A control method and device of a multi-rotor unmanned aerial vehicle

Abstract

The specification discloses a control method and device of a multi-rotor unmanned aerial vehicle. First, millimeter wave signals received by a plurality of millimeter wave radars located on the ground are acquired. Second, according to the millimeter wave signals, millimeter wave signals corresponding to the unmanned aerial vehicle are determined. Third, for each millimeter wave radar, according to the millimeter wave signals corresponding to the unmanned aerial vehicle received by the millimeter wave radar, a horizontal distance between the unmanned aerial vehicle and the millimeter wave radar and a straight-line distance between the unmanned aerial vehicle and the millimeter wave radar are determined as distance information of the unmanned aerial vehicle corresponding to the millimeter wave radar. Finally, according to the distance information of the unmanned aerial vehicle corresponding to each millimeter wave radar, a three-dimensional coordinate of a position where the unmanned aerial vehicle is located is determined, and the three-dimensional coordinate is sent to the unmanned aerial vehicle to guide the unmanned aerial vehicle to land. According to the method, the three-dimensional coordinate of the unmanned aerial vehicle can be determined more accurately in extreme weather by the plurality of millimeter wave radars located on the ground, and the unmanned aerial vehicle can land accurately.

Description

TECHNICAL FIELD

[0001] The present specification relates to the technical field of computer technology, and particularly relates to a control method and device of a multi-rotor unmanned aerial vehicle. BACKGROUND

[0002] At present, an unmanned aerial vehicle usually uses an RTK (Real-time kinematic) carrier phase difference technology to position the unmanned aerial vehicle. A reference station and a mobile station installed on the unmanned aerial vehicle simultaneously receive signals transmitted by the same satellite at the same time, and the reference station transmits measured carrier phase observation values, pseudo-range observation values, reference station coordinates and the like to the mobile station in motion in real time through a 4G network, and the mobile station receives information transmitted by the reference station through the 4G network and differentially processes the carrier phase observation values in real time to obtain coordinates of the unmanned aerial vehicle.

[0003] In actual application, this method is affected by network signals, and in extreme weather such as rain, snow, wind, storm and the like, the received RTK reference station signals have a large time delay due to the influence of ionosphere, troposphere, air, electromagnetic waves and the like, which reduces the accuracy of determined positioning data of the unmanned aerial vehicle. Moreover, the scene of landing of the unmanned aerial vehicle is mainly in urban areas, and a large number of high-rise buildings cause a multipath effect, which causes a large deviation of determined positioning data of the unmanned aerial vehicle, and further causes the unmanned aerial vehicle to be unable to land accurately.

[0004] Therefore, how to improve the accuracy of determined positioning data of the unmanned aerial vehicle to complete accurate landing of the unmanned aerial vehicle is a problem to be solved. SUMMARY

[0005] The present specification provides a control method and device of a multi-rotor unmanned aerial vehicle to partially solve the above problems existing in the prior art.

[0006] The present specification adopts the following technical solution:

[0007] The present specification provides a control method of a multi-rotor unmanned aerial vehicle, comprising:

[0008] acquiring millimeter wave signals received by a plurality of millimeter wave radars located on the ground;

[0009] determining millimeter wave signals corresponding to the unmanned aerial vehicle according to the millimeter wave signals;

[0010] for each millimeter wave radar, determining a horizontal distance between the unmanned aerial vehicle and the millimeter wave radar and a straight line distance between the unmanned aerial vehicle and the millimeter wave radar as distance information of the unmanned aerial vehicle corresponding to the millimeter wave radar according to the millimeter wave signals corresponding to the unmanned aerial vehicle received by the millimeter wave radar;

[0011] According to distance information of each millimeter wave radar corresponding to the unmanned aerial vehicle, three-dimensional coordinates of a position where the unmanned aerial vehicle is located are determined.

[0012] The three-dimensional coordinates are sent to the unmanned aerial vehicle to guide the unmanned aerial vehicle to land.

[0013] Optionally, before the millimeter wave signals received by the millimeter wave radars located on the ground are acquired, the method further comprises:

[0014] If a communication connection request sent by the unmanned aerial vehicle is received, a communication connection with the unmanned aerial vehicle is established through a preset communication connection mode, the communication connection request is sent after the unmanned aerial vehicle receives a communication broadcast signal, and the communication connection mode comprises a WiFi connection.

[0015] For each millimeter wave radar located on the ground, a start instruction is sent to the millimeter wave radar to enable the millimeter wave radar to start radar scanning.

[0016] Optionally, the millimeter wave signal corresponding to the unmanned aerial vehicle is determined according to the millimeter wave signal, and specifically comprises:

[0017] The Doppler spectrum corresponding to each millimeter wave signal is determined.

[0018] The millimeter wave signal with a frequency width of the Doppler spectrum greater than a set frequency width threshold is determined as a millimeter wave signal generated when a rotor rotates, as the millimeter wave signal corresponding to the unmanned aerial vehicle.

[0019] Optionally, the rotor provided on the unmanned aerial vehicle comprises a plurality of rotor blades.

