A method and system for precise landing of unmanned aerial vehicles in complex environments

Abstract

The present invention discloses a method and system for precise landing of an unmanned aerial vehicle (UAV) in a complex environment, wherein the system comprises: a first ground beacon, a second ground beacon, an inertial navigation module, a satellite positioning module, a radio guidance module, a visual guidance module, and an onboard computer. The onboard computer is used to obtain current flight data of the UAV, receive and process data from each positioning module, and judge the three altitude stages in which the UAV is guided to land. If the UAV is in the high-altitude stage, the satellite positioning module is used to perform real-time correction; if the UAV is in the medium-altitude stage, the radio guidance module is used to periodically correct the landing route; if the UAV is in the low-altitude stage, the radio guidance module is controlled to be turned off, and the visual navigation module is used to correct the landing route of the UAV.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicle (UAV) navigation technology, and in particular to a method for accurately landing an UAV in a complex environment and a UAV guided landing system in a complex environment. Background Art

[0002] Unmanned aerial vehicles (UAVs) boast advantages such as light weight, low risk of casualties, excellent maneuverability, and a simple cabin design. Beyond their promising military applications, they are also gradually emerging in the civilian sector. With the recent development of UAVs, especially their rapid application in various fields, UAV technology has advanced rapidly in various countries. For example, with the revolutionary technological innovations in various fields brought about by artificial intelligence (AI), the powerful combination of UAVs and AI has further advanced the intelligent development of UAVs, enabling them to more conveniently acquire important information on the ground or at low altitudes, such as images, terrain, and moving objects, thus facilitating their application in a variety of scenarios. For example, in earthquake relief and disaster relief, UAVs can be used to deliver important supplies or rescue tools, search for the injured, or provide valuable reference information for the preparation of appropriate rescue measures.

[0003] Drones must land at their designated destinations after completing or executing missions, making landing navigation crucial. However, traditional drone landing relies on inertial navigation systems, satellite positioning systems, or a single technology for positioning and landing, or direct manual remote control. However, due to errors in inertial navigation and the potential for interference with satellite positioning systems, as demands for drone landing accuracy and reliability increase, a single navigation system is no longer sufficient.

[0004] Based on this, some have proposed the concept of multi-mode navigation to achieve autonomous and precise drone landing. For example, Chinese patent application CN201710809914.6 proposes a multi-mode navigation drone landing guidance system and method. This system uses a designated parking space, with the aircraft serving as a reference point, and a cooperative light array positioned near the parking space. Combining radio direction finding, visual guidance, satellite positioning, and data fusion, the system guides the drone to automatically land at the designated parking space, thereby improving the accuracy and reliability of autonomous drone landing. This method targets highly suitable geographical environments where a well-defined parking space or platform can be established. This allows for a parking space reference point to be set within the space, and a cooperative light array to be positioned nearby to guide the drone to landing, such as a very flat lawn or plain. Furthermore, the parking space and parking space reference line are pre-defined. Therefore, this method requires very high landing accuracy; for example, the drone must land near or within the parking space reference point.

[0005] However, in some complex geographical environments, for example, the terrain is a high mountain canyon, or a post-disaster site in a mountainous area, it is very difficult to set up such a parking space in advance, not to mention preparing the parking space baseline in advance and setting up a cooperative light array near the parking space. In such an environment, such a setting is not very realistic. Even if it is to be built immediately, it is very time-consuming and labor-intensive. For post-disaster rescue scenarios with complex geographical environments such as mountainous areas, resources and time are very precious, and even every second counts.

[0006] It can be seen from this that in view of the complex environment surrounding the landing point, it is impossible to set up some clear guidance at the landing point in advance, such as a clear parking space, cooperative light array, etc., and usually in such an environment, the closer to the landing point, the less signal there is (for example, no satellite signal, and the wireless signal is also very poor), or there are other interference signals that may lure the drone to other places. Therefore, how to guide the drone to land in such a complex environment is an urgent problem that needs to be solved. Summary of the Invention

[0007] The purpose of the present invention is to provide a method and system for accurately landing drones in complex environments, which can partially solve or alleviate the above-mentioned deficiencies in the prior art and can guide drones to land in complex environments.

[0008] In order to solve the above-mentioned technical problems, the present invention specifically adopts the following technical solutions:

[0009] The first aspect of the present invention is to provide a UAV guided landing system in a complex environment, which includes: a first ground beacon for transmitting a radio beacon signal; a second ground beacon for transmitting an optical beacon signal; an inertial navigation module for guiding the UAV to land at a destination throughout the entire process; a satellite positioning module for real-time positioning of the UAV; a radio guidance module for receiving the radio beacon signal transmitted by the first ground beacon; a visual guidance module for receiving the optical beacon signal transmitted by the second ground beacon or performing image matching based on a pre-stored destination image to guide the landing; an onboard computer for obtaining the current flight data of the UAV and judging the three altitude stages in which the UAV is guided to land. If the current flight altitude is greater than a first preset altitude threshold, it is judged to be a high-altitude stage; if the current flight altitude is less than or equal to the first preset altitude threshold and greater than the second preset altitude threshold, it is judged to be a low-altitude stage. It is determined to be the mid-altitude stage; if the current flight altitude is less than or equal to the second preset altitude threshold, it is determined to be the third low-altitude stage; and when it is determined that the UAV is guided to land in the high-altitude stage, the navigation data of the inertial navigation module is mainly used, and the landing route guided by the inertial navigation module is corrected in real time according to the real-time positioning data of the satellite positioning module; when it is determined that the UAV is in the mid-altitude stage, the radio guidance module is started, and the radio beacon signal received by the radio guidance module is periodically obtained, so as to periodically correct the landing route of the UAV according to the radio beacon signal; if it is determined that the UAV is in the low-altitude stage, the radio guidance module is controlled to be turned off, and the visual navigation module is started to receive the optical beacon signal, so as to correct the landing route of the UAV according to the optical beacon signal or the pre-stored destination image matching.

