A method, system and medium for detecting attitude of unmanned aerial vehicle based on solar image

Abstract

The present invention relates to the field of unmanned aerial vehicles, and provides a method, system and medium for detecting the attitude of unmanned aerial vehicles based on solar images, including: obtaining a solar image by photographing with a camera carried by an unmanned aerial vehicle; determining the pixel coordinates of the solar center point in the solar image; calculating the actual solar altitude angle and the actual solar azimuth angle in the camera coordinate system according to the pixel coordinates of the solar center point; establishing a relative position relationship model among the earth, the sun and the unmanned aerial vehicle, and calculating the theoretical solar altitude angle and the theoretical solar azimuth angle based on the time information and position information of the unmanned aerial vehicle photographing the solar image; calculating the deviation between the actual solar altitude angle and the theoretical solar altitude angle, and between the actual solar azimuth angle and the theoretical solar azimuth angle, and obtaining the attitude of the unmanned aerial vehicle. The present invention uses solar information for attitude detection, and is not affected by complex electromagnetic environments; it can be used for initial attitude calibration of unmanned aerial vehicles, especially calibration of heading.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicles (UAVs), and in particular to a method, system and medium for detecting the attitude of an unmanned aerial vehicle (UAV) based on a solar image. Background Art

[0002] The existing mainstream drone sensors include gyroscopes, accelerometers, magnetometers, GPS, barometers, etc., and drone attitude estimation is achieved through multi-sensor fusion algorithms. The gyroscope integrates the drone attitude, and due to the gyroscope's own characteristics and noise, the attitude obtained by integration gradually diverges after a period of time. Therefore, multi-sensor fusion is used to correct the attitude. The accelerometer corrects the pitch and roll angles in a stable flight state, and the magnetometer corrects the heading angle. GPS and barometer correct the attitude through speed and position information.

[0003] Under ideal working conditions, the multi-sensor fusion algorithm can achieve accurate estimation of the drone attitude, but it also introduces problems such as system complexity and parameter optimization. At the same time, for scenarios where sensors cannot work normally, such as magnetometer interference, GPS signal suppression deception, etc., the multi-sensor fusion algorithm cannot solve the above problems, so the drone attitude measurement system will quickly fail. In view of the above sensor failure or interference scenarios, the present invention proposes a drone attitude detection system and method based on solar images to realize the detection of drone attitude.

[0004] In view of the limitations of drone attitude measurement technology, the existing solutions are mainly as follows: 1. Use high-precision inertial navigation to keep the drone’s attitude from diverging for a long time, but it still cannot completely solve the problem of drone attitude divergence.

[0005] 2. Use magnetometer to collect geomagnetic data, and match it with existing geomagnetic field data to achieve 3-axis attitude detection of drones. However, magnetometers are easily interfered by the external environment and cannot be used in complex electromagnetic environments.

[0006] 3. Use a monocular camera to detect the horizon and calculate the drone attitude information based on the ground line to solve the drone attitude problem. However, this technology is easily affected by clouds, complex terrain, light, etc.

[0007] 4. Use optical flow sensors to measure the horizontal speed of the drone to correct its attitude. However, this technology is mainly used in indoor scenes and at a flight altitude of 3 to 5 meters. It is easily affected by light outdoors and has great limitations. Summary of the invention

[0008] In view of the problems existing in the existing technology, a method, system and medium for detecting the attitude of UAV based on solar images are provided. The method innovatively proposes to use the position of the sun to solve the attitude of the UAV. Compared with the traditional solution method, it is not affected by the electromagnetic environment and can be applied in complex electromagnetic environments. At the same time, a general fisheye lens + Baade film combination is used, combined with a solar pixel extraction algorithm, which can quickly realize solar position detection with low-cost simple hardware and low computing power.

[0009] Through visual detection and recognition of the sun, the sun position vector is calculated according to the current drone position and time, and the drone attitude is solved.

[0010] The first aspect of the present invention proposes a method for detecting the attitude of a UAV based on a solar image, comprising: The solar image was obtained by taking pictures with the camera carried by the drone; Determine the pixel coordinates of the sun center point in the sun image; Calculate the actual solar altitude angle and actual solar azimuth angle in the camera coordinate system according to the pixel coordinates of the solar center point; Establish a relative position relationship model between the earth, the sun, and the drone, and calculate the theoretical solar altitude angle and theoretical solar azimuth angle based on the time and position information of the drone's solar image. The deviations between the actual solar altitude angle and the theoretical solar altitude angle, and between the actual solar azimuth angle and the theoretical solar azimuth angle are calculated to obtain the attitude of the UAV.

