Method and device for measuring height of unmanned aerial vehicle in landing stage, medium and equipment

Abstract

The invention provides an unmanned aerial vehicle landing stage height measurement method and device, a medium and equipment, and the method comprises the steps: taking a current air pressure height as a height fusion index when a current stage is an initial descending stage; when the current stage is a near-earth descent stage, taking the current air pressure height and the current visual height as height fusion indexes; when the current stage is a landing stage, taking the current visual height as a height fusion index; according to the height fusion index and the height variation, fusion processing is carried out to obtain the current fusion height of the unmanned aerial vehicle relative to the landing field, and the height variation is the height difference, obtained based on inertial measurement, of the unmanned aerial vehicle at the current moment relative to the previous moment. By considering the instability of the barometer at low height and the measurement range limitation of visual identification, the precision of the height fusion index is optimized in stages, and the accuracy of the current fusion height calculation result is improved, so that the safe landing of the unmanned aerial vehicle is ensured.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicles (UAVs), and in particular to a method, device, medium and equipment for measuring the height of an unmanned aerial vehicle (UAV) during its landing phase. Background Art

[0002] With the development of low-altitude urban transportation, drones are increasingly used in logistics distribution, urban inspection, emergency rescue and other fields due to their flexibility and high maneuverability. The control process of drones includes take-off, flight and landing. Among them, the landing phase is one of the most complex and critical phases in the flight process of drones.

[0003] During the landing process of a drone, the corresponding parameters need to be adjusted according to the change in its altitude to achieve a safe landing. The accuracy of altitude measurement is extremely high during the landing phase of a drone. How to accurately and quickly obtain the altitude of a drone during the landing phase has become a problem that technicians in this field continue to pay attention to. Summary of the invention

[0004] The purpose of the present invention is to provide a method, device, medium and equipment for measuring the height of an unmanned aerial vehicle during the landing phase, so as to improve the above-mentioned problems.

[0005] In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows: In a first aspect, an embodiment of the present invention provides a method for measuring the height of a drone during landing phase, the method comprising: When the current stage is the initial descent stage, the current pressure altitude is used as the altitude fusion indicator; When the current stage is the ground-closed descent stage, the current pressure altitude and the current visual altitude are used as altitude fusion indicators; When the current stage is the landing stage, the current visual altitude is used as the altitude fusion indicator; A fusion process is performed based on the height fusion index and the height change to obtain a current fusion height of the UAV relative to the landing field, wherein the height change is a height difference of the UAV at a current moment relative to a previous moment obtained based on inertial measurement.

[0006] In a second aspect, an embodiment of the present invention provides a device for measuring the height of a drone during landing phase, the device comprising: The first processing unit is used to use the current pressure altitude as the altitude fusion index when the current stage is the initial descent stage; use the current pressure altitude and the current visual altitude as the altitude fusion index when the current stage is the near-ground descent stage; and use the current visual altitude as the altitude fusion index when the current stage is the landing stage; The second processing unit is used to perform fusion processing according to the height fusion index and the height change to obtain a current fusion height of the UAV relative to the landing field, wherein the height change is the height difference of the UAV at a current moment relative to a previous moment obtained based on inertial measurement.

[0007] In a third aspect, an embodiment of the present invention provides a storage medium having a computer program stored thereon, and the computer program implements the above method when executed by a processor.

[0008] In a fourth aspect, an embodiment of the present invention provides an electronic device, comprising: a processor and a memory, wherein the memory is used to store one or more programs; when the one or more programs are executed by the processor, the above method is implemented.

