Natural reserve ecological monitoring and protection method based on unmanned aerial vehicle

Abstract

The invention relates to the technical field of environmental protection, in particular to a natural reserve ecological monitoring and protection method based on an unmanned aerial vehicle, which comprises the monitoring steps of monitoring task planning, equipment selection and platform base station construction, monitoring and data analysis processing, and protection measure and application. According to the invention, the inspection route is formulated according to the range of the protection area, the unmanned aerial vehicle nest is built on a proper road section, and the inspection unmanned aerial vehicle does not need to reserve return flight electric energy to continuously advance in the flight inspection process, so that the inspection monitoring range is greatly expanded, and the unmanned aerial vehicle enters the storage bin when passing through the unmanned aerial vehicle nest; under the auxiliary positioning of the top limiting structure and the centering structure, the charging structure is in butt joint with the charging structure, electric energy is supplemented, information collected by a previous flight path is transmitted to a data base station carried in the nest body shell through the charging structure for interaction, and data processing and analysis are carried out in time.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection technology, and in particular to a method for ecological monitoring and protection of a nature reserve based on an unmanned aerial vehicle (UAV). Background Art

[0002] A nature reserve refers to an area of ​​land, land water or sea where representative natural ecosystems, natural concentrated distributions of rare and endangered wild animal and plant species, natural relics of special significance and other protected objects are located. A certain area is demarcated in accordance with the law to provide special protection and management. With the continuous development of science and technology, drones are gradually being applied to ecological monitoring of nature reserves in existing technologies.

[0003] However, the current working method of using drones for environmental monitoring is to first release the drone for cruise shooting and monitoring. After it moves to a certain range, it reserves enough power or fuel for return. The operating range of the drone is greatly reduced. When the area of ​​the protected area is too large, multiple drones are needed for inspections many times, which is a large workload and there is still room for improvement. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for ecological monitoring and protection of nature reserves based on drones to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A method for ecological monitoring and protection of nature reserves based on drones includes the following steps: monitoring mission planning, equipment selection and platform base station construction, monitoring and data analysis and processing, and protection measures and application monitoring. The specific steps are as follows: S1 Monitoring Mission Planning: Plan the flight routes and monitoring frequency of drones based on the terrain, ecological types, and protected areas of the nature reserve, and increase the monitoring frequency and accuracy of key areas such as rare species habitats, water sources, and ecologically fragile areas; Selection of S2 equipment and construction of platform base stations: Based on the planned flight route, drone platforms with built-in drone data interaction structures and data base stations are built at appropriate sections of the route. UAVs with long flight time, high-resolution imaging, multispectral imaging, thermal imaging, and other capabilities are customized to meet different ecological monitoring needs. S3 Monitoring and Data Analysis and Processing: Utilize the various camera functions onboard drones to monitor vegetation, wildlife, and human activities. The platform's onboard base stations are used to perform pre-processing operations such as denoising, correction, and splicing on the images, videos, and spectra collected by drones. AI algorithms and machine learning models are used to analyze and model the monitoring data. For example, vegetation health models can be established by analyzing vegetation spectral data, and population dynamics models can be established by analyzing wildlife activity trajectories. The analysis results are displayed on the monitoring platform in intuitive charts and maps, generating regular monitoring reports. S4 Protection measures and applications: Based on the monitoring results, formulate ecological restoration plans, such as vegetation restoration and wetland restoration, etc., use the thermal imaging and night vision functions of drones to conduct anti-poaching patrols at night, promptly detect and notify law enforcement personnel to deal with poaching, and make the wonderful images and data monitored into popular science videos or exhibitions to publicize the ecological value and protection achievements of nature reserves to the public.

[0006] Furthermore, in steps S2 and S3, the drone platform needs to provide power supply to the drones on the flight route, and the information collected by the drones needs to be recovered and analyzed.

[0007] Furthermore, the UAV platform includes: The drone nest includes a nest shell, wherein a plurality of storage compartments are provided inside the nest shell; A top limiting structure, comprising a limiting rod, wherein the limiting rod is suspended and installed on the top of the storage bin; The charging structure includes a base, which is fixedly mounted on the rear edge of the bottom of the storage compartment; The centering structure includes a support plate, which is slidably mounted on the edges of both sides of the storage bin; The inspection drone is stored inside the storage warehouse.

