Helical navigation method and drone

Abstract

The application provides a tracking target position information acquisition method, a hovering navigation method and an unmanned aerial vehicle. The tracking target position information acquisition method comprises the following steps: selecting a tracking target; acquiring parameters such as a heading angle β of a flying vehicle and an optoelectronic platform azimuth angle α; calculating a horizontal distance X between the flying vehicle and the tracking target; making the flying vehicle fly around the tracking target; and acquiring tracking target position information such as a latitude circle radius R of a latitude circle where the flying vehicle is located, a latitude circle half angle θ of the latitude circle, a longitude deviation amount ΔL of the flying vehicle and the tracking target, and the like in sequence. w The application summarizes the calculation methods of an east component ΔE and a north component ΔN when the unmanned aerial vehicle flies at different heading angles β and observes the tracking target at different optoelectronic platform azimuth angles α. Meanwhile, the application can automatically set a hovering mode and a hovering radius through the optoelectronic platform azimuth angle α and the horizontal distance X between the unmanned aerial vehicle and the tracking target, thereby solving the problems of poor real-time performance and poor observation effect of the traditional method.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) navigation, and more particularly to a hovering navigation method and a UAV. Background Technology

[0002] With few limitations imposed by weather conditions, drones can infiltrate enemy airspace for day and night reconnaissance and accurately transmit real-time target images and information to the combat command center, enabling battlefield commanders to promptly grasp the battlefield situation and formulate combat plans. Drones have gradually demonstrated their enormous power in modern local wars.

[0003] During UAV missions, hovering is a common maneuver performed by UAVs when conducting long-term reconnaissance around a target. Traditional UAV hovering navigation methods continuously calculate navigation parameters such as lateral deviation and lateral offset speed of the desired trajectory based on a predetermined hovering radius, desired hovering pattern, and UAV position, altitude, and ground speed information obtained from sensors. These parameters, along with UAV attitude motion information obtained from attitude motion sensors, are input into the lateral control loop to obtain rudder deflection commands, thus guiding the UAV to hover along the desired flight path.

[0004] In the process of realizing this invention, the applicant found that the traditional UAV hovering navigation method is relatively complicated in calculating the position information of a specific tracking target in the task of reconnaissance in unfamiliar environment, and has low accuracy and poor real-time performance. It can only set the flight path by roughly estimating the target position. Moreover, when the UAV is tracking a moving target, it cannot correct the flight path in time according to the changes in the position of the tracking target, and the tracking target is often lost, making it difficult to achieve the best tracking effect. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] In view of this, the present invention provides a hovering navigation method and an unmanned aerial vehicle (UAV), which is expected to at least partially solve one of the above-mentioned technical problems.

[0007] (II) Technical Solution

[0008] In a first aspect of the present invention, a method for obtaining tracking target location information is provided, comprising:

[0009] Step A: Identify targets within the field of view of the aircraft's camera and select the target to track;

[0010] Step B: Lock onto and track the target, and obtain the aircraft's heading angle β, the electro-optical platform's azimuth angle α, the straight-line distance L between the aircraft and the target, and the aircraft's actual flight altitude H;

[0011] Step C, calculate the horizontal distance X between the aircraft and the tracked target: ;

[0012] Step D: Using the real-time position of the tracked target as the center of rotation and the horizontal distance X as the predetermined rotation radius Rturn, the aircraft is made to rotate around the tracked target.

[0013] Step E: Calculate the angle θ between the observation direction of the photoelectric platform and the north direction based on the heading angle β of the aircraft and the azimuth angle α of the photoelectric platform; calculate the north component ΔN and east component ΔE of the spatial vector from the aircraft to the tracked target in the spatial rectangular coordinate system based on the horizontal distance X and the angle θ.

[0014] Step F: Calculate the geocentric radius R of the spacecraft's location. q : Geocentric latitude B EC : Where B is the geographical latitude of the aircraft, H is the actual flight altitude of the aircraft, and R is the geographical latitude of the aircraft. a R b f represents the Earth's semi-major axis, semi-minor axis, and ellipsoid, respectively.