[0009] Compared with the prior art, the embodiment of the present invention provides a method, device, medium and equipment for measuring the altitude of a drone during landing. When the current stage is the initial descent stage, the current pressure altitude is used as the altitude fusion index; when the current stage is the near-ground descent stage, the current pressure altitude and the current visual altitude are used as the altitude fusion index; when the current stage is the landing stage, the current visual altitude is used as the altitude fusion index; the altitude fusion index and the altitude change are fused to obtain the current fused altitude of the drone relative to the landing field, wherein the altitude change is the altitude difference of the drone at the current moment relative to the previous moment obtained based on inertial measurement. Considering the instability of the barometer at low altitudes and the measurement range limitation of visual recognition, the accuracy of the altitude fusion index is optimized in stages to improve the accuracy of the current fused altitude calculation result to ensure the safe landing of the drone.

[0010] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0012] Figure 1 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention.

[0013] Figure 2 One of the flow charts of the method for measuring the height of a UAV during landing phase provided by an embodiment of the present invention.

[0014] Figure 3 A schematic diagram of a high-level fusion process of a federated Kalman filter provided in an embodiment of the present invention.

[0015] Figure 4 The second flowchart of the method for measuring the height of a UAV during landing phase provided by an embodiment of the present invention.

[0016] Figure 5 The third flowchart of the method for measuring the height of a UAV during landing phase provided by an embodiment of the present invention.

[0017] Figure 6 The fourth flowchart of the method for measuring the height of a UAV during landing phase provided by an embodiment of the present invention.

[0018] Figure 7 A schematic diagram of a unit of a device for measuring the height of a UAV during landing phase provided by an embodiment of the present invention.

[0019] In the figure: 10 - processor; 11 - memory; 12 - bus; 13 - communication interface; 601 - first processing unit; 602 - second processing unit. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0023] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0024] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0025] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0027] The embodiment of the present invention provides an electronic device, which may be a central control unit of a drone, a low-altitude flight management server, or a user terminal device, such as a mobile phone, a computer, etc. Figure 1 , a schematic diagram of the structure of an electronic device. The electronic device includes a processor 10, a memory 11, and a bus 12. The processor 10 and the memory 11 are connected via the bus 12, and the processor 10 is used to execute an executable module stored in the memory 11, such as a computer program.

[0028] The processor 10 can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the method for measuring the height of the drone during the landing phase can be completed by the hardware integrated logic circuit in the processor 10 or the instructions in the form of software. The above-mentioned processor 10 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components.

[0029] The memory 11 may include a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk memory.

[0030] The bus 12 may be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus. Figure 1 Although only one bidirectional arrow is used in the figure, it does not mean that there is only one bus 12 or only one type of bus 12 .

[0031] The memory 11 is used to store programs, such as programs corresponding to the device for measuring the height of the drone during the landing phase. The device for measuring the height of the drone during the landing phase includes at least one software function module that can be stored in the memory 11 in the form of software or firmware or fixed in the operating system (OS) of the electronic device. After receiving the execution instruction, the processor 10 executes the program to implement the method for measuring the height of the drone during the landing phase.

[0032] Possibly, the electronic device provided by the embodiment of the present invention further includes a communication interface 13. The communication interface 13 is connected to the processor 10 via a bus.

[0033] It should be understood that Figure 1The structure shown is only a schematic diagram of a portion of the electronic device. The electronic device may also include Figure 1 More or fewer components as shown, or with Figure 1 Different configurations shown. Figure 1 Each component shown in the figure can be implemented by hardware, software or a combination thereof.

[0034] The method for measuring the height of a drone during landing provided by the embodiment of the present invention can be applied to, but not limited to, Figure 1 For detailed procedures, please refer to the electronic equipment shown in Figure 2 ,The altitude measurement during the landing phase of the UAV includes : S41, S42, S43 and S50, which are described as follows.

[0035] S41, when the current stage is the initial descent stage, the current pressure altitude is used as an altitude fusion index.

[0036] It should be noted that in the initial descent stage, the altitude of the drone is greater than the first threshold, which exceeds the effective measurement range of the visual recognition altitude measurement method, so the current pressure altitude is used as the altitude fusion indicator.

[0037] S42, when the current stage is a near-ground descent stage, the current pressure altitude and the current visual altitude are used as altitude fusion indicators.