[0011] As a preferred solution, the camera carried by the drone is a fisheye camera, and a Bader film is attached to the lens of the fisheye camera.

[0012] As a preferred solution, the method for determining the pixel coordinates of the sun center point includes: Detect yellow-orange pixel regions in the sun image in color space; Determine the center point coordinates of the yellow-orange pixel area as the sun center point pixel coordinates.

[0013] As a preferred solution, the detecting of the yellow-orange pixel area in the sun image in the color space includes: Use RGB color information to extract yellow-orange sun pixels; Abnormal pixels are eliminated through clustering algorithm.

[0014] As a preferred solution, the actual solar altitude angle and the actual solar azimuth angle are calculated according to the pixel coordinates of the solar center point, specifically including: Convert the pixel coordinates of the sun center point from pixel coordinates to the camera coordinate system; In the camera coordinate system, calculate the actual solar altitude angle and the actual solar azimuth angle.

[0015] As a preferred solution, the method for determining the theoretical solar altitude angle and the theoretical solar azimuth angle includes: Calculate the declination angle information, noon altitude angle and sun running angle according to the time information and position information when the drone takes the solar image; Construct a spatial coordinate system to determine the solar daily trajectory; Obtain the position of the sun in the daily trajectory based on the declination angle information, noon altitude angle and solar movement angle; The theoretical solar altitude angle and theoretical solar azimuth angle are calculated based on the position of the sun in the daily trajectory.

[0016] As a preferred solution, the specific process of constructing the spatial coordinate system includes: The y-axis is established in the south direction, the x-axis is 90° clockwise, and the z-axis is established perpendicular to the xy plane.

[0017] A second aspect of the present invention proposes a system including a memory and a processor, wherein the memory stores a computer program corresponding to the method for detecting the attitude of a UAV based on solar images as described in the first aspect and which can be loaded and executed by the processor.

[0018] The third aspect of the present invention proposes a computer-readable storage medium having computer program instructions stored thereon. When the program instructions are executed by a processor, they are used to implement the process corresponding to the method for detecting the attitude of a drone based on a solar image described in the second aspect.

[0019] Compared with the prior art, the beneficial effects of adopting the above technical solution are: 1. Use solar information for attitude detection, which is not affected by complex electromagnetic environment. The present invention proposes low-cost and low-computing power solar detection. By using a general fisheye lens + Baade film combination and combining with a solar pixel extraction algorithm, it can quickly detect the solar position with low-cost simple hardware and low computing power, and then quickly determine the attitude of the drone.

[0020] 2. It can be used for initial attitude calibration of UAV, especially heading calibration. The present invention realizes attitude measurement of UAV based on sun position detection, filling the gap in attitude detection of UAV in this regard. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart of a method for detecting the attitude of a UAV based on a solar image according to an embodiment of the present application.

[0022] Figure 2 This is a schematic diagram comparing images taken with and without a Bader film in an embodiment of the present application, wherein: Figure 2 (a) is the sun image under the Baade filter scene. Figure 2(b) is the image of the sun without filtering.

[0023] Figure 3 This is a schematic diagram of obtaining the pixel coordinates of the sun center point in an embodiment of the present application, wherein: Figure 3 (a) is the dedistorted image taken by the fisheye camera. Figure 3 (b) is a schematic diagram of color space detection of yellow-orange pixels. Figure 3 (c) Schematic diagram for determining the center point coordinates.

[0024] Figure 4 This is a schematic diagram of the sun's apparent trajectory model according to an embodiment of the present application.

[0025] Figure 5 Schematic diagram of the geometric relationship between the declination angle and the midday altitude angle in an embodiment of the present application.

[0026] Figure 6 Schematic diagram of the daily trajectory of the sun's apparent motion according to an embodiment of the present application.

[0027] Figure 7 Schematic diagram of calculation of solar altitude angle and azimuth angle according to an embodiment of the present application.

[0028] Figure 8 A schematic diagram of an electronic device according to an embodiment of the present application.

[0029] Fig. 9 A schematic diagram of the structure of a computer system suitable for implementing the embodiments of the present application. DETAILED DESCRIPTION

[0030] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more comprehensive and complete and fully convey the concept of the example embodiments to those skilled in the art.