[0015] Step G, based on the northward component ΔN and the geocentric radius R q Obtain the geocentric latitude deviation ΔB between the aircraft and the tracked target. C In order to obtain the geocentric latitude B of the target being tracked. ECC With geographical latitude B C ;

[0016] Step H, based on the Earth's central radius R of the spacecraft's location. q Geocentric latitude B EC Obtain the radius R of the latitude circle where the spacecraft is located. w Based on the radius R of the latitude circle where the aircraft is located w Obtain the circumference C of the weft coil b According to the eastward vector ΔE and the circumference C of the latitude circle... b Obtain the geographical longitude deviation ΔL between the aircraft and the tracked target.

[0017] In a second aspect of the present invention, a hovering navigation method is provided, comprising:

[0018] The method for obtaining the location information of the tracking target as described above;

[0019] Following step H, the following is also included:

[0020] Step I, based on the Earth's semi-major axis R a Geographic latitude B of the target being tracked CObtain the geocentric radius R at the center of the spiral circle. p :

[0021] Step J, based on the geographical longitude deviation ΔL and the geocentric latitude B of the tracking target... ECC The geocentric latitude of the spacecraft B EC The Earth's central radius R at the center of the spiral circle p Obtain the eastward component Δx and northward component Δy of the spatial vector from the current position to the center of the hovering circle in a Cartesian coordinate system; obtain the distance D from the current position of the aircraft to the center of the hovering circle from the eastward vector Δx and the northward component Δy; obtain the lateral offset D of the aircraft from the distance D and the hovering radius Rturn. Z ;

[0022] Step K involves obtaining the angle γ between the spatial vector from the center of the hovering circle to the current position of the spacecraft and the eastward direction, based on the eastward component Δx and the northward component Δy, and then obtaining the lateral offset velocity D based on this angle γ. Zd ;

[0023] Step L, the lateral offset D Z and lateral offset speed D Zd The lateral control loop of the aircraft is input to obtain the rudder deflection command, which guides the aircraft to circle around the target.

[0024] In a third aspect of the invention, the drone includes: a memory; and a processor electrically coupled to the memory, configured to execute, based on instructions stored in the memory, the method for acquiring tracking target location information as described above or the drone hovering and navigation method as described above.

[0025] (III) Beneficial Effects

[0026] As can be seen from the above technical solution, the present invention has at least one of the following beneficial effects compared to the prior art:

[0027] (1) By combining the azimuth angle α and the UAV heading angle β when tracking the target using the photoelectric platform, along with the straight-line distance L between the UAV and the tracked target measured by the lidar and the UAV's flight altitude H, the eastward component ΔE and the northward component ΔN of the spatial vector from the UAV to the tracked target in the spatial rectangular coordinate system are obtained. Compared with the traditional method of obtaining these two parameters, this invention summarizes the calculation method of the eastward component ΔE and the northward component ΔN when the UAV flies at different heading angles β and observes and tracks the target using different photoelectric platform azimuth angles α; at the same time, this invention can automatically obtain and set the hovering mode through the photoelectric platform azimuth angle α, avoiding the impact on the flight safety of the UAV caused by unreasonable trajectory setting.

[0028] (2) By using the eastward component ΔE and northward component ΔN of the spatial vector from the UAV to the tracked target in the spatial rectangular coordinate system, the geocentric radius Rq and geocentric latitude B of the UAV's location are obtained. EC and the circumference C of the latitude circle where the drone is located b This allows us to obtain the geocentric latitude deviation ΔB between the UAV and the tracked target. C The deviation ΔL between the UAV and the geographic longitude is calculated in real time, using the position of the target tracked by the photoelectric platform as the hovering center, compared to traditional methods for obtaining the geocentric latitude and longitude deviation between the UAV and the tracked target. This avoids the problems of tedious manual calculation and the inability to achieve optimal observation results due to the only rough estimation of the target position during hovering flight.