[0010] The guided landing system of the present invention uses an onboard computer to acquire the drone's current flight data and receives feedback from each positioning module for data processing. This system then determines whether the real-time positioning data from each module is correct and issues corresponding drone control commands to the flight controller. Specifically, the system determines the three altitude stages in which the drone is guided to land. For example, when the drone is guided to land at high altitude, the drone's landing guidance data is primarily based on data from the inertial navigation module. The inertial navigation module's real-time positioning data is used to make real-time corrections to the landing path guided by the inertial navigation module. Because the drone is landing at high altitude, positioning accuracy errors do not affect the drone's landing, and loss of satellite positioning data does not affect the drone's landing. When the drone is in mid-altitude, satellite positioning data may be lost due to interference and other factors. Therefore, during this mid-altitude phase, the radio guidance module is simultaneously activated, without disabling the satellite positioning module, and periodically acquires the radio beacon signals received by the radio guidance module to periodically correct the drone's landing path based on these radio beacon signals. When the UAV is in the low-altitude stage, the radio guidance module is controlled to be turned off, and the visual navigation module is started to receive the optical beacon signal, so as to correct the landing route of the UAV according to the optical beacon signal, or to perform image matching between the pre-stored image of the destination / landing point and the image currently collected by the current visual navigation module, so as to correct the landing route of the UAV.

[0011] In some embodiments of the present invention, the onboard computer is specifically used to process data of the optical beacon signal, generate a fifth control instruction, and send it to the flight controller of the UAV to control the UAV to land under the auxiliary guidance of the visual guidance module, wherein the fifth control instruction includes the relative position between the second ground beacon and the UAV.

[0012] In some embodiments of the present invention, the onboard computer is specifically used to determine whether the UAV deviates from the preset landing course based on the strength of the radio beacon signal. If so, a third control instruction is generated and sent to the flight controller of the UAV to control the UAV to stop landing and correct the landing course, wherein the third control instruction includes the relative position between the first ground beacon and the UAV.

[0013] In some embodiments of the present invention, the onboard computer is a lightweight onboard computer.

[0014] In some embodiments of the present invention, when the onboard computer determines that the current flight altitude is less than or equal to the first preset altitude threshold and greater than the second preset altitude threshold, the onboard computer is also used to control the activation of the radio guidance module while controlling the activation of the visual navigation module to receive the optical beacon signal, so as to correct the landing route of the UAV according to the optical beacon signal, or to correct the landing route of the UAV according to image matching of the currently collected terrain image and the pre-stored destination image.

[0015] A second aspect of the present invention is to provide a method for accurately landing a drone in a complex environment based on the above-mentioned guided landing system, comprising the following steps:

[0016] Acquire the current flight data (including the current flight altitude) of the UAV in real time through the onboard computer, and determine whether the current flight altitude is less than or equal to a first preset altitude threshold and greater than a second preset altitude threshold;

[0017] If the current flight altitude is greater than the first preset altitude threshold, the onboard computer determines that the UAV is currently in a high-altitude phase, and acquires real-time positioning data from the satellite positioning module in real time, so as to make real-time corrections to the landing route guided by the inertial navigation module based on the real-time positioning data;

[0018] If the current flight altitude is less than or equal to the first preset altitude threshold and greater than the second preset threshold, the onboard computer determines that the UAV is currently in the mid-air phase, activates the radio guidance module to receive a radio beacon signal transmitted by a first ground beacon, and periodically corrects the landing route according to the radio beacon signal;

[0019] If the current flight altitude is less than or equal to the second preset altitude threshold, the onboard computer determines that the UAV is currently in a low-altitude phase, controls the satellite positioning module and the radio guidance module to be turned off, and activates the visual guidance module to receive the optical beacon signal emitted by the second ground beacon, and corrects the landing route of the UAV under the guidance of the inertial navigation module according to the optical beacon signal; or, performs image matching based on the currently collected terrain image and the pre-stored destination image to correct the landing route of the UAV.

[0020] In some embodiments of the present invention, the step of correcting the landing route according to the optical beacon signal specifically includes the steps of: the onboard computer processes the optical beacon signal, generates a fifth control instruction, and sends it to the flight controller of the UAV to control the UAV to land under the auxiliary guidance of the visual guidance module, wherein the fifth control instruction includes the relative position between the second ground beacon and the UAV.