[0008] Furthermore, the nest shell is fixedly mounted on the upper side of the support plate, an overhead support frame is fixedly mounted on the bottom of the support plate, a servo motor is fixedly mounted on the front edges of both sides of the nest shell, a sealing door is hinged on the lower edge of the front opening of the storage bin, one end of the hinged shaft of the sealing door is linked to the servo motor No. 1 through a gear set, a driving roller is rotatably mounted inside the sealing door, an outer rotor motor is fixedly mounted inside the driving roller, both ends of the stator of the outer rotor motor are fixedly connected to the sealing door, and a conveyor belt is rotatably sleeved on the inner surface of the sealing door through the driving roller.

[0009] Furthermore, a support rod is fixedly installed on the upper side of the limit rod, the upper end of the support rod is fixedly connected to the top of the storage bin, and the bottom of the limit rod is rotatably sleeved with a No. 2 conveyor belt through a driving roller.

[0010] Furthermore, a guide plate is fixedly installed in the middle of the front side of the base, charging seats are fixedly installed at both ends of the guide plate, a vertical plate is fixedly installed on the upper side of the base, and contact terminals are fixedly installed on the upper edge of the front side of the vertical plate.

[0011] Furthermore, the bottom of the storage bin is rotatably sleeved with several No. 3 conveyor belts through a driving roller, the inner surface of the abutment plate is rotatably embedded with an auxiliary roller, the bottom of the abutment plate is fixedly installed with a connecting plate, the connecting plate is slidably clamped in the connecting plate movable groove, the connecting plate movable groove is opened at the bottom of the storage bin, the upper side opening of the connecting plate movable groove is opened at the interval of each No. 3 conveyor belt, a bidirectional screw is rotatably installed in the connecting plate movable groove, both ends of the bidirectional screw are screwed and sleeved with the connecting plate, and the middle part of the bidirectional screw is fixedly connected to the output shaft of the No. 2 servo motor.

[0012] Furthermore, the inspection drone includes: The fuselage has wings fixedly installed on the four side edges; The monitoring head is rotatably mounted on the lower front edge of the fuselage through an electromechanical structure. The monitoring head is embedded with a high-definition visible light camera, a multispectral camera, a thermal imaging camera, etc. The support legs are fixedly installed on the edges of both sides of the bottom of the fuselage; Contact charging port, embedded on the back of the support foot; The connection contacts are embedded on the rear side of the fuselage.

[0013] Compared with the prior art, the present invention has the following beneficial effects: An inspection route is formulated according to the scope of the protected area, and drone nests are built on appropriate sections of the road. During the inspection process, the inspection drone does not need to reserve return power to continue moving, which greatly increases the scope of inspection and monitoring. When passing through the drone nest, it enters the storage compartment and docks with the charging structure under the auxiliary positioning of the top limit structure and the centering structure to replenish power. The information collected from the previous flight journey is transmitted to the data base station carried in the nest shell through the charging structure for interaction, so as to carry out data processing and analysis in time.

[0014] The outer shell of the nest is erected at a certain height in the air through pallets and overhead supports, which facilitates the take-off and landing of inspection drones, reduces interference, and prevents damage to the drone nest caused by the activities of wild animals. The opening and closing of the sealing door is controlled by the No. 1 servo motor under the transmission of the gear set. The opening limit of the sealing door is the horizontal placement state, which serves as an extended inspection drone landing platform. When the inspection drone lands at the sealing door, the inspection drone is sent into the storage bin through the No. 1 conveyor belt, and then the storage bin opening is closed again.

[0015] The first conveying belt sends the inspection unmanned plane into the storage bin, and then the third transmission belt is connected in relay, at this time, the second servo motor rotates the bidirectional screw rod, and then the two connecting plates are rubbed to approach each other, drive the two groups of abutting plates to abut against the surface of the body and the side surface of the supporting leg at the same time, and the inspection unmanned plane is forced to center, at this time, the third transmission belt continues to convey the inspection unmanned plane to the rear side of the storage bin, the second conveying belt abuts against the upper middle part of the unmanned plane during the conveying process, and the top of the inspection unmanned plane is pressed and limited, and cooperates with the third transmission belt to strengthen the backward pushing force on the inspection unmanned plane, until the contact type charging interface and the charging seat are mutually attached to supply electric energy, and the various connecting contacts and the various contact terminals are mutually contacted, and the data base station built in the nest shell is used for data interaction. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is the whole structure schematic diagram of the present application; Figure 2 It is the unmanned plane nest schematic diagram in the present application; Figure 3 It is the door sealing schematic diagram in the present application; Figure 4 It is the driving roller schematic diagram in the present application; Figure 5 It is the top limiting structure schematic diagram in the present application; Figure 6 It is the charging structure schematic diagram in the present application; Figure 7 It is the centering structure schematic diagram in the present application; Figure 8 It is the centering structure schematic diagram in the present application; Figure 9 It is the centering structure schematic diagram in the present application; Figure 10 It is the inspection unmanned plane schematic diagram in the present application; Figure 11 It is the inspection unmanned plane schematic diagram in the present application; Figure 12 It is the overhead support frame schematic diagram in the present application.

