and downward-looking camera in Example 2 of the present invention;

[0050] Figure 7 This is a schematic diagram of three-point feature solution in Example 3 of the present invention;

[0051] Figure 8 Schematic diagram of relative coordinate position transformation in Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] The purpose of the present invention is to provide a system and method for measuring the water capacity of polar lakes, which can automatically measure the lake elevation and the underwater topography data of the lake, and then determine the water capacity of polar lakes, thereby improving the observation accuracy of polar lakes.

[0054] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] Example 1

[0056] The present embodiment provides a polar lake water capacity measurement system, including: an unmanned boat, an unmanned boat-mounted module, a drone, an unmanned boat-mounted module and a ground operation module; the unmanned boat is used to carry the unmanned boat-mounted module; the unmanned boat-mounted module is connected to the unmanned boat-mounted module and the ground operation module; the unmanned boat-mounted module is used to measure lake shoreline point cloud data and single-beam ranging data under the lake; the drone is used to carry the unmanned boat-mounted module; the unmanned boat-mounted module is also connected to the ground operation module; the ground operation module is also connected to the drone and the unmanned boat respectively; the ground operation module is used to obtain the path planned by the unmanned boat, and use the ADRC algorithm to control the drone to move with the unmanned boat at a preset height directly above the unmanned boat; the unmanned boat-mounted module is used to obtain lake surface point cloud data and attitude data of the unmanned boat-mounted module; the unmanned boat-mounted module It is also used to determine the coordinate system conversion parameters of the unmanned boat and the unmanned aerial vehicle according to the posture data of the unmanned boat-borne module; the ground operation module is also used to determine the lake surface point cloud data in the geographic coordinate system, the lake shoreline point cloud data in the geographic coordinate system and the single-beam ranging data under the lake in the geographic coordinate system according to the coordinate system conversion parameters; the ground operation module is also used to construct a three-dimensional topographic map on the water according to the lake surface point cloud data in the geographic coordinate system; the ground operation module is also used to construct a three-dimensional topographic map along the lake according to the lake shoreline point cloud data in the geographic coordinate system; the ground operation module is also used to construct a three-dimensional topographic map of the lake bottom according to the single-beam ranging data under the lake in the geographic coordinate system; the ground operation module is also used to determine the water capacity of the lake based on the three-dimensional topographic map on the water, the three-dimensional topographic map along the lake shore and the three-dimensional topographic map of the lake bottom.

[0057] Among them, the unmanned boat module includes: a first computer, an underwater single-beam sensor, a linear array laser radar sensor and a first UWB data transmission unit; the first computer is connected to the underwater single-beam sensor, the linear array laser radar sensor and the first UWB data transmission unit respectively; the first computer is used to control the underwater single-beam sensor to obtain the single-beam ranging data under the lake; the first computer is also used to control the linear array laser radar sensor to obtain the lake shoreline point cloud data; the first UWB data transmission unit is also connected to the ground operation module; the first computer is also used to control the first UWB data transmission unit to transmit the single-beam ranging data under the lake and the lake shoreline point cloud data. Specifically, the model of the underwater single-beam sensor is PSA-916; the model of the linear array laser radar sensor is 128-line laser radar.

[0058] In addition, the unmanned boat module is also equipped with a posture cube and an infrared beacon positioning light array. The states of the posture cube and the infrared beacon positioning light array are different when the unmanned boat has different postures.

[0059] The unmanned aerial vehicle module includes: a second computer, a gimbal, a downward-looking camera, an array laser radar sensor, and a second UWB data transmission unit; the second computer is connected to the downward-looking camera, the array laser radar sensor, and the second UWB data transmission unit respectively; the gimbal has an anti-shake function and is used to carry the downward-looking camera and the array laser radar sensor. The downward-looking camera is used to shoot the posture cube and the infrared beacon positioning light array; the second computer is used to determine the posture data of the unmanned boat-borne module based on the image of the posture cube and the image of the infrared beacon positioning light array, and to determine the coordinate system conversion parameters of the unmanned boat and the unmanned aerial vehicle based on the posture data of the unmanned boat-borne module; the second computer is used to control the array laser radar sensor to obtain lake surface point cloud data; the second UWB data transmission unit is connected to the ground operation module; the second computer is used to control the second UWB data transmission unit to transmit the lake surface point cloud data and coordinate system conversion parameters. Among them, the array laser radar sensor is a 128-line array laser radar sensor.