[0020] The millimeter wave signal corresponding to the unmanned aerial vehicle is determined, and specifically comprises:

[0021] According to the rotation center of the rotor, the rotating speed of the rotor, and the distance from the scattering point corresponding to the plurality of rotor blades to the rotation center, the scattering point coordinates corresponding to the plurality of rotor blades are determined.

[0022] According to the scattering point coordinates corresponding to the plurality of rotor blades, the scattering center corresponding to the unmanned aerial vehicle is determined.

[0023] According to the scattering center corresponding to the unmanned aerial vehicle, the millimeter wave signal of the scattering center corresponding to the unmanned aerial vehicle is determined.

[0024] Optionally, the millimeter wave radar comprises a plurality of receiving antennas.

[0025] According to the millimeter wave signal corresponding to the unmanned aerial vehicle received by the millimeter wave radar, the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar is determined, and specifically comprises:

[0026] from a plurality of receiving antennas, taking one receiving antenna as a reference, as a reference receiving antenna;

[0027] According to the millimeter wave signal corresponding to the unmanned aerial vehicle received by the reference receiving antenna and the millimeter wave signal corresponding to the unmanned aerial vehicle received by the other receiving antennas, the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar is determined.

[0028] Optionally, according to the millimeter wave signal corresponding to the unmanned aerial vehicle received by the reference receiving antenna and the millimeter wave signal corresponding to the unmanned aerial vehicle received by the other receiving antennas, the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar is determined, specifically including:

[0029] According to the millimeter wave signal corresponding to the unmanned aerial vehicle received by the reference receiving antenna, the millimeter wave signal corresponding to the unmanned aerial vehicle received by the other receiving antennas, and the distance between the reference receiving antenna and the other receiving antennas, the amplitude of the millimeter wave signal corresponding to the unmanned aerial vehicle based on the distance is determined.

[0030] According to the millimeter wave signal corresponding to the unmanned aerial vehicle received by the reference receiving antenna at the first time, the millimeter wave signal corresponding to the unmanned aerial vehicle received by the other receiving antennas at the second time, and the time interval from the first time to the second time, the amplitude of the millimeter wave signal corresponding to the unmanned aerial vehicle based on the time interval is determined, and the second time is the next time of the first time.

[0031] According to the amplitude of the millimeter wave signal corresponding to the unmanned aerial vehicle based on the distance and the amplitude of the millimeter wave signal corresponding to the unmanned aerial vehicle based on the time interval, the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar is determined.

[0032] Optionally, according to the distance information of each millimeter wave radar corresponding to the unmanned aerial vehicle, the three-dimensional coordinates of the position where the unmanned aerial vehicle is located are determined, specifically including:

[0033] For each millimeter wave radar, according to the distance information of the millimeter wave radar corresponding to the unmanned aerial vehicle, taking the millimeter wave radar as the coordinate origin, the two-dimensional coordinates of the unmanned aerial vehicle corresponding to the millimeter wave radar are determined.

[0034] According to the two-dimensional coordinates of the unmanned aerial vehicle corresponding to each millimeter wave radar and the position information corresponding to each millimeter wave radar, the three-dimensional coordinates of the unmanned aerial vehicle are determined.

[0035] The present specification provides a control system of an unmanned aerial vehicle, comprising: an unmanned aerial vehicle, a plurality of millimeter wave radars located on the ground, and a server;

[0036] The millimeter wave radar is configured to send the received millimeter wave signal to the server.

[0037] The server is configured to acquire millimeter wave signals received by a plurality of millimeter wave radars located on the ground, determine a millimeter wave signal corresponding to the UAV according to the millimeter wave signals, determine, for each millimeter wave radar, a horizontal distance between the UAV and the millimeter wave radar and a straight-line distance between the UAV and the millimeter wave radar as distance information of the millimeter wave radar corresponding to the UAV according to the millimeter wave signal corresponding to the UAV received by the millimeter wave radar, determine a three-dimensional coordinate of a position where the UAV is located according to the distance information of the millimeter wave radar corresponding to the UAV, and send the three-dimensional coordinate to the UAV to guide the UAV to land.

[0038] Optionally, the UAV is configured to send a communication connection request to the server if the communication broadcast signal of the server is received.

[0039] The server is configured to establish a communication connection with the UAV through a preset communication connection mode if the communication connection request sent by the UAV is received, and send a start instruction to each millimeter wave radar located on the ground, and the communication connection mode includes a WiFi connection.

[0040] The millimeter wave radar is configured to start radar scanning after the start instruction sent by the server is received.

[0041] The present specification provides a computer readable storage medium, the storage medium stores a computer program, and the computer program is executed by a processor to implement the control method of the multi-rotor UAV.

[0042] The present specification provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the control method of the multi-rotor UAV when executing the program.

