Mooring flight platform fixed point positioning method based on electromagnetic sensing

Abstract

The invention relates to the technical field of unmanned aerial vehicle positioning, in particular to a mooring flight platform fixed-point positioning method based on electromagnetic sensing. The moored flight platform fixed point positioning method based on electromagnetic sensing comprises the following steps: establishing electromagnetic signal information: arranging a plurality of electromagnetic signal emitters in a to-be-positioned area, and recording specific position information and related data by each emitter; electromagnetic signal position information is transmitted, wherein the electromagnetic signal position information is transmitted to a ground control center through a network, and real-time updating is ensured. According to the system and the method, electromagnetic signal detection is matched with GPS signals for dual positioning, so that the mooring unmanned aerial vehicle can still realize accurate positioning under the condition that the GPS signals are unstable, the operation reliability of the mooring unmanned aerial vehicle is effectively improved, and meanwhile, the identification advantage of the electromagnetic signals and the stability characteristic of mooring flight of the unmanned aerial vehicle are combined; the method can effectively improve the positioning capability of the mooring unmanned aerial vehicle in a complex environment, and has important technical value and market demand.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle positioning, and in particular to a fixed-point positioning method for a tethered flying platform based on electromagnetic sensing. Background Art

[0002] A drone is an unmanned aircraft controlled by a radio remote control device and a self-contained program control device. A tethered drone, also known as a tethered drone, is a special form of a multi-rotor drone that uses ground power transmitted through a tethered cable as a power source instead of traditional lithium batteries. Its most important feature is its ability to hover for a long time.

[0003] However, the existing tethered drone positioning technology still faces certain challenges, such as unstable GPS signals and insufficient positioning accuracy in complex environments. To this end, researchers have explored a series of new positioning methods, among which positioning methods based on electromagnetic signals have gradually attracted attention. As a carrier for information storage and transmission, electromagnetic signals have the advantages of low cost, easy acquisition, and easy identification, and can be widely used in tethered drone positioning. By arranging electromagnetic signals in a specific area, tethered drones can obtain their relative position and related information by scanning codes, thereby achieving autonomous positioning.

[0004] In the case of GPS denial or low accuracy of the drone's inertial navigation system, it is necessary to obtain the drone's current accurate location information in real time, and make timely adjustments to ensure the safety of the tethered drone after the tethered drone exceeds the safety range. At the same time, the tethered drone positioning method based on electromagnetic signals can establish effective communication between the tethered drone and the ground station, enhance the tethered drone's real-time data transmission capability, and adapt to changing operating environments. Therefore, the tethered drone positioning method based on electromagnetic signals combines the recognition advantages of electromagnetic signals with the stable characteristics of drone tethered flight, and can effectively improve the tethered drone's positioning capability in complex environments, which has important technical value and market demand. Summary of the invention

[0005] The purpose of the present invention is to provide a fixed-point positioning method for a tethered flying platform based on electromagnetic sensing, so as to solve the problems of unstable GPS signals of traditional tethered UAVs and insufficient positioning accuracy in complex environments proposed in the above background technology.

[0006] To achieve the above object, the present invention provides a method for fixed-point positioning of a tethered flying platform based on electromagnetic sensing, comprising the following steps:

[0007] S1. Establish electromagnetic signal information: Arrange multiple electromagnetic signal transmitters in the area to be located, and each transmitter records specific location information and related data;

[0008] S2. Transmit electromagnetic signal location information: Transmit the electromagnetic signal location information to the ground control center through the network to ensure real-time updates;

[0009] S3. Identify electromagnetic signal information: The tethered drone uses the electromagnetic signal identification module to scan the electromagnetic signals in the flight area and identify their contents;

[0010] S4. Obtaining the position of the tethered drone: sending the identified electromagnetic signal information and position information to the tethered drone navigation system to obtain the relative position of the tethered drone;

[0011] S5. Obtaining global positioning coordinates: calculating the actual coordinates of the tethered drone based on the information provided by the electromagnetic signal, and converting the relative position into global positioning coordinates;

[0012] S6. Information comparison and calibration: Positioning calibration is performed by comparing GPS signals and electromagnetic signal information;

[0013] S7, information feedback: The optimized positioning results are transmitted back to the ground control center in real time to realize the monitoring and navigation of the tethered UAV.