[0038] It should be noted that during the near-ground descent phase, the altitude of the UAV is less than or equal to the first threshold and greater than the second threshold. The current pressure altitude and the current visual altitude are used as altitude fusion indicators for fusion processing to ensure the accuracy of the final result.

[0039] When the current stage is the landing stage, S43 uses the current visual altitude as an altitude fusion indicator.

[0040] It should be noted that during the landing phase, the altitude of the drone is less than or equal to the second threshold. At this time, the barometric altimeter is easily affected by environmental factors (such as temperature and air pressure) in the low altitude range near the ground, so the current visual altitude is used as the altitude fusion indicator.

[0041] Among them, the initial descent stage is higher than the near-ground descent stage, the near-ground descent stage is higher than the landing stage, the current pressure altitude is the altitude between the UAV and the landing field measured by the pressure altitude measurement method at the current moment, and the current visual altitude is the altitude between the UAV and the landing field measured by the visual recognition altitude measurement method at the current moment.

[0042] S50, performing fusion processing according to the altitude fusion index and the altitude change amount to obtain the current fusion altitude of the UAV relative to the landing field.

[0043] The height change is the height difference of the drone at the current moment relative to the previous moment obtained based on inertial measurement. The fusion processing method can be fused through the Federated Kalman Filter algorithm. The current fusion height can be used as a control parameter for the drone's landing phase.

[0044] In the method for measuring the altitude of a drone during landing provided in an embodiment of the present invention, taking into account the instability of the barometer at low altitudes and the measurement range limitation of visual recognition, the accuracy of the altitude fusion index is optimized in stages to improve the accuracy of the current fusion altitude calculation result, so as to ensure the safe landing of the drone.

[0045] Optionally, the height change is calculated as:

[0046] in, Indicates the height change, It represents the vertical acceleration of the drone, which can be measured by the inertial measurement device deployed on the drone. t is the current moment, t-1 is the previous moment, and t in the formula is greater than or equal to 1. When t is 1, t-1=0, indicating the initial moment.

[0047] The embodiment of the present invention further provides a filter group, which includes a first Kalman filter, a second Kalman filter and a main filter, wherein the first Kalman filter, the second Kalman filter and the main filter constitute a Federated Kalman Filter. The filter group can use a Federated Kalman filter algorithm to fuse the current pressure altitude, the current visual altitude and the altitude change, eliminate the respective measurement errors, and obtain more accurate altitude data, that is, obtain the current fused altitude of the drone relative to the reference surface.

[0048] On this basis, regarding the content in S50, the present invention also provides an optional implementation method, please refer to the following.

[0049] When the UAV is in the initial descent stage, S50, the step of fusing the altitude fusion index and the altitude change to obtain the current fusion altitude of the UAV relative to the landing field includes: S511, S512 and S513, which are specifically described as follows.

[0050] S511, input the current air pressure altitude and altitude change into the first Kalman filter.

[0051] S512, the first Kalman filter generates a current pressure altitude estimate and a current pressure altitude covariance estimate according to the current pressure altitude, altitude change, the fusion altitude at the last moment, and the fusion covariance at the last moment.

[0052] S513, the main filter determines the current fusion altitude and the current fusion covariance at the current moment according to the current pressure altitude estimate, the current pressure altitude covariance estimate, and the altitude change.

[0053] When the UAV is in the near-ground descent phase, S50, the steps of fusing the altitude fusion index and the altitude change to obtain the current fusion altitude of the UAV relative to the landing field include: S521, S522, S523, S524 and S525, which are described in detail as follows.

[0054] S521, input the current air pressure altitude and altitude change into the first Kalman filter.

[0055] S522, input the current visual altitude and altitude change into a second Kalman filter.

[0056] S523, the first Kalman filter generates a current pressure altitude estimate and a current pressure altitude covariance estimate according to the current pressure altitude, altitude change, the fusion altitude at the last moment, and the fusion covariance at the last moment.