[0017] Figure: 1. UAV nest; 101. Nest shell; 102. Storage compartment; 103. Pallet; 104. Overhead support; 105. Servo motor No. 1; 106. Door seal; 107. Drive roller; 108. Outer rotor motor; 109. Conveyor belt No. 1; 2. Top limit structure; 201. Limit rod; 202. Support rod; 203. Conveyor belt No. 2; 3. Charging structure; 301. Base; 302. Vertical plate; 303. Guide Guide plate; 304, charging base; 305, contact terminal; 4, centering structure; 401, No. 3 conveyor belt; 402, connecting plate movable groove; 403, abutment plate; 404, auxiliary roller; 405, connecting plate; 406, bidirectional screw rod; 407, No. 2 servo motor; 5, inspection drone; 501, fuselage; 502, wings; 503, monitoring head; 504, support leg; 505, contact charging interface; 506, connecting contact. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] See also Figures 1-12 In an embodiment of the present invention, a method for ecological monitoring and protection of a nature reserve based on a drone includes the following steps: monitoring mission planning, equipment selection and platform base station construction, monitoring and data analysis and processing, and protection measures and application monitoring. The specific steps are as follows: S1 Monitoring Mission Planning: Plan the flight routes and monitoring frequency of drones based on the terrain, ecological types, and protected areas of the nature reserve, and increase the monitoring frequency and accuracy of key areas such as rare species habitats, water sources, and ecologically fragile areas; Selection of S2 equipment and construction of platform base stations: Based on the planned flight route, drone platforms with built-in drone data interaction structures and data base stations are built at appropriate sections of the route. UAVs with long flight time, high-resolution imaging, multispectral imaging, thermal imaging, and other capabilities are customized to meet different ecological monitoring needs. S3 Monitoring and Data Analysis and Processing: Utilize the various camera functions onboard drones to monitor vegetation, wildlife, and human activities. The platform's onboard base stations are used to perform pre-processing operations such as denoising, correction, and splicing on the images, videos, and spectra collected by drones. AI algorithms and machine learning models are used to analyze and model the monitoring data. For example, vegetation health models can be established by analyzing vegetation spectral data, and population dynamics models can be established by analyzing wildlife activity trajectories. The analysis results are displayed on the monitoring platform in intuitive charts and maps, generating regular monitoring reports. S4 Protection measures and applications: Based on the monitoring results, formulate ecological restoration plans, such as vegetation restoration and wetland restoration, etc., use the thermal imaging and night vision functions of drones to conduct anti-poaching patrols at night, promptly detect and notify law enforcement personnel to deal with poaching, and make the wonderful images and data monitored into popular science videos or exhibitions to publicize the ecological value and protection achievements of nature reserves to the public.

[0020] In steps S2 and S3, the drone platform needs to provide power to the drones on the flight route and recover, analyze and process the information collected by the drones.

[0021] The drone platform includes: a drone nest 1, including a nest shell 101, with several storage compartments 102 opened inside the nest shell 101; a top limiting structure 2, including a limiting rod 201, which is suspended and installed on the top of the storage compartment 102; a charging structure 3, including a base 301, which is fixedly installed on the rear edge of the bottom of the storage compartment 102; a centering structure 4, including a supporting plate 403, which is slidably installed on the two side edges of the storage compartment 102; an inspection drone 5, which is stored inside the storage compartment 102 Specifically, an inspection route is formulated according to the scope of the protected area, and a drone nest 1 is built on a suitable section of the road. During the flight inspection process, the inspection drone 5 does not need to reserve return power to continue moving, which greatly improves the scope of inspection and monitoring. When passing through the drone nest 1, it enters the storage bin 102, and with the auxiliary positioning of the top limit structure 2 and the centering structure 4, it docks with the charging structure 3 to replenish power, and transmits the information collected from the previous flight journey through the charging structure 3 to the data base station carried in the nest shell 101 for interaction, so as to carry out data processing and analysis in time.