[0029] (3) Because the target can be continuously tracked and observed through the photoelectric platform, and the lateral deviation D of the UAV during hovering flight can be quickly and in real time calculated through this invention. Z With lateral offset speed D Zd It guides the drone to hover along a trajectory that maintains a fixed distance from the target. By consistently hovering with the target at its center, it avoids the frequent course corrections caused by target movement and the influence of other factors such as wind interference, achieving the most ideal reconnaissance and observation results and minimizing the possibility of losing track of the target. Attached Figure Description

[0030] Figure 1 This is a flowchart of the drone hovering and navigation method according to an embodiment of the present invention.

[0031] Figure 2 For example Figure 1 The diagram shows the flight trajectory of the UAV when it is hovering and circling to track the target in the UAV hovering navigation method shown.

[0032] Figure 3 For example Figure 1 The diagram shows the angle between the observation direction of the UAV's optoelectronic platform and the north direction in the UAV hovering navigation method.

[0033] Figure 4 For example Figure 1 The diagram illustrates the relationship between different vertical lines and latitudes in the drone hovering and navigation method.

[0034] Figure 5 For example Figure 1 The diagram shows the latitude circle and radius of the UAV in the UAV hovering navigation method.

[0035] Figure 6 This is a schematic diagram illustrating the overall working principle of the drone hovering and navigation method implemented in an embodiment of the present invention. Detailed Implementation

[0036] This invention proposes a method for acquiring target location information, a hovering navigation method, and a drone, which can guide the drone to hover and adjust the trajectory in real time according to the relative positional relationship between the drone and the target being tracked.

[0037] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0038] In the embodiments described below, a complete hovering navigation method will be provided, and the method for obtaining the tracking target's position information will be described therein. However, those skilled in the art will understand that the tracking target's position information can be used in other fields besides hovering navigation, such as providing precise position information for missiles and artillery shells to strike targets. Therefore, the method for obtaining the tracking target's position information described below can be implemented independently of the hovering navigation method and should also be within the scope of protection of this invention. Furthermore, although the following embodiments use a drone as an example, other aircraft, such as manned aircraft and loitering munitions, can also be applied.

[0039] In an exemplary embodiment of the present invention, a method for hovering and guiding a drone is provided. Based on a predetermined tracking target, hovering radius, desired hovering mode, and drone position, altitude, and ground speed information obtained from sensors, the method continuously and in real time tracks the target, obtains navigation parameters such as lateral deviation and lateral offset speed of the drone's desired trajectory, and ultimately guides the drone to hover and track the target along the desired route.

[0040] Figure 1 This is a flowchart of a drone hovering and navigation method according to an embodiment of the present invention. Figure 1 As shown, the drone hovering and navigation method in this embodiment includes:

[0041] Step A: Use the YOLO deep learning algorithm and the Scale-invariant feature transform (SIFT) algorithm to identify and track targets within the field of view of the visible light camera. On the observation interface, the real-time detected targets are bounded out and the target type and its ID are output. The target to be tracked is selected.

[0042] In this step, YOLO and SIFT target recognition and tracking technologies are used to identify and display common battlefield targets in real time, so that when it is necessary to change the target tracking and hovering flight, the target can be quickly switched.

[0043] In this step, the target to be tracked can be selected automatically, selected by the drone operator, or automatically selected and then corrected by the drone operator; all of these are within the scope of protection of this invention.

[0044] Step B: Lock onto and track the target, and obtain the aircraft's heading angle β, the electro-optical platform's azimuth angle α, and the straight-line distance L between the aircraft and the target.

[0045] Step B further includes:

[0046] Sub-step B1 involves using an optoelectronic platform to lock onto and track the target.

[0047] Sub-step B2 involves obtaining the heading angle β of the aircraft and the azimuth angle α of the photoelectric platform from the corresponding sensors installed on the aircraft.

[0048] In sub-step B3, the straight-line distance L between the UAV and the tracked target is measured using a laser rangefinder, and the distance L and the azimuth angle α of the photoelectric platform are output to the observation interface.

[0049] Those skilled in the art will understand that the azimuth angle α of the optoelectronic platform is obtained by a corresponding sensor mounted on the aircraft. Besides laser ranging, other methods can also be used to measure the straight-line distance between the UAV and the tracked target, such as radar ranging, which will not be elaborated upon here.