[0057] S524, the second Kalman filter generates a current visual altitude estimate and a current visual altitude covariance estimate according to the current visual altitude, the altitude change, the fusion altitude at the last moment, and the fusion covariance at the last moment.

[0058] S525, the main filter determines the current fusion altitude and the current fusion covariance at the current moment according to the current pressure altitude estimate, the current pressure altitude covariance estimate, the current visual altitude estimate, the current visual altitude covariance estimate, and the altitude change.

[0059] When the UAV is in the landing stage, S50, the step of fusing the height fusion index and the height change to obtain the current fusion height of the UAV relative to the landing field includes: S531, S532 and S533, which are specifically described as follows.

[0060] S531, input the current visual altitude and altitude change into the second Kalman filter.

[0061] S532, the second Kalman filter generates a current visual altitude estimate and a current visual altitude covariance estimate according to the current visual altitude, the altitude change, the fusion altitude at the last moment, and the fusion covariance at the last moment.

[0062] S533, the main filter determines the current fusion height and the current fusion covariance at the current moment according to the current visual height estimation value, the current visual height covariance estimation value and the height change.

[0063] Please refer to Figure 3 , Figure 3 A schematic diagram of a federated Kalman filter altitude fusion process provided by an embodiment of the present invention. The first Kalman filter is a pressure altitude Kalman filter, and the second Kalman filter is a visual altitude Kalman filter. Indicates the current air pressure altitude. Indicates the height change, Indicates the current visual height. Indicates the current pressure altitude estimate, Represents the estimated value of the current high and low pressure covariance, Represents the current visual height estimate, represents the current visual height covariance estimate, Indicates the current fusion height, Represents the current fusion covariance.

[0064] like Figure 3 As shown, the altitude change is derived from the measurement data of the inertial measurement unit, the current pressure altitude is derived from the measurement data of the barometer, and the current visual altitude is derived from the measurement data of the visual recognition model. By controlling the first switch set at the rear end of the barometer and the second switch at the rear end of the visual recognition model, the corresponding altitude fusion index and altitude change can be input into the filter group in the initial descent stage, the near-ground descent stage, and the landing stage.

[0065] During the initial descent stage and the near-ground descent stage, the first switch is in a closed state, and during the near-ground descent stage and the landing stage, the second switch is in a closed state.

[0066] Taking the near-ground descent phase as an example, the current pressure altitude and altitude change are input into the first Kalman filter. The current visual altitude and altitude change are input into the second Kalman filter. The main filter will feed back the current fusion altitude and current fusion covariance obtained to the first Kalman filter and the second Kalman filter. Therefore, the first Kalman filter and the second Kalman filter can obtain the fusion altitude and fusion covariance of the previous moment.

[0067] Then, the first Kalman filter generates a current pressure altitude estimate and a current pressure altitude covariance estimate according to the current pressure altitude, altitude change, fusion altitude at the last moment, and fusion covariance at the last moment. The second Kalman filter generates a current visual altitude estimate and a current visual altitude covariance estimate according to the current visual altitude, altitude change, fusion altitude at the last moment, and fusion covariance at the last moment.

[0068] The first Kalman filter can send the current pressure altitude estimate and the current pressure altitude covariance estimate to the main filter, and the second Kalman filter can send the current visual altitude estimate and the current visual altitude covariance estimate to the main filter. The main filter determines the current fusion altitude and the current fusion covariance at the current moment according to the current pressure altitude estimate, the current pressure altitude covariance estimate, the current visual altitude estimate, the current visual altitude covariance estimate, and the altitude change.

[0069] It should be understood that the height data of the inertial measurement unit is combined with the federated Kalman filter algorithm. Fusion eliminates the respective measurement errors and obtains more accurate height data.

[0070] It should be noted that when the drone enters the landing phase Moments, covariance and Altitude estimation based on route Perform calculations.