[0014] As a further improvement of the technical solution, the specific operation steps of establishing electromagnetic signal information in step S1 are:

[0015] S11. Determine the positioning area: According to the operational requirements of the tethered UAV, select a suitable area for electromagnetic signal layout to ensure that the area is suitable for the flight altitude and tethered activity range of the tethered UAV. At the same time, use the interface of the area in the tethered UAV navigation system to mark important reference points and relative positions;

[0016] S12. Plan the layout of electromagnetic signals: divide the selected area into several small areas. Each small area should be of appropriate size to ensure that the tethered drone can effectively scan the electromagnetic signal within a certain altitude. Select one or more electromagnetic signal placement points for each small area.

[0017] S13, generate electromagnetic signal: prepare location information and related data for each electromagnetic signal. Each electromagnetic signal needs to record the following information: ID number, geographic coordinates and related attributes. The information format is: ID number + longitude + latitude + related attributes. At the same time, use electromagnetic signal generation software to generate the corresponding electromagnetic signal image;

[0018] S14. Fixed signal transmitter: Fix the electromagnetic signal transmitter at the corresponding location according to the planned location, and ensure that the electromagnetic signal transmitter is stable and unobstructed, and maintains a sufficient visual range to avoid being blocked by obstacles;

[0019] S15. Record electromagnetic signal information: record the specific location of each electromagnetic signal on the tethered drone navigation system map, and create an electromagnetic signal database to organize and record the information of each electromagnetic signal, including ID, coordinates and related attributes;

[0020] S16. Verify electromagnetic signal recognition: Use a tethered drone to conduct a flight test on the arranged electromagnetic signal to ensure that the tethered drone can successfully identify the electromagnetic signal and extract information, record the success rate of the tethered drone in identifying the electromagnetic signal, and adjust the position and direction of the electromagnetic signal to improve the recognition effect.

[0021] As a further improvement of the technical solution, the specific operation steps of transmitting the electromagnetic signal position information in step S2 are:

[0022] S21. Data packaging and transmission: Packing the location information of the electromagnetic signal into a transmittable data format, and sending the packaged data to the ground control center via a 5G or 4G network connection;

[0023] S22. The ground control center receives data: At the ground control center, the electromagnetic signal location information is received through the server, and the received data format is decoded and analyzed;

[0024] S23, data updating and storage: updating the received position information to the database of the ground control center;

[0025] S24, Feedback and Confirmation: The ground control center should send a confirmation message to the tethered drone to ensure that it has successfully received the location information.

[0026] As a further improvement of the technical solution, the specific operation steps of identifying the electromagnetic signal information in step S3 are:

[0027] S31. Automatic scanning of electromagnetic signals: When the tethered drone executes the flight path, the electromagnetic signal recognition module performs real-time scanning. The electromagnetic signal recognition module automatically recognizes the electromagnetic signal in the image captured by the camera according to the image processing algorithm. At the same time, the electromagnetic signal recognition module relies on the image sensor to capture the electromagnetic signal image at a frequency of 10 frames per second and collects sufficient image data for processing. In addition, when the electromagnetic signal cannot be recognized or is recognized incorrectly, the tethered drone sets a corresponding processing mechanism;

[0028] S32, electromagnetic signal information decoding: processing the captured image, identifying the electromagnetic signal shape and feature points in the image, decoding the electromagnetic signal information, and extracting the included content;

[0029] S33, result storage: storing the identified electromagnetic signal information in the internal storage system or cache of the tethered drone.

[0030] As a further improvement of the technical solution, in step S31, when the electromagnetic signal cannot be identified or is identified incorrectly, the tethered drone sets a corresponding processing mechanism including:

[0031] Repeatedly identify the same electromagnetic signal to increase the number of identification times;

[0032] Record the electromagnetic signal ID that failed to be identified;

[0033] Adjust the flight position to increase the visible range of electromagnetic signals.

[0034] As a further improvement of the technical solution, the specific operation steps for obtaining the position of the tethered drone in step S4 are:

[0035] S41, obtaining electromagnetic signal data: organizing the obtained electromagnetic signal information into a unified format and transmitting it to the tethered UAV navigation system;

[0036] S42. Marking position information: The position information contained in the electromagnetic signal information is marked using the tethered UAV navigation system. At the same time, the tethered UAV navigation system in the ground control center can observe the marked information in real time.

