WO2020103049A1 - Terrain prediction method and device of rotary microwave radar, and system and unmanned aerial vehicle - Google Patents

Abstract

A terrain prediction method and device of a rotary microwave radar, and a system and an unmanned aerial vehicle. The method comprises: acquiring first position information of N target points and a radar scanning angle that are measured by the rotary microwave radar in a rotation process, wherein a rotation axis of the rotary microwave radar is provided perpendicular to a course axis of the unmanned aerial vehicle; converting the first position information of the N target points to second position information; and according to the second position information of the N target points and the radar scanning angle, determining a terrain parameter of a ground, such as a slope gradient, and an altitude of the unmanned aerial vehicle from the ground. The rotation axis of the rotary microwave radar is provided perpendicular to the course axis of the unmanned aerial vehicle, so that a scanning range of the rotary microwave radar on a horizontal plane can be enlarged, and then the accurate and comprehensive measurement of the ground can be implemented, thereby improving the accuracy of the ground measurement.

Description

Terrain prediction method, device, system and drone of rotating microwave radar Technical field

Embodiments of the present invention relate to the technical field of unmanned aerial vehicles, and in particular, to a terrain prediction method, device, system, and unmanned aerial vehicle of a rotating microwave radar.

Background technique

At present, drones can be used in a variety of scenarios. For example, in the power industry, large-scale cable patrols and real-time reconstruction of cable 3D images are required. In the second generation of agricultural drones, a 360 ° horizontal plane is proposed. Functional indicators. In these operating scenarios, most drones need to fly near the ground, and to avoid accidentally hitting the ground when climbing. On relatively flat ground, based on the Global Positioning System (GPS) and Inertial Measurement Unit (IMU) data, the UAV can complete the above tasks more smoothly; in more rugged terrain, unmanned The aircraft needs to adjust its movements in advance, perform operations such as climbing, descending, decelerating, braking, etc., to achieve near-Earth flight and even constant-height flight; in this way, the UAV can better complete the above operations. Therefore, it is necessary to predict the terrain information of the ground on which the drone is operating.

In the conventional technology, the position information of multiple target points measured by the rotating microwave radar is generally determined, based on the position information of these target points, a ground model is determined, and the terrain information of the ground is obtained based on the ground model. However, in the actual situation, due to the limited installation position of the rotating microwave radar, the measured target point cannot accurately and comprehensively reflect the ground information, thereby affecting the accuracy of terrain prediction.

Summary of the invention

Embodiments of the present invention provide a terrain prediction method, device, system, and drone of a rotating microwave radar, which are used to improve the accuracy of terrain prediction.

In a first aspect, an embodiment of the present invention provides a terrain prediction method of a rotating microwave radar, including:

Obtain the first position information and radar scanning angle of N target points measured by the rotating microwave radar during rotation, where N is a positive integer, the rotating microwave radar is installed on the drone, and the rotating microwave radar The rotation axis of is set perpendicular to the course axis of the drone; the first position information is the linear distance of the target point relative to the rotating microwave radar;

Convert the first position information of the N target points into second position information, where the second position information is the coordinate information of the target point in the coordinate system of the movable carrier;

The terrain parameters of the ground are determined according to the second position information of the N target points and the radar scanning angle, and the terrain parameters include at least one of the following: the slope and the height of the drone from the ground.

In a second aspect, an embodiment of the present invention provides a rotating microwave radar control system, including: including: a memory and a processor;

The memory is used to store program codes;

The processor calls the program code, and when the program code is executed, it is used to perform the following operations:

Obtain the first position information and radar scanning angle of N target points measured by the rotating microwave radar during rotation, where N is a positive integer, the rotating microwave radar is installed on the drone, and the rotating microwave radar The rotation axis of is set perpendicular to the course axis of the drone; the first position information is the linear distance of the target point relative to the rotating microwave radar;

Convert the first position information of the N target points into second position information, where the second position information is the coordinate information of the target point in the coordinate system of the movable carrier;

The terrain parameters of the ground are determined according to the second position information of the N target points and the radar scanning angle, and the terrain parameters include at least one of the following: the slope and the height of the drone from the ground.

In a third aspect, an embodiment of the present invention provides a radar detection device, including: an antenna device and the control system according to the second aspect, the control system is in communication connection with the antenna device.

According to a fourth aspect, an embodiment of the present invention provides a drone, a rack, a flight control system, and the radar detection device according to the third aspect, the rotating microwave radar is mounted on the rack,

The flight control system is in communication with the radar detection device to obtain the terrain parameters, and the flight control system controls the drone according to the terrain parameters.

The terrain prediction method, device, system and drone of a rotating microwave radar provided by an embodiment of the present invention acquire first position information and radar scanning angles of N target points measured by the rotating microwave radar during rotation, wherein the rotating microwave radar The axis of rotation is set perpendicular to the UAV ’s heading axis. The first position information of N target points is converted into second position information, and the ground position is determined according to the second position information of N target points and the radar scan angle Terrain parameters, such as slope, height of the drone from the ground, etc. Since this embodiment sets the rotation axis of the rotary microwave radar perpendicular to the UAV's heading axis, this can increase the horizontal scanning range of the rotary microwave radar, thereby achieving accurate and comprehensive measurement of the ground, thereby improving the ground measurement Accuracy.

BRIEF DESCRIPTION

In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings used in the description of the embodiments or the prior art. Obviously, the drawings in the following description These are some embodiments of the present invention. For those of ordinary skill in the art, without paying any creative work, other drawings can be obtained based on these drawings.

FIG. 1 is a schematic structural diagram of a drone involved in an embodiment of this application;

2 is a flowchart of a terrain prediction method of a rotating microwave radar according to Embodiment 1 of the present invention;

3 is a schematic diagram of a scanning range of a rotary microwave radar according to an embodiment of the present invention;

4 is a flowchart of a terrain prediction method for a rotating microwave radar according to Embodiment 2 of the present invention;

FIG. 5 is a schematic diagram of obstacles involved in Embodiment 2 of the present invention;

6 is a schematic structural diagram of a control system of a rotary microwave radar according to an embodiment of the present invention;

7 is a schematic structural diagram of a radar detection device according to an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a drone provided by an embodiment of the present invention.

detailed description

To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of the embodiments of the present invention, but not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

The embodiments of the present invention provide a terrain prediction method, device, system and unmanned aerial vehicle of a rotating microwave radar. The drone may be a rotorcraft (rotorcraft), for example, a multirotor aircraft propelled by multiple propulsion devices through air, and the embodiments of the present invention are not limited thereto.