[0031] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0032] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0033] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0034] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In view of the interference of traditional UAV attitude measurement, the embodiments of the present invention propose a UAV attitude detection method based on solar images, which can detect the attitude of the UAV by taking images with a camera when the sun is visible, and is not affected by complex electromagnetic environments. Please refer to Figure 1 , the specific plan is as follows: Step 1: Use the camera on the drone to capture the sun image.

[0035] Since the drone attitude detection method proposed in this embodiment relies on the captured image of the sun, this embodiment equips the drone with a fisheye camera. The field of view of the fisheye camera lens is greater than 180°, and it can capture a complete image of the sky. In order to reflect excess sunlight and weaken the intensity of sunlight, a filter is provided on the lens of the fisheye camera. Preferably, the filter is made of a Bader film, which is tightly attached to the lens glass to ensure that the captured image of the sun can clearly observe information such as the sun's outline. Figure 2 The following is a comparison of images taken with and without a Bader film, where (a) is a sun image under a Bader film filtering scenario, and (b) is a sun image without filtering. By combining a general fisheye lens + Bader film with a sun pixel extraction algorithm, the sun position detection can be quickly achieved with low-cost, simple hardware and low computing power.

[0036] Step 2: Determine the pixel coordinates of the sun center point in the sun image.

[0037] Because the image was captured using a Bader film, the sun in the captured image is obviously orange-yellow, which is obviously different from the background color (gray-black) and noise. Therefore, in this embodiment, RGB color information is used to screen the sun pixels, thereby achieving fast and accurate detection.

[0038] For details, please refer to Figure 3 , Figure 3 (a) shows the fisheye camera dedistorted image, the color-based sun pixel fast screening algorithm detects the yellow-orange pixel area in the sun image in the color space, as shown in Figure 3 (b) As shown in the figure, the values ​​of the three colors of the sun image RGB are significantly different from those of the noise point and the background color RGC. Therefore, the RGB threshold is directly used to extract the sun pixel point, and the center point coordinates of the yellow-orange pixel area are determined as the pixel coordinates of the sun center point, as shown in Figure 3 (c) In one embodiment, abnormal pixels are eliminated by clustering algorithm.

[0039] Step 3: Calculate the actual solar altitude angle and the actual solar azimuth angle based on the pixel coordinates of the solar center point.

[0040] In this embodiment, a specific method for calculating the actual solar altitude angle and the actual solar azimuth angle is given. First, the pixel coordinates of the solar center point of the solar image are converted from the pixel coordinate system to the camera coordinate system:

[0041] In the camera coordinate system, calculate the actual sun altitude angle:

[0042] In the camera coordinate system, calculate the actual solar azimuth:

[0043] in, is the horizontal and vertical coordinates of the camera coordinate system.

[0044] Step 4: Establish a relative position relationship model among the earth, the sun, and the UAV, and determine the theoretical solar altitude angle and theoretical solar azimuth angle when the UAV takes the solar image based on the solar apparent motion model of the UAV.

[0045] After calculating the actual solar altitude angle and the actual solar azimuth angle, it is also necessary to calculate the theoretical solar altitude angle and the theoretical solar azimuth angle for comparison. In this embodiment, a relative position relationship model of the earth, the sun, and the drone is established to construct a solar apparent motion model relative to the drone, and then the sun's daily trajectory, altitude angle, azimuth angle and other information are calculated based on the current location (latitude and longitude) and the Gregorian calendar date. Please refer to Figure 4 .

[0046] The specific process is as follows: (1) Calculate the declination angle: Declination refers to the angle between the incident sun light and the Earth's equator, which affects the calculation of the sun's altitude angle. The declination angle information, noon altitude angle and sun running angle are calculated based on the time information and position information when the drone takes the solar image. Among them, the time information includes the current date, hour, minute and other information; the position information includes the longitude and latitude information.

[0047] Declination :

[0048] Among them, the sun angle (rad):

[0049] in, It is to calculate the number of days in a year, for example It corresponds to January 1st.

[0050] (2) Calculate the noon altitude angle h refer to Figure 5 , using latitude and declination , we can get the sun, ground (i.e., drone position), noon altitude angle Angle relationship:

[0051] (3) Calculate the solar orbit angle (i.e. the sun's orbit angle)

[0052] φ is the angle of the sun's arc at noon, which is used to represent the position of the sun in a rising and setting cycle. Combined with the constructed apparent motion model, the coordinate information of the sun can be obtained. From noon The duration of sunshine express.