[0037] As a further improvement of the technical solution, the specific operation steps of obtaining the global positioning coordinates in step S5 are:

[0038] S51, obtaining the current position of the tethered drone: using the GPS module carried by the tethered drone to obtain its current geographical location information, including longitude and latitude, and recording it as the current position of the tethered drone = current longitude, current latitude;

[0039] S52, calculating the relative position: selecting the most recently identified electromagnetic signal position information as a reference point for calculating the relative position, and recording its geographic coordinates as reference point position = x, y;

[0040] S53, relative position calculation: calculate the relative position of the tethered drone relative to the identified electromagnetic signal as current longitude - x, current latitude - y.

[0041] As a further improvement of the technical solution, the specific operation steps of information comparison and fusion in step S6 are:

[0042] S61, collecting information: collecting the current flight status of the tethered UAV, including its flight direction f, flight speed v, and the time difference t between when it recognizes the electromagnetic signal and when the current GPS module transmits the position;

[0043] S62, information comparison: calculating the distance s flown by the tethered UAV within the time difference, and adding the distance s to the reference point position to obtain the calculated position, and comparing the calculated position with the relative position to obtain the comparison result;

[0044] S63. Position calibration: In the comparison result, if the error between the longitude and latitude is between ±0.1 and ±0.5 degrees, the position information transmitted by the GPS module shall prevail; otherwise, the position information of the identified electromagnetic signal shall prevail.

[0045] As a further improvement of the technical solution, the step of calculating the distance s=vt flown by the tethered UAV within the time difference and obtaining the calculated position in step S62 is:

[0046] Convert the flight direction f into radians;

[0047] The calculated latitude change is Where R is the radius of the earth;

[0048] The calculated longitude change is Where cos(y) is the cosine of y (calculated in radians);

[0049] The calculated position is obtained = Δlon, Δlat.

[0050] As a further improvement of the technical solution, the specific operation steps of information feedback in step S7 are:

[0051] S71, information transmission: the navigation system synchronizes the position information of the tethered UAV to the navigation interface on the ground control center through the navigation interface;

[0052] S72, updating navigation information: the navigation system updates the navigation status of the tethered UAV according to the received position data, and establishes the relationship between the tethered UAV and the ground target;

[0053] S73, optimize flight path: re-plan the real-time flight path based on the updated tethered drone position and electromagnetic signal position information.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] 1. In the fixed-point positioning method of the tethered flying platform based on electromagnetic perception, electromagnetic signal detection is set to cooperate with GPS signal for dual positioning, so that the tethered UAV can still achieve accurate positioning when the GPS signal is unstable, thereby effectively improving the reliability of the tethered UAV operation. At the same time, it can be applied to a variety of complex environments, including small spaces and areas with weak GPS signals, thereby greatly expanding the application scope of tethered UAVs.

[0056] 2. In the fixed-point positioning method of the tethered flying platform based on electromagnetic perception, electromagnetic signals are set to replace traditional high-precision sensors. The low cost of transmitting and deploying electromagnetic signals is utilized. Compared with high-precision sensors, it can provide an economical and effective alternative for tethered drone positioning.

[0057] 3. In the fixed-point positioning method of the tethered flying platform based on electromagnetic perception, by making the positioning method compatible with the existing tethered UAV navigation system, it is convenient for system integration and upgrading without large-scale transformation. At the same time, it can be combined with the navigation system for real-time identification and data transmission, which can ensure that the data of the tethered UAV is updated in time during the flight, thereby improving the flexibility of task execution. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 The figure is a schematic diagram of the steps of the method for fixed-point positioning of a tethered flying platform based on electromagnetic sensing of the present invention.

[0059] Figure 2 This is a schematic diagram of electromagnetic signal information recognition by a tethered drone of the present invention.

[0060] Figure 3 The diagram is a schematic diagram of the operation of information comparison and calibration of the tethered drone of the present invention. DETAILED DESCRIPTION

[0061] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] In a specific embodiment, Figure 1 As shown, the fixed-point positioning method of a tethered flying platform based on electromagnetic sensing includes the following steps:

[0063] The first step is to establish electromagnetic signal information: multiple electromagnetic signal transmitters are arranged in the area to be located, and each transmitter records specific location information and related data. In actual application, since the tethered drone is powered by ground power transmitted by the tethered cable, although it has the ability to hover for a long time, its flight range has certain limitations. Therefore, the area to be located in this step needs to be smaller than the flight range of the tethered drone.