[0043] The above at least one technical solution adopted by the present specification can achieve the following beneficial effects:

[0044] In the control method of the multi-rotor unmanned aerial vehicle provided in the specification, firstly, millimeter wave signals received by a plurality of millimeter wave radars located on the ground are acquired. Secondly, according to the millimeter wave signals, millimeter wave signals corresponding to the unmanned aerial vehicle are determined. Then, for each millimeter wave radar, according to the millimeter wave signals corresponding to the unmanned aerial vehicle received by the millimeter wave radar, a horizontal distance between the unmanned aerial vehicle and the millimeter wave radar and a straight-line distance between the unmanned aerial vehicle and the millimeter wave radar are determined as distance information of the unmanned aerial vehicle corresponding to the millimeter wave radar. Finally, according to the distance information of the unmanned aerial vehicle corresponding to each millimeter wave radar, a three-dimensional coordinate of a position where the unmanned aerial vehicle is located is determined, and the three-dimensional coordinate is sent to the unmanned aerial vehicle to guide the unmanned aerial vehicle to land.

[0045] As can be seen from the above method, the method can determine the three-dimensional coordinate of the position where the unmanned aerial vehicle is located through the horizontal distance and the straight-line distance between the plurality of millimeter wave radars located on the ground and the unmanned aerial vehicle, and guide the unmanned aerial vehicle to land. Compared with the prior art, the method can determine the relatively accurate three-dimensional coordinate of the unmanned aerial vehicle in extreme weather through the plurality of millimeter wave radars located on the ground, and thus the unmanned aerial vehicle can land accurately. BRIEF DESCRIPTION OF DRAWINGS

[0046] The drawings described herein are used to provide further understanding of the specification, constitute a part of the specification, the illustrative embodiments of the specification and the description thereof are used to explain the specification, and do not constitute an improper limitation on the specification. In the drawings:

[0047] Figure 1 It is a schematic diagram of the control system of the unmanned aerial vehicle in the specification;

[0048] Figure 2 It is a flowchart of the control method of the multi-rotor unmanned aerial vehicle in the specification;

[0049] Figure 3 It is a schematic diagram for determining the three-dimensional coordinate of the unmanned aerial vehicle provided in the embodiment of the specification;

[0050] Figure 4 It is a schematic diagram of an electronic device corresponding to Figure 1 provided in the specification. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical scheme and advantages of the specification clearer, the technical scheme of the specification will be described clearly and completely in combination with the specific embodiments of the specification and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the specification, not all the embodiments. Based on the embodiments in the specification, all other embodiments obtained by those skilled in the art without making creative efforts belong to the scope of protection of the specification.

[0052] The present specification provides a control system of a UAV, which comprises a UAV, a plurality of millimeter wave radars located on the ground, and a server. Specifically as Figure 1 shown.

[0053] Figure 1 A schematic diagram of a control system of a UAV in the present specification.

[0054] In Figure 1 It can be seen that a communication connection relationship can be established between each millimeter wave radar and the server, and the server comprises a Wi-Fi function. Figure 1 The dashed line in the figure represents the communication broadcast signal sent by the server through the Wi-Fi function. When the UAV can be positioned by the Global Navigation Satellite System (GNSS), reaches the upper space of the plurality of millimeter wave radars and the server located on the ground, the UAV receives the communication broadcast signal, and then the UAV can send a communication connection request to the server, and establish a communication connection between the server and the UAV. Once the communication connection between the server and the UAV is successfully established, the server can send a start instruction to each millimeter wave radar for each millimeter wave radar located on the ground. After each millimeter wave radar receives the start instruction, the radar scanning is started to position the UAV, Figure 1 The solid line in the figure represents the millimeter wave signal emitted by the millimeter wave radar when the radar scanning is started.

[0055] The technical solutions provided by the embodiments of the present specification will be described in detail below with reference to the accompanying drawings.

[0056] Figure 2 A flowchart of a control method of a multi-rotor UAV in the present specification, comprising the following steps:

[0057] S200: Obtain the millimeter wave signal received by the plurality of millimeter wave radars located on the ground.

[0058] In the embodiments of the present specification, the execution subject of the control method of the multi-rotor UAV involved in the present specification can be a device such as a server arranged at the take-off and landing place of the UAV. Of course, the execution subject for controlling the UAV can also be a specified device capable of processing data and capable of sending data, which can be arranged at the take-off and landing place of the UAV. In order to facilitate description, the control method of the multi-rotor UAV provided by the present specification will be described below with the server arranged at the take-off and landing place of the UAV as the execution subject.

[0059] In the embodiments of the present application, the unmanned aerial vehicle can be positioned by a global navigation satellite system, and reach the upper air of a plurality of millimeter wave radars located on the ground. If the server receives a communication connection request sent by the unmanned aerial vehicle, the server establishes a communication connection with the unmanned aerial vehicle through a preset communication connection mode. The communication connection request mentioned here is sent by the unmanned aerial vehicle after receiving the communication broadcast signal, and the communication connection mode includes WiFi connection. Then, for each millimeter wave radar located on the ground, a start instruction is sent to the millimeter wave radar to start radar scanning.