[0060] Example 2

[0061] The embodiment provides a polar lake water capacity measurement system, which is applied to cross-domain polar lake water capacity measurement. The main functions are: realizing cross-domain unmanned system collaborative work control; realizing the synchronization of all sensor data time axes and the transformable same-dimensional pose coordinates of observation units.

[0062] The device is divided into three parts: (1) UAV-mounted module: This module is mainly mounted on the UAV platform, including NVIDIA TX2 microcomputer, data transmission module, downward-looking camera, anti-shake gimbal, array laser radar and UWB module; (2) Ground operation module: This module is mainly the operation platform for ground operators, including a ground microcomputer equipped with a 3060Ti NVIDIA graphics card, two data transmission and UWB modules; (3) Unmanned boat-mounted module: It is mainly mounted on the unmanned boat platform, including NVIDIA TX2 microcomputer, data transmission module, underwater single beam, posture cube, infrared beacon positioning light array, linear array laser radar and UWB module.

[0063] The connection and control of the device with the cross-domain unmanned system (UAV and its ground station, unmanned boat and its ground station) are described as follows: the ground microcomputer is connected to the ground station microcomputer control system of the unmanned boat and the UAV through the industrial bus, and the operation planning of the unmanned boat and the UAV is connected to the cross-domain integrated measurement system. In addition, the bus is also equipped with the RTK base station used by the UAV and the unmanned boat. The UAV cooperates with the unmanned boat through the UWB positioning communication module. The underwater single-beam and 16-line laser radar is mounted on the unmanned boat operation platform, and the array laser radar is mounted on the UAV operation platform. The three-dimensional terrain of the lake area is measured through the ground microcomputer terminal, and the relevant parameters of the lake water content are estimated. Such as: current water content measurement, maximum water content estimation of the lake, future water injection estimation of the lake, and future evaporation estimation of the lake.

[0064] As the user's direct operation platform for the entire cross-domain lake measurement system, the ground microcomputer module provides an interactive system interface for the ROS robot under the Ubuntu 18.04 version of the Linux embedded system used by external users. First, the Ethernet interface of the Ubuntu embedded system is used to establish a service control platform compatible with the industrial bus, allowing users (expedition team members) to control and run C# scripts with acquisition and measurement functions through the bus. After the user terminal establishes a remote control connection with the unmanned boat ground microcomputer system and the unmanned aerial vehicle ground microcomputer system through the bus, the user terminal can issue control instructions to the unmanned system operation end, and the operation end will feedback the response status information and real-time measurement data to the user (expedition team member) terminal (if long-distance data transmission is involved, large-capacity data such as point clouds are stored in the local machine).

[0065] The RTK module provides customized coordinates with an accuracy of less than 2 cm for drones and unmanned boats. Each device is equipped with a corresponding RTK module, and the drone and unmanned boat platforms are equipped with corresponding RTK antenna receivers. The drone uses the D-rtk2 RTK base station, and the unmanned boat uses a single-point RTK positioning module. The GPS data used for modeling is D-RTK2 data, and the unmanned boat RTK only provides track planning and underwater modeling.

[0066] The UWB module is used for positioning the unmanned boat in valleys with poor signals and for cross-domain system relative position recording and communication. This module is not required in open areas. The module can be deployed in waters with special geological structures such as caves that require depth measurement. It is divided into four positioning base stations, and the communication positioning module is installed on the unmanned boat to determine the position of the unmanned boat. Because UWB has good penetration and positioning functions.

[0067] The drone-mounted observation module is a unit used to measure the three-dimensional structure of the canyon and the surrounding rock, soil and snow-capped mountains. The observation sensor mainly uses an array laser radar, which can perform three-dimensional modeling of the part above the lake surface. In addition, the downward-looking camera can be combined with DRTK-2 to obtain orthophotos with elevation information. In this way, the orthophoto area of ​​the photographed object is calculated (the measured object can be the water area or the area of ​​floating ice on the lake). The operation unit obtains two types of sensor data, the first type is the point cloud data obtained by the laser radar, and the second type is the orthophotos obtained by the high-resolution camera. Both types of data have corresponding posture information. The corresponding three-dimensional imaging data can be obtained at the drone ground station.