[0022] Example 1 like Figures 1-4As shown in FIG. 12, in the embodiment, the nest shell 101 is fixedly installed on the upper side of the supporting plate 103, the overhead support frame 104 is fixedly installed on the bottom of the supporting plate 103, the first servo motor 105 is fixedly installed on the front edge of the two sides of the nest shell 101, the sealing door 106 is hingedly connected to the lower edge of the front side opening of the storage bin 102, one end of the hinged shaft of the sealing door 106 is connected to the first servo motor 105 through a gear set, the driving roller 107 is rotatably installed in the sealing door 106, the outer rotor motor 108 is fixedly installed in the driving roller 107, the stator of the outer rotor motor 108 is fixedly connected to the sealing door 106, and the first conveying belt 109 is rotatably sleeved with the driving roller 107 on the inner side surface of the sealing door 106.

[0023] In the embodiment, the nest shell 101 is erected in the air at a certain height through the supporting plate 103 and the overhead support frame 104, which facilitates the take-off and landing of the inspection unmanned aerial vehicle 5 and reduces interference, and also avoids damage to the unmanned aerial vehicle nest 1 caused by the activities of wild animals. The opening and closing of the sealing door 106 are controlled by the first servo motor 105 through the transmission of the gear set. The opening limit of the sealing door 106 is a horizontally placed state, which serves as an extended inspection unmanned aerial vehicle 5 landing platform. When the inspection unmanned aerial vehicle 5 lands at the sealing door 106, the inspection unmanned aerial vehicle 5 is sent into the storage bin 102 through the first conveying belt 109, and then the storage bin 102 opening is closed.

[0024] Embodiment Two On the basis of embodiment one, in order to supplement the specific charging and data interaction mode after the inspection unmanned aerial vehicle 5 is sent into the storage bin 102 in embodiment one.

[0025] As Figure 2 , 5-11, in this embodiment, a support rod 202 is fixedly installed on the upper side of the limit rod 201, and the upper end of the support rod 202 is fixedly connected to the top of the storage bin 102, and the bottom of the limit rod 201 is rotatably sleeved with the No. 2 conveyor belt 203 through the driving roller 107; a guide plate 303 is fixedly installed on the middle part of the front side of the base 301, and charging seats 304 are fixedly installed at both ends of the guide plate 303, and a vertical plate 302 is fixedly installed on the upper side of the base 301, and a contact terminal 305 is fixedly installed on the upper edge of the front side of the vertical plate 302; a number of No. 3 conveyor belts 401 are rotatably sleeved on the inner bottom of the storage bin 102 through the driving roller 107, and an auxiliary roller 404 is rotatably embedded on the inner surface of the abutment plate 403, and a connecting plate 405 is fixedly installed on the bottom of the abutment plate 403, and the connecting plate 405 is slidably clamped in the connecting plate movable groove 402. 2 is opened at the bottom of the storage bin 102, and the upper opening of the connecting plate movable groove 402 is opened at the interval of each No. 3 conveyor belt 401. A two-way screw rod 406 is rotatably installed in the connecting plate movable groove 402. The two ends of the two-way screw rod 406 are screwed and sleeved with the connecting plate 405, and the middle part of the two-way screw rod 406 is fixedly connected to the output shaft of the No. 2 servo motor 407; the inspection drone 5 includes: a fuselage 501, with wings 502 fixedly installed at the four side edges; a monitoring head 503, which is rotatably installed on the lower edge of the front side of the fuselage 501 through an electromechanical structure, and the monitoring head 503 is embedded with a high-definition visible light camera, a multi-spectral camera, a thermal imaging camera, etc.; a support leg 504, which is fixedly installed on the two side edges of the bottom of the fuselage 501; a contact charging interface 505, which is embedded on the rear side of the support leg 504; and a connection contact 506, which is embedded on the rear side of the fuselage 501.

[0026] During the specific implementation, after the No. 1 conveyor belt 109 sends the inspection drone 5 into the storage bin 102, it is relayed by each No. 3 conveyor belt 401. At this time, the two-way screw rod 406 is rotated by the No. 2 servo motor 407, and then the two connecting plates 405 are rubbed close to each other, driving the two sets of abutment plates 403 to abut against the surfaces of the fuselage 501 and the support legs 504 on both sides at the same time, forcing the inspection drone 5 to return to the center. At this time, the No. 3 conveyor belt 401 continues to transport the inspection drone 5 to the rear side of the storage bin 102. During the transportation process, the No. 2 conveyor belt 203 abuts against the middle of the upper side of the drone, suppresses and limits the top of the inspection drone 5, and cooperates with the No. 3 conveyor belt 401 to strengthen the backward thrust applied to the inspection drone 5 until the contact charging interface 505 and the charging seat 304 are in contact with each other for power replenishment, and at the same time, the various connection contacts 506 and the various contact terminals 305 are in contact with each other, and data exchange is carried out with the data base station built into the nest shell 101.