[0071] Based on the above, regarding how to obtain the current air pressure altitude between the drone and the landing field, the embodiment of the present invention also provides an optional implementation method, please refer to Figure 4 When the UAV is in the initial descent stage and the near-ground descent stage, the UAV landing stage altitude measurement method also includes: S11 and S12, which are described in detail as follows.

[0072] S11, obtaining the current landing field temperature, the current landing field air pressure, and the current drone air pressure.

[0073] It should be understood that a barometer may be provided on the drone to obtain the current drone air pressure, and a barometer and a temperature measuring device may be provided at the landing field to obtain the current landing field air pressure and the current landing field temperature.

[0074] S12, obtaining the current air pressure altitude between the drone and the landing field according to the current landing field temperature, the current landing field air pressure, and the current drone air pressure.

[0075] Optionally, the current pressure altitude between the drone and the landing field is calculated as follows:

[0076] in, Indicates the current air pressure altitude (unit, meter), Indicates the current landing field temperature (unit: Kelvin, K), Indicates the current drone air pressure (unit: Pascal, Pa), It represents the current air pressure at the landing field (unit: Pascal, Pa), L represents the rate of decrease of temperature with altitude (can be 0.0065 K / m), R represents the gas constant, whose value can be 287.05 J / (kg·K), g is the standard acceleration of gravity, which is about 9.80665 m / s², and M is the average molar mass of air, which is about 0.028964 kg / mol.

[0077] Based on the above, regarding how to obtain the current visual altitude of the drone, the embodiment of the present invention also provides an optional implementation method, please refer to Figure 5 When the UAV is in the near-ground descent phase, the UAV landing phase altitude measurement method further includes: S21 and S22, which are described in detail as follows.

[0078] S21, collecting the first type of images corresponding to the first type of targets deployed at the landing site.

[0079] The first type of target is a large target. Large targets are usually a set of fixed images that have obvious characteristics compared to other things in the landing field environment. The images need to have a fixed outline size and features that can be used to distinguish the direction. They are mainly used to assist in the initial landing stage positioning. The large target is at the same height as the landing field.

[0080] S22, inputting the first type of image and the current posture of the drone into the visual recognition model to obtain the current visual altitude.

[0081] It should be noted that the visual recognition model can be a machine learning model trained to a convergence state through label data, also known as a target recognition model, which is deployed in the electronic device. The recognition success rate in different scenarios is greater than δ.

[0082] When the height of the UAV is less than or equal to the first threshold (the effective recognition upper limit of the first type of target), that is, when the height of the large target image can be clearly observed, visual recognition is turned on, and the first type of image and the current posture of the UAV are input into the visual recognition model to obtain the current visual height.

[0083] Based on the above, regarding how to obtain the current visual altitude of the drone, the embodiment of the present invention also provides an optional implementation method, please refer to Figure 6 When the UAV is in the landing phase, the UAV landing phase height measurement method further includes: S31 and S32, which are described in detail as follows.

[0084] S31, collecting the second type of images corresponding to the second type of targets deployed at the landing site.

[0085] Among them, the plane area of ​​the second type of target is smaller than that of the first type of target. The second type of target is a small target, which is an additional identification feature on the large target. It is mainly used as a supplementary positioning method when the flight altitude is lower than a certain level and the camera field of view cannot fully capture the image of the large target. It assists the aircraft in near-ground positioning and final landing. The small target needs to have a fixed outline size and features for distinguishing the direction.

[0086] S32, inputting the second type of image and the current posture of the UAV into the visual recognition model to obtain the current visual altitude.

[0087] When the height of the UAV is less than or equal to the second threshold (the effective recognition upper limit of the second type of target), that is, when the small target image can be clearly observed, the second type of image and the current posture of the UAV are input into the visual recognition model to obtain the current visual height to ensure its accuracy.

