WO2021031975A1

WO2021031975A1 - Method and device for determining heading of unmanned aerial vehicle, and unmanned aerial vehicle

Info

Publication number: WO2021031975A1
Application number: PCT/CN2020/108929
Authority: WO
Inventors: 李颖杰; 张添保; 陈刚
Original assignee: 深圳市道通智能航空技术有限公司
Priority date: 2019-08-19
Filing date: 2020-08-13
Publication date: 2021-02-25
Also published as: CN110488865A; CN110488865B

Abstract

A method and device for selecting a heading angle initial value of an unmanned aerial vehicle, and an unmanned aerial vehicle. The method comprises: measuring the flight altitude of an unmanned aerial vehicle and magnetic field parameters in the flight environment of the unmanned aerial vehicle (S21); updating the heading angle initial value according to the flight altitude and the magnetic field parameters (S22); performing data fusion on data acquired by a sensor and the heading angle initial value to obtain a corrected heading angle (S23); and determining the heading of the unmanned aerial vehicle according to the corrected heading angle (S24). According to the method, a most accurate heading angle initial value can be obtained by measuring magnetic field parameters in the flight environment of an unmanned aerial vehicle (10) within a preset flight altitude range of the unmanned aerial vehicle (10), so that the heading angle still has a certain degree of accuracy when the unmanned aerial vehicle (10) takes off in a ground environment having magnetic interference, thereby reducing the probability of crash when the unmanned aerial vehicle (10) takes off in a ground environment having magnetic interference, and improving the flight safety.

Description

UAV heading determination method, device and UAV

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on August 19, 2019, the application number is 201910765629.8, and the application title is "UAV heading determination method, device and UAV", the entire content of which is by reference Incorporated in this application.

Technical field

This application relates to the field of drone technology, and in particular to a method and device for determining the heading of the drone, and the drone.

Background technique

Multi-rotor UAV heading control is directly related to the flight stability and flight safety of UAV. In the three attitude channels of UAV roll, pitch, and yaw, the yaw angle, that is, the heading angle, is given by the magnetometer as an initial value, and other sensors perform post-correction to it to finally get the fused heading angle. The magnetometer measures the earth's magnetic field data, and the three-axis magnetic readings given by it are extremely susceptible to environmental influences, so the given initial value often deviates from the true course. As the drone flies, other sensors participate in the heading angle fusion process, and accurate heading angle information will be obtained. When the heading angle has a large deviation from the initial heading angle given by the magnetometer, the aircraft will make a large heading The correction is reflected in the flight process, that is, the heading angle will have a large change, from flying to a slash, and at worst, a runaway bomber caused by a large correction of the heading angle.

The accuracy of the initial value of the heading angle directly affects the flight safety and flight quality of the multi-rotor UAV from take-off to obtaining the multi-sensor fusion heading angle. Therefore, how to give the initial value of the heading angle to minimize and avoid The initial value error has become an important task.

Summary of the invention

In order to solve the above technical problems, the embodiments of the present invention provide a method, a device and a drone for determining the accuracy of the initial value of the drone's heading angle.

To solve the above technical problems, the embodiments of the present invention provide the following technical solutions: a method for determining the heading of an unmanned aerial vehicle. The method for determining the UAV heading includes:

Detecting the flying height of the drone and the magnetic field parameters in the flying environment of the drone;

Update the initial value of the heading angle according to the flight altitude and the magnetic field parameters;

Perform data fusion between the data collected by the sensor and the initial value of the heading angle to obtain the corrected heading angle;

Determine the heading of the drone according to the corrected heading angle.

Optionally, the detecting the flying height of the drone and the magnetic field parameters in the flying environment of the drone includes:

Real-time detection of whether the flying height of the drone is less than a preset flying height threshold;

When the flying height of the drone is less than the flying height threshold, the magnetic field parameters in the flying environment of the drone are detected every preset time.

Optionally, the updating the initial value of the heading angle according to the flying height and the magnetic field parameter includes:

Calculating the error of the magnetic field parameter detected each time;

Obtain the heading angle of the drone when the detected error of the magnetic field parameter is the smallest, and use the heading angle as the initial value of the heading angle.

Optionally, the calculating the error of the magnetic field parameter detected each time includes:

Obtaining the latitude and longitude of the location of the drone;

Obtain the reference magnetic field parameters according to the latitude and longitude of the location of the drone;

The magnetic field parameter and the reference magnetic field parameter are compared to calculate the error of the magnetic field parameter.

Optionally, the magnetic field parameters include magnetic field strength and magnetic field inclination.

Optionally, the flying height threshold is 1.5-2m.

Optionally, the preset time is 10-30 ms.

Optionally, the determining the heading of the drone according to the corrected heading angle includes:

Update the attitude of the drone according to the current attitude of the drone and the corrected heading angle;

Determine the heading of the drone according to the updated attitude of the drone.

Optionally, the updating the attitude of the drone according to the current attitude of the drone and the initial value of the heading angle includes:

Acquiring the quaternion of the current attitude of the drone;

Obtain the yaw angle according to the initial value of the heading angle and the corrected heading angle;

According to the yaw angle, the quaternion with the UAV Z axis as the rotation axis is obtained:

Determine the updated quaternion of the UAV's attitude through the following formula:

q=r*q ₀

Where r is the quaternion with the Z axis of the drone as the axis of rotation, q ₀ is the quaternion of the current attitude of the drone, and q is the quaternion of the updated attitude of the drone number.