FIG. 1 is a schematic structural diagram of an unmanned aerial vehicle according to an embodiment of the present application. This embodiment uses a rotorless unmanned aerial vehicle as an example for description.

The drone 100 may include a power system, a flight control system, and a rack. The drone 100 can communicate with the control terminal wirelessly, the control terminal can display the flight information of the drone, etc. The control terminal can communicate with the drone 100 wirelessly for remote manipulation of the drone 100.

The rack may include a fuselage 110 and a tripod 120 (also called landing gear). The fuselage 110 may include a center frame 111 and one or more arms 112 connected to the center frame 111, and the one or more arms 112 extend radially from the center frame. The tripod 120 is connected to the fuselage 110 for supporting when the drone 100 is landing. In addition, a mounting member 130 is mounted between the tripods 120. The mounting member 130 may be a photographing device, a liquid storage tank, and emergency supplies Wait for any product that can be carried on the drone.

The power system may include one or more electronic governors (abbreviated as electric governors), one or more propellers 140 and one or more motors 150 corresponding to the one or more propellers 140, wherein the motor 150 is connected to the electronic governor Between the speed governor and the propeller 140, the motor 150 and the propeller 140 are disposed on the arm 112 of the drone 100; the electronic governor is used to receive the driving signal generated by the flight control system and provide a driving current to the motor according to the driving signal, The rotation speed of the motor 150 is controlled. The motor 150 is used to drive the propeller 140 to rotate, thereby providing power for the flight of the drone 100, which enables the drone 100 to achieve one or more degrees of freedom of movement. In some embodiments, the drone 100 can rotate about one or more rotation axes. For example, the rotation axis may include a roll axis, a yaw axis, and a pitch axis. It should be understood that the motor 150 may be a DC motor or an AC motor. In addition, the motor 150 may be a brushless motor or a brush motor.

The flight control system may include a flight controller and a sensing system. The sensor system is used to measure the attitude information of the UAV, that is, the position information and status information of the UAV 100 in space, for example, three-dimensional position, three-dimensional angle, three-dimensional velocity, three-dimensional acceleration, and three-dimensional angular velocity. The sensing system may include, for example, at least one of sensors such as a gyroscope, an ultrasonic sensor, an electronic compass, an inertial measurement unit (Inertial Measurement Unit (IMU), a visual sensor, a global navigation satellite system, and a barometer. For example, the global navigation satellite system may be a global positioning system (Global Positioning System, GPS). The flight controller is used to control the flight of the drone 100. For example, the flight of the drone 100 can be controlled according to the attitude information measured by the sensor system. It should be understood that the flight controller may control the drone 100 according to pre-programmed program instructions, or may control the drone 100 by responding to one or more control instructions from the control terminal.

As shown in FIG. 1, the UAV's tripod 120 may also be equipped with a rotating microwave radar 160. The rotating microwave radar 160 may be used for ranging, but is not limited to ranging. The UAV may include two or more tripods 120, and the rotary microwave radar 160 is carried on one of the tripods 120.

It should be understood that the above naming of the components of the UAV is for identification purposes only, and should not be construed as a limitation to the embodiments of the present invention.

FIG. 2 is a flowchart of a terrain prediction method for a rotating microwave radar according to Embodiment 1 of the present invention. As shown in FIG. 2, the method in this embodiment may include:

S201. Acquire first position information and radar scanning angles of N target points measured by the rotating microwave radar during rotation, where N is a positive integer, the rotating microwave radar is installed on the drone, and the rotation The rotation axis of the microwave radar is set perpendicular to the course axis of the drone; the first position information is the straight-line distance of the target point relative to the rotating microwave radar. Specifically, the rotating microwave radar can be installed on the tripod of the drone. It should be noted that the rotary microwave radar can also be installed at other locations of the drone, for example, it can be installed at the bottom of the center body of the drone.

S202. Convert the first position information of the N target points into second position information according to the radar scanning angle, where the second position information is the coordinate information of the target point in the coordinate system of the movable carrier.

S203. Determine the terrain parameters of the ground according to the second position information of the N target points, where the terrain parameters include at least one of the following: the slope and the height of the drone from the ground.

The existing rotating microwave radar is installed horizontally on the UAV, that is, the rotating axis of the rotating microwave radar is set horizontally on the UAV's heading axis, so that the horizontal 360 ° scanning of the map cannot be achieved, making the measured distance inaccurate and comprehensive. Reflect the ground information, thereby affecting the accuracy of terrain prediction.

In order to solve this technical problem, in this embodiment, the rotary microwave radar is vertically installed on the drone, that is, the rotation axis of the rotary microwave radar is perpendicular to the heading axis of the drone, so that the horizontal scanning of the rotary microwave radar can be increased The range, for example, can scan the object 360 ° on the horizontal plane, thereby achieving accurate and comprehensive measurement of the ground.

In this embodiment, the rotating microwave radar measures the ground during rotation to obtain the distance between the rotating microwave radar and the ground. When the radar scanning angle of the rotating microwave radar is different, the target of the rotating microwave radar to measure the ground Points are not the same. As shown in Example 3, the larger the radar scanning angle, the greater the number of target points measured by the rotating microwave radar.