[0064] First, according to the operational requirements of the tethered UAV, select a suitable area for electromagnetic signal layout to ensure that the area is suitable for the flight altitude and tethered activity range of the tethered UAV. At the same time, use the interface of the area in the tethered UAV navigation system to mark important reference points and relative positions.

[0065] Then divide the selected area into several small areas. Each small area should be of appropriate size to ensure that the tethered drone can effectively scan the electromagnetic signal within a certain altitude. Select one or more electromagnetic signal transmitter placement points for each small area to ensure that the electromagnetic signal transmitter is arranged on the flight path of the tethered drone and can be identified under most lighting conditions.

[0066] Next, prepare location information and related data for each electromagnetic signal. Each electromagnetic signal needs to record the following information: ID number (unique identifier), geographic coordinates (which can be expressed in string form, such as "latitude and longitude"), and related attributes (for example, "temperature sensor location", "photo point", etc.). The information format is: ID number + longitude + latitude + related attributes. For example, the content of an electromagnetic signal is: QR001, 39.9042, 116.4074, temperature sensor location. At the same time, the electromagnetic signal generation software is used to generate the corresponding electromagnetic signal image.

[0067] Then fix the electromagnetic signal transmitter at the corresponding location according to the planned position, while ensuring that the electromagnetic signal transmitter is stable, unobstructed, and maintains a sufficient visual range to avoid being blocked by obstacles.

[0068] At the same time, the specific location of each electromagnetic signal is recorded on the tethered drone navigation system map for subsequent comparison and search, and an electromagnetic signal database is created to organize and record the information of each electromagnetic signal, including ID, coordinates and related attributes, which can be organized in the form of a table, as shown in the following table.

[0069] Electromagnetic signal ID latitude longitude Related properties QR001 39.9042 116.4074 Temperature sensor location QR002 39.9045 116.4076 Photo Spot …… …… …… ……

[0070] Finally, use a tethered drone to conduct a flight test on the arranged electromagnetic signal to ensure that the tethered drone can successfully identify the electromagnetic signal and extract information, record the success rate of the tethered drone in identifying the electromagnetic signal, and adjust the position and direction of the electromagnetic signal to improve the recognition effect. In addition, it is necessary to regularly maintain and update the electromagnetic signal information, regularly detect the status of the electromagnetic signal to ensure that it is not damaged or blocked, and if the information on the electromagnetic signal needs to be updated, regenerate the electromagnetic signal and replace the original electromagnetic signal, and make an update record in the electromagnetic signal database.

[0071] Step 2: Transmit electromagnetic signal location information: Transmit the electromagnetic signal location information to the ground control center via the network to ensure real-time updates.

[0072] First, the location information of the electromagnetic signal (wherein the location information includes the above-mentioned ID number, longitude, latitude and related attributes) is packaged into a transmittable data format, such as JSON format, as shown below:

[0073] ID:QR001;

[0074] Longitude: 39.9042;

[0075] Latitude: 116.4074;

[0076] Related attributes: Temperature sensor location.

[0077] The packaged data is sent to the ground control center via 5G or 4G network connection.

[0078] Then, at the ground control center, the electromagnetic signal location information is received through the server, and the received data format is unpacked and parsed to ensure that the information is correctly understood.

[0079] Then, the received location information is updated to the database of the ground control center. This step requires: confirming the uniqueness of the data to avoid duplicate records. Update the electromagnetic signal location information to ensure the timeliness of the data.

[0080] Finally, the ground control center should send a confirmation message to the tethered drone to ensure that it has successfully received the location information. At the same time, a monitoring system can be established to detect the status of data transmission in real time, such as the success rate of data reception, transmission delay, etc., to ensure the stability and reliability of the system in operation.

[0081] Step 3: Figure 2 As shown, identifying electromagnetic signal information: the tethered drone uses the electromagnetic signal identification module it carries to scan the electromagnetic signals within the flight area and identify their content.