Optionally, the quaternion with the Z axis of the drone as the rotation axis is calculated by the following formula

Wherein ψ ₀ is the yaw angle, and r is a quaternion with the UAV Z axis as the rotation axis.

Optionally, before the real-time detection of the flying height of the drone and the magnetic field parameters in the flying environment of the drone, the method further includes:

After the drone is turned on, initialize the initial value of the heading angle.

In order to solve the above technical problems, the embodiments of the present invention also provide the following technical solutions: a device for determining the heading of an unmanned aerial vehicle.

The device for determining the UAV heading includes: a detection module for detecting the flying height of the UAV and the magnetic field parameters in the flying environment of the UAV;

The heading angle update module updates the initial value of the heading angle according to the flight altitude and the magnetic field parameters;

The data fusion module is used for data fusion between the data collected by the sensor and the initial value of the heading angle to obtain the corrected heading angle;

The heading determination module is used to determine the heading of the UAV according to the corrected heading angle.

Optionally, the detection module includes a flying height detection unit and a magnetic field parameter detection unit;

The height detection unit is used to detect in real time whether the flying height of the drone is less than a preset flying height threshold;

The magnetic field parameter detection unit is configured to detect the magnetic field parameter in the flying environment of the drone every preset time when the flying height of the drone is less than the flying height threshold.

Optionally, the heading angle update module includes an error calculation unit and a heading angle initial value determination unit;

The error calculation unit is used to calculate the error of the magnetic field parameter detected each time;

The initial heading angle determination unit is used to obtain the heading angle of the UAV when the detected error of the magnetic field parameter is the smallest, and use it as the initial heading angle.

Optionally, the error calculation unit includes a positioning subunit, a reference magnetic field parameter acquisition subunit, and an error calculation subunit;

The positioning subunit is used to obtain the latitude and longitude of the location of the drone;

The reference magnetic field parameter acquisition subunit is used to obtain reference magnetic field parameters according to the latitude and longitude of the location of the drone;

The error calculation subunit is used to compare the magnetic field parameter with the reference magnetic field parameter to calculate the error of the magnetic field parameter.

Optionally, a storage module is further included, and the storage module is used to store the flying height threshold and the preset time.

Optionally, the flying height threshold is 1.5-2m;

The preset time is 10-30ms.

Optionally, the heading determination module includes an attitude update unit and a heading update unit;

The attitude update unit is used to update the attitude of the drone according to the current attitude of the drone and the corrected heading angle;

The heading update unit is used to determine the heading of the drone according to the updated attitude of the drone.

In order to solve the above technical problems, the embodiments of the present invention also provide the following technical solutions: an unmanned aerial vehicle. The drone includes:

body;

An arm, connected to the fuselage;

The power device is arranged on the arm and is used to provide power for the drone to fly;

A magnetometer, set on the fuselage, used to obtain the initial value of the heading angle of the drone;

A variety of sensors are provided on the fuselage for collecting corresponding flight data; and

The flight controller is located on the fuselage;

The flight controller includes:

Processor; and

A memory communicatively connected with the processor; wherein the memory stores instructions executable by the processor, and the instructions are executed by the processor so that the processor can be used to execute the above The method for determining the heading of the UAV described.

Compared with the prior art, the method for selecting the initial value of the heading angle of the drone provided by the embodiment of the present invention can be within the preset flying height range of the drone by detecting the magnetic field parameters in the flying environment of the drone. Obtain the most accurate initial value of the heading angle to eliminate the influence of the external environment on the magnetometer, provide a more accurate initial value of the heading angle for the UAV data fusion, and realize the UAV in the ground environment with magnetic interference In medium take-off, the heading angle still has a certain degree of accuracy, which reduces the probability of UAV taking off in a ground environment with magnetic interference, and improves flight safety.

Description of the drawings

One or more embodiments are exemplified by the pictures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Elements with the same reference numbers in the drawings are represented as similar elements. Unless otherwise stated, the figures in the attached drawings do not constitute a limitation of scale.

Figure 1 is a schematic diagram of an application environment of an embodiment of the present invention;

2 is a schematic flowchart of a method for determining a heading of a drone provided by an embodiment of the present invention;

Figure 3 is a schematic diagram of the flow of S21 in Figure 2;

FIG. 4 is a graph of UAV flight height versus flight time provided by an embodiment of the present invention;

FIG. 5 is a graph of three-axis readings of a UAV magnetometer versus flight time according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of the flow of S22 in FIG. 2;

FIG. 7 is a schematic diagram of the flow of S221 in FIG. 6;

FIG. 8 is a structural block diagram of an apparatus for determining a UAV heading provided by an embodiment of the present invention;

Fig. 9 is a structural block diagram of a drone provided by an embodiment of the present invention.

detailed description

In order to facilitate the understanding of the present invention, the present invention will be described in more detail below with reference to the drawings and specific embodiments. It should be noted that when an element is expressed as being "fixed to" another element, it can be directly on the other element, or there can be one or more elements in between. When an element is said to be "connected" to another element, it can be directly connected to the other element, or there may be one or more intervening elements in between. The terms "upper", "lower", "inner", "outer", "bottom", etc. used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention. The invention and simplified description do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance.

Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the technical field of the present invention. The terms used in the specification of the present invention in this specification are only for the purpose of describing specific embodiments, and are not used to limit the present invention. The term "and/or" as used in this specification includes any and all combinations of one or more related listed items.

In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

The embodiment of the present invention provides a method and device for determining the heading of a drone. The method and device can detect the magnetic field parameters in the flying environment of the drone within the preset flying height range of the drone. Obtain the most accurate initial value of the heading angle to eliminate the influence of the external environment on the magnetometer, and provide a more accurate initial value of the heading angle for the UAV 10 to perform data fusion. When taking off in a ground environment, the heading angle still has a certain degree of accuracy, which reduces the probability of bombing the UAV 10 taking off in a ground environment with magnetic interference, and improves flight safety. The following examples illustrate the application environment of the UAV heading determination method and device.

FIG. 1 is a schematic diagram of the application environment of the system for selecting the initial value of the drone heading angle provided by an embodiment of the present invention; as shown in FIG. 1, the application scenario includes the drone 10, the wireless network 20, the intelligent terminal 30 and the user 40 . The user 40 can operate the smart terminal 30 to control the drone 10 through the wireless network 20.

The UAV 10 may be an unmanned aerial vehicle driven by any type of power, including but not limited to a rotary wing UAV, a fixed wing UAV, an umbrella wing UAV, a flapping wing UAV, and a helicopter model. In this embodiment, a multi-rotor drone is taken as an example for presentation.

The unmanned aerial vehicle 10 may have a corresponding volume or power according to actual needs, so as to provide load capacity, flight speed, and flight range that can meet the needs of use. One or more sensors may be added to the drone 10 to enable the drone 10 to realize corresponding functions.

For example, in this embodiment, the drone 10 is provided with at least one sensor of an accelerometer, a gyroscope, a magnetometer, a GPS navigator, and a vision sensor.

The UAV 10 also includes a flight controller, which serves as a control core for UAV flight and data transmission, and integrates one or more modules to execute corresponding logic control programs.

The smart terminal 30 may be any type of smart device used to establish a communication connection with the drone 10, such as a mobile phone, a tablet computer, or a smart remote control. The smart terminal 30 may be equipped with one or more different user 40 interaction devices to collect instructions from the user 40 or display and feedback information to the user 40.

These interactive devices include but are not limited to: buttons, display screens, touch screens, speakers, and remote control joysticks. For example, the smart terminal 30 may be equipped with a touch screen, through which the user 40 receives the remote control instruction of the drone 10 and displays the image information obtained by aerial photography to the user 40 through the touch screen. The user 40 can also Switch the image information currently displayed on the display through the remote control touch screen.

In some embodiments, the UAV 10 and the smart terminal 30 can also integrate existing image visual processing technologies to further provide more intelligent services. For example, the drone 10 can collect images through a dual-lens camera, and the smart terminal 30 can analyze the images, so as to realize the gesture control of the drone 10 by the user 40.

The wireless network 20 may be a wireless communication network used to establish a data transmission channel between two nodes based on any type of data transmission principle, such as a Bluetooth network located in different signal frequency bands, a WiFi network, a wireless cellular network, or a combination thereof.

Fig. 2 is an embodiment of a method for determining a heading of a drone provided by an embodiment of the present invention. As shown in Figure 2, the method for determining the heading of the UAV can be executed by the flight controller of the UAV, and includes the following steps:

S21: Detect the flying height of the drone and the magnetic field parameters in the flying environment of the drone.

Specifically, an air pressure detection device may be used to detect the flight height of the drone 10, which includes a barometer, a sensor protection cover, and a duct. The barometer is sealed in the sensor protection cover, and is installed in the drone together with the sensor protection cover. On the human-machine 10, one end of the conduit is connected with the sensor protection cover, and the other end extends upward after passing through the sensor protection cover.

The sensor protection cover and the duct are provided, and the nozzle position at the top of the duct is set to extend upward, so as to effectively isolate the external environment of the barometer from the turbulence generated by the rotation of the blades, thereby preventing the barometer from being inadequate Stabilizing the interference of the atmospheric pressure environment helps to ensure accurate detection of the atmospheric pressure height.

In some embodiments, at least two sensors such as air pressure detection device, accelerometer, GPS and ultrasonic can be used at the same time, and then complementary filtering or Kalman filtering can be used to fuse the data of these sensors to correct each other, and finally obtain the flight of UAV 10 height.

Specifically, a magnetometer is used to detect the magnetic field parameters of the drone 10, and the magnetic field parameters include magnetic field strength and magnetic field inclination.

S22. Update the initial value of the heading angle according to the flying height and the magnetic field parameters.

Specifically, the initial value of the heading angle can be obtained through a variety of sensors, such as an electronic compass, a magnetometer, and an acceleration sensor. However, the aforementioned various sensors are easily affected by the external environment and cannot accurately obtain the heading angle, which affects the attitude estimation. Because this kind of error is random, it cannot be eliminated in advance. For example, the magnetometer is susceptible to interference from the magnetic field generated by the surrounding environment (such as high-voltage lines, iron ore factories, etc.), thereby affecting the output of the heading angle. For another example, other reasons such as ground fluctuations and the shaking of the UAV 10 body cause the turbulence of the carrier attached to the electronic compass, and the heading angle obtained by the electronic compass shows large fluctuations.