The rotating microwave radar measures the N target points on the ground during the rotation process to obtain the first position information of the N target points. The first position information is the linear distance of the target point relative to the rotating microwave radar. Each first position information reflects the distance between the rotating microwave radar and the ground when rotating to the corresponding scanning angle. For the same target point, if the ground where the target point is located is high, the distance between the rotating microwave radar and the ground is low. If the ground on which the target point is located is low, the distance between the rotating microwave radar and the ground is large; for example, if the distance between the rotating microwave radar and the different target points on the ground is large, it means that the flatness of the ground is low. For the same multiple target points, if the distance between the rotating microwave radar and the ground is small, it means that the slope of the ground where the multiple target points are located is high, and if the distance between the rotating microwave radar and the ground is large, it means that the The slope of the ground where multiple target points are located is low.

The first position information of each target point measured by the rotating microwave radar is the measured coordinates in the radar coordinate system, that is, spherical coordinates. In order to facilitate subsequent calculations, it is necessary to convert the first position information in the radar coordinate system to the coordinate information in the coordinate system of the movable carrier, and then obtain the second position information of the N target points.

Optionally, the above-mentioned movable carrier may be an unmanned aerial vehicle, a remote-controlled vehicle, or a handheld gimbal.

Optionally, the second position information may be coordinate information of the target point in a Cartesian coordinate system whose movable carrier is the origin.

In an example, the first position information of the N target points can be converted into second position information according to the following formula (1):

Where ri is the linear distance between the target point i and the rotating microwave radar, and θ _i is the angle of declination between the target point i and the xy plane,

It is the angle corresponding to a single light grid, and (x _Ri , y _Ri , z _Ri ) is the second position information of the target point i.

In this way, according to the above steps, the second position information of each of the N target points is obtained, and based on the second position information of the N target points and the radar scanning angle, the terrain parameters of the ground where the N target points are located are determined The terrain parameters include: the slope of the ground, the height of the drone from the ground, and optionally, the terrain parameters may also include the flatness of the ground, etc.

It can be seen from FIG. 3 that the scanning range of the rotating microwave radar in this embodiment in the vertical direction is 120 °, so that not only the points on the ground but also the points on the non-ground can be scanned, thereby improving the scanning range. In this way, when determining the terrain parameters of the ground, the terrain parameters of the ground can be determined according to the radar scanning angle and the second position information corresponding to each of the N target points. For example, according to the radar scanning angle, target points on the ground are obtained from N target points, and then, based on the second position information of the target points on the ground, the terrain parameters of the ground are determined.

In this embodiment, by acquiring the first position information and radar scanning angle of the N target points measured by the rotating microwave radar during the rotation, the rotation axis of the rotating microwave radar is set perpendicular to the course axis of the drone, and N Convert the first position information of the target point into the second position information, and determine the terrain parameters of the ground according to the second position information of the N target points and the radar scanning angle, such as the slope, the height of the drone from the ground, etc. . Since this embodiment sets the rotation axis of the rotary microwave radar perpendicular to the UAV's heading axis, this can increase the horizontal scanning range of the rotary microwave radar, thereby achieving accurate and comprehensive measurement of the ground, thereby improving the ground measurement Accuracy.

Optionally, to further improve the overall measurement of the ground, the first position information of the N target points is collected by a 360-degree horizontal scan of the horizontal microwave radar, and the radar scanning angle is the starting position of the rotary microwave radar compared to 0 degrees The absolute angle of rotation. Optionally, as shown in FIG. 3, the 0-degree starting position of the rotating microwave radar is set parallel to the horizontal plane of the earth.

In some embodiments, in a possible implementation manner of determining the terrain parameters of the ground based on the second position information of the N target points and the radar scan angle in S203, the following steps A and B may be included;

Wherein, in step A, a plane equation of the ground is constructed according to the second position information of the N target points and the radar scanning angle.

As can be seen from the above, the first position information of each of the N target points can be converted into second position information according to formula (1), and then the second position information of each of the N target points Is (x _Ri , y _Ri , z _Ri ). Then, based on the second position information of the N target points and the radar scanning angle, the plane equation of the ground can be constructed.

For example, as shown in FIG. 3, the radar scanning angle of the rotating microwave radar is ± 60 °, where when scanning at + 60 °, points on the ground may not be scanned. Therefore, according to the radar scanning angle, from N Among the target points, M target points whose radar scanning angle is within a preset range (for example, 0 ° to -60 °) are acquired. Then, based on the second position information of M target points, a plane equation of the ground is constructed.

Optionally, the second position information and the M target points whose radar scanning angle meets the preset condition are acquired from the N target points.

In order to avoid errors in the scanning process, in this embodiment, the target point where the second position information among the N target points meets the preset value is recorded as a point on the ground, for example, the Z coordinate value in the second position information is less than the preset value The target point is recorded as a point on the ground. At the same time, the coordinate point of the radar scanning angle within the preset range is taken as the point on the ground. In this way, M target points can be acquired from the N target points according to the second position information of the N target points and the radar scanning angle.

Step A2: Construct a plane equation according to the second position information of the M target points.

According to the above steps, M target points on the ground can be obtained, and the plane equation of the ground is constructed based on the M target points on the ground.

In some embodiments, a possible implementation manner of step A2 may include: step A11 and step A12.

Step A11: Convert the second position information of the M target points into third position information, where the third position information is the position information of the target point in the aircraft coordinate system.

For example, according to the following formula (2), the second position information of the M target points is converted into position information in the aircraft coordinate system, where formula (2) is an example, and this embodiment is not limited to this, for example, Any variation of formula (2).

Among them, due to the offset caused by the installation, there is an angle between the starting grating scale axis x _{R of the} rotating microwave radar and the forward direction axis x _{A of the} drone

(x _Ri , y _Ri , z _Ri ) is the second position information of the target point i, (x _Ai , y _Ai , z _Ai ) is the position information of the target point i in the aircraft coordinate system, that is, the third position of the target point i location information.

Step A12: Construct the plane equation according to the third position information of the M target points.

In this embodiment, the second position information of the target points on the M grounds is converted into third position information, which can correct the offset caused by the installation of the rotating microwave radar, so that the starting grating scale axis x _{R of the} rotating microwave radar There is an angle with the drone's forward axis x _A

The problem. In this way, building the plane equation of the ground based on the third position information of the M target points can improve the accuracy of the plane equation construction.