[0068] The unmanned boat observation module is a load operation platform used to model the bottom terrain of the lake water area and the terrain along the lake. The single-beam sensor model used for measurement is PSA-916, and the laser radar sensor model used for measurement is 128-line laser radar. The single-beam sensor is used to establish the three-dimensional terrain of the bottom of the lake, and the 128-line laser radar is used to establish the three-dimensional terrain of the area where the lake connects with the surrounding mountains.

[0069] For the submodules of this device mounted on the UAV - TX2 microcomputer and downward-looking camera, and the submodule mounted on the unmanned boat - infrared beacon positioning light array and posture cube. The TX2 microcomputer on the UAV receives the infrared beacon positioning light array and posture cube located in the time constant collected by the downward-looking camera, and obtains the distance, roll, pitch and heading information of the positioning light array through the visual principle. The posture cube serves as the second information source to supplement the roll and pitch information. This part is used to control the alignment of the sensor observation time axis in the cross-domain collaborative operation between the UAV and the unmanned boat to ensure the consistency of the vertical coordinates. Ensure that the UAV always remains at a vertical height of 20m above the unmanned boat to realize the data obtained during the laser radar and single-beam modeling is the actual terrain corresponding data.

[0070] The Profinet bus embedded device module is used to connect the user terminal microcomputer, the UAV ground microcomputer, the unmanned boat ground microcomputer, the UWB control module and the ground communication antenna control module into a topological structure through the industrial bus. This allows users to communicate in real time through the user terminal microcomputer, control any device on the bus, and realize the mutual cooperation of all units in the cross-domain system.

[0071] like Figure 2-4 , the working space of the entire cross-domain unmanned operation platform is delineated on the basis of the unmanned boat establishing a geographic fence along the lake shore. First, the unmanned boat collects high-precision GPS points along the shore of the lake (the lake elevation is fixed by default at this time). At this time, the geographic fence range of the feasible track of the lake is obtained. The obtained geographic information coordinates are input into the ground control consoles of the unmanned boat and the drone. The two consoles respectively plan the track and route speed of the unmanned boat and the drone at a relative elevation of 50m or 100m. In order to ensure the safety of the cross-domain system and the smooth operation. The priority of the route during operation is that the unmanned boat is greater than the drone. That is, the drone always follows the unmanned boat to measure directly above it. At this time, the sensor data sequence of the same geographic information coordinate longitude and latitude at the same time can be obtained. Through the dual correspondence between time and space, the three modeling data are placed in the same four-dimensional coordinate system (longitude, latitude, elevation, and time). In the subsequent modeling process, the overall modeling and measurement of the lake are realized according to this coordinate system. Such as Figure 5-6 In the description of the overall operation of the system, the part involving the coordinated action of the UAV and the unmanned boat is involved. The ultimate goal of this action is to achieve data synchronization, that is, at the same longitude and latitude, the same time, and different altitudes. Figure 5 The airborne downward-looking camera in the image recognizes the optical flow beacon of the unmanned boat, ensuring that the pixel is in a fixed position in the field of view of the airborne downward-looking camera of the drone, that is, the center of the unmanned boat defaults to the center of its airborne camera lens, and the center of the unmanned boat defaults to the center of the optical flow beacon. The pose cube is a sign to assist the optical flow beacon in confirming the motion state of the unmanned boat. The pose cube allows the drone to confirm the left and right shaking, U-turn, reverse, forward and other actions of the boat body.