In this embodiment, by detecting the magnetic field parameters in the flying environment of the drone, the initial value of the heading angle with the highest accuracy is obtained to eliminate the influence of the external environment on the magnetometer, which provides data fusion for the drone 10 More accurate initial value of heading angle.

In some embodiments, the heading angle obtained by the electronic compass can also be processed and corrected by the median method and Kalman filter to obtain a more accurate heading angle.

S23: Perform data fusion between the data collected by the sensor and the initial value of the heading angle to obtain a corrected heading angle.

Specifically, the aforementioned sensor includes at least one of an accelerometer, a magnetometer, a gyroscope, a positioner, and a vision sensor.

The technology of data fusion is to analyze, sort, and fuse the data collected by the sensors. Multi-sensor fusion data can correct the initial value of the heading angle, thereby giving more accurate heading angle data.

The data collected by the sensor and the initial value of the heading angle can be processed by a variety of different data fusion algorithms, such as: weighted average method, normalized weighted average method, Kalman filter, and extended Kalman filter.

In this embodiment, data fusion is performed on data collected by multiple sensors based on the weighted average method. Specifically, the first step is to initialize the various software and hardware to be used, such as sensor initialization and Kalman filter initialization, etc.; the second step is to obtain IMU data, and then use this part of the data to make a judgment to see if Need to do attitude angle compensation, if it needs compensation, what is the specific value; the third step is to obtain the data collected by sensors such as accelerometer, magnetometer, gyroscope, locator and vision sensor, and do relevant weighting for this part of the data value Averaging operation, Kalman filter the obtained data value, thereby generating the corrected heading angle.

S24. Determine the heading of the UAV 10 according to the corrected heading angle.

Specifically, the attitude of the drone 10 is updated according to the current attitude of the drone 10 and the corrected heading angle, and further, the attitude of the drone 10 is determined according to the updated attitude of the drone 10 The heading of the drone 10 is described.

_{Specifically, the current quaternion q 0} of the attitude of the drone 10 is obtained; according to the initial value of the heading angle and the corrected heading angle, the heading deflection angle ψ _{0 is obtained} , and the heading deflection angle ψ ₀ Is the difference between the initial value of the heading angle and the corrected heading angle.

Establish a body coordinate system, the body coordinate system is fixedly connected with the drone, the body coordinate system conforms to the right-hand rule, the origin is at the center of gravity of the drone, the X axis points to the direction of the drone, and the Y axis is from the origin Point to the right side of the drone, and the Z-axis direction is determined by the right-hand rule based on the X and Y axes.

According to the yaw angle ψ ₀ , the quaternion with the Z axis of the drone 10 as the rotation axis is obtained:

According to the quaternion r with the Z axis of the drone 10 as the rotation axis and the quaternion q _{0 of the} current attitude of the drone 10, the new quaternion of the attitude of the drone 10 is obtained q=r*q ₀ .

The embodiments of the present invention provide a method and device for determining the heading of the drone. The method and device can detect the magnetic field parameters in the flying environment of the drone within the preset flying height range of the drone. Obtain the most accurate initial value of the heading angle to eliminate the influence of the external environment on the magnetometer, and provide a more accurate initial value of the heading angle for the UAV 10 to perform data fusion. Taking off in a ground environment, the heading angle still has a certain degree of accuracy, which reduces the probability of the UAV 10 taking off in a ground environment with magnetic interference, and improves flight safety.

In some embodiments, before detecting the flying height of the drone, it includes: after the drone is turned on, initializing the initial value of the heading angle, and the initial value of the heading angle is given by a magnetometer.

In order to make the updated initial value of the heading angle more accurate, it is necessary to accurately detect the flying height of the drone and the magnetic field parameters in the flying environment of the drone. In some embodiments, please refer to Fig. 3, S21 includes the following step:

S211: Detect in real time whether the flying height of the drone is less than a preset flying height threshold. Preferably, the flying height threshold of the drone 10 is 1.5-2 m, and the flying height threshold is derived from the existing flight data of the drone 10.

Specifically, please refer to Figures 4 and 5 together. Figure 4 shows the altitude information of the drone during a flight, and Figure 5 shows the corresponding three-axis readings of the magnetometer during the flight. In this flight, the UAV 10 only changes the altitude, and does not perform actions in the roll and pitch channels. In Figure 4, hAGL represents the fusion altitude, and hBaro represents the barometer altitude. In Figure 5, x represents the magnetic induction reading of the x-axis of the magnetometer, y represents the magnetic induction reading of the y-axis of the magnetometer, and the z axis represents the magnetic induction reading of the z-axis of the magnetometer. Comparing Figure 4 and Figure 5, it can be seen that as the height of the drone increases, its magnetometer readings also change. The reason for analysis is that the magnetic field is affected by the ground when the drone takes off, which causes the magnetometer reading to change. Under normal circumstances, the impact of the take-off ground on the magnetic field is widespread, and the impact is more severe in an environment containing metal or other magnetic objects. In the past, the initial value of the heading angle of the UAV 10 was usually given on the ground, which led to the inaccuracy of the initial value.