[0021] In some embodiments of the present invention, the step of correcting the landing route of the UAV according to the radio beacon signal specifically includes the following steps: the onboard computer determines whether the UAV currently deviates from the landing course based on the strength of the radio beacon signal; if deviated, the onboard computer generates and sends a third control instruction to the UAV to control the UAV to stop landing and correct the course; wherein the third control instruction includes the relative position between the first ground beacon and the UAV; if not deviated, the onboard computer controls the UAV to continue landing under the guidance of the inertial navigation module, and when the UAV lands to the second preset height threshold, starts the visual guidance module to assist in guiding the UAV to land to the destination.

[0022] In some embodiments of the present invention, when the onboard computer determines that the current flight altitude is less than or equal to the first preset altitude threshold and greater than the second preset threshold, and starts the radio guidance module, the visual guidance module is started to assist in guiding the drone to land at the destination.

[0023] The third aspect of the present invention is to provide an electronic device for guiding the landing of a drone in a complex environment, which includes a memory, a processor, and a computer program stored in the memory and runnable on the processor, and is characterized in that the steps of the above method are implemented when the processor executes the program.

[0024] Beneficial effects: 1) The present application adopts a phased approach of using different modules for guidance or auxiliary guidance. For example, when the UAV is in the high-altitude landing stage, since the satellite signal will not be interfered with, the UAV's flight route is corrected in real time by the positioning data of the satellite positioning module. When the UAV is in the mid-altitude landing stage, since it can receive radio signals, the UAV's landing course is periodically corrected by the radio signals received by the radio guidance module while the satellite positioning module corrects the course in real time. This not only avoids the errors caused by using only the inertial navigation module to a certain extent, but also ensures that the UAV does not deviate from the established landing route by correcting the course in real time and correcting the course periodically. When the UAV is in the low-altitude stage during the landing process, that is, when its flight altitude drops to the second preset height threshold, the satellite positioning module is affected by the geographical environment and is very weak or even has no signal, and the radio guidance module is also easily interfered with or misled. Therefore, in order to avoid interference or misleading that may cause the UAV to deviate, the satellite positioning module and the radio guidance module are turned off, and the most intuitive visual guidance module is directly used to assist the inertial navigation model for guidance, thereby improving the accuracy and reliability of landing in complex environments. And because the visual guidance module is used for auxiliary guidance when entering the low-altitude stage, and the low-altitude stage is usually only a few hundred meters high, even if there is sudden fog or heavy rain that interferes with the line of sight after entering the low-altitude stage, it is still possible to land under the guidance of the inertial navigation module.

[0025] 2) In the existing technology, a camera is added to the drone to collect images, and then the drone is guided according to the image data, or other data is combined with the image data to guide the drone to fly or land. However, in some special application scenarios, such as disaster relief areas with harsh environments, the drone itself needs to carry supplies, etc., so the drone's own weight is required not to be too heavy. However, since image data processing is required, and even the image data is combined with other data for processing, this will inevitably require the drone to be equipped with a high-performance onboard computer. A high-performance onboard computer will inevitably have more computing units than a general onboard computer, that is, its own weight is heavier than that of a general onboard computer, thereby limiting the weight of supplies that the drone can carry.

[0026] 3) Compared with the method of setting up parking spaces and cooperative light arrays at the landing point in advance in the prior art, the present application does not need to set up guidance facilities such as parking spaces and cooperative light arrays precisely at the landing point in advance, thereby avoiding the waste of manpower and financial resources to build guidance devices such as parking spaces in the post-disaster rescue stage, and also avoiding safety accidents caused by sudden aftershocks or landslides during the construction process; and in different stages of landing, different guidance modules are used to assist the inertial navigation module in guidance, avoiding the situation in the prior art where multi-mode data fusion calculation is used throughout the process, and the multi-mode data fusion calculation cannot be performed due to interference or signal loss in the low-altitude stage or near the landing point, and thus the inability to continue guidance, thereby ensuring the stability of guided landing in complex environments.

[0027] 4) If a large amount of image data is used to assist in guiding the landing, or the image data is fused with other data, it will inevitably consume a lot of energy, thereby reducing the cruising time of the drone. In this application, by reasonably allocating various modules at various stages of the drone landing (for example, when the flight altitude is greater than the first preset altitude threshold, the satellite positioning module and the inertial navigation module are used for guidance; when it is less than the first preset altitude threshold but greater than the second preset altitude threshold, the satellite positioning module and the radio module are used to perform real-time correction and periodic correction on the landing route guided by the inertial navigation module, respectively; and when the flight altitude is less than or equal to the second preset altitude threshold, the visual guidance module is directly used to assist the inertial navigation module for guidance), the overall energy consumption of the drone is reduced, so that the drone has a longer cruising time, and can perform more tasks or different types of tasks at one time, thereby improving work efficiency. For example, after the materials are delivered, a search and rescue mission is carried out, thereby improving rescue efficiency.

[0028] 5) Compared with the method of using a satellite positioning module or a radio module throughout the entire process of drone landing, however, in some complex environments, the closer the drone is to the destination, the more likely it is that radio interference will occur, thereby misleading the drone; in this application, when the drone is close to the destination, that is, the flight altitude is less than or equal to the second preset altitude threshold, the visual guidance module is used to assist the inertial navigation module in guiding the drone, thereby avoiding the situation where the drone lands erroneously due to radio interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a functional module diagram of a UAV guided landing system in a complex environment according to an exemplary embodiment of the present invention;

[0030] Figure 2 The figure is a flow chart of a method for precise landing of a UAV in a complex environment according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying 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 of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] Herein, suffixes such as "module," "component," or "unit" used to represent elements are only used to facilitate description of the present invention and have no specific meaning. Therefore, "module," "component," or "unit" may be used interchangeably.