[0072] The present invention collects three-dimensional models of terrain in the air and in the water respectively through two types of laser radars and a single-beam sensor included therein. The area array laser radar mounted on the drone is used to establish the three-dimensional features of the surface above the lake surface; the 128-line laser radar mounted on the unmanned boat is used to collect the three-dimensional structure of ice and snow on the lake surface and the surrounding surface; the single-beam sensor mounted on the unmanned boat is used to collect the three-dimensional structure of the bottom terrain of the lake (using multi-point depth sampling and surface fitting to establish a three-dimensional surface). The present invention has a high degree of modularization, efficient measurement methods, and is convenient for the expansion of bus equipment. The user terminal can easily realize automatic measurement through the bus (the measurement results are the three-dimensional structure of the underwater terrain, the three-dimensional structure of the water-air interface surface, and the three-dimensional structure of the rock and soil surface in the area where the lake is located), and a sub-module combining the optical array and the posture cube is set to solve the problem of difficult cross-domain sensor fusion, which solves the problem of inaccurate sensor data and measurement errors caused by posture changes. The originally cumbersome and costly polar lake measurement work can be operated in a short time, and the acquired data is more accurate.

[0073] Example 3

[0074] This embodiment provides a method for measuring the water capacity of polar lakes. The method is applied to the polar lake water capacity measurement system described in Example 1. The method includes:

[0075] Obtain the path planned by the unmanned boat, and use the ADRC algorithm to control the drone to move with the unmanned boat at a preset height directly above the unmanned boat;

[0076] Obtain lake shoreline point cloud data and single-beam ranging data under the lake;

[0077] Obtain lake surface point cloud data and attitude data of the unmanned boat module;

[0078] According to the attitude data of the unmanned boat module, the coordinate system conversion parameters of the unmanned boat and the unmanned aerial vehicle are determined;

[0079] According to the coordinate system conversion parameters, the lake surface point cloud data in the geographic coordinate system, the lake shoreline point cloud data in the geographic coordinate system and the single beam ranging data under the lake in the geographic coordinate system are determined;

[0080] Construct a three-dimensional water topographic map based on the lake surface point cloud data in the geographic coordinate system;

[0081] Construct a three-dimensional topographic map of the lake coast based on the lake shoreline point cloud data in the geographic coordinate system;

[0082] Construct a three-dimensional topographic map of the lake bottom based on the single-beam ranging data under the lake in the geographic coordinate system;

[0083] The water capacity of the lake is determined based on the three-dimensional topographic map of the water, the three-dimensional topographic map of the lake coast and the three-dimensional topographic map of the lake bottom.

[0084] Specifically, this embodiment provides a method for ensuring the synchronization of the posture of the observation data acquisition platform when the unmanned vehicle-mounted module and the unmanned boat-mounted module work in coordination:

[0085] Step 1: The position and posture information of the UAV can be determined through the UAV's own RTK positioning and its own attitude, so as to obtain the precise position and posture of the UAV and the UAV in the geodetic coordinate system.

[0086] Step 2: The UAV module obtains the infrared beacon positioning light array and position cubic information of the UAV. The position is calculated by the TX2 microcomputer on the UAV and fed back to the UAV, thereby obtaining the position information of the UAV relative to the UAV. Calculation principle: The acquisition of the position state is based on direct linear transformation and feature point solution method.

[0087] The specific process is as follows:

[0088] (1) The unmanned aerial vehicle equipment obtains the image information of the positioning light array and position cube carried by the unmanned boat;

[0089] (2) The image sensor feeds information back to the drone's onboard microcomputer for data calculation. First, the coded information of each face of the pose cube is detected, the corresponding ID is obtained, and the position coordinates of the cube's visible angle of view are generated;

[0090] (3) In the previous step, the focal length information is obtained by locating the specific size of the light array and the cube and the pixel size in the field of view. The principle of the three-point feature detection method is as follows: Figure 7 Among them, F, G, and H represent the feature points on the object to be measured (the posture cube on the unmanned boat payload platform), f, g, and h are the corresponding positions of the feature points F, G, and H on the imaging plane (inside the drone payload camera); the outer dimensions of the object to be measured (the actual size of the posture cube is known) are the lengths of FG, FH, and GH, the coordinates of f, g, and h are obtained through the algorithm, the distance from point A to the image plane is the focal length f, the side length of the triangle fgh is known (the pixel point inside the imaging plane), and the lengths of the line segments Ag, Af, and Ah can be determined according to the cosine theorem.