Combining the analysis of Figure 4 and Figure 5, it can be concluded that the uncertainty of the ground environment will cause the magnetic field information given by the magnetometer to be inaccurate, resulting in inaccurate initial heading angle. This effect is inversely proportional to the quadratic power of the distance. By detecting the real-time height of the drone, it is found that when the height of the drone reaches 1.5-2m, the magnetometer reading no longer changes significantly. The influence is already very weak. At this time, the magnetometer can give more accurate magnetic field information, so that the updated initial value of the heading angle is also more accurate. Therefore, the present invention sets the flying height threshold of the drone 10 to 1.5- 2m. Moreover, under normal circumstances, the flying height of the UAV is much higher than the altitude of 1.5-2m, so updating the initial value of the heading angle at the altitude of 1.5-2m will not affect the normal flight.

Specifically, an air pressure detecting device is used to detect the flying height of the drone 10, which includes a barometer, a sensor protection cover, and a duct. The barometer is sealed in the sensor protection cover and installed in the unmanned aircraft together with the sensor protection cover. On the machine 10, one end of the conduit is connected with the sensor protection cover, and the other end extends upward after passing through the sensor protection cover. In the present invention, the sensor protection cover and the pipe are arranged, and the position of the nozzle at the top of the pipe is set to extend upward, so as to effectively isolate the external environment where the barometer is located from the turbulence generated by the rotation of the blades, thereby avoiding the pressure of the barometer. The interference of unstable air pressure environment helps to ensure the accurate detection of air pressure height.

S212: When the flying height of the drone is less than the flying height threshold, detect the magnetic field parameters in the flying environment of the drone every preset time. The preset time is 10-15 ms.

Specifically, firstly, the flying height of the drone detected by the above-mentioned air pressure detection device, accelerometer, GPS and ultrasonic sensors is acquired in real time. Then compare the flying height of the drone with the flying height threshold of the drone. When the flying height of the drone is less than the flying height threshold, the magnetometer detects that the drone is flying at this time every 10-15ms Magnetic field parameters at altitude. The magnetic field parameter includes at least one of a magnetic field strength, a magnetic field inclination angle, and a magnetic field deflection angle.

In some embodiments, the preset time can be set according to the take-off ground environment. For example, when the take-off ground environment contains a lot of metal or other magnetic objects (such as high-voltage lines, iron ore factories, etc.), the take-off ground environment has an impact on the magnetic force. The magnetic field interference generated by the meter is strong, and the preset time can be reduced, for example, to 5-9 ms. For another example, when the take-off ground environment contains less metal or other magnetic objects, and the magnetic field generated by the take-off ground environment is weaker than the magnetic field generated by the magnetometer, the preset time can be increased, for example, to 16-20 ms.

In order to make the updated initial value of the heading angle more accurate, in some embodiments, referring to FIG. 6, S22 includes the following steps:

S221: Calculate the error of the magnetic field parameter detected each time.

Specifically, the World Geomagnetic Field Model (WMM) provides a reference magnetic field quantity for the error judgment of the magnetic field parameters obtained by the magnetometer. WMM is a mathematical model of the earth’s main magnetic field. The model can be used to calculate the geomagnetic field characteristic quantities at any point in the world. . According to the longitude, latitude, altitude, time and other information provided by the UAV GPS receiver, as well as the world geomagnetic field model WMM published by the National Geophysical Data Center of the United States, the interference determination of the magnetic field during the flight of the UAV is made.

In this embodiment, the analysis is mainly performed from two aspects. One is to compare the local magnetic field intensity measured by the magnetometer with the reference magnetic field provided by WMM, and the other is to compare the local magnetic field inclination measured by the magnetometer with the reference magnetic field provided by WMM. . When there is a large error between these two values, it is determined that there is magnetic field interference.

S222: Obtain the heading angle of the UAV when the detected magnetic field parameter error is the smallest and use it as an initial value of the heading angle.

Specifically, after the unmanned aerial vehicle is powered on, the magnetic field parameters before take-off of the unmanned aerial vehicle are calculated through the magnetometer readings, and the above-mentioned magnetic field parameters are used as the first magnetic field parameters.

After the drone takes off and the flying height of the drone is less than the flying height threshold, the magnetic field parameters at the flying height of the drone at this time are acquired every preset time, and the magnetic field parameters are used as the second The magnetic field parameter, the first magnetic field parameter is compared with the second magnetic field parameter, if the error between the second magnetic field and the parameter reference magnetic field is smaller than the error between the first magnetic field parameter and the reference magnetic field, then the second magnetic field parameter is replaced The first magnetic field parameter, that is, the second magnetic field parameter becomes the first magnetic field parameter, and cyclically, when the flying height of the drone reaches the flying height threshold, the first magnetic field parameter is The optimal magnetic field parameter, that is, the error between the first magnetic field parameter and the reference magnetic field is the smallest, and the heading angle at the flying height of the UAV corresponding to the optimal magnetic field parameter can be obtained to obtain the corresponding magnetic field parameter error. The heading angle at which the drone is flying.

Specifically, the flying height threshold of the drone 10 is 1.5-2m. When the flying height of the drone reaches the flying height threshold, the impact of the take-off ground environment on the magnetometer is already very weak. At this time, the heading angle obtained by the magnetometer is more accurate, and this heading angle is used as the initial value of the heading angle to complete the update of the initial value of the heading angle. Moreover, under normal circumstances, the flying height of the UAV is much higher than the altitude of 1.5-2m, so updating the initial value of the heading angle at the altitude of 1.5-2m will not affect the normal flight.