[0053] Sunshine duration By declination With latitude angle express:

[0054] At noon Longitude Calculated:

[0055] Sun track angle for:

[0056] Among them, the value range of t is the solar sunshine time [ ]. D is the time measurement of a day. If the time is calculated in minutes, it is: 60*24=1440; seconds is 60*60*24=86400, and so on.

[0057] (4) Construct the solar apparent motion coordinate model and calculate the daily trajectory coordinate information The sun rotates at a fixed angle to the earth (apparent sphere), so a functional relationship between its daily trajectory and date can be established. Axis (the altitude of the sun at noon in the south in the northern hemisphere), clockwise for Axis, vertical Plane building Axis, construct a spatial coordinate system, such as Figure 6 As shown in the figure, the red line represents the sun's trajectory, and the center of the circle is It is easy to derive from the relationship in the figure that The coordinates are expressed as .

[0058] The angle between the sun's orbital disk and the Earth's spherical section The noon altitude angle h, latitude angle It can be expressed by the declination angle combined with the previous noon altitude angle formula:

[0059] is the radius of the sun's orbit ring, which is the radius of the earth and express:

[0060] Here, the effect of altitude is not considered and the value of R is 1.

[0061] At this point, the expression for the sun's position can be determined in the constructed spatial coordinate system:

[0062] (5) Calculation of solar altitude and azimuth like Figure 7 As shown, the theoretical solar altitude angle and the theoretical solar azimuth angle at the corresponding position can be determined based on the sun position.

[0063]

[0064]

[0065] in, is the solar altitude angle, The azimuth of the sun is defined as the angle between the sun's position clockwise and due north, plus 90°.

[0066] Step 5: Calculate the deviation between the actual solar altitude angle and the theoretical solar altitude angle, and between the actual solar azimuth angle and the theoretical solar azimuth angle to obtain the UAV attitude.

[0067] Based on the angle value of the sun pixel center in the camera coordinate system in the sun image taken by the drone and the theoretical angle value in the constructed solar apparent motion model, the drone attitude at this time is obtained by calculating the angle difference between the two, thereby realizing the correction of the drone attitude.

[0068] Please refer to Figure 8 The embodiment of the present invention also proposes a detection system 100, including a memory 101 and a processor 102, wherein the memory 101 stores a computer program corresponding to the aforementioned method for detecting the attitude of a UAV based on solar images, which can be loaded and executed by the processor 102. The system can use solar information for attitude detection and is not affected by complex electromagnetic environments; the system can be used for initial attitude calibration of UAVs, especially calibration of heading; Fig. 9 A schematic diagram of the structure of a computer system suitable for implementing an electronic device of an embodiment of the present application is shown.

[0069] It should be noted that Fig. 9 The computer system 200 of the electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0070] like Fig. 9 As shown, the computer system 200 includes a central processing unit (CPU) 201, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 202 or the program loaded from the storage part 208 to the random access memory (RAM) 203, such as executing the method described in the above embodiment. In the RAM 203, various programs and data required for system operation are also stored. The CPU 201, the ROM 202 and the RAM 203 are connected to each other through the bus 204. The input / output (I / O) interface 205 is also connected to the bus 204.

[0071] The following components are connected to the I / O interface 205: an input section 206 including a keyboard, a mouse, etc.; an output section 207 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 208 including a hard disk, etc.; and a communication section 209 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 209 performs communication processing via a network such as the Internet. A drive 210 is also connected to the I / O interface 205 as needed. A removable medium 211, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 210 as needed so that a computer program read therefrom is installed into the storage section 208 as needed.

[0072] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through the communication part 209, and / or installed from a removable medium 211. When the computer program is executed by the central processing unit (CPU) 201, various functions defined in the system of the present application are executed.

[0073] It should be noted that the computer-readable medium shown in the embodiment of the present application may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, device or device. In the present application, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, which may send, propagate, or transmit programs for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0074] The flowchart and block diagram in the accompanying drawings illustrate the possible architecture, functions and operations of the system, method and computer program product according to various embodiments of the present application. Wherein, each box in the flowchart or block diagram can represent a module, a program segment, or a part of the code, and the above-mentioned module, program segment, or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0075] The units involved in the embodiments described in this application may be implemented by software or hardware, and the units described may also be set in a processor. The names of these units do not, in some cases, constitute limitations on the units themselves.