[0033] As used herein, terms such as "upper," "lower," "inner," "outer," "front," "back," "one end," and "the other end" indicate positions or locations based on those shown in the accompanying drawings. These terms are intended solely to facilitate and simplify the description of the present invention and are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] As used herein, unless otherwise expressly specified or limited, the terms "installed," "provided with," and "connected" should be understood broadly. For example, "connected" may refer to a fixed connection, a detachable connection, or an integral connection; it may refer to a mechanical connection, a direct connection, an indirect connection via an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention on a case-by-case basis.

[0035] As used herein, "and / or" includes any and all combinations of one or more of the associated listed items.

[0036] Herein, "plurality" means two or more than two, ie, it includes two, three, four, five, etc.

[0037] Example 1 See Figure 1, is a functional module diagram of a guided landing system according to an exemplary embodiment of the present invention. Specifically, the guided landing system includes: an onboard computer 11, an inertial navigation module 12, a satellite positioning module 13, a radio guidance module 14, a visual guidance module 15, a first ground beacon 16 for transmitting radio signals, and a second ground beacon 17 for transmitting optical signals. The onboard computer 11 is electrically connected to the flight controller of the UAV and is configured to send corresponding control instructions to the flight controller and receive flight data fed back by the flight controller, such as flight altitude. The inertial navigation module 12 is electrically connected to the onboard computer 11 and the flight controller, respectively, and is configured to guide the UAV to land toward its destination through the flight controller. The satellite positioning module 13 is electrically connected to the onboard computer 11 and the flight controller for real-time positioning of the UAV. The radio guidance module 14 is electrically connected to the onboard computer 11 and the flight controller, and is configured to receive radio signals transmitted by the first ground beacon 16. The visual guidance module 15 is electrically connected to the onboard computer 11 and is configured to receive optical signals transmitted by the second ground beacon 17.

[0038] In some embodiments, the onboard computer 11 is used to obtain flight data such as the current flight altitude of the UAV from the flight controller or the satellite positioning module, and determine whether the current flight altitude is less than or equal to a first preset altitude threshold and greater than a second preset altitude threshold. If it is greater than the first preset altitude threshold, a first control instruction is sent to the satellite positioning module 13 to control the satellite positioning module 13 to feedback real-time positioning data (for example, the real-time coordinates of the UAV), and to perform real-time corrections to the landing route guided by the inertial navigation module 12 based on the real-time positioning data, that is, the satellite positioning module assists the inertial navigation module in guiding the UAV to land at the destination.

[0039] Specifically, the onboard computer 11 generates a second control instruction indicating a real-time correction of the landing route based on the real-time positioning data, and sends it to the flight controller, which then corrects the flight route / flight trajectory of the UAV in real time based on the second control instruction.

[0040] In some embodiments, when it is determined that the current flight altitude is less than or equal to a first preset altitude threshold and greater than a second preset altitude threshold, the onboard computer 11 is also used to start the radio guidance module 14, and periodically obtain the radio beacon signal received by the radio guidance module 14 and transmitted by the first ground beacon 16, and periodically correct the heading of the UAV according to the radio beacon signal; specifically, the onboard computer 11 determines whether the UAV deviates from the landing heading based on the radio signal. If so, it generates and sends a third control instruction to the flight controller to control the UAV to stop landing, and correct the heading of the UAV before landing.

[0041] Specifically, the relative position of the radio beacon (ie, the first ground beacon) and the UAV can be calculated based on the radio beacon signal strength received by the radio guidance module.

[0042] A three-dimensional coordinate system is constructed with the drone as the coordinate origin. Through radio guidance, the radio beacon, that is, the azimuth of the first ground beacon relative to the origin (that is, the drone), can be obtained. Mobile flight is performed according to this azimuth. If one second is a control cycle, the drone compares the azimuths measured before and after every second of flight to see if they are consistent. If there is an angle error, the flight route is corrected.

[0043] In some embodiments, when it is determined that the current flight altitude is less than or equal to the second preset altitude threshold, the onboard computer 11 sends a fourth control instruction to the visual guidance module 15 to start the visual navigation module 15 to assist the inertial navigation module in guiding the UAV to land to the destination; specifically, the onboard computer 11 obtains the optical signal emitted by the second ground beacon received by the visual navigation module 15, and performs data processing based on the optical information to obtain the fifth control instruction, and sends it to the flight controller to control the UAV to land to the destination.

[0044] In some embodiments, the beacon location only needs to know the distance and azimuth from the landing point, as well as the relative position, and does not need to be set near the landing point.

[0045] In other embodiments, the onboard computer may also perform terrain matching (for example, comparing the current terrain image within the range of the shooting device captured by the visual navigation module with the destination image pre-stored in the onboard computer; the specific comparison method may adopt existing image matching methods, such as image similarity algorithms), and control the flight controller to guide the UAV flight based on the matching results, and integrate the satellite positioning module or the inertial navigation module for navigation to improve the accuracy of guided landing.