In some embodiments, a possible implementation manner of step A12 may include: step A121:

In step A121, the Z coordinate value in the third position information of the M target points is a dependent variable, and the X coordinate value and Y coordinate value are independent variables to construct the plane equation.

Because in the measurement process, the error mainly comes from r and θ, where r is the straight-line distance between the target point and the rotating microwave radar, and θ is the angle between the target point and the xy plane. Therefore, in this embodiment, in the third position information of the M target points, the Z coordinate value with the least associated variable is the dependent variable, and the X coordinate value and the Y coordinate value are the independent variables to establish a plane equation.

For example, construct a plane equation of the ground as shown in formula (3):

z ＝ ax + by + c

Among them, a is the intercept of the plane equation on the X axis, b is the intercept of the plane equation on the Y axis, the intercept of the plane equation on the Z axis is -1, and c is the constant term of the plane equation.

In some embodiments, a possible implementation manner of step A121 may include: step A1211 and step A1212:

Step A1211. Using the least square method, the Z coordinate value in the third position information of the M target points is the dependent variable, the X coordinate value and the Y coordinate value are the independent variables, and the third The position information is linearly fitted to determine the intercept of the plane equation on the X, Y, and Z axes, respectively.

First, determine the error e of the above formula (3), for example, as shown in formula (4):

e = z-ax-by-c, (4)

Next, determine the optimization function Q of the error, that is, the optimization function of formula (4), as shown in formula (5):

Differentiate the optimization function Q with respect to a, b, and c, respectively, and obtain a linear equation as shown in formula (6):

The third position information of the M points is brought into the above formula (6) to determine the intercept of the plane equation on the X, Y, and Z axes, that is, to determine a and b, where the intercept of the plane equation on the Z axis is -1:

among them,

Step A1212: Determine the constant in the plane equation according to the intercept of the plane equation on the X, Y, and Z axes and the third position information of the center point of the M target points, respectively.

First, according to the third position information of the M target points, determine the third position information of the center point 1 of the M target points, for example, the third position information of the center point 1 is

Since the M target points are all points on the ground, the center point is also a point on the ground, which satisfies the plane mode of the ground. Therefore, the third position information of the center point 1 is brought into the plane of the above formula (4) In the equation, the parameter constant term for obtaining the plane equation is c as shown in formula (7):

Through the above formula, the coefficients and constants in the plane mode of the ground can be obtained, and then the plane equation of the ground can be determined.

Step B: Determine the terrain parameters of the ground according to the plane equation.

In this embodiment, the third position information of the M target points on the ground is linearly fitted through the above method to accurately determine the plane equation of the ground. Based on the plane equation, the terrain parameters of the ground are determined, for example, the height of the drone from the ground is determined according to the plane equation, and / or the slope of the ground is determined according to the plane equation.

In some embodiments, if the terrain parameter is the height of the drone from the ground, a possible implementation manner of the foregoing step B may include: Step B1:

Step B1: Determine the height of the drone from the ground according to the intercept of the plane equation on the X, Y, and Z axes and the constant.

For example, according to the formula (8) of the point-to-plane distance, the distance between the plane equation of any point on the drone and the ground can be determined, and the distance can be determined as the height of the drone to the ground.

Where d is the intercept of the plane equation on the Z axis. From the above, d = 1, therefore, the above formula 8 can be transformed into the following formula (9):

In this way, to determine the height of the drone and the ground, the third position information of any point on the drone can be brought into formula (9), and the height of the drone from the ground can be determined.

In some embodiments, the height of the origin of the rotating microwave radar from the ground is taken as the height of the drone from the ground. In this case, the above step B1 may include steps B11 and B12.

Step B11: Determine the height of the origin of the rotating microwave radar from the ground according to the intercept of the plane equation on the X, Y, and Z axes and the constant.

Step B12: Determine the height of the UAV from the ground according to the height of the origin of the rotating microwave radar from the ground.

Specifically, the third position information of the origin of the rotating microwave radar is (0,0,0), so that the third position information of the origin of the rotating microwave radar is brought into the above formula (9), and the determined position of the rotating microwave radar The height d of the origin of is from the ground is:

Optionally, assuming that the drone is flying back and forth along the x-direction route without involving the change of the roll angle, the height d of the origin of the rotating microwave radar from the ground can be directly used as the height of the drone from the ground.

In some embodiments, if the terrain parameter is the slope of the ground, a possible implementation manner of the foregoing step B may include: step B2 and step B3:

Step B2: Convert the plane equation in the plane coordinates to the plane equation in the world coordinate system.

Step B3: Determine the slope of the ground according to the plane equation in the world coordinate system.

If the drone has attitude changes, the aircraft coordinate system will change. Therefore, the plane equation estimated in the aircraft coordinate system needs to be transferred to the world coordinate system. According to the plane equation in the world coordinate system, determine the slope of the ground.

In this embodiment, the plane equation of the ground can be shown as formula (10):

among them,

Homogeneous coordinates,

According to the following formulas (11) and (12), determine the normal vector of the plane equation in the aircraft coordinate system

Normal vector of the plane equation in the world coordinate system

The relationship between:

acquired

due to

In this way, the intercept constant terms of the X-axis, Y-axis and Z-axis of the plane equation in the world coordinate system can be determined, that is, a _G , b _G , -1 and the constant term c _G can be obtained.

At this time, the determined height of the drone from the ground is

The absolute height corresponding to the vertical axis of the z-axis is

Then, the slope of the ground is determined according to the plane equation in the world coordinate system determined above.

For example, the slope of the ground is determined according to the arc tangent of the X-axis intercept of the plane equation in the world coordinate system. That is, the slope of the ground α = -atana _G.

In this embodiment, M target points on the ground are selected from the second position information of the N target points and the radar scanning angle, and based on the third position information of the M target points, a plane equation of the ground is constructed and based on The constructed plane equation determines the height of the drone from the ground and the slope of the ground, thereby eliminating the interference of non-ground points on the plane equation construction process and improving the accuracy of the determination of the plane equation. At the same time, M target points are selected from N target points to construct the ground equation, which reduces the amount of data to be processed, thereby reducing the amount of calculation, and increasing the construction speed of the ground plane equation, thereby improving Determine the speed of the terrain parameters of the ground.