[0076] As another aspect, the present application further provides a computer program product or a computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the method for detecting the attitude of a drone based on a solar image described in the above embodiment.

[0077] As another aspect, the present application also provides a computer-readable medium, which may be included in the electronic device described in the above embodiment; or may exist independently without being assembled into the electronic device. The above computer-readable medium carries one or more programs, and when the above one or more programs are executed by an electronic device, the electronic device implements the drone attitude detection method based on solar images described in the above embodiment.

[0078] It should be noted that, although several modules or units of the equipment for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiments of the present application, the features and functions of two or more modules or units described above can be embodied in one module or unit. On the contrary, the features and functions of one module or unit described above can be further divided into being embodied by multiple modules or units.

[0079] Through the description of the above implementation methods, it is easy for those skilled in the art to understand that the example implementation methods described here can be implemented by software, or by combining software with necessary hardware. Therefore, the technical solution according to the implementation method of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, including several instructions to enable a computing device (which can be a personal computer, a server, a touch terminal, or a network device, etc.) to execute the method according to the implementation method of the present application.

[0080] For those skilled in the art, the specific meanings of the above terms in the present invention can be understood in specific situations; the drawings in the embodiments are used to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0081] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for detecting the attitude of a UAV based on a solar image, characterized in that: include: The solar image was obtained by taking pictures with the camera carried by the drone; Determine the pixel coordinates of the sun center point in the sun image; Calculate the actual solar altitude angle and the actual solar azimuth angle according to the pixel coordinates of the solar center point; Establish a relative position relationship model between the earth, the sun, and the drone, and calculate the theoretical solar altitude angle and theoretical solar azimuth angle based on the time and position information of the drone's solar image. The deviations between the actual solar altitude angle and the theoretical solar altitude angle, and between the actual solar azimuth angle and the theoretical solar azimuth angle are calculated to obtain the attitude of the UAV.

2. The method for detecting the attitude of a UAV based on a solar image according to claim 1, characterized in that: The camera carried by the drone is a fisheye camera, and a Bader film is attached to the lens of the fisheye camera.

3. The method for detecting the attitude of a UAV based on a solar image according to claim 2, characterized in that: The method for determining the pixel coordinates of the sun center point comprises: Detect yellow-orange pixel regions in the sun image in color space; Determine the center point coordinates of the yellow-orange pixel area as the sun center point pixel coordinates.

4. The method for detecting the attitude of a UAV based on a solar image according to claim 3, characterized in that: Detecting the yellow-orange pixel area in the sun image in the color space includes: Use RGB color information to extract yellow-orange sun pixels; Abnormal pixels are eliminated through clustering algorithm.

5. The method for detecting the attitude of a UAV based on a solar image according to claim 1, characterized in that: The method of calculating the actual solar altitude angle and the actual solar azimuth angle according to the pixel coordinates of the solar center point specifically includes: Convert the pixel coordinates of the sun center point from pixel coordinates to the camera coordinate system; In the camera coordinate system, calculate the actual solar altitude angle and the actual solar azimuth angle.

6. The method for detecting the attitude of a UAV based on a solar image according to claim 1, characterized in that: The method for determining the theoretical solar altitude angle and the theoretical solar azimuth angle comprises: Calculate the declination angle information, noon altitude angle and sun running angle according to the time information and position information when the drone takes the solar image; Construct a spatial coordinate system to determine the solar daily trajectory; Obtain the position of the sun in the daily trajectory based on the declination angle information, noon altitude angle and solar movement angle; The theoretical solar altitude angle and theoretical solar azimuth angle are calculated based on the position of the sun in the daily trajectory.

7. The method for detecting the attitude of a UAV based on a solar image according to claim 6, characterized in that: The specific process of constructing the spatial coordinate system includes: The y-axis is established in the south direction, the x-axis is 90° clockwise, and the z-axis is established perpendicular to the xy plane.

8. A system, characterized in that: It includes a memory and a processor, wherein the memory stores a computer program corresponding to the method for detecting the attitude of a UAV based on a solar image according to any one of claims 1 to 7, which can be loaded and executed by the processor.

9. A computer-readable storage medium having computer program instructions stored thereon, characterized in that: When the program instructions are executed by the processor, they are used to implement the process corresponding to the method for detecting the attitude of a drone based on a solar image as described in any one of claims 1 to 7.

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