[0060] It should be noted that when the communication broadcast signal propagates in the transmission medium, part of the energy will be converted into heat energy or absorbed by the transmission medium, thereby causing the signal strength to continuously weaken, resulting in that the unmanned aerial vehicle outside a certain range cannot receive the communication broadcast information. Therefore, the unmanned aerial vehicle needs to be positioned by a global navigation satellite system and fly to the upper air of the server, so that the unmanned aerial vehicle receives the server communication broadcast signal when the distance between the unmanned aerial vehicle and the server is within the set distance range, and establishes a communication connection accordingly. That is, if the unmanned aerial vehicle can receive the server communication broadcast signal, it means that the unmanned aerial vehicle is within the set distance range from the server.

[0061] Further, the server can obtain the millimeter wave signals received by the plurality of millimeter wave radars located on the ground. The millimeter wave signals mentioned here contain distance information corresponding to each obstacle and speed information corresponding to each obstacle. The distance information mentioned here can refer to the straight-line distance from the millimeter wave radar to each obstacle. The speed information mentioned here can refer to the Doppler speed, that is, the relative motion speed between the unmanned aerial vehicle and each obstacle.

[0062] In the present application, the unmanned aerial vehicle applying the control method of the multi-rotor unmanned aerial vehicle provided by the present application can be used to perform delivery tasks in the delivery field, such as using the unmanned aerial vehicle to perform express delivery, logistics, take-out and other business scenarios.

[0063] S202: According to the millimeter wave signal, determine the millimeter wave signal corresponding to the unmanned aerial vehicle.

[0064] In actual application, since all objects can reflect millimeter wave signals, this will interfere with the millimeter wave radar to identify the position of the unmanned aerial vehicle. Therefore, the server can need to screen the millimeter wave signal corresponding to the unmanned aerial vehicle from the reflected millimeter wave signal.

[0065] In the embodiments of the present application, the server can determine the millimeter wave signal corresponding to the unmanned aerial vehicle according to the millimeter wave signal.

[0066] Specifically, the server can convert the Doppler velocity into the movement speed of the obstacle according to the speed information of each obstacle in the millimeter wave signal. Generally, the speed of the static obstacle is basically zero. The server can distinguish the static obstacle from the dynamic obstacle by the movement speed of the obstacle, and remove the interference of the static obstacle. Then, the millimeter wave signal corresponding to the dynamic obstacle is distinguished to determine the millimeter wave signal corresponding to the unmanned aerial vehicle.

[0067] In actual application, since the obstacles such as unmanned aerial vehicles, vehicles and pedestrians have movement speeds, the server cannot distinguish the unmanned aerial vehicle from other dynamic obstacles by the movement speed. However, the Doppler spectrum corresponding to the millimeter wave signal reflected by the rotating rotor of the unmanned aerial vehicle is special. Based on this, the server can distinguish the unmanned aerial vehicle from other dynamic obstacles by the Doppler spectrum.

[0068] In the embodiment of the present application, the unmanned aerial vehicle is provided with a plurality of rotors. The server can screen the millimeter wave signal generated when the rotor rotates from the millimeter wave signal as the millimeter wave signal corresponding to the unmanned aerial vehicle.

[0069] Specifically, the server can determine the Doppler spectrum corresponding to each millimeter wave signal from the millimeter wave signal. The millimeter wave signal with a frequency width of the Doppler spectrum greater than a set frequency width threshold is determined as the millimeter wave signal generated when the rotor rotates as the millimeter wave signal corresponding to the unmanned aerial vehicle. That is, since the frequency width of the Doppler spectrum of the millimeter wave signal corresponding to the unmanned aerial vehicle is greater than the frequency width of the Doppler spectrum of the millimeter wave signal corresponding to the dynamic obstacle, the server can distinguish the unmanned aerial vehicle from other dynamic obstacles by the frequency width of the Doppler spectrum.

[0070] In actual application, since the rotor provided on the unmanned aerial vehicle includes a plurality of rotor blades, each rotor blade will reflect the millimeter wave signal. The server can characterize the millimeter wave signal corresponding to the unmanned aerial vehicle as the millimeter wave signal reflected by a plurality of isolated scattering centers based on the multiple scattering center theory.

[0071] In the embodiment of the present application, the rotor provided on the unmanned aerial vehicle includes a plurality of rotor blades. The server can determine the coordinates of the scattering points corresponding to the plurality of rotor blades according to the rotation center of the rotor, the rotation speed of the rotor, and the distance from the rotation center to the scattering points corresponding to the plurality of rotor blades. Then, the scattering center corresponding to the unmanned aerial vehicle is determined according to the coordinates of the scattering points corresponding to the plurality of rotor blades. Finally, the millimeter wave signal of the scattering center corresponding to the unmanned aerial vehicle is determined according to the scattering center corresponding to the unmanned aerial vehicle.