In some embodiments, the flying height threshold can be set according to the take-off ground environment. For example, when the take-off ground environment contains a lot of metal or other magnetic objects (such as high-voltage lines, iron ore factories, etc.), the take-off ground environment has a negative impact on the magnetic force. The magnetic field interference generated by the meter is strong, and the flying height threshold can be increased, for example, to 3-5m. For another example, when the take-off ground environment contains less metal or other magnetic objects, and the magnetic field generated by the magnetometer is weakly interfered by the take-off ground environment, the flying height threshold can be reduced, for example, to 1-1.4m .

In order to accurately calculate the error of the magnetic field parameter in the flying environment of the drone, which is detected every predetermined time. In some embodiments, referring to FIG. 7, S221 includes the following steps:

S2211: Obtain the latitude and longitude of the location of the drone.

Specifically, the longitude, latitude, altitude, time and other information of the location of the drone can be obtained through the GPS receiver onboard the drone.

S2212: Obtain reference magnetic field parameters according to the latitude and longitude of the location of the drone.

Specifically, check the WMM table according to the latitude and longitude obtained by GPS to obtain the local magnetic field strength, magnetic field inclination, magnetic field declination and other information.

S2213: Compare the magnetic field parameter with the reference magnetic field parameter, and calculate the error of the magnetic field parameter in the flying environment of the drone.

Specifically, the comparison is mainly made from two aspects. One is to compare the local magnetic field intensity measured by the magnetometer with the reference magnetic field provided by WMM, and the other is to compare the local magnetic field inclination measured by the magnetometer with the reference magnetic field provided by WMM. When there is a large error between these two values, it is determined that there is magnetic field interference.

It should be noted that in each of the above embodiments, there is not necessarily a certain sequence between the above steps. A person of ordinary skill in the art can understand from the description of the embodiments of this application that in different embodiments, the above steps There can be different execution orders, that is, they can be executed in parallel, they can be exchanged, and so on.

As another aspect of the embodiments of the present application, the embodiments of the present application provide an apparatus 50 for determining the heading of a drone. Referring to FIG. 8, the UAV heading determination device 50 includes a detection module 51, a heading angle update module 52, a data fusion module 53, and a heading determination module 54.

The flying height detection module 51 is used to detect the flying height of the drone and the magnetic field parameters in the flying environment of the drone.

The heading angle update module 52 is used to update the initial value of the heading angle according to the flying height and the magnetic field parameters.

The data fusion module 53 is configured to perform data fusion between the data collected by the sensor and the initial value of the heading angle to obtain the corrected heading angle.

The heading determination module 54 is used to determine the heading of the UAV according to the corrected heading angle.

Specifically, in this embodiment, when the heading angle update module 52 receives the drone flight height detected by the flight height detection module 51 and the magnetic field parameters in the drone flight environment, the heading angle update module 52 Obtain the accurate initial value of the heading angle under the magnetic field parameters at different flight altitudes; then the data fusion module 53 respectively fuse the received initial value of the heading angle with the data collected by the sensor to obtain the corrected heading angle; the final heading The determining module 54 is configured to determine the heading of the UAV 10 according to the corrected heading angle.

Therefore, in this embodiment, the most accurate initial heading angle value is obtained by detecting the magnetic field parameters in the flying environment of the drone, so as to eliminate the influence of the external environment on the magnetometer and perform data for the drone 10 Fusion provides a more accurate initial value of the heading angle, enabling the UAV 10 to take off in a ground environment with magnetic interference. The heading angle still has a certain degree of accuracy, which reduces the UAV 10 in a ground environment with magnetic interference. The probability of taking off the bomber improves flight safety. The following examples illustrate the application environment of the UAV heading determination method and device.

In some embodiments, the UAV heading determination device 50 further includes a storage module 55 configured to store the flying height threshold and the preset time.

Preferably, the flying height threshold of the drone is 1.5-2m; the preset time is 10-30ms.

Wherein, in some embodiments, the heading angle update module 52 includes an error calculation unit and a heading angle initial value determination unit. The error calculation unit is used to calculate the error of the magnetic field parameter detected each time; the initial value determination unit of the heading angle is used to obtain the heading angle of the drone when the detected error of the magnetic field parameter is the smallest, and use it as The initial value of the heading angle.

Wherein, in some embodiments, the error calculation unit includes a positioning subunit, a reference magnetic field parameter acquisition subunit, and an error calculation subunit; the positioning subunit is used to obtain the latitude and longitude of the location of the drone; The reference magnetic field parameter acquisition subunit is used to obtain reference magnetic field parameters according to the latitude and longitude of the location of the drone; the error calculation subunit is used to compare the magnetic field parameters with the reference magnetic field parameters to calculate the magnetic field The error of the parameter.

Among them, in some embodiments, the heading determination module 54 includes an attitude update unit and a heading update unit. The attitude update unit is used to update the attitude of the drone according to the current attitude of the drone and the corrected heading angle; the heading update unit is used to update the attitude of the drone according to the updated attitude To determine the heading of the drone.

Wherein, the attitude update unit is specifically used to obtain the quaternion q _{0 of the} _{current attitude of the UAV 10; obtain the heading deflection angle ψ 0} according to the initial value of the heading angle and the corrected heading angle; According to the heading deflection angle ψ ₀ , the quaternion with the Z axis of the UAV 10 as the rotation axis is obtained:

According to the quaternion r with the Z axis of the drone 10 as the rotation axis and the quaternion q _{0 of the} current attitude of the drone 10, the new attitude q=r* of the drone 10 is obtained q ₀ .