[0046] In some embodiments, the onboard computer is a lightweight onboard computer with low performance.

[0047] Example 2 Based on the above-mentioned guided landing system, the present invention also provides a method for precise landing of a UAV in a complex environment, which is described in detail below with reference to specific embodiments and drawings.

[0048] See also Figure 2 , is a flow chart of a method for precise landing of a UAV in a complex environment according to an exemplary embodiment of the present invention. Specifically, the method includes the steps of:

[0049] S201, obtain the current flight altitude of the UAV in real time, and determine whether the current flight altitude is less than or equal to the first preset altitude threshold and greater than the second preset altitude threshold. If it is greater than the first preset altitude threshold, execute step S202; if it is less than or equal to the first preset altitude threshold and greater than the second preset altitude threshold, execute step S203; if it is less than or equal to the second preset altitude threshold, execute step S204.

[0050] In some embodiments, the onboard computer obtains the current flight altitude of the drone from the drone's flight controller or satellite positioning module.

[0051] In some embodiments, the first preset altitude threshold and the second preset altitude threshold are pre-set according to the current geographical environment of the landing point.

[0052] Of course, in other embodiments, the propagation limit distance of the radio signal emitted by the first ground beacon is used as the first preset height threshold, and the propagation limit distance of the optical beacon signal emitted by the second ground beacon is used as the second preset height threshold.

[0053] For example, when the flight altitude exceeds the first preset altitude threshold, the radio guidance module on the drone will not receive the radio beacon signal transmitted by the first ground beacon, or the radio beacon signal will be extremely weak. If the flight altitude is less than or equal to the first preset altitude threshold, the radio guidance module on the drone will receive the radio beacon signal transmitted by the first ground beacon. Of course, during the descent of the drone, the first reception of the radio beacon signal transmitted by the first ground beacon may be directly used as the basis, that is, if the first reception of the radio beacon signal transmitted by the first ground beacon (greater than or equal to the preset signal strength) is the radio beacon signal transmitted by the first ground beacon, step S203 is executed.

[0054] For another example, when the flight altitude exceeds the second preset altitude threshold, the visual guidance module on the drone will not receive the optical beacon signal emitted by the second ground beacon (or the signal is very weak). If the flight altitude is less than or equal to the second preset altitude threshold, the visual guidance module on the drone will receive the optical beacon signal emitted by the second ground beacon. Of course, during the descent of the drone, the first receipt of the optical beacon signal emitted by the second ground beacon may be directly used as the criterion. That is, if the first receipt of the radio beacon signal (greater than or equal to the preset strength) emitted by the second ground beacon is a signal, step S204 is executed.

[0055] Once the drone enters the landing phase, the onboard computer begins to obtain the drone's flight altitude in real time and compares the current flight altitude with two preset altitude thresholds. Only when the flight altitude is greater than the preset altitude thresholds will the inertial navigation module be activated to guide the drone to land. Before the drone enters the landing phase, the drone can fly under any guidance method in the existing technology.

[0056] S202: The onboard computer obtains real-time positioning data from the satellite positioning module, and corrects the landing route of the UAV in real time according to the positioning data, and executes step S201.

[0057] In some embodiments, if the current flight altitude of the drone is greater than a first preset altitude threshold, it indicates that the drone is currently still in a high-altitude stage. At this stage, the satellite positioning signal is very strong because it is not affected by the geographical environment of the landing point. Therefore, based on the real-time positioning data of the satellite positioning module, for example, the real-time coordinates of the drone, the flight route / landing route of the drone under the guidance of the inertial navigation module is corrected in real time.

[0058] In some embodiments, the onboard computer obtains real-time positioning data, such as the coordinates of the drone, and generates corresponding navigation commands based on the real-time positioning data and sends them to the flight controller of the drone. The flight controller executes the navigation commands and corrects the landing route in real time.

[0059] S203, the onboard computer periodically obtains the radio beacon signal transmitted by the first ground beacon received by the radio guidance module, and corrects the landing heading of the UAV according to the radio beacon signal, executing step S201.

[0060] In some embodiments, if the drone's current flight altitude is less than or equal to a first preset altitude threshold but greater than a second preset altitude threshold, the drone is currently in mid-air. During this phase, the drone enters the communication range of a first ground beacon, meaning the radio guidance module can receive a radio beacon signal transmitted by the first ground beacon. Therefore, the onboard computer activates the radio guidance module and periodically acquires the radio signal received by the radio guidance module. Based on the radio beacon signal, the onboard computer determines whether the drone has deviated from its course. If so, a fifth control instruction is generated and sent to the flight controller to stop the drone from landing and correct its course. If not, no action is taken, allowing the drone to continue landing under the guidance of the inertial navigation module. When the onboard computer determines that the drone has landed at the second preset altitude threshold, a corresponding control instruction is generated to activate the visual guidance module to assist the inertial navigation module in guiding the drone to land. In other words, while the satellite positioning module performs real-time corrections, the radio guidance module periodically performs corrections, thereby further improving the accuracy and reliability of guidance.

[0061] In this embodiment, radio direction finding technology is used to determine whether the drone has deviated from its course. Specifically, the relative position of the radio beacon, that is, the second ground beacon and the drone can be determined based on the strength of the received radio signal, so that whether the drone has deviated from its course can be determined based on the relative position.