[0050] Step C: Based on the actual flight altitude H of the UAV given by the radio altimeter and the real-time laser ranging result L, calculate the horizontal distance X between the UAV and the tracked target using the distance formula between two points:

[0051] (1)

[0052] Step D: Using the real-time position of the tracked target as the hovering center and the horizontal distance X between the UAV and the tracked target as the predetermined hovering radius Rturn, the UAV hovers around the tracked target.

[0053] The predetermined turning radius Rturn is constrained by the UAV's turning performance; the turning mission begins when the UAV's turning performance is met. The turning pattern is determined by the azimuth angle α when the electro-optical platform locks onto and tracks the target, as shown in the attached figure. Figure 2 As shown, specifically, as shown in the following formula:

[0054] (2)

[0055] Step E: As attached Figure 3As shown, based on the UAV's heading angle β and the electro-optical platform's azimuth angle α, the angle θ between the electro-optical platform's observation direction and the north direction is calculated. Furthermore, based on the horizontal distance X between the UAV and the tracked target, the eastward component ΔE and the northward component ΔN of the spatial vector from the UAV to the tracked target in the Cartesian coordinate system are calculated.

[0056] (3)

[0057] (4)

[0058] Step F: Obtain the geocentric radius R of the drone's location based on the drone's latitude B. q And based on the drone's altitude H and geographical latitude B, the drone's geocentric latitude B can be obtained. EC :

[0059] (5)

[0060] (6)

[0061] The actual flight altitude H and geographical latitude B of the drone are obtained by the corresponding sensors on board.

[0062] To describe the position of a UAV relative to the Earth and perform navigation and positioning, the first step is to select a reference ellipsoid. Thanks to advancements in satellite and telemetry technologies, global geodetic data can now be obtained using satellite measurements, allowing for the fitting of a global geodetic coordinate system. The WGS_84 coordinate system, established in 1984, is a global geodetic coordinate system suitable for global positioning. Selecting the WGS_84 coordinate system determines the Earth's semi-major axis and ellipsoidal parameters. Based on this coordinate system, the Earth's semi-major axis R... a = 6378137.0m, short half-axis R b = 6356752.3m, Earth's ellipsoid f = 0.003352811.

[0063] Commonly used perpendicular lines and latitudes for a point on the Earth's surface include: geographic perpendicular and geographic latitude, and geocentric perpendicular and geocentric latitude. The geographic perpendicular is the normal to a point on the reference ellipsoid, and the angle between the geographic perpendicular and the equatorial plane is the geographic latitude. The geocentric perpendicular is the line connecting a point on the reference ellipsoid to the Earth's center, and the angle between the geocentric perpendicular and the equatorial plane is the geocentric latitude. (See attached diagram.) Figure 4 As shown. Let the location of the UAV be C, the geocenter be O, CA be the geographic perpendicular, B be the geographic latitude, and CO be the geocentric perpendicular, which is also the geocentric radius R. q The geocentric latitude is B EC .

[0064] Step G involves using the northward component ΔN of the spatial vector from the UAV to the tracked target in a Cartesian coordinate system and the geocentric radius R of the UAV's location. q The geocentric latitude deviation ΔB between the UAV and the target was calculated. C And then obtain the geocentric latitude B of the target being tracked. ECC With geographical latitude B C :

[0065] (7)

[0066] (8)

[0067] (9)

[0068] Step H, based on the UAV's geocentric latitude B EC The Earth's central radius R of the location of the drone q The radius R of the latitude circle where the UAV is located is calculated using equation (10). w As attached Figure 5 As shown. The circumference C of this weft circle is obtained from equation (11). b Based on the eastward component ΔE of the spatial vector from the UAV to the tracked target in the Cartesian coordinate system and the circumference C of the latitude circle, b Obtain the geographical longitude deviation ΔL between the UAV and the target, as shown in equation (12):

[0069] (10)

[0070] (11)

[0071] (12)

[0072] Those skilled in the art will understand that this invention uses the azimuth angle α of the photoelectric platform and the heading angle β of the UAV to obtain the eastward component ΔE and the northward component ΔN of the spatial vector from the UAV to the tracked target in a spatial rectangular coordinate system, and calculates the geocentric radius R of the UAV's location. q With geocentric latitude B EC This allows us to obtain the geographical longitude deviation ΔL and geocentric latitude deviation ΔB between the UAV and the tracked target. C Then, the geocentric latitude B of the target being tracked is obtained. ECC With geographical latitude B C Compared to existing technologies, this invention can track targets in real time and calculate target location information, avoiding the tediousness of manual calculations or the problem of only being able to roughly estimate the target location.