FIG. 9 is a structural block diagram of a drone 10 provided by an embodiment of the present invention. As shown in FIG. 9, the UAV 10 may include: a body, an arm, a power unit, a magnetometer, various sensors, a flight controller, and a communication module 130. Among them, the flight controller includes a processor 110 and a memory 120.

The arm is connected with the fuselage; the power device is arranged on the arm and is used to provide power for the drone to fly.

The magnetometer is used to obtain the initial value of the heading angle of the drone. The multiple types of sensors are used to collect corresponding flight data, and the multiple types of sensors may be accelerometers, gyroscopes, magnetometers, GPS navigators, and vision sensors.

The processor 110, the memory 120, and the communication module 130 establish a communication connection between any two through a bus.

The processor 110 may be of any type and has one or more processing cores. It can perform single-threaded or multi-threaded operations, and is used to parse instructions to perform operations such as obtaining data, performing logical operation functions, and issuing operation processing results.

As a non-transitory computer-readable storage medium, the memory 120 can be used to store non-transitory software programs, non-transitory computer-executable programs and modules, such as the program corresponding to the method for determining the heading of a drone in the embodiment of the present invention Instructions/modules (for example, the flying height detection module 51, the heading angle update module 52, the data fusion module 53, the heading determination module 54, the storage module 55 shown in FIG. 8). The processor 110 executes various functional applications and data processing of the UAV heading determination device 50 by running the non-transient software programs, instructions, and modules stored in the memory 120, that is, to realize the unmanned operation in any of the foregoing method embodiments. How to determine the aircraft heading.

The memory 120 may include a program storage area and a data storage area. The program storage area may store an operating system and an application program required by at least one function; the data storage area may store data created according to the use of the drone heading determination device 50 Wait. In addition, the memory 120 may include a high-speed random access memory, and may also include a non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some embodiments, the memory 120 may optionally include memories remotely provided with respect to the processor 110, and these remote memories may be connected to the drone 10 via a network. Examples of the aforementioned networks include but are not limited to the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

The memory 120 stores instructions that can be executed by the at least one processor 110; the at least one processor 110 is used to execute the instructions to implement the drone heading determination method in any of the foregoing method embodiments, for example, The above-described method steps 21, 22, 23, 24, etc. are executed to realize the functions of the modules 51-55 in FIG. 8.

The communication module 130 is a functional module used to establish a communication connection and provide a physical channel. The communication module 130 may be any type of wireless or wired communication module 130, including but not limited to a WiFi module or a Bluetooth module.

Further, the embodiment of the present invention also provides a non-transitory computer-readable storage medium, the non-transitory computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are executed by one or more processors 110 is executed, for example, executed by one of the processors 110 in FIG. 9, so that the one or more processors 110 can execute the method for determining the drone heading in any of the foregoing method embodiments, for example, execute the

steps

21, 22, 23, 24, etc., realize the functions of modules 51-55 in Figure 8.

The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in One place, or it can be distributed to multiple network units. Some or all of the modules may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

Through the description of the above implementation manners, those of ordinary skill in the art can clearly understand that each implementation manner can be implemented by means of software plus a general hardware platform, and of course, it can also be implemented by hardware. A person of ordinary skill in the art can understand that all or part of the processes in the methods of the foregoing embodiments can be implemented by instructing relevant hardware by a computer program in a computer program product. The computer program can be stored in a non-transitory computer. In the read storage medium, the computer program includes program instructions, and when the program instructions are executed by a related device, the related device can execute the procedures of the embodiments of the foregoing methods. Wherein, the storage medium may be a magnetic disk, an optical disk, a read-only memory (Read-Only Memory, ROM), or a random access memory (Random Access Memory, RAM), etc.

The above products can execute the method for determining the heading of the drone provided by the embodiments of the present invention, and have the corresponding functional modules and beneficial effects for executing the method for determining the heading of the drone. For technical details not described in detail in this embodiment, please refer to the method for determining the heading of the drone provided in the embodiment of the present invention.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, not to limit them; under the idea of the present invention, the technical features of the above embodiments or different embodiments can also be combined. The steps can be implemented in any order, and there are many other variations of different aspects of the present invention as described above. For the sake of brevity, they are not provided in the details; although the present invention has been described in detail with reference to the foregoing embodiments, the ordinary The skilled person should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or equivalently replace some of the technical features; and these modifications or replacements do not divorce the essence of the corresponding technical solutions from the implementations of the present invention Examples of the scope of technical solutions.