[0088] In an optional implementation, after obtaining the current fused height of the drone relative to the landing field, it can also be converted according to a conversion coefficient to obtain the current height of the drone relative to the height reference plane. The conversion coefficient represents the height difference between the landing field and the height reference plane.

[0089] See also Figure 7 , Figure 7 An embodiment of the present invention provides a device for measuring the height of a drone during the landing phase. Optionally, the device for measuring the height of a drone during the landing phase is applied to the electronic device described above.

[0090] The device for measuring the altitude of a drone during landing phase includes: a first processing unit 601 and a second processing unit 602 .

[0091] The first processing unit 601 is used to use the current pressure altitude as the altitude fusion index when the current stage is the initial descent stage; use the current pressure altitude and the current visual altitude as the altitude fusion index when the current stage is the near-ground descent stage; and use the current visual altitude as the altitude fusion index when the current stage is the landing stage; The second processing unit 602 is used to perform fusion processing according to the height fusion index and the height change to obtain the current fusion height of the UAV relative to the landing field, wherein the height change is the height difference of the UAV at the current moment relative to the previous moment obtained based on inertial measurement.

[0092] Optionally, the second processing unit 602 may execute the above S50, and the first processing unit 601 may execute the above other steps.

[0093] It should be noted that the device for measuring the height of a drone during landing provided in this embodiment can execute the method flow shown in the above method flow embodiment to achieve the corresponding technical effect. For the sake of brief description, for parts not mentioned in this embodiment, reference can be made to the corresponding contents in the above embodiment.

[0094] The embodiment of the present invention further provides a storage medium, which stores computer instructions and programs, and when the computer instructions and programs are read and run, the method for measuring the height of the landing phase of the drone in the above embodiment is executed. The storage medium may include a memory, a flash memory, a register, or a combination thereof.

[0095] The following provides an electronic device, which may be a central control unit of a drone, a low-altitude flight management server, or a user terminal device, such as a mobile phone, a computer, etc. The electronic device may be Figure 1 As shown, the above-mentioned method for measuring the height of the drone during the landing phase can be implemented; specifically, the electronic device includes: a processor 10, a memory 11, and a bus 12. The processor 10 can be a CPU. The memory 11 is used to store one or more programs. When the one or more programs are executed by the processor 10, the above-mentioned method for measuring the height of the drone during the landing phase is executed.

[0096] In summary, the embodiment of the present invention provides a method, device, medium and equipment for measuring the altitude of a drone during landing. When the current stage is the initial descent stage, the current pressure altitude is used as the altitude fusion index; when the current stage is the near-ground descent stage, the current pressure altitude and the current visual altitude are used as the altitude fusion index; when the current stage is the landing stage, the current visual altitude is used as the altitude fusion index; the altitude fusion index and the altitude change are fused to obtain the current fused altitude of the drone relative to the landing field, wherein the altitude change is the altitude difference of the drone at the current moment relative to the previous moment obtained based on inertial measurement. Considering the instability of the barometer at low altitudes and the measurement range limitation of visual recognition, the accuracy of the altitude fusion index is optimized in stages to improve the accuracy of the current fused altitude calculation result to ensure the safe landing of the drone.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0098] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for measuring the height of an unmanned aerial vehicle during landing phase, characterized in that: The method comprises: When the current stage is the initial descent stage, the current pressure altitude is used as the altitude fusion indicator; When the current stage is the ground-closed descent stage, the current pressure altitude and the current visual altitude are used as altitude fusion indicators; When the current stage is the landing stage, the current visual altitude is used as the altitude fusion indicator; A fusion process is performed based on the height fusion index and the height change to obtain a current fusion height of the UAV relative to the landing field, wherein the height change is a height difference of the UAV at a current moment relative to a previous moment obtained based on inertial measurement.