[0073] It should be noted that in this embodiment, steps A through H can be executed independently to obtain the location information of the tracked target. This target location information can support UAV hovering navigation or other potential applications. The application of the aforementioned target location information in UAV hovering navigation will be further explained below.

[0074] Step I: Based on the geographic latitude B of the target being tracked C Calculate the geocentric radius R at the center of the spiral circle. p :

[0075] (13)

[0076] Step J: Obtain the distance D from the UAV to the center of the hovering circle and the UAV's lateral deviation D. Z .

[0077] When using a coordinate system fixed to the Earth's center as the origin for navigation and positioning, methods typically employ both spatial rectangular coordinates and latitude / longitude and altitude. When calculating the distance between two points in space, the latitude / longitude and altitude information needs to be converted to a spatial rectangular coordinate system for calculation. This is based on the geographical longitude deviation ΔL between the hovering center and the current UAV position, and the geocentric latitude B of the hovering center. ECC The geocentric latitude B of the drone EC And the Earth's central radius R at the center of the spiral circle p The eastward component Δx and the northward component Δy of the spatial vector from the current position to the center of the spiral circle are calculated in the spatial rectangular coordinate system:

[0078] (14)

[0079] The distance D from the current position of the drone to the center of the hovering circle can be obtained from the formula for the distance between two points:

[0080] (15)

[0081] Based on the distance D of the UAV from the center of the hovering circle and the predetermined hovering radius Rturn, the lateral deviation D of the UAV is calculated using equation (16). Z :

[0082] (16)

[0083] Step K: Obtain the angle γ between the spatial vector from the center of the hovering circle to the current position of the UAV and the eastward direction, and obtain the lateral offset velocity D based on this angle γ. Zd ;

[0084] The angle γ between the spatial vector from the center of the hovering circle to the current position of the UAV and the eastward direction is:

[0085] (17)

[0086] Depending on the hovering method, the obtained lateral offset velocity will also be different, as shown in equation (18):

[0087] (18)

[0088] Among them, V dn V is the northbound ground speed of the drone. de The eastward ground speed of the drone can be obtained from the drone's corresponding sensors.

[0089] Step L: Set the lateral offset D of the drone Z and lateral offset speed D Zd The rudder deflection command is output to the UAV's lateral control loop, enabling the UAV to fly along the desired route.

[0090] When the UAV attempts to hover and guide the target, steps A to L are repeated according to a preset period, guiding the UAV to hover around the target in real time. The preset period is between 10 ms and 50 ms. Preferably, the preset period is between 20 ms and 30 ms. In this embodiment, the preset period is 25 ms.

[0091] In this embodiment, the lateral offset and lateral deflection speed of the UAV relative to the tracked target are calculated in real time and input into the lateral control loop to obtain the rudder deflection command. The flight path of the UAV is corrected in real time to maintain hovering flight centered on the tracked target. This avoids the influence of other factors such as target movement, complex target position information calculation and wind interference, and can achieve the most ideal reconnaissance and observation effect.

[0092] Furthermore, the hovering navigation method provided by this invention can realize real-time calculation of the target's position information and guide the UAV to hover along a trajectory at a fixed distance from the target. It improves the inconvenience of manual calculation when locating unfamiliar targets and setting corresponding hovering trajectories, avoids the problem of not being able to use the target as the hovering center when hovering in place for reconnaissance, and can also correct the trajectory in time when the target moves slowly, maintain tracking, and is less likely to lose the target, and does not require manual setting of flight paths.

[0093] According to another aspect of the present invention, a drone is also provided. The drone includes: a memory; and a processor electrically coupled to the memory, configured to execute, based on instructions stored in the memory, the target location information acquisition method described above or the drone hovering and navigation method described above.