[0062] S204: The onboard computer activates the visual guidance module to receive the optical beacon signal emitted by the second ground beacon, and guides the UAV to land at the destination according to the optical beacon signal.

[0063] In some embodiments, if the drone's flight altitude is less than a second preset altitude, indicating that the drone is currently in a low-altitude phase, during which, due to the influence of the geographical environment, both satellite and radio signals may be subject to ground interference and lose data, or experience anomalies, thereby rendering the satellite positioning module and the radio guidance module inoperable. Therefore, the onboard computer sends a control instruction indicating the activation of the visual guidance module, thereby activating the visual guidance module to receive the optical beacon signal from the second ground beacon (of course, the satellite positioning module and the radio guidance module are correspondingly disabled), and obtains the optical beacon signal from the visual guidance module. The optical beacon signal is then processed to obtain a third control instruction, which is then sent to the drone's flight controller to control the drone's landing. That is, when the drone descends to a certain altitude, the visual guidance module assists the inertial navigation module in guiding the drone to land.

[0064] The guided landing method of this embodiment does not require pre-setting of parking spaces and cooperative light arrays, etc., and different modules are used to assist the inertial navigation module at different stages of landing. For example, in the low-altitude stage, only the visual guidance module is used to assist the inertial navigation model for guidance (to avoid the influence of interference signals or no signals); in the medium-altitude stage, the satellite positioning module and the radio guidance module are used to perform real-time correction and periodic correction on the inertial navigation, respectively; in the high-altitude stage, the satellite positioning module is used to perform real-time correction on the inertial navigation module.

[0065] Of course, in other embodiments, if images of the landing point / destination are pre-stored, such as satellite images or images taken from high altitude, when the visual guidance module is started, the images taken by the visual guidance module can be compared with the pre-stored satellite images or images taken from high altitude, and the inertial navigation module can be corrected according to the comparison results.

[0066] Example 3 Based on the above-mentioned guided landing system, the present invention also provides another guided landing method for a UAV in a complex environment, which includes the various steps in the above-mentioned Example 2, except that, when it is determined in step S201 that the current flight altitude is less than or equal to the first preset altitude threshold and greater than the second preset altitude threshold (of course, at this time the second preset altitude threshold is not the communication distance limit of the second ground beacon, but is set according to the physical environment of the current landing point, and when it is higher than the second preset altitude threshold, the visual guidance module can also receive the optical beacon signal), while starting the radio guidance module, the visual navigation module is also started to receive the optical beacon signal, so as to correct the landing route of the UAV under the guidance of the inertial navigation module according to the optical beacon signal.

[0067] Accordingly, when the UAV descends to the second preset altitude threshold, the onboard computer directly controls to shut down the radio guidance module and the satellite positioning module, and only retains the visual guidance module to assist the inertial navigation module.

[0068] Example 4 Based on the above-mentioned guided landing system, the present invention also provides another guided landing method for a drone in a complex environment, which includes the various steps in the above-mentioned Example 2 or 3. The difference is that after the drone lands, the location of the current landing point (for example, coordinates) is compared with the destinations corresponding to each task in the pre-stored task list, and the destination closest to the current landing point is set as the next landing point, that is, the task corresponding to the destination is set as the new task to be executed.

[0069] Of course, further, the current remaining energy consumption (such as the remaining power) can be detected in advance, and the flight distance can be estimated based on the current remaining energy consumption. Then, the tasks in the above task list can be preliminarily screened based on the estimated flight distance, that is, the tasks corresponding to the destinations whose distance from the corresponding destination to the current landing point is less than the estimated flight distance are selected as candidate tasks, and then the destination closest to the current landing point is selected from the candidate tasks as the next landing point.

[0070] In a third aspect of the present invention, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described above when executing the program. For ease of explanation, only the parts related to the embodiments of this specification are shown. For specific technical details not disclosed, please refer to the method section of the embodiments of this specification. The electronic device may be any electronic device including various electronic devices, PCs, network cloud servers, or even mobile phones, tablet computers, PDAs (Personal Digital Assistants), POS (Point of Sales), vehicle-mounted computers, desktop computers, and the like.

[0071] Specifically, the bus may include any number of interconnected buses and bridges that link together various circuits including one or more processors represented by processors and memories represented by memories. The bus may also link together various other circuits such as peripherals, voltage regulators, and power management circuits, which are all well known in the art and, therefore, will not be described further herein. The communication interface provides an interface between the bus and a receiver and / or transmitter, which may be separate independent receivers or transmitters or the same component such as a transceiver, providing a unit for communicating with various other devices over a transmission medium. The processor is responsible for managing the bus and general processing, while the memory may be used to store data used by the processor when performing operations.

[0072] Through the description of the above embodiments, it is easy for those skilled in the art to understand that the example embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solution according to the embodiments of the present disclosure can be embodied in the form of a software product, which can be stored in a computer-readable storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes several instructions to enable a computing device (which can be a personal computer, a server, or a network device, etc.) to execute the above-mentioned method according to the embodiments of the present disclosure.

[0073] The computer-readable storage medium may include a data signal propagated in baseband or as part of a carrier wave, wherein the readable program code is carried. The data signal propagated may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The readable storage medium may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or component. The program code contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination thereof.