[0091] (4) Based on the three-point features of each face of the cube, the cosine theorem and elimination method are used. :

[0092]

[0093] Calculate the cosine of the angle between the focus and the three points of the target object:

[0094]

[0095] Let x = FG, y = GH, z = FH, a = Ah, b = Af, c = Ag, α = ∠FAH, β = ∠GAH, γ = ∠FAH. Calculate the coordinates of the target detection point (F, G, H) relative to the focus of the drone camera. By using the parameters a, b, c, as well as the focal length of the camera and the coordinates of point f on the image plane (x f ,y f ), the coordinates of point g on the image plane (x g ,y g ), the coordinates of point h on the image plane (x h ,y h ), the image center coordinates (u0, v0), calculate the coordinates (X FM ,Y FM ,Z FM ), the coordinates of the feature point G in the camera coordinate system (X GM ,Y GM ,Z GM) and the coordinates of the feature point H in the camera coordinate system (X HM ,Y HM ,Z HM ):

[0096]

[0097]

[0098]

[0099] At present, the position information of the target detection point relative to the camera is obtained, where (X FM ,Y FM ,Z FM )、(X GM ,Y GM ,Z GM ) and (X HM ,Y HM ,Z HM ) are the coordinates of the three feature points on the pose cube (the coordinate system is the body coordinate system). Figure 8 As shown: The pose cubic coordinates of the unmanned boat payload in the body coordinate system are obtained by the above formula. Since the unmanned boat payload and itself are rigid bodies, the coordinates of the boat-borne laser radar and underwater sonar can also be obtained. The pose conversion between the coordinate system of the drone payload camera and the object under test can be achieved through two matrix functions: rotation and translation.

[0100] Step 3: In order to ensure the time axis alignment and posture consistency of the observation data, the UAV, as a unit with more flexible movement and faster sensor data transmission, adjusts its posture through the Active Disturbance Rejection Control (ADRC) to ensure that the UAV is directly above the unmanned boat at a relative height of 20m.

[0101] Step 4: The UAV obtains the area array laser radar observation data, the unmanned boat obtains the linear array laser radar observation data, and the underwater single beam data. The longitude and latitude of the three types of data in the geographical coordinate system are aligned by the device of the present invention. Alignment means that under the same time axis, the longitude and latitude errors in the geographical coordinate systems of all observation units do not exceed 2 cm, and the absolute altitude difference does not exceed 2 cm as the time axis moves. The result of step 2 is to generate their respective relative coordinate systems and the transformation matrix with the geographical coordinate system. Step three ADRC expanded control algorithm ensures that the UAV follows the unmanned boat while carrying a payload and performs relatively static operations.

[0102] Step 5: The microcomputer system on the ground obtains the three types of data observed above and the drone RTK data on the same time axis. The lidar data is used for terrain modeling through the catagrography algorithm, and the underwater sonar data is used for three-dimensional modeling through the origin surface fitting function. Combined with various three-dimensional models with geodetic coordinate systems, they are imported into the written software to generate a three-dimensional structure and obtain parameters such as the lake's water storage capacity, maximum water solubility, and water area.

[0103] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0104] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A system for measuring water capacity of polar lakes, characterized in that: include: Unmanned boats, unmanned boat-mounted modules, drones, drone-mounted modules and ground-operated modules; The unmanned boat is used to carry the unmanned boat-borne module; The unmanned boat module is connected to the unmanned boat module and the ground operation module; the unmanned boat module is used to measure the lake shoreline point cloud data and the single beam ranging data under the lake; The drone is used to carry the drone-mounted module; the drone-mounted module is also connected to the ground operation module; the ground operation module is also connected to the drone and the unmanned boat respectively; the ground operation module is used to obtain the path planned by the unmanned boat, and use the ADRC algorithm to control the drone to move with the unmanned boat at a preset height directly above the unmanned boat; the drone-mounted module is used to obtain lake surface point cloud data and attitude data of the unmanned boat-mounted module; the drone-mounted module is also used to determine the coordinate system conversion parameters of the unmanned boat and the drone according to the attitude data of the unmanned boat-mounted module; The ground operation module is also used to determine the lake surface point cloud data in the geographic coordinate system, the lake shoreline point cloud data in the geographic coordinate system, and the single beam ranging data under the lake in the geographic coordinate system according to the coordinate system conversion parameters; The ground operation module is also used to construct a three-dimensional topographic map on the water based on the lake surface point cloud data in the geographic coordinate system; the ground operation module is also used to construct a three-dimensional topographic map along the lake based on the lake shoreline point cloud data in the geographic coordinate system; the ground operation module is also used to construct a three-dimensional topographic map on the lake bottom based on the single-beam ranging data under the lake in the geographic coordinate system; the ground operation module is also used to determine the water capacity of the lake based on the three-dimensional topographic map on the water, the three-dimensional topographic map along the lake shore and the three-dimensional topographic map on the lake bottom.