[0094] Figure 6This is a schematic diagram illustrating the overall working principle of the UAV hovering and navigation method according to an embodiment of the present invention. Figure 6 As shown, in this embodiment, after the hovering begins, the photoelectric platform provides information such as the hovering center, the predetermined hovering radius, and the hovering mode to the processor in the UAV. Simultaneously, parameters such as the UAV's position, altitude, ground speed, and the straight-line distance between the UAV's altitude and the tracked target are provided to the processor by corresponding sensors. The processor obtains the lateral offset D according to the UAV hovering navigation method provided by this invention. Z and lateral offset speed D Zd These two parameters are then input into the UAV's lateral control loop. The lateral control loop, combined with the UAV's attitude motion information provided by the attitude motion sensor, obtains the rudder deflection command, which is then input into the UAV's flight control system via the rudder loop, ultimately guiding the UAV to track and hover along the desired flight path.

[0095] The embodiments of the present invention have now been described in detail with reference to the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of the present invention.

[0096] In summary, this invention can calculate the target position information in real time, avoiding the tediousness of manual calculation or the problem that the target position can only be roughly estimated for hovering flight. This allows the UAV to hover around the preset tracking target, improving the shortcomings of traditional technology where only the hovering direction and radius are set, resulting in difficulty in accurately controlling the hovering center position and tedious calculation. It has good application prospects.

[0097] It should be noted that for some implementation methods, if they are not the key content of this invention and are well known to those skilled in the art, they are not described in detail in the accompanying drawings or the main text of the specification. In this case, they can be understood by referring to the relevant prior art.

[0098] Unless explicitly stated otherwise, the numerical parameters in the specification and claims of this invention may be approximate values ​​and can be changed according to the content of this invention. Specifically, all figures in the specification and claims indicating the content of composition, reaction conditions, etc., should be understood to be modified by the term "about" in all cases, which means that there may be variations of ±10% in some embodiments, ±5% in some embodiments, ±1% in some embodiments, and ±0.5% in some embodiments.

[0099] Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element or step does not exclude the presence of a plurality of such elements or steps.

[0100] The ordinal numbers, such as Arabic numerals and letters, used in the specification and claims to modify the corresponding steps are intended only to clearly distinguish one step with a certain name from another step with the same name, and do not imply that the step has any ordinal number, nor do they represent the order of one step with another. Furthermore, unless specifically described or steps must occur in a specific order, the order of the above steps is not limited to what is listed above and can be varied or rearranged according to the desired design.

[0101] This invention can be implemented using hardware comprising several different components and a suitably programmed computer. Various component embodiments of the invention can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. The physical implementation of the hardware structure includes, but is not limited to, physical devices, including, but not limited to, transistors, memristors, DNA computers, microcontrollers, microprocessors, or digital signal processors (DSPs).

[0102] The present invention can also be implemented as a device or apparatus program (e.g., a computer program and computer program product) for performing part or all of the methods described herein. Such a program implementing the invention can be stored on a computer-readable medium or can take the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0103] The algorithms and displays provided herein are not related to any particular computer, virtual system, or other inherent device. Various general-purpose systems can also be used in conjunction with the teachings herein. The required structure for constructing such systems is apparent from the above description. Furthermore, this invention is not directed to any particular programming language. It should be understood that the contents of this invention can be implemented using various programming languages, and the description of specific languages ​​herein is for the purpose of disclosing the best mode of implementation of the invention.