[0072] Specifically, the server can take the location of the millimeter wave radar as the coordinate origin, the center of rotation of the rotor as (x0, y0, z0), the rotation speed of the rotor as ω, the distance from the scattering points corresponding to the rotor blades to the center of rotation as r, and the initial phase of the millimeter wave signal corresponding to the rotor blades as Thus, the coordinates of the scattering points corresponding to the rotor blades are determined as Secondly, the scattering center corresponding to the unmanned aerial vehicle is determined according to the coordinates of the scattering points corresponding to the rotor blades. Finally, the millimeter wave signal of the scattering center corresponding to the unmanned aerial vehicle is determined according to the scattering center corresponding to the unmanned aerial vehicle. The specific formula is as follows:

[0073]

[0074] In the above formula, M can be used to represent the millimeter wave signal of the scattering center corresponding to the unmanned aerial vehicle. A r may be used to represent the amplitude of the millimeter wave signal reflected by the scattering point. λ can be used to represent the wavelength of the millimeter wave signal. may be used to represent the distance of the millimeter wave signal transmission. j can be used to represent the imaginary unit. may be used to represent the millimeter wave signal reflected by one scattering center received by the millimeter wave radar, and the unmanned aerial vehicle can include multiple scattering centers. As can be seen from the above formula, the millimeter wave signals reflected by the scattering points corresponding to the rotor blades can be obtained by the above formula to obtain the millimeter wave signals reflected by the rotor. Further, the millimeter wave signals reflected by the rotor can be obtained by the above formula to obtain the millimeter wave signals reflected by the unmanned aerial vehicle.

[0075] S204: For each millimeter wave radar, according to the millimeter wave signal corresponding to the unmanned aerial vehicle received by the millimeter wave radar, the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar is determined, and the straight line distance between the unmanned aerial vehicle and the millimeter wave radar is determined as the distance information of the millimeter wave radar corresponding to the unmanned aerial vehicle.

[0076] In actual application, the millimeter wave radar includes a plurality of receiving antennas, and the amplitudes of the millimeter wave signals received by different receiving antennas are the same, and the amplitudes of the millimeter wave signals received by the same receiving antenna at different times are the same. Based on this, the server can determine the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar based on the amplitude of the received millimeter wave signal.

[0077] In the embodiment of the present application, the server can take one receiving antenna as a reference receiving antenna from a plurality of receiving antennas. Then, according to the millimeter wave signal corresponding to the unmanned aerial vehicle received by the reference receiving antenna and the millimeter wave signal corresponding to the unmanned aerial vehicle received by the other receiving antennas, the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar is determined.

[0078] Specifically, the server can determine the amplitude of the millimeter wave signal corresponding to the UAV based on the distance according to the millimeter wave signal corresponding to the UAV received by the reference receiving antenna, the millimeter wave signal corresponding to the UAV received by the other receiving antenna, and the distance between the reference receiving antenna and the other receiving antenna. For example, the millimeter wave radar contains two receiving antennas. The specific formula is as follows:

[0079]

[0080]

[0081]

[0082]

[0083]

[0084] In the above formula, d can be used to represent the distance between the first receiving antenna and the second receiving antenna. B1 can be used to represent the millimeter wave signal corresponding to the UAV received by the first receiving antenna. B2 can be used to represent the millimeter wave signal corresponding to the UAV received by the second receiving antenna. As can be seen from the above formula, the server divides the two millimeter wave signals to obtain the millimeter wave signal corresponding to the distance between the first receiving antenna and the second receiving antenna. And the derivative of the millimeter wave signal corresponding to the distance between the first receiving antenna and the second receiving antenna is determined to determine the amplitude of the millimeter wave signal corresponding to the UAV based on the distance.

[0085] Secondly, according to the millimeter wave signal corresponding to the UAV received by the reference receiving antenna at the first time, the millimeter wave signal corresponding to the UAV received by the other receiving antenna at the second time, and the time interval from the first time to the second time, the amplitude of the millimeter wave signal corresponding to the UAV based on the time interval is determined. The second time is the next time of the first time. For example, the first receiving antenna. The specific formula is as follows:

[0086]

[0087]

[0088]

[0089]

[0090]

[0091] In the above formula, Δt can be used to represent the time interval from the first time to the second time. T1 can be used to represent the millimeter wave signal corresponding to the unmanned aerial vehicle received by the first receiving antenna at the first time. T2 can be used to represent the millimeter wave signal corresponding to the unmanned aerial vehicle received by the first receiving antenna at the first time. As can be seen from the above formula, the server divides the two millimeter wave signals to obtain the millimeter wave signal corresponding to the time interval from the first time to the second time. And the derivative of the millimeter wave signal corresponding to the time interval from the first time to the second time is determined to determine the amplitude of the millimeter wave signal corresponding to the unmanned aerial vehicle based on the time interval.

[0092] Finally, according to the amplitude of the millimeter wave signal corresponding to the unmanned aerial vehicle based on the distance, and the amplitude of the millimeter wave signal corresponding to the unmanned aerial vehicle based on the time interval, the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar is determined. The specific formula is as follows:

[0093]

[0094] In the above formula, can be used to represent the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar. Because the amplitudes of the millimeter wave signals received by different receiving antennas are the same, and the amplitudes of the millimeter wave signals received by the same receiving antenna at different times are the same. Based on this, dividing the amplitudes can obtain the value of D as 1. And because the time interval from the first time to the second time Δt, the distance between the first receiving antenna and the second receiving antenna d, the distance from the scattering point corresponding to the rotor blade to the rotation center r, and the rotation speed of the rotor ω are known, the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar can be obtained

[0095] It should be noted that the more the number of receiving antennas contained in the millimeter wave radar, the more accurate the calculated horizontal distance and straight line distance between the unmanned aerial vehicle and the millimeter wave radar.