Optionally, if the radar scanning angle of the rotating microwave radar is too small, for example, less than the preset scanning angle, the plane model may degenerate, causing the estimated plane to shift to the vertical plane, making the plane equation and the Y axis The component of intercept b is too large and the estimated distance is too small. At this time, the intercept on the Y axis in the plane equation is determined as a preset value, and a new plane equation is obtained. For example, the preset value is 0. At this time, the new plane equation is obtained as shown in formula (13):

z ＝ ax + c (13)

According to the above method, the height of the drone from the ground and / or the slope of the ground can be determined. For the specific process, refer to the description of the foregoing embodiment, and details are not described herein again.

Optionally, if the rotating microwave radar makes one rotation, the number of effective target points obtained by scanning is too small, that is, the above M is less than the preset number, for example, M is less than 8, at this time, the Z coordinate value of the M target points can be The average value is taken as the height of the drone from the ground, where the Z coordinate value of the M target points is the Z coordinate value in the position information of the M target points in the aircraft coordinate system.

According to the above steps, the method of this embodiment can accurately and quickly determine terrain parameters such as slope, height of the drone from the ground, and so on.

FIG. 4 is a flowchart of a terrain prediction method for a rotating microwave radar according to Embodiment 2 of the present invention. Based on the foregoing embodiments, the method in the embodiments of the present application may further include:

S401. Acquire first position information of N target points measured by a rotating microwave radar during rotation.

S402. Convert the first position information of the N target points into second position information.

Wherein, for the specific execution process of the above S301 and S302, reference may be made to the description of the above embodiment, which will not be repeated here.

S403. Construct an environment map according to the second location information of the N target points.

In this embodiment, the rotating microwave radar is vertically installed on the UAV, and can scan 360 ° horizontal obstacles to obtain the position information of N target points. The N target points can reflect the ground information more comprehensively and accurately. The second position information of the N target points, the environment map is constructed with high accuracy, which is more realistic.

S404. Perform obstacle division on the environment map.

According to the above steps, after obtaining the environment map, next, scan 360 ° according to the current horizontal level of the rotating microwave radar, obtain the global coordinate information, and perform morphological processing based on the global coordinate information to divide the obstacles, for example, as shown in It shows that the ground and obstacles are segmented on the environmental map, thereby improving the obstacle avoidance performance of the UAV and ensuring the safe flight of the UAV.

In some embodiments, a possible implementation manner of the foregoing S303 may include: step C1 and step C2:

Step C1: Convert the second position information of the N target points into fourth position information, where the fourth position information is position information of the target point in world coordinates.

When constructing an environment map, in order to prevent the influence of the drone's attitude change on the target point position information, it is necessary to convert the second position information of each of the N target points into position information in the world coordinate system, The position information of the target point in the world coordinate system is recorded as the fourth position information of the target point.

Optionally, the second position information of the N target points is converted into fourth position information, which may be that the second position information of the N target points is first converted into third position information, wherein the third The position information is the position information of the target point in the aircraft coordinate system; then, the third position information of the N target points is converted into fourth position information.

Specifically, according to the above formula (2), the second position information of the N target points can be converted into third position information. Next, the third position information of the N target points may be converted into fourth position information based on any existing method.

Optionally, converting the third position information of the N target points into fourth position information may include: acquiring quaternion attitude information and offset of the drone; according to the N targets The third position information of the point, the quaternion attitude information and the offset of the drone, convert the third position information of the N target points into fourth position information.

For example, to obtain the quaternion attitude information q and the aircraft offset of the drone transmitted by the flight control system of the drone

Next, according to the third position information of the N target points, the quaternion attitude information and the offset of the UAV, the third position information of the N target points is converted into the fourth position information. For example, according to the following formula (14), the third position information of N target points is converted into fourth position information:

Where R (q) is the rotation matrix of the drone, and (x _Gi , y _Gi , z _Gi ) is the fourth position information of the target point i.

Step C2: Construct the environment map according to the fourth position information of the N target points.

According to the above steps, the fourth position information of the N target points is obtained, and then based on the fourth position information of the N target points, a 3D point cloud map is constructed to obtain an environment map. Wherein, according to the fourth position information of the N target points, a method of constructing an environment map may be constructed by collecting existing methods, which will not be repeated here.

The method of this embodiment constructs an environment map based on the second position information of N target points, and divides the obstacles on the constructed environment map, thereby achieving 360 ° obstacle avoidance of the drone, thereby improving unmannedness Flight safety.

6 is a schematic structural diagram of a control system for a rotating microwave radar according to an embodiment of the present invention. As shown in FIG. 6, the control system 600 for a rotating microwave radar in this embodiment may include: a memory 601 and a processor 602; It is connected to the processor 602 via a bus. The memory 601 may include read-only memory and random access memory, and provide instructions and data to the processor 602. A portion of the memory 601 may also include non-volatile random access memory.

The memory 601 is used to store program codes;

The processor 602 calls the program code, and when the program code is executed, it is used to perform the following operations:

Obtain the first position information and radar scanning angle of N target points measured by the rotating microwave radar during rotation, where N is a positive integer, the rotating microwave radar is installed on the drone, and the rotating microwave radar The rotation axis of is set perpendicular to the course axis of the drone; the first position information is the linear distance of the target point relative to the rotating microwave radar;

Convert the first position information of the N target points into second position information, where the second position information is the coordinate information of the target point in the coordinate system of the movable carrier;

The terrain parameters of the ground are determined according to the second position information of the N target points and the radar scanning angle, and the terrain parameters include at least one of the following: the slope and the height of the drone from the ground.

Optionally, the first position information of the N target points is collected by the rotating microwave radar scanning 360 degrees to the horizontal plane, and the radar scanning angle is the rotation of the rotating microwave radar compared to the starting position of 0 degrees Absolute angle.

Optionally, the 0-degree starting position of the rotating microwave radar is set parallel to the horizontal plane of the earth.