Claims

A method for determining the heading of an unmanned aerial vehicle, applied to an unmanned aerial vehicle, characterized in that it includes:

Detecting the flying height of the drone and the magnetic field parameters in the flying environment of the drone;

Update the initial value of the heading angle according to the flight altitude and the magnetic field parameters;

Perform data fusion between the data collected by the sensor and the initial value of the heading angle to obtain the corrected heading angle;

Determine the heading of the drone according to the corrected heading angle.
The method according to claim 1, wherein:

The detecting the flying height of the drone and the magnetic field parameters in the flying environment of the drone includes:

Real-time detection of whether the flying height of the drone is less than a preset flying height threshold;

When the flying height of the drone is less than the flying height threshold, the magnetic field parameters in the flying environment of the drone are detected every preset time.
The method according to claim 2, wherein:

The updating the initial value of the heading angle according to the flying height and the magnetic field parameter includes:

Calculating the error of the magnetic field parameter detected each time;

Obtain the heading angle of the UAV when the error of the detected magnetic field parameter is the smallest, and use the heading angle as the initial value of the heading angle.
The method according to claim 3, wherein:

The calculating the error of the magnetic field parameter detected each time includes:

Obtaining the latitude and longitude of the location of the drone;

Obtain the reference magnetic field parameters according to the latitude and longitude of the location of the drone;

The magnetic field parameter and the reference magnetic field parameter are compared to calculate the error of the magnetic field parameter.
The method according to claim 2, wherein:

The magnetic field parameters include magnetic field strength and magnetic field inclination.
The method according to claim 2, wherein:

The flying height threshold is 1.5-2m.
The method according to claim 2, wherein:

The preset time is 10-30ms.
The method according to claim 4, wherein:

The determining the heading of the drone according to the corrected heading angle includes:

Update the attitude of the drone according to the current attitude of the drone and the corrected heading angle;

Determine the heading of the drone according to the updated attitude of the drone.
The method according to claim 8, wherein:

The updating the attitude of the drone according to the current attitude of the drone and the initial value of the heading angle includes:

Acquiring the quaternion of the current attitude of the drone;

Obtain the yaw angle according to the initial value of the heading angle and the corrected heading angle;

According to the yaw angle, the quaternion with the UAV Z axis as the rotation axis is obtained:

Determine the updated attitude quaternion of the UAV through the following formula:

q=r*q 0 ;

Where, r is the quaternion with the Z axis of the drone as the rotation axis, q 0 is the quaternion of the current attitude of the drone, and q is the quaternion of the updated attitude of the drone .
The method according to claim 9, characterized in that the method further comprises: calculating the quaternion with the Z-axis of the drone as the rotation axis through the following formula:

Wherein ψ 0 is the yaw angle, and r is a quaternion with the UAV Z axis as the rotation axis.
The method according to claim 1, wherein:

Before the detecting the flying height of the drone and the magnetic field parameters in the flying environment of the drone, the method further includes:

After the drone is turned on, initialize the initial value of the heading angle.
A device for determining the heading of an unmanned aerial vehicle is characterized in that it comprises:

A detection module for detecting the flying height of the drone and the magnetic field parameters in the flying environment of the drone;

The heading angle update module updates the initial value of the heading angle according to the flight altitude and the magnetic field parameters;

The data fusion module is used for data fusion between the data collected by the sensor and the initial value of the heading angle to obtain the corrected heading angle;

The heading determination module is used to determine the heading of the UAV according to the corrected heading angle.
The UAV heading determination device according to claim 12, wherein:

The detection module includes a flying height detection unit and a magnetic field parameter detection unit;

The height detection unit is used to detect in real time whether the flying height of the drone is less than a preset flying height threshold;

The magnetic field parameter detection unit is configured to detect the magnetic field parameter in the flying environment of the drone every preset time when the flying height of the drone is less than the flying height threshold.
The UAV heading determination device according to claim 13, wherein:

The heading angle update module includes an error calculation unit and a heading angle initial value determination unit;

The error calculation unit is used to calculate the error of the magnetic field parameter detected each time;

The initial heading angle determination unit is used to obtain the heading angle of the UAV when the detected error of the magnetic field parameter is the smallest, and use it as the initial heading angle.
The UAV heading determination device according to claim 14, wherein:

The error calculation unit includes a positioning subunit, a reference magnetic field parameter acquisition subunit, and an error calculation subunit;

The positioning subunit is used to obtain the latitude and longitude of the location of the drone;

The reference magnetic field parameter acquisition subunit is used to obtain reference magnetic field parameters according to the latitude and longitude of the location of the drone;

The error calculation subunit is used to compare the magnetic field parameter with the reference magnetic field parameter to calculate the error of the magnetic field parameter.
The UAV heading determination device according to claim 12, wherein:

The magnetic field parameters include magnetic field strength and magnetic field inclination.
The UAV heading determination device according to claim 13, characterized in

Yu, it also includes a storage module configured to store the flight height threshold and the preset

time.
The UAV heading determination device according to claim 13, characterized in

in,

The flying height threshold is 1.5-2m;

The preset time is 10-30ms.
The UAV heading determination device according to claim 12, wherein:

The course determination module includes an attitude update unit and a course update unit;

The attitude update unit is used to update the attitude of the drone according to the current attitude of the drone and the corrected heading angle;

The heading update unit is used to determine the heading of the drone according to the updated attitude of the drone.
An unmanned aerial vehicle, characterized in that it includes:

body;

An arm, connected to the fuselage;

The power device is arranged on the arm and is used to provide power for the drone to fly;

A magnetometer, set on the fuselage, used to obtain the initial value of the heading angle of the drone;

A variety of sensors are provided on the fuselage for collecting corresponding flight data; and

The flight controller is located on the fuselage;

The flight controller includes:

Processor; and

A memory communicatively connected with the processor; wherein the memory stores instructions executable by the processor, and the instructions are executed by the processor so that the processor can be used to execute The method for determining the UAV heading described in any one of 1-11.