[0096] S206: According to the distance information of each millimeter wave radar corresponding to the unmanned aerial vehicle, the three-dimensional coordinates of the position of the unmanned aerial vehicle are determined.

[0097] In the embodiments of the present specification, the server can determine the three-dimensional coordinates of the position of the unmanned aerial vehicle according to the distance information of each millimeter wave radar corresponding to the unmanned aerial vehicle.

[0098] In actual application, the server can determine the three-dimensional coordinates of the unmanned aerial vehicle through the straight line distance of the unmanned aerial vehicle by four millimeter wave radars, but the cost of four millimeter wave radars is high. The present method can determine the three-dimensional coordinates of the unmanned aerial vehicle through at least two millimeter wave radars.

[0099] In the embodiments of this specification, the server can, for each millimeter-wave radar, determine the two-dimensional coordinates of the drone corresponding to that millimeter-wave radar, using the millimeter-wave radar as the origin, based on the distance information of the drone corresponding to that millimeter-wave radar. Then, based on the two-dimensional coordinates of the drone corresponding to each millimeter-wave radar and the position information corresponding to each millimeter-wave radar, the server determines the three-dimensional coordinates of the drone. Specifically, as follows... Figure 3 As shown.

[0100] Figure 3 This is a schematic diagram illustrating the determination of the three-dimensional coordinates of a UAV as provided in the embodiments of this specification.

[0101] exist Figure 3 In this process, a Cartesian coordinate system (X1, Y1) is generated, using the UAV and millimeter-wave radar 1 as references. A plane 1 is generated based on the horizontal and linear distances between the UAV and millimeter-wave radar 1. Similarly, a Cartesian coordinate system (X2, Y2) is generated, using the UAV and millimeter-wave radar 2 as references. A plane 2 is generated based on the horizontal and linear distances between the UAV and millimeter-wave radar 2. The point where plane 1 and plane 2 intersect represents the UAV's three-dimensional coordinates.

[0102] S208: Send the three-dimensional coordinates to the drone to guide the drone to land.

[0103] In the embodiments described in this specification, the server can send three-dimensional coordinates to the drone to guide the drone to land.

[0104] Specifically, the server can transmit data between the drone and the server via methods such as Wi-Fi, Bluetooth, 4G, and 5G. The drone can then use its own 3D coordinates to land at the target location.

[0105] As can be seen from the above process, this method can filter millimeter-wave signals that match the rotor rotation to obtain the corresponding millimeter-wave signal for the UAV. Based on the corresponding millimeter-wave signal, the horizontal and straight-line distances between the UAV and several ground-based millimeter-wave radars are determined to obtain the three-dimensional coordinates of the UAV's location, guiding the UAV to land. Compared to existing technologies, this method, using several ground-based millimeter-wave radars, can determine the UAV's more accurate three-dimensional coordinates even in extreme weather conditions, thus enabling the UAV to land precisely.

[0106] This specification also provides a computer-readable storage medium storing a computer program that can be used to execute the above-described... Figure 1A control method for a multi-rotor unmanned aerial vehicle is provided.

[0107] This instruction manual also provides Figure 4 One of the corresponding Figure 1 A schematic diagram of the structure of an electronic device. (e.g.) Figure 4 At the hardware level, the electronic device includes a processor, internal bus, network interface, memory, and non-volatile memory, and may also include other hardware required for the business operations. The processor reads the corresponding computer program from the non-volatile memory into memory and then runs it to achieve the above-mentioned functions. Figure 1 The control method for the multi-rotor UAV described above. Of course, in addition to software implementation, this specification does not exclude other implementation methods, such as logic devices or a combination of hardware and software, etc. That is to say, the execution subject of the following processing flow is not limited to individual logic units, but can also be hardware or logic devices.