[0082] First, when the tethered drone executes the flight path, it performs real-time scanning through the electromagnetic signal recognition module. The electromagnetic signal recognition module automatically recognizes the electromagnetic signal in the image captured by the camera according to the image processing algorithm. At the same time, the electromagnetic signal recognition module relies on the image sensor to capture the electromagnetic signal image at a frequency of 10 frames per second and collects enough image data for processing. In addition, when the electromagnetic signal cannot be recognized or is recognized incorrectly, the tethered drone sets a corresponding processing mechanism:

[0083] Repeatedly identify the same electromagnetic signal to increase the number of identification times;

[0084] Record the electromagnetic signal ID that failed to be identified;

[0085] Adjust the flight position to increase the visible range of electromagnetic signals.

[0086] The captured image is then processed to identify the electromagnetic signal shape and feature points in the image, decode the electromagnetic signal information, extract the content contained, such as ID, location information and related attributes, and verify the identified content to ensure the integrity and correctness of the information. If the electromagnetic signal is incomplete, it will be marked as invalid.

[0087] The identified electromagnetic signal information is then stored in the internal storage system or cache of the tethered drone to provide a basis for subsequent operations. The recording format is as follows:

[0088] Electromagnetic signal information list = electromagnetic signal 1, electromagnetic signal 2, electromagnetic signal 3, ..., electromagnetic signal n.

[0089] Step 4: Get the position of the tethered drone: Send the identified electromagnetic signal information and position information to the tethered drone navigation system to get the relative position of the tethered drone.

[0090] First, the acquired electromagnetic signal information is organized into a unified format, while ensuring that it includes the necessary location information, and transmitted to the tethered drone navigation system.

[0091] The tethered drone navigation system is then used to mark the location information contained in the electromagnetic signal information, while the tethered drone navigation system in the ground control center can observe the marked information in real time.

[0092] Step 5. Obtain global positioning coordinates: Calculate the actual coordinates of the tethered drone based on the information provided by the electromagnetic signal and convert the relative position into global positioning coordinates.

[0093] First, the GPS module carried by the tethered drone is used to obtain its current geographic location information, including longitude and latitude, and recorded as the current location of the tethered drone = current longitude, current latitude.

[0094] Then, the most recently identified electromagnetic signal position information is selected as a reference point for calculating the relative position, and its geographic coordinates are recorded as reference point position = x, y.

[0095] Then the relative position of the tethered drone with respect to the identified electromagnetic signal is calculated as the current longitude - x, the current latitude - y.

[0096] Step 6: Figure 3 As shown, information comparison and calibration: positioning calibration is performed by comparing GPS signal and electromagnetic signal information.

[0097] First, the current flight status of the tethered drone is collected, including its flight direction f, flight speed v, and the time difference t between when it recognizes the electromagnetic signal and when the current GPS module transmits the position;

[0098] Then calculate the distance s=vt that the tethered drone flies during this time difference, and add it to the reference point position to get the calculated position. The steps are as follows:

[0099] Convert the flight direction f into radians;

[0100] The calculated latitude change is Where R is the radius of the earth;

[0101] The calculated longitude change is Where cos(y) is the cosine of y (calculated in radians);

[0102] The calculated position is obtained = Δlon, Δlat.

[0103] At the same time, the calculated position is compared with the relative position, and the comparison result is obtained.

[0104] Finally, in the comparison results, if the error between longitude and latitude is between ±0.1 and ±0.5 degrees, the location information transmitted by the GPS module shall prevail, otherwise the location information of the identified electromagnetic signal shall prevail. If the GPS signal is weak or the current location of the tethered drone sent by the GPS is not received, the location information of the identified electromagnetic signal shall prevail.

[0105] Step 7: Information feedback: The optimized positioning results are transmitted back to the ground control center in real time to realize the monitoring and navigation of the tethered UAV.

[0106] First, the navigation system synchronizes the tethered drone's location information to the navigation interface on the ground control center through the navigation interface.

[0107] The navigation system then updates the navigation status of the tethered UAV based on the received position data and establishes the relationship between the tethered UAV and the ground target.

[0108] Then, based on the updated tethered drone position and electromagnetic signal location information, the real-time flight path is replanned to ensure that the drone can accurately reach the target location.