[0074] The program code for performing the operations of the present disclosure may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, and the like, as well as conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a stand-alone software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving a remote computing device, the remote computing device may be connected to the user computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0075] The computer-readable medium carries one or more programs. When the one or more programs are executed by a device, the computer-readable medium implements the following functions: obtaining the current flight altitude of the UAV in real time, and determining whether the current flight altitude is less than or equal to a first preset altitude threshold and greater than a second preset altitude threshold; if the current flight altitude is greater than the first preset altitude threshold, the onboard computer obtains real-time positioning data from the satellite positioning module in real time, and corrects the landing route under the guidance of the inertial navigation module in real time based on the real-time positioning data; if the current flight altitude is less than or equal to the first preset altitude threshold and greater than the second preset threshold, the onboard computer activates the radio guidance module to receive a radio beacon signal transmitted by a first ground beacon, and periodically corrects the landing route based on the radio beacon signal; if the current flight altitude is less than or equal to the second preset altitude threshold, the onboard computer controls the shutdown of the satellite positioning module and the radio guidance module, and activates the visual guidance module to receive an optical beacon signal transmitted by a second ground beacon, and corrects the landing route of the UAV under the guidance of the inertial navigation module based on the optical beacon signal.

[0076] Those skilled in the art will appreciate that the modules described above can be distributed in the device according to the description of the embodiment, or can be modified accordingly to be used in one or more devices that are different from the embodiment. The modules of the above embodiment can be combined into one module or further divided into multiple submodules.

[0077] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better embodiment. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), including a number of instructions for enabling a computer terminal (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in each embodiment of the present invention.

[0078] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0079] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A method for precise landing of a UAV in a complex environment, characterized by: The method is based on a UAV guided landing system in a complex environment, which includes: a first ground beacon for transmitting a radio beacon signal, a second ground beacon for transmitting an optical beacon signal, an inertial navigation module for guiding the UAV to land at a destination throughout the entire process, a satellite positioning module for real-time positioning of the UAV, a radio guidance module for receiving the radio beacon signal transmitted by the first ground beacon, a visual guidance module for receiving the optical beacon signal transmitted by the second ground beacon, or collecting terrain images within a field of view, and an onboard computer. Accordingly, the method includes the steps of: Acquiring, by the onboard computer, current flight data of the UAV in real time, and determining whether the current flight altitude is less than or equal to the propagation limit distance of the radio signal transmitted by the first ground beacon and greater than the propagation limit distance of the optical beacon signal transmitted by the second ground beacon; If the current flight altitude is greater than the propagation limit distance of the radio signal transmitted by the first ground beacon, the onboard computer determines that the UAV is currently in a high-altitude phase, and obtains real-time positioning data from the satellite positioning module in real time, so as to make real-time corrections to the landing route guided by the inertial navigation module based on the real-time positioning data; If the current flight altitude is less than or equal to the propagation limit distance of the radio signal transmitted by the first ground beacon and greater than the propagation limit distance of the optical beacon signal transmitted by the second ground beacon, the onboard computer determines that the UAV is currently in the mid-air phase and activates the radio guidance module to receive the radio beacon signal transmitted by the first ground beacon, so that the landing path is periodically corrected according to the radio beacon signal while the satellite positioning module performs real-time corrections; If the current flight altitude is less than or equal to the propagation limit distance of the optical beacon signal emitted by the second ground beacon, the onboard computer determines that the UAV is currently in a low-altitude stage, controls the satellite positioning module and the radio guidance module to be turned off, and starts the visual guidance module to receive the optical beacon signal emitted by the second ground beacon, and corrects the landing route of the UAV under the guidance of the inertial navigation module according to the optical beacon signal; or, performs image matching between the terrain image currently collected by the visual guidance module and the pre-stored destination image to correct the landing route of the UAV.

2. The method according to claim 1, characterized in that The step of correcting the landing route according to the optical beacon signal specifically comprises the steps of: The onboard computer processes the optical beacon signal, generates a fifth control instruction, and sends it to the flight controller of the UAV to control the UAV to land under the auxiliary guidance of the visual guidance module, wherein the fifth control instruction includes the relative position between the second ground beacon and the UAV.

3. The method according to claim 1, characterized in that The step of correcting the landing route of the UAV according to the radio beacon signal specifically includes the following steps: the onboard computer determines whether the UAV currently deviates from the landing course according to the strength of the radio beacon signal; if deviated, the onboard computer generates and sends a third control instruction to the UAV to control the UAV to stop landing and correct the course; wherein the third control instruction includes the relative position between the first ground beacon and the UAV; if not deviated, the onboard computer controls the UAV to continue landing under the guidance of the inertial navigation module, and when the UAV lands to the propagation limit distance of the optical beacon signal emitted by the second ground beacon, the visual guidance module is activated to assist in guiding the UAV to land to the destination.

4. The method according to claim 1, wherein When it is determined that the current flight altitude is less than or equal to the propagation limit distance of the radio signal emitted by the first ground beacon, and greater than the propagation limit distance of the optical beacon signal emitted by the second ground beacon, and the radio guidance module is activated, the visual guidance module is activated to assist in guiding the drone to land at the destination.