[0108] In the 1990s, it was quite obvious to distinguish whether an improvement in a technology was in hardware (e.g., improvement in circuit structures of diodes, transistors, switches, etc.) or in software (improvement in method flow). However, as technology has evolved, many improvements in method flow today can be considered as direct improvements in hardware circuit structures. Designers almost always obtain the corresponding hardware circuit structures by programming the improved method flow into hardware circuits. Therefore, it cannot be said that an improvement in a method flow cannot be implemented by hardware entity modules. For example, a programmable logic device (PLD) (e.g., a field programmable gate array (FPGA)) is an integrated circuit whose logic function is determined by user programming of the device. A digital system is "integrated" on a PLD by the designer programming it, rather than by asking a chip manufacturer to design and fabricate a custom integrated circuit chip. Moreover, instead of manually fabricating integrated circuit chips, this programming is now mostly implemented by "logic compiler" software, which is similar to software compilers used in program development, and the original code to be compiled is written in a specific programming language, which is called a hardware description language (HDL), and there are many such languages, such as ABEL (Advanced Boolean Expression Language), AHDL (Altera Hardware Description Language), Confluence, CUPL (Cornell University Programming Language), HDCal, JHDL (Java Hardware Description Language), Lava, Lola, MyHDL, PALASM, RHDL (Ruby Hardware Description Language), etc., and the most commonly used are VHDL (Very-High-Speed Integrated Circuit Hardware Description Language) and Verilog. Those skilled in the art should be aware that, as long as the method flow is logically programmed in the above-mentioned hardware description languages and programmed into an integrated circuit, a hardware circuit implementing the logical method flow can be easily obtained.

[0109] The controller can be implemented in any suitable way, for example, the controller can take the form of a microprocessor or processor and a computer readable medium storing computer readable program code, such as software or firmware, executable by the (micro)processor, logic gates, switches, an application specific integrated circuit (ASIC), a programmable logic controller and an embedded microcontroller, examples of which include but are not limited to the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20 and Silicone Labs C8051F320, the memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art will also know that, in addition to being implemented in pure computer readable program code, the controller can equally well be implemented to perform the same functions using logic gates, switches, an application specific integrated circuit, a programmable logic controller and an embedded microcontroller, etc. by means of a logical programming of the method steps. The controller can thus be considered as a hardware component, and the means comprised therein for performing the various functions can be considered as structures within the hardware component. Alternatively, the means for performing the various functions can even be considered as both a software module implementing the method and a structure within the hardware component.

[0110] The systems, apparatuses, modules or units illustrated by the above embodiments can be specifically implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, the computer can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0111] For the sake of description, the above apparatuses are described in functional division and are described respectively. Of course, the functions of the units can be implemented in the same or multiple software and / or hardware when implementing the present specification.

[0112] Those skilled in the art will understand that the embodiments of the present specification can be provided as a method, a system, or a computer program product. Therefore, the present specification can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present specification can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0113] The specification is presented with reference to flow diagrams and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the specification. It will be understood that each block of the flow diagrams and / or block diagrams, and combinations of blocks in the flow diagrams and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processing element or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flow diagrams and / or block diagrams block or blocks. Figure 1 The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Flow diagrams and / or block diagrams can also present a method, apparatus or computer program product to achieve functions specified in flow diagrams and / or block diagrams block or blocks. Figure 1 The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Flow diagrams and / or block diagrams can also present a method, apparatus or computer program product to achieve functions specified in flow diagrams and / or block diagrams block or blocks.

[0114] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the flow diagrams and / or block diagrams block or blocks. Figure 1 The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Flow diagrams and / or block diagrams can also present a method, apparatus or computer program product to achieve functions specified in flow diagrams and / or block diagrams block or blocks. Figure 1 The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Flow diagrams and / or block diagrams can also present a method, apparatus or computer program product to achieve functions specified in flow diagrams and / or block diagrams block or blocks.

[0115] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flow diagrams and / or block diagrams block or blocks. Figure 1 The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Flow diagrams and / or block diagrams can also present a method, apparatus or computer program product to achieve functions specified in flow diagrams and / or block diagrams block or blocks. ​ The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Flow diagrams and / or block diagrams can also present a method, apparatus or computer program product to achieve functions specified in flow diagrams and / or block diagrams block or blocks.

[0116] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0117] The memory can include non-persistent memory and / or storage mechanisms such as, for example, random access memory (RAM), non-volatile memory (NVM), and / or a persistent memory such as, for example, read-only memory (ROM) or flash memory. The memory is an example of computer-readable media.

[0118] Computer-readable media includes permanent and non-permanent, movable and non-movable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer-readable media does not include transitory media such as modulated data signals and carriers.

[0119] It should also be noted that the terms "comprising", "containing", or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or apparatus that comprises a list of elements does not only include those elements, but can also include other elements not expressly listed or inherent to such process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0120] Those skilled in the art will appreciate that embodiments of the present specification can be provided as methods, systems or computer program products. Therefore, the present specification can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Moreover, the present specification can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0121] The present specification can be described in the general context of computer-executable instructions, such as program modules, executed by computers. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The present specification can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in both local and remote computer storage media including storage devices.

[0122] The various embodiments described in this specification are described using a numbering of embodiments approach: these are each individually integrated contributions pertaining to different but related aspects of the description. Each of the various embodiments can stand on its own, and each can be combined with the subject matter of other embodiments to produce further embodiments. Where appropriate, therefore, the contents of the specification can be regarded as being incorporated by reference, including the description, drawings, claims, abstract and the like.

[0123] The above description is embodied in the form of examples only, and is not intended to limit the specification. The specification can be variously changed and modified by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the specification should be included in the scope of the claims of the specification.