[0109] In summary, in the case of GPS denial or low accuracy of the drone inertial navigation system, the set electromagnetic signal can be used to obtain the drone's current accurate location information in real time, and make timely adjustments after the tethered drone exceeds the safety range to ensure the safety of the tethered drone. At the same time, the tethered drone positioning method based on electromagnetic signals can establish effective communication between the tethered drone and the ground station, enhance the real-time data transmission capability of the tethered drone, and adapt to the changing operating environment. Therefore, the tethered drone positioning method based on electromagnetic signals combines the recognition advantages of electromagnetic signals with the stable characteristics of drone tethered flight, can effectively improve the positioning capability of tethered drones in complex environments, and has important technical value and market demand.

[0110] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A fixed-point positioning method for a tethered flying platform based on electromagnetic sensing, characterized in that: The following steps are involved: S1. Establish electromagnetic signal information: Arrange multiple electromagnetic signal transmitters in the area to be located, and each transmitter records specific location information and related data; S2. Transmit electromagnetic signal location information: Transmit the electromagnetic signal location information to the ground control center through the network to ensure real-time updates; S3. Identify electromagnetic signal information: The tethered drone uses the electromagnetic signal identification module to scan the electromagnetic signals in the flight area and identify their contents; S4. Obtaining the position of the tethered drone: sending the identified electromagnetic signal information and position information to the tethered drone navigation system to obtain the relative position of the tethered drone; S5. Obtaining global positioning coordinates: calculating the actual coordinates of the tethered drone based on the information provided by the electromagnetic signal, and converting the relative position into global positioning coordinates; S6. Information comparison and calibration: Positioning calibration is performed by comparing GPS signals and electromagnetic signal information; S7, information feedback: The optimized positioning results are transmitted back to the ground control center in real time to realize the monitoring and navigation of the tethered UAV.

2. The method for fixed-point positioning of a tethered flying platform based on electromagnetic sensing according to claim 1, characterized in that: The specific operation steps of establishing electromagnetic signal information in step S1 are: S11. Determine the positioning area: According to the operational requirements of the tethered UAV, select a suitable area for electromagnetic signal layout to ensure that the area is suitable for the flight altitude and tethered activity range of the tethered UAV. At the same time, use the interface of the area in the tethered UAV navigation system to mark important reference points and relative positions; S12. Plan the layout of electromagnetic signals: divide the selected area into several small areas. Each small area should be of appropriate size to ensure that the tethered drone can effectively scan the electromagnetic signal within a certain altitude. Select one or more electromagnetic signal placement points for each small area. S13, generate electromagnetic signal: prepare location information and related data for each electromagnetic signal. Each electromagnetic signal needs to record the following information: ID number, geographic coordinates and related attributes. The information format is: ID number + longitude + latitude + related attributes. At the same time, use electromagnetic signal generation software to generate the corresponding electromagnetic signal image; S14. Fix the electromagnetic signal transmitter: fix the electromagnetic signal transmitter at the corresponding location according to the planned location, and ensure that the electromagnetic signal transmitter is stable and unobstructed, and maintains a sufficient visual range to avoid being blocked by obstacles; S15. Record electromagnetic signal information: record the specific location of each electromagnetic signal on the tethered drone navigation system map, and create an electromagnetic signal database to organize and record the information of each electromagnetic signal, including ID, coordinates and related attributes; S16. Verify electromagnetic signal recognition: Use a tethered drone to conduct a flight test on the arranged electromagnetic signal to ensure that the tethered drone can successfully identify the electromagnetic signal and extract information, record the success rate of the tethered drone in identifying the electromagnetic signal, and adjust the position and direction of the electromagnetic signal to improve the recognition effect.

3. The method for fixed-point positioning of a tethered flying platform based on electromagnetic sensing according to claim 1, characterized in that: The specific operation steps of transmitting the electromagnetic signal position information in step S2 are: S21. Data packaging and transmission: Packing the location information of the electromagnetic signal into a transmittable data format, and sending the packaged data to the ground control center via a 5G or 4G network connection; S22. The ground control center receives data: At the ground control center, the electromagnetic signal location information is received through the server, and the received data format is decoded and analyzed; S23, data updating and storage: updating the received position information to the database of the ground control center; S24, Feedback and Confirmation: The ground control center should send a confirmation message to the tethered drone to ensure that it has successfully received the location information.