Optionally, the movable carrier is an unmanned aerial vehicle, a remote-controlled vehicle, or a handheld gimbal.

Optionally, the second position information is the coordinate information of the target point in the Cartesian coordinate system where the movable carrier is the origin.

Optionally, the processor 602 is specifically used to:

Construct a plane equation of the ground based on the second position information of the N target points and the radar scanning angle;

According to the plane equation, the terrain parameters of the ground are determined.

Optionally, the processor 602 is specifically used to:

Determining M target points from the N target points according to the second position information of the N target points and the radar scanning angle, where M is a positive integer less than or equal to N;

According to the position information of the M target points, a plane equation is constructed.

Optionally, the processor 602 is specifically used to:

Obtain the second position information and the M target points whose radar scanning angle satisfies the preset condition from the N target points.

Optionally, the processor 602 is specifically used to:

Convert the second position information of the M target points into third position information, where the third position information is the position information of the target point in the aircraft coordinate system;

According to the third position information of the M target points, the plane equation is constructed.

Optionally, the processor 602 is specifically used to:

The plane equation is constructed by taking the Z coordinate value in the third position information of the M target points as the dependent variable and the X coordinate value and the Y coordinate value as the independent variables.

Optionally, the processor 602 is specifically used to:

Using least squares method, taking the Z coordinate value in the third position information of the M target points as the dependent variable, the X coordinate value and the Y coordinate value as the independent variables, and perform the third position information of the M target points Linear fitting processing to determine the intercept of the plane equation on the X, Y and Z axes respectively;

The constant in the plane equation is determined according to the intercept of the plane equation on the X, Y, and Z axes and the third position information of the center point of the M target points.

Optionally, the processor 602 is specifically used to:

The height of the drone from the ground is determined according to the intercept of the plane equation on the X, Y, and Z axes and the constant.

Optionally, the processor 602 is specifically used to:

Determine the height of the origin of the rotating microwave radar from the ground according to the intercept of the plane equation on the X, Y, and Z axes and the constant;

The height of the UAV from the ground is determined according to the height of the origin of the rotating microwave radar from the ground.

Optionally, the processor 602 is specifically used to:

Convert the plane equation in the plane coordinates to the plane equation in the world coordinate system;

The slope of the ground is determined according to the plane equation in the world coordinate system.

Optionally, the processor 602 is specifically used to:

The slope of the ground is determined according to the arc tangent of the X-axis intercept of the plane equation in the world coordinate system.

Optionally, the processor 602 is also used to:

If the radar scanning angle of the rotating microwave radar is smaller than the preset value scanning angle, the intercept on the Y axis in the plane equation is determined as the preset value, and a new plane equation is obtained;

According to the new plane equation, determine the height of the drone from the ground and / or the slope of the ground.

Optionally, the processor 602 is also used to:

If the M is less than the preset number, the average value of the Z coordinate values of the M target points is used as the height of the drone from the ground.

Optionally, the processor 602 is further configured to: construct an environment map according to the second location information of the N target points.

Optionally, the processor 602 is also used to:

Obstacle division is performed on the environment map.

Optionally, the processor 602 is specifically used to:

Converting the second position information of the N target points into fourth position information, where the fourth position information is position information of the target point in world coordinates;

Construct the environment map according to the fourth position information of the N target points.

Optionally, the processor 602 is specifically used to:

Convert the second position information of the N target points into position information in the aircraft coordinate system;

The position information of the N target points in the aircraft coordinate system is converted into position information in the world coordinate system.

Optionally, the processor 602 is specifically used to:

Obtain the quaternion attitude information and offset of the drone;

The third position information of the N target points is converted into fourth position information according to the third position information of the N target points, quaternion attitude information and offset of the UAV.

Optionally, the control system of the rotary microwave radar in this embodiment may be a rotary microwave radar, or the system is a drone, or the system is a control terminal of the drone.

The control system of the rotating microwave radar of this embodiment may be used to execute the technical solutions of the above method embodiments of the present invention. The implementation principles and technical effects are similar, and are not described here again.

7 is a schematic structural diagram of a radar detection device according to an embodiment of the present invention. As shown in FIG. 6, the radar detection device 700 of this embodiment includes an antenna device 701 and a control system 702 for a rotating microwave radar. The control system 702 of the rotating microwave radar is in communication connection with the antenna device 701. Among them, the control system 702 of the rotating microwave radar can adopt the structure of the embodiment shown in FIG. 6, which correspondingly can implement the technical solutions shown in FIG. 2 and FIG. 4 and their corresponding embodiments. The implementation principles and technical effects are similar. I will not repeat them here. Optionally, the antenna device 701 may be a rotating microwave radar.

FIG. 8 is a schematic structural diagram of a drone provided by an embodiment of the present invention. As shown in FIG. 8, the drone 800 of this embodiment includes: a frame (not shown in the figure), a flight control system 801, and a radar The detection device 802, wherein the radar detection device 802 can adopt the structure of the embodiment shown in FIG. 7, which correspondingly can implement the technical solutions shown in FIGS. 2 and 4 and their corresponding embodiments, and the implementation principles and technical effects are similar, I won't repeat them here. Among them, the rotating microwave radar in the radar detection device 802 is mounted on the rack. The flight control system 801 is in communication with the radar detection device 802 to obtain terrain parameters, and the flight control system 801 controls the drone 800 according to the terrain parameters.

Alternatively, if the terrain parameter of the ground includes the slope of the ground, the flight control system 801 may control the subsequent actions of the drone 800 according to the slope of the ground.

Optionally, if the terrain parameters of the ground include the flatness of the ground, the flight control system 801 may control the height setting of the UAV 800 and / or control the UAV 800 to avoid obstacles according to the flatness of the ground.

Optionally, if the terrain parameters of the ground include: the height value of the drone from the ground, the flight control system 801 can perform obstacle avoidance according to the height value of the drone from the ground, for example: to prevent the drone 800 from colliding with the ground In addition, the crops can also be controlled by the drone 800 for precise spraying, because spraying requires constant height spraying.