Claims

1. A control method of a multi-rotor drone, characterized by, The method comprises the following steps: acquiring millimeter wave signals received by a plurality of millimeter wave radars located on the ground; determining millimeter wave signals corresponding to the unmanned aerial vehicle according to the millimeter wave signals; for each millimeter wave radar, determining a horizontal distance between the unmanned aerial vehicle and the millimeter wave radar and a straight-line distance between the unmanned aerial vehicle and the millimeter wave radar as distance information of the unmanned aerial vehicle corresponding to the millimeter wave radar according to the millimeter wave signals corresponding to the unmanned aerial vehicle received by the millimeter wave radar; determining a three-dimensional coordinate of a position where the unmanned aerial vehicle is located according to the distance information of the unmanned aerial vehicle corresponding to each millimeter wave radar; sending the three-dimensional coordinate to the unmanned aerial vehicle to guide the unmanned aerial vehicle to land; wherein the millimeter wave radar comprises a plurality of receiving antennas; determining the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar according to the millimeter wave signals corresponding to the unmanned aerial vehicle received by the millimeter wave radar specifically comprises: taking one receiving antenna as a reference receiving antenna from the plurality of receiving antennas; determining the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar according to the millimeter wave signals corresponding to the unmanned aerial vehicle received by the reference receiving antenna and the millimeter wave signals corresponding to the unmanned aerial vehicle received by the other receiving antennas; determining the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar according to the millimeter wave signals corresponding to the unmanned aerial vehicle received by the reference receiving antenna and the millimeter wave signals corresponding to the unmanned aerial vehicle received by the other receiving antennas specifically comprises: determining an amplitude of the millimeter wave signals corresponding to the unmanned aerial vehicle based on a distance between the reference receiving antenna and the other receiving antennas according to the millimeter wave signals corresponding to the unmanned aerial vehicle received by the reference receiving antenna, the millimeter wave signals corresponding to the unmanned aerial vehicle received by the other receiving antennas, and the distance between the reference receiving antenna and the other receiving antennas; determining an amplitude of the millimeter wave signals corresponding to the unmanned aerial vehicle based on a time interval between a first time and a second time according to the millimeter wave signals corresponding to the unmanned aerial vehicle received by the reference receiving antenna at the first time and the millimeter wave signals corresponding to the unmanned aerial vehicle received by the other receiving antennas at the second time, the second time being a next time of the first time; determining the horizontal distance between the unmanned aerial vehicle and the millimeter wave radar according to the amplitude of the millimeter wave signals corresponding to the unmanned aerial vehicle based on the distance and the amplitude of the millimeter wave signals corresponding to the unmanned aerial vehicle based on the time interval.

2. The method of claim 1, wherein, Before acquiring millimeter wave signals received by a plurality of millimeter wave radars located on the ground, the method further comprises: if a communication connection request sent by the unmanned aerial vehicle is received, establishing a communication connection with the unmanned aerial vehicle through a preset communication connection mode, the communication connection request being sent by the unmanned aerial vehicle after receiving a communication broadcast signal, and the communication connection mode comprising a WiFi connection; for each millimeter wave radar located on the ground, sending a start instruction to the millimeter wave radar to enable the millimeter wave radar to start radar scanning.

3. The method of claim 1, wherein, determining millimeter wave signals corresponding to the unmanned aerial vehicle according to the millimeter wave signals specifically comprises: determining a Doppler spectrum corresponding to each millimeter wave signal; determining, as the millimeter wave signal corresponding to the unmanned aerial vehicle, a millimeter wave signal whose frequency width of the Doppler spectrum is greater than a set frequency width threshold, and which is generated when the rotor rotates.

4. The method of claim 1, wherein, The rotor provided on the unmanned aerial vehicle includes a plurality of rotor blades. The method for determining the millimeter wave signal corresponding to the unmanned aerial vehicle specifically includes: determining the coordinates of the scattering points corresponding to the plurality of rotor blades according to the rotation center of the rotor, the rotation speed of the rotor, and the distances from the scattering points corresponding to the plurality of rotor blades to the rotation center; determining the scattering center corresponding to the unmanned aerial vehicle according to the coordinates of the scattering points corresponding to the plurality of rotor blades; determining the millimeter wave signal corresponding to the scattering center of the unmanned aerial vehicle according to the scattering center corresponding to the unmanned aerial vehicle.

5. The method of claim 1, wherein, determining the three-dimensional coordinates of the position of the unmanned aerial vehicle according to the distance information of each millimeter wave radar corresponding to the unmanned aerial vehicle, specifically including: for each millimeter wave radar, determining the two-dimensional coordinates of the unmanned aerial vehicle corresponding to the millimeter wave radar with the millimeter wave radar as the coordinate origin according to the distance information of the millimeter wave radar corresponding to the unmanned aerial vehicle; determining the three-dimensional coordinates of the unmanned aerial vehicle according to the two-dimensional coordinates of the unmanned aerial vehicle corresponding to each millimeter wave radar and the position information corresponding to each millimeter wave radar.

6. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, and the computer program is executed by the processor to implement the method in any one of claims 1-5.

7. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the program to implement the method in any one of claims 1-5.

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