2. The method for measuring the height of a drone during landing phase as claimed in claim 1, characterized in that: When the UAV is in the initial descent stage, the step of fusing the height fusion index with the height change to obtain the current fusion height of the UAV relative to the landing field includes: Inputting the current air pressure altitude and the altitude change into a first Kalman filter; The first Kalman filter generates a current pressure altitude estimate and a current pressure altitude covariance estimate according to the current pressure altitude, the altitude change, the fusion altitude at the last moment, and the fusion covariance at the last moment; The main filter determines the current fusion altitude and the current fusion covariance at the current moment according to the current pressure altitude estimate, the current pressure altitude covariance estimate, and the altitude change.

3. The method for measuring the height of a drone during landing phase as claimed in claim 1, characterized in that: When the UAV is in the near-ground descent stage, the step of fusing the altitude fusion index with the altitude change to obtain the current fusion altitude of the UAV relative to the landing field includes: Inputting the current air pressure altitude and the altitude change into a first Kalman filter; Inputting the current visual altitude and the altitude change into a second Kalman filter; The first Kalman filter generates a current pressure altitude estimate and a current pressure altitude covariance estimate according to the current pressure altitude, the altitude change, the fusion altitude at the last moment, and the fusion covariance at the last moment; The second Kalman filter generates a current visual height estimation value and a current visual height covariance estimation value according to the current visual height, the height change, the fusion height at the last moment, and the fusion covariance at the last moment; The main filter determines the current fusion altitude and the current fusion covariance at the current moment according to the current pressure altitude estimate, the current pressure altitude covariance estimate, the current visual altitude estimate, the current visual altitude covariance estimate, and the altitude change.

4. The method for measuring the height of a drone during landing phase as claimed in claim 1, characterized in that: When the UAV is in the landing stage, the step of fusing the height fusion index with the height change to obtain the current fusion height of the UAV relative to the landing field includes: Inputting the current visual altitude and the altitude change into a second Kalman filter; The second Kalman filter generates a current visual height estimation value and a current visual height covariance estimation value according to the current visual height, the height change, the fusion height at the last moment, and the fusion covariance at the last moment; The main filter determines the current fusion height and the current fusion covariance at the current moment according to the current visual height estimation value, the current visual height covariance estimation value and the height change.

5. The method for measuring the height of a drone during landing phase as claimed in claim 1, characterized in that: When the UAV is in the initial descent stage and the near-ground descent stage, the method further includes: Get the current landing field temperature, current landing field air pressure, and current drone air pressure; The current air pressure altitude between the drone and the landing field is obtained according to the current landing field temperature, the current landing field air pressure, and the current drone air pressure.

6. The method for measuring the height of a drone during landing phase as claimed in claim 1, characterized in that: When the UAV is in a near-ground descent phase, the method further includes: Collecting a first type of image corresponding to a first type of target deployed at the landing site; The first type of image and the current posture of the drone are input into a visual recognition model to obtain the current visual altitude.

7. The method for measuring the height of a drone during landing phase as claimed in claim 6, characterized in that: When the drone is in the landing phase, the method further includes: Collecting a second type of image corresponding to a second type of target deployed at the landing field, wherein a plane area of ​​the second type of target is smaller than a plane area of ​​the first type of target; The second type of image and the current posture of the UAV are input into a visual recognition model to obtain the current visual altitude.

8. A device for measuring the height of a drone during landing, characterized in that: The device comprises: The first processing unit is used to use the current pressure altitude as the altitude fusion index when the current stage is the initial descent stage; use the current pressure altitude and the current visual altitude as the altitude fusion index when the current stage is the near-ground descent stage; and use the current visual altitude as the altitude fusion index when the current stage is the landing stage; The second processing unit is used to perform fusion processing according to the height fusion index and the height change to obtain a current fusion height of the UAV relative to the landing field, wherein the height change is the height difference of the UAV at a current moment relative to a previous moment obtained based on inertial measurement.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

10. An electronic device, characterized in that: include: A processor and a memory, the memory being used to store one or more programs; When the one or more programs are executed by the processor, the method according to any one of claims 1 to 7 is implemented.

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