2. A polar lake water capacity measurement system according to claim 1, characterized in that: The unmanned boat module comprises: The first computer, underwater single beam sensor, linear array laser radar sensor and the first UWB data transmission unit; The first computer is respectively connected to the underwater single beam sensor, the linear array laser radar sensor and the first UWB data transmission unit; The first computer is used to control the underwater single-beam sensor to obtain single-beam ranging data under the lake; The first computer is also used to control the linear array laser radar sensor to obtain lake shoreline point cloud data; The first UWB data transmission unit is also connected to the ground operation module; the first computer is also used to control the first UWB data transmission unit to transmit the lakeside single-beam ranging data and the lakeshore point cloud data.

3. A polar lake water capacity measurement system according to claim 2, characterized in that: The model of the underwater single beam sensor is PSA-916; The model of the linear array laser radar sensor is a 128 linear array laser radar sensor.

4. A polar lake water capacity measurement system according to claim 2, characterized in that: The unmanned boat-borne module is also provided with a posture cube and an infrared beacon positioning light array.

5. A polar lake water capacity measurement system according to claim 4, characterized in that: The unmanned aerial vehicle module comprises: a second computer, a downward-looking camera, an area array laser radar sensor, and a second UWB data transmission unit; The second computer is respectively connected to the downward-looking camera, the area array laser radar sensor and the second UWB data transmission unit; The downward-looking camera is used to photograph the posture cube and the infrared beacon positioning light array; The second computer is used to determine the posture data of the unmanned boat module according to the image of the posture cube and the image of the infrared beacon positioning light array, and determine the coordinate system conversion parameters of the unmanned boat and the unmanned aerial vehicle according to the posture data of the unmanned boat module; The second computer is used to control the area array laser radar sensor to obtain lake surface point cloud data; The second UWB data transmission unit is connected to the ground operation module; the second computer is used to control the second UWB data transmission unit to transmit the lake surface point cloud data and the coordinate system conversion parameters.

6. A polar lake water capacity measurement system according to claim 5, characterized in that: The area array laser radar sensor is a 128 area array laser radar sensor.

7. A polar lake water capacity measurement system according to claim 5, characterized in that: The drone-mounted module also includes: PTZ; The gimbal is used to carry the downward-looking camera and the area array laser radar sensor.

8. A method for measuring water capacity of polar lakes, characterized in that: The above method is applied to the polar lake water capacity measurement system according to any one of claims 1 to 7, and the method comprises: Obtain the path planned by the unmanned boat, and use the ADRC algorithm to control the drone to move with the unmanned boat at a preset height directly above the unmanned boat; Obtain lake shoreline point cloud data and single-beam ranging data under the lake; Obtain lake surface point cloud data and attitude data of the unmanned boat module; Determining coordinate system conversion parameters of the unmanned boat and the unmanned aerial vehicle according to the posture data of the unmanned boat-borne module; Determine lake surface point cloud data in a geographic coordinate system, lake shoreline point cloud data in a geographic coordinate system, and single-beam ranging data under the lake in a geographic coordinate system according to the coordinate system conversion parameters; Constructing a three-dimensional topographic map on water based on the lake surface point cloud data in the geographic coordinate system; Constructing a three-dimensional topographic map of the lake coast based on the lake coastline point cloud data in the geographic coordinate system; constructing a three-dimensional topographic map of the lake bottom according to the single-beam ranging data under the lake in the geographic coordinate system; The water capacity of the lake is determined based on the three-dimensional topographic map above the water, the three-dimensional topographic map of the lake coast and the three-dimensional topographic map of the lake bottom.

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