4. The method for fixed-point positioning of a tethered flying platform based on electromagnetic sensing according to claim 1, characterized in that: The specific operation steps of identifying electromagnetic signal information in step S3 are: S31. Automatic scanning of electromagnetic signals: When the tethered drone executes the flight path, the electromagnetic signal recognition module performs real-time scanning. The electromagnetic signal recognition module automatically recognizes the electromagnetic signal in the image captured by the camera according to the image processing algorithm. At the same time, the electromagnetic signal recognition module relies on the image sensor to capture the electromagnetic signal image at a frequency of 10 frames per second and collects sufficient image data for processing. In addition, when the electromagnetic signal cannot be recognized or is recognized incorrectly, the tethered drone sets a corresponding processing mechanism; S32, electromagnetic signal information decoding: processing the captured image, identifying the electromagnetic signal shape and feature points in the image, decoding the electromagnetic signal information, and extracting the included content; S33, result storage: storing the identified electromagnetic signal information in the internal storage system or cache of the tethered drone.

5. The method for fixed-point positioning of a tethered flying platform based on electromagnetic sensing according to claim 4 is characterized in that: In step S31, when the electromagnetic signal cannot be identified or is identified incorrectly, the tethered drone sets a corresponding processing mechanism including: Repeatedly identify the same electromagnetic signal to increase the number of identification times; Record the electromagnetic signal ID that failed to be identified; Adjust the flight position to increase the visible range of electromagnetic signals.

6. The method for fixed-point positioning of a tethered flying platform based on electromagnetic sensing according to claim 1, characterized in that: The specific operation steps for obtaining the position of the tethered drone in step S4 are: S41, obtaining electromagnetic signal data: organizing the obtained electromagnetic signal information into a unified format and transmitting it to the tethered UAV navigation system; S42. Marking position information: The position information contained in the electromagnetic signal information is marked using the tethered UAV navigation system. At the same time, the tethered UAV navigation system in the ground control center can observe the marked information in real time.

7. The method for fixed-point positioning of a tethered flying platform based on electromagnetic sensing according to claim 1, characterized in that: The specific operation steps for obtaining the global positioning coordinates in step S5 are: S51, obtaining the current position of the tethered drone: using the GPS module carried by the tethered drone to obtain its current geographical location information, including longitude and latitude, and recording it as the current position of the tethered drone = current longitude, current latitude; S52, calculating the relative position: selecting the most recently identified electromagnetic signal position information as a reference point for calculating the relative position, and recording its geographic coordinates as reference point position = x, y; S53, relative position calculation: calculate the relative position of the tethered drone relative to the identified electromagnetic signal as current longitude - x, current latitude - y.

8. The method for fixed-point positioning of a tethered flying platform based on electromagnetic sensing according to claim 7, characterized in that: The specific operation steps of information comparison and fusion in step S6 are: S61, collecting information: collecting the current flight status of the tethered UAV, including its flight direction f, flight speed v, and the time difference t between when it recognizes the electromagnetic signal and when the current GPS module transmits the position; S62, information comparison: calculating the distance s flown by the tethered UAV within the time difference, and adding the distance s to the reference point position to obtain the calculated position, and comparing the calculated position with the relative position to obtain the comparison result; S63. Position calibration: In the comparison result, if the error between the longitude and latitude is between ±0.1 and ±0.5 degrees, the position information transmitted by the GPS module shall prevail; otherwise, the position information of the identified electromagnetic signal shall prevail.

9. The method for fixed-point positioning of a tethered flying platform based on electromagnetic sensing according to claim 8, characterized in that: In step S62, the distance s=vt flown by the tethered drone within the time difference is calculated, and the steps of obtaining the calculated position are: Convert the flight direction f into radians; The calculated latitude change is Where R is the radius of the earth; The calculated longitude change is Where cos(y) is the cosine of y (calculated in radians); The calculated position is obtained = Δlon, Δlat.

10. The method for fixed-point positioning of a tethered flying platform based on electromagnetic sensing according to claim 1, characterized in that: The specific operation steps of information transmission in step S7 are: S71, information transmission: the navigation system synchronizes the position information of the tethered UAV to the navigation interface on the ground control center through the navigation interface; S72, updating navigation information: the navigation system updates the navigation status of the tethered UAV according to the received position data, and establishes the relationship between the tethered UAV and the ground target; S73, optimize flight path: re-plan the real-time flight path based on the updated tethered drone position and electromagnetic signal position information.

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