[0104] Similarly, it should be understood that, in order to simplify the invention and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. At the same time, the method of the invention should not be construed as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, the various inventive aspects consist of fewer than all the features of the preceding single embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0105] The specific embodiments described above have provided a detailed explanation of the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hovering navigation method, characterized in that, include: Step A: Identify targets within the field of view of the aircraft's camera and select the target to track; Step B: Lock onto and track the target, and obtain the aircraft's heading angle β, the electro-optical platform's azimuth angle α, the straight-line distance L between the aircraft and the target, and the aircraft's actual flight altitude H; Step C, calculate the horizontal distance X between the aircraft and the tracked target: ; Step D: Using the real-time position of the tracked target as the center of rotation and the horizontal distance X as the predetermined rotation radius Rturn, the aircraft is made to rotate around the tracked target. In the step of causing the aircraft to hover around the tracking target, the hovering mode is determined by the azimuth angle α when the photoelectric platform locks onto the tracking target: ; Step E: Calculate the angle θ between the observation direction of the photoelectric platform and the north direction based on the heading angle β of the aircraft and the azimuth angle α of the photoelectric platform; calculate the north component ΔN and east component ΔE of the spatial vector from the aircraft to the tracked target in the spatial rectangular coordinate system based on the horizontal distance X and the angle θ. in, ; , ; Step F: Calculate the geocentric radius R of the spacecraft's location. q : Geocentric latitude B EC : Where B is the geographical latitude of the aircraft, H is the actual flight altitude of the aircraft, and R is the geographical latitude of the aircraft. a R b f represents the Earth's semi-major axis, semi-minor axis, and ellipsoid, respectively. Step G, based on the northward component ΔN and the geocentric radius R q Obtain the geocentric latitude deviation ΔB between the aircraft and the tracked target. C In order to obtain the geocentric latitude B of the target being tracked. ECC With geographical latitude B C ; in, , , ; Step H, based on the Earth's central radius R of the spacecraft's location. q Geocentric latitude B EC Obtain the radius R of the latitude circle where the spacecraft is located. w Based on the radius R of the latitude circle where the aircraft is located w Obtain the circumference C of the weft coil b According to the eastward vector ΔE and the circumference C of the latitude circle... b Obtain the geographical longitude deviation ΔL between the aircraft and the tracked target; in, , , ; Step I, based on the Earth's semi-major axis R a Geographic latitude B of the target being tracked C Obtain the geocentric radius R at the center of the spiral circle. p : Step J, based on the geographical longitude deviation ΔL and the geocentric latitude B of the tracking target... ECC The geocentric latitude of the spacecraft B EC The Earth's central radius R at the center of the spiral circle p Obtain the eastward component Δx and northward component Δy of the spatial vector from the current position to the center of the hovering circle in a Cartesian coordinate system; obtain the distance D from the current position of the aircraft to the center of the hovering circle from the eastward vector Δx and the northward component Δy; obtain the lateral offset D of the aircraft from the distance D and the hovering radius Rturn. Z ; Step K involves obtaining the angle γ between the spatial vector from the center of the hovering circle to the current position of the spacecraft and the eastward direction, based on the eastward component Δx and the northward component Δy, and then obtaining the lateral offset velocity D based on this angle γ. Zd ; Step L, the lateral offset D Z and lateral offset speed D Zd Inputting the lateral control loop of the aircraft yields rudder deflection commands, guiding the aircraft to circle around the target being tracked; The step L is followed by: repeating steps A to L according to a preset period to guide the aircraft to hover around the target in real time, wherein the preset period is between 10 ms and 50 ms. In step A, the YOLO deep learning algorithm and the SIFT scale-invariant feature transformation algorithm are used to identify and track targets within the field of view of the aircraft camera. In step B, the straight-line distance L between the aircraft and the tracked target is obtained by a laser rangefinder; the heading angle β and the azimuth angle α of the electro-optical platform are obtained by corresponding sensors installed on the aircraft. In step K, the northward ground speed Vdn and the eastward ground speed Vde of the aircraft are obtained by corresponding sensors installed on the aircraft.

2. The hovering navigation method according to claim 1, characterized in that, In step I, f represents the Earth's ellipsoid.

3. The hovering navigation method according to claim 1, characterized in that, In step J, , , .

4. The hovering navigation method according to claim 1, characterized in that, In step K, , ， Among them, V dn and V de These are the northward and eastward ground speeds of the aircraft, respectively.

5. The hovering navigation method according to claim 1, characterized in that, The aircraft can be a drone, a manned aircraft, or a loitering munition.

6. A drone, characterized in that, include: Memory; as well as A processor, electrically coupled to the memory, is configured to execute the hovering navigation method as described in any one of claims 1 to 5 based on instructions stored in the memory.

Images