5. A UAV guided landing system in complex environments, comprising: a first ground beacon for transmitting a radio beacon signal; a second ground beacon, configured to transmit an optical beacon signal; Inertial navigation module, used to guide the drone to land at its destination throughout the entire process; Satellite positioning module, used for real-time positioning of drones; a radio guidance module, configured to receive a radio beacon signal transmitted by the first ground beacon; a visual guidance module, configured to receive an optical beacon signal emitted by the second ground beacon, or to collect an image of the terrain within a field of view; The onboard computer is configured to obtain current flight data of the UAV and determine the three altitude stages in which the UAV is guided to land. If the current flight altitude is greater than the propagation limit distance of the radio signal transmitted by the first ground beacon, the flight is determined to be in the high-altitude stage; if the current flight altitude is less than or equal to the propagation limit distance of the radio signal transmitted by the first ground beacon and greater than the propagation limit distance of the optical beacon signal transmitted by the second ground beacon, the flight is determined to be in the medium-altitude stage; if the current flight altitude is less than or equal to the propagation limit distance of the optical beacon signal transmitted by the second ground beacon, the flight is determined to be in the low-altitude stage; and when it is determined that the UAV is guided to land in the high-altitude stage, the UAV is controlled to be guided to land primarily using the navigation data of the inertial navigation module and to make real-time corrections to the landing path based on the real-time positioning data of the satellite positioning module; and when it is determined that the UAV is in the medium-altitude stage, the radio guidance module is activated and the radio beacon signal received by the radio guidance module is periodically obtained to periodically correct the landing path of the UAV based on the radio beacon signal. If it is determined that the UAV is in a low-altitude stage, the radio guidance module is controlled to be turned off, and the visual guidance module is activated to receive the optical beacon signal, so as to correct the landing route of the UAV based on the optical beacon signal or based on the terrain image currently collected by the visual guidance module and the pre-stored destination image.

6. The system according to claim 5, characterized in that The onboard computer is specifically used to process data of the optical beacon, generate a fifth control instruction based on the processing result, and send it to the flight controller of the UAV to control the UAV to land under the auxiliary guidance of the visual guidance module, wherein the fifth control instruction includes the relative position between the second ground beacon and the UAV.

7. The system according to claim 5, characterized in that The onboard computer is specifically used to determine whether the UAV deviates from the preset landing course based on the strength of the radio beacon signal. If so, a third control instruction is generated and sent to the flight controller of the UAV to control the UAV to stop landing and correct the landing course, wherein the third control instruction includes the relative position between the first ground beacon and the UAV.

8. The system according to claim 5, wherein: The onboard computer is a lightweight onboard computer.

9. The system according to claim 5, characterized in that When the onboard computer determines that the current flight altitude is less than or equal to the propagation limit distance of the radio signal emitted by the first ground beacon, and greater than the propagation limit distance of the optical beacon signal emitted by the second ground beacon, the onboard computer is also used to control the activation of the radio guidance module while controlling the activation of the visual guidance module to receive the optical beacon signal or image information, so as to correct the landing route of the UAV according to the optical beacon signal, or to perform image matching based on the currently collected terrain image and the pre-stored destination image to correct the landing route of the UAV.

10. An electronic device for guiding a drone to land in a complex environment, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: The electronic device is applied to a UAV guided landing system in a complex environment. The UAV guided landing system includes: a first ground beacon for transmitting a radio beacon signal, a second ground beacon for transmitting an optical beacon signal, an inertial navigation module for guiding the UAV to land at a destination throughout the entire process, a satellite positioning module for real-time positioning of the UAV, a radio guidance module for receiving the radio beacon signal transmitted by the first ground beacon, a visual guidance module for receiving the optical beacon signal transmitted by the second ground beacon, or collecting terrain images within a field of view, and the electronic device serving as an onboard computer. When the processor executes the program, the following steps are implemented: Acquire current flight data of the UAV in real time, and determine whether the current flight altitude of the UAV is less than or equal to the propagation limit distance of the radio signal transmitted by the first ground beacon and greater than the propagation limit distance of the optical beacon signal transmitted by the second ground beacon; If the current flight altitude is greater than the propagation limit distance of the radio signal transmitted by the first ground beacon, the UAV is determined to be in a high-altitude stage, and real-time positioning data from the satellite positioning module is obtained in real time, so as to make real-time corrections to the landing route guided by the inertial navigation module based on the real-time positioning data; If the current flight altitude is less than or equal to the propagation limit distance of the radio signal transmitted by the first ground beacon and greater than the propagation limit distance of the optical beacon signal transmitted by the second ground beacon, the UAV is determined to be in the mid-air phase, and the radio guidance module is activated to receive the radio beacon signal transmitted by the first ground beacon, and the landing route is periodically corrected according to the radio beacon signal; If the current flight altitude is less than or equal to the propagation limit distance of the optical beacon signal emitted by the second ground beacon, it is determined that the UAV is currently in a low-altitude stage, and the satellite positioning module and the radio guidance module are controlled to be turned off, and the visual guidance module is started to receive the optical beacon signal emitted by the second ground beacon. Then, the landing route of the UAV under the guidance of the inertial navigation module is corrected according to the optical beacon signal, or the terrain image currently taken by the visual guidance module is obtained and matched with the pre-stored destination image to correct the landing route of the UAV under the guidance of the inertial navigation module.

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