Those of ordinary skill in the art may understand that all or part of the steps to implement the above method embodiments may be completed by program instructions related hardware. The foregoing program may be stored in a computer-readable storage medium, and when the program is executed, It includes the steps of the above method embodiments; and the foregoing storage media include: read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disks or optical discs, etc., which can store program codes Medium.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than limiting it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or replacements do not deviate from the essence of the corresponding technical solutions of the technical solutions of the embodiments of the present invention range.

Claims (47)

1. A terrain prediction method of rotating microwave radar, which is characterized by including:

   Obtain the first position information and radar scanning angle of N target points measured by the rotating microwave radar during rotation, where N is a positive integer, the rotating microwave radar is installed on the drone, and the rotating microwave radar The rotation axis of is set perpendicular to the course axis of the drone; the first position information is the linear distance of the target point relative to the rotating microwave radar;

   Convert the first position information of the N target points into second position information, where the second position information is the coordinate information of the target point in the coordinate system of the movable carrier;

   The terrain parameters of the ground are determined according to the second position information of the N target points and the radar scanning angle, and the terrain parameters include at least one of the following: the slope and the height of the drone from the ground.
2. The method according to claim 1, wherein the first position information of the N target points is acquired by the rotating microwave radar scanning a horizontal plane 360 degrees, and the radar scanning angle is the rotating microwave radar phase The absolute angle of rotation relative to the starting position of 0 degrees.
3. The method according to claim 2, wherein the 0-degree starting position of the rotating microwave radar is set parallel to the horizontal plane of the earth.
4. The method according to any one of claims 1 to 3, wherein the movable carrier is an unmanned aerial vehicle, a remote control vehicle, or a hand-held gimbal.
5. The method according to any one of claims 1 to 3, wherein the second position information is coordinate information of the target point in a Cartesian coordinate system whose movable carrier is the origin.
6. The method according to any one of claims 1-5, wherein the determining the terrain parameters of the ground based on the second position information of the N target points and the radar scanning angle includes:

   Construct a plane equation of the ground based on the second position information of the N target points and the radar scanning angle;

   According to the plane equation, the terrain parameters of the ground are determined.
7. The method according to claim 6, wherein the constructing a plane equation of the ground based on the second position information of the N target points and the radar scanning angle includes:

   Determining M target points from the N target points according to the second position information of the N target points and the radar scanning angle, where M is a positive integer less than or equal to N;

   According to the second position information of the M target points, a plane equation is constructed.
8. The method according to claim 7, wherein the determining M target points from the N target points according to the second position information of the N target points and the radar scanning angle includes:

   Obtain the second position information and the M target points whose radar scanning angle satisfies the preset condition from the N target points.
9. The method according to claim 8, wherein the constructing a plane equation according to the second position information of the M target points includes:

   Convert the second position information of the M target points into third position information, where the third position information is the position information of the target point in the aircraft coordinate system;

   According to the third position information of the M target points, the plane equation is constructed.
10. The method according to claim 9, wherein the constructing the plane equation according to the third position information of the M target points includes:

    The plane equation is constructed by taking the Z coordinate value in the third position information of the M target points as the dependent variable and the X coordinate value and the Y coordinate value as the independent variables.
11. The method according to claim 10, characterized in that the Z coordinate value in the third position information of the M target points is a dependent variable, and the X coordinate value and Y coordinate value are independent variables. Plane equations, including:

    Using least squares method, the Z coordinate value in the third position information of the M target points is the dependent variable, and the X coordinate value and the Y coordinate value are the independent variables. Linear fitting processing to determine the intercept of the plane equation on the X, Y and Z axes respectively;

    The constant in the plane equation is determined according to the intercept of the plane equation on the X, Y, and Z axes and the third position information of the center point of the M target points.
12. The method according to claim 11, wherein determining the terrain parameters of the ground according to the plane equation includes:

    The height of the drone from the ground is determined according to the intercept of the plane equation on the X, Y, and Z axes and the constant.
13. The method according to claim 12, wherein the determining the height of the drone from the ground according to the intercept on the X, Y, and Z axes of the plane equation and the constant includes:

    Determine the height of the origin of the rotating microwave radar from the ground according to the intercept of the plane equation on the X, Y, and Z axes and the constant;

    The height of the UAV from the ground is determined according to the height of the origin of the rotating microwave radar from the ground.
14. The method according to claim 11, wherein the determining the slope of the ground according to the plane equation includes:

    Convert the plane equation in the plane coordinates to the plane equation in the world coordinate system;

    The slope of the ground is determined according to the plane equation in the world coordinate system.
15. The method according to claim 14, wherein the determining the slope of the ground according to the plane equation in the world coordinate system includes:

    The slope of the ground is determined according to the arc tangent of the X-axis intercept of the plane equation in the world coordinate system.
16. The method according to claim 1, wherein the method further comprises:

    If the radar scanning angle of the rotating microwave radar is smaller than the preset value scanning angle, the intercept on the Y axis in the plane equation is determined as the preset value, and a new plane equation is obtained;

    According to the new plane equation, determine the height of the drone from the ground and / or the slope of the ground.
17. The method according to claim 7, wherein the method further comprises:

    If the M is less than the preset number, the average value of the Z coordinate values of the M target points is used as the height of the drone from the ground.
18. The method according to claim 1, wherein the method further comprises:

    According to the second location information of the N target points, an environment map is constructed.
19. The method of claim 18, further comprising:

    Obstacle division is performed on the environment map.
20. The method according to claim 18 or 19, wherein the constructing an environment map according to the second location information of the N target points includes:

    Converting the second position information of the N target points into fourth position information, where the fourth position information is position information of the target point in world coordinates;

    Construct the environment map according to the fourth position information of the N target points.
21. The method according to claim 20, wherein the converting the second position information of the N target points into fourth position information includes:

    Convert the second position information of the N target points into third position information, where the third position information is the position information of the target point in the aircraft coordinate system;

    Convert the third position information of the N target points into fourth position information.
22. The method according to claim 21, wherein the converting the third position information of the N target points into fourth position information includes:

    Obtain the quaternion attitude information and offset of the drone;

    The third position information of the N target points is converted into fourth position information according to the third position information of the N target points, quaternion attitude information and offset of the UAV.
23. A control system of a rotary microwave radar, which is characterized by comprising: a memory and a processor;

    The memory is used to store program codes;

    The processor calls the program code, and when the program code is executed, it is used to perform the following operations:

    Obtain the first position information and radar scanning angle of N target points measured by the rotating microwave radar during rotation, where N is a positive integer, the rotating microwave radar is installed on the drone, and the rotating microwave radar The rotation axis of is set perpendicular to the course axis of the drone; the first position information is the linear distance of the target point relative to the rotating microwave radar;

    Convert the first position information of the N target points into second position information, where the second position information is the coordinate information of the target point in the coordinate system of the movable carrier;

    The terrain parameters of the ground are determined according to the second position information of the N target points and the radar scanning angle, and the terrain parameters include at least one of the following: the slope and the height of the drone from the ground.
24. The system according to claim 23, wherein the first position information of the N target points is acquired by the rotating microwave radar scanning a horizontal plane 360 degrees, and the radar scanning angle is the phase of the rotating microwave radar The absolute angle of rotation relative to the starting position of 0 degrees.
25. The system according to claim 24, wherein the 0-degree starting position of the rotating microwave radar is set parallel to the horizontal plane of the earth.
26. The system according to any one of claims 23-25, wherein the movable carrier is an unmanned aerial vehicle, a remote control vehicle, or a hand-held gimbal.
27. The system according to any one of claims 23-25, wherein the second position information is coordinate information of the target point in a Cartesian coordinate system whose movable carrier is the origin.
28. The system according to claim 23, wherein the processor is specifically configured to:

    Construct a plane equation of the ground based on the second position information of the N target points and the radar scanning angle;

    According to the plane equation, the terrain parameters of the ground are determined.
29. The system according to claim 28, wherein the processor is specifically configured to:

    Determining M target points from the N target points according to the second position information of the N target points and the radar scanning angle, where M is a positive integer less than or equal to N;

    According to the position information of the M target points, a plane equation is constructed.
30. The system according to claim 29, wherein the processor is specifically configured to:

    Obtain the second position information and the M target points whose radar scanning angle satisfies the preset condition from the N target points.
31. The system according to claim 30, wherein the processor is specifically configured to:

    Convert the second position information of the M target points into third position information, where the third position information is the position information of the target point in the aircraft coordinate system;

    According to the third position information of the M target points, the plane equation is constructed.
32. The system according to claim 31, wherein the processor is specifically configured to:

    The plane equation is constructed by taking the Z coordinate value in the third position information of the M target points as the dependent variable and the X coordinate value and the Y coordinate value as the independent variables.
33. The system according to claim 32, wherein the processor is specifically configured to:

    Using least squares method, the Z coordinate value in the third position information of the M target points is the dependent variable, and the X coordinate value and the Y coordinate value are the independent variables. Linear fitting processing to determine the intercept of the plane equation on the X, Y and Z axes respectively;

    The constants in the plane equation are determined according to the intercepts of the plane equation on the X, Y, and Z axes and the third position information of the center points of the M target points.
34. The system according to claim 33, wherein the processor is specifically configured to:

    The height of the drone from the ground is determined according to the intercept of the plane equation on the X, Y, and Z axes and the constant.
35. The system according to claim 34, wherein the processor is specifically configured to:

    Determine the height of the origin of the rotating microwave radar from the ground according to the intercept of the plane equation on the X, Y, and Z axes and the constant;

    The height of the UAV from the ground is determined according to the height of the origin of the rotating microwave radar from the ground.
36. The system according to claim 33, wherein the processor is specifically configured to:

    Convert the plane equation in the plane coordinates to the plane equation in the world coordinate system;

    The slope of the ground is determined according to the plane equation in the world coordinate system.
37. The system according to claim 36, wherein the processor is specifically configured to:

    The slope of the ground is determined according to the arc tangent of the X-axis intercept of the plane equation in the world coordinate system.
38. The system according to claim 23, wherein the processor is further configured to:

    If the radar scanning angle of the rotating microwave radar is smaller than the preset value scanning angle, the intercept on the Y axis in the plane equation is determined as the preset value, and a new plane equation is obtained;

    According to the new plane equation, determine the height of the drone from the ground and / or the slope of the ground.
39. The system according to claim 29, wherein the processor is further configured to:

    If the M is less than the preset number, the average value of the Z coordinate values of the M target points is used as the height of the drone from the ground.
40. The system according to claim 23, wherein the processor is further configured to construct an environment map according to the second position information of the N target points.
41. The system according to claim 40, wherein the processor is further configured to:

    Obstacle division is performed on the environment map.
42. The system according to claim 40 or 41, wherein the processor is specifically configured to:

    Converting the second position information of the N target points into fourth position information, where the fourth position information is position information of the target point in world coordinates;

    Construct the environment map according to the fourth position information of the N target points.
43. The system according to claim 41, wherein the processor is specifically configured to:

    Convert the second position information of the N target points into position information in the aircraft coordinate system;

    The position information of the N target points in the aircraft coordinate system is converted into position information in the world coordinate system.
44. The system according to claim 30 or 43, wherein the processor is specifically configured to:

    Obtain the quaternion attitude information and offset of the drone;

    The third position information of the N target points is converted into fourth position information according to the third position information of the N target points, quaternion attitude information and offset of the UAV.
45. The system according to any one of claims 23 to 44, wherein the system is a rotary microwave radar, or the system is a drone, or the system is a control terminal of the drone.
46. A radar detection device, characterized by comprising: an antenna device and a control system according to any one of claims 23-45, the control system being in communication connection with the antenna device.
47. A drone, characterized by comprising: a frame, a flight control system and the radar detection device of claim 46, the rotating microwave radar is mounted on the frame,

    The flight control system is in communication with the radar detection device to obtain the terrain parameters, and the flight control system controls the drone according to the terrain parameters.

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