[0027] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0028] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for ecological monitoring and protection of nature reserves based on drones, characterized in that: The monitoring steps include monitoring task planning, equipment selection and platform base station construction, monitoring and data analysis and processing, and protective measures and applications. The specific steps are as follows: S1 Monitoring Mission Planning: Plan the flight routes and monitoring frequency of drones based on the terrain, ecological types, and protected areas of the nature reserve, and increase the monitoring frequency and accuracy of key areas (such as rare species habitats, water sources, and ecologically fragile areas); Selection of S2 equipment and construction of platform base stations: Based on the planned flight route, drone platforms with built-in drone data interaction structures and data base stations are built at appropriate sections of the route. UAVs with long flight time, high-resolution imaging, multispectral imaging, thermal imaging, and other capabilities are customized to meet different ecological monitoring needs. S3 Monitoring and Data Analysis and Processing: Utilizes the various camera functions onboard drones to monitor vegetation, wildlife, and human activities. The platform's onboard base station performs pre-processing operations such as denoising, correction, and splicing on the images, videos, and spectral data collected by drones. AI algorithms and machine learning models are used to analyze and model the monitoring data. For example, vegetation health models can be established by analyzing vegetation spectral data, and population dynamics models can be established by analyzing wildlife activity trajectories. The analysis results are displayed on the monitoring platform in intuitive charts and maps, generating regular monitoring reports. S4 Protection measures and applications: Based on the monitoring results, formulate ecological restoration plans, such as vegetation restoration and wetland restoration, etc., use the thermal imaging and night vision functions of drones to conduct anti-poaching patrols at night, promptly detect and notify law enforcement personnel to deal with poaching, and make the wonderful images and data monitored into popular science videos or exhibitions to publicize the ecological value and protection achievements of nature reserves to the public.

2. The method for ecological monitoring and protection of nature reserves based on drones according to claim 1 is characterized in that: In steps S2 and S3, the drone platform needs to provide power to the drones on the flight route and recover, analyze and process the information collected by the drones.

3. The method for ecological monitoring and protection of nature reserves based on drones according to claim 2, characterized in that: The UAV platform includes: A drone nest (1) comprises a nest shell (101), wherein a plurality of storage compartments (102) are provided inside the nest shell (101); A top limiting structure (2) includes a limiting rod (201), wherein the limiting rod (201) is suspended and installed on the top of the storage bin (102); A charging structure (3) comprising a base (301), wherein the base (301) is fixedly mounted on the rear edge of the inner bottom of the storage bin (102); The centering structure (4) includes a support plate (403), wherein the support plate (403) is slidably mounted on the edges of both sides of the storage bin (102); The inspection drone (5) is stored inside the storage bin (102).

4. The method for ecological monitoring and protection of nature reserves based on drones according to claim 3 is characterized in that: The nest shell (101) is fixedly mounted on the upper side of the support plate (103), and an overhead support frame (104) is fixedly mounted on the bottom of the support plate (103). A servo motor (105) is fixedly mounted on the front edges of both sides of the nest shell (101). A sealing door (106) is hingedly connected to the lower edge of the front opening of the storage bin (102). One end of the hinge shaft of the sealing door (106) is linked to the servo motor (105) through a gear set. A driving roller (107) is rotatably mounted inside the sealing door (106), and an outer rotor motor (108) is fixedly mounted inside the driving roller (107). Both ends of the stator of the outer rotor motor (108) are fixedly connected to the sealing door (106). The inner surface of the sealing door (106) is rotatably sleeved with a conveyor belt (109) through the driving roller (107).

5. The method for ecological monitoring and protection of nature reserves based on drones according to claim 4 is characterized in that: A support rod (202) is fixedly mounted on the upper side of the limiting rod (201), the upper end of the support rod (202) is fixedly connected to the top of the storage bin (102), and the bottom of the limiting rod (201) is rotatably sleeved with a second conveyor belt (203) via a driving roller (107).

6. The method for ecological monitoring and protection of nature reserves based on drones according to claim 5, characterized in that: A guide plate (303) is fixedly mounted on the middle of the front side of the base (301), charging seats (304) are fixedly mounted on both ends of the guide plate (303), a vertical plate (302) is fixedly mounted on the upper side of the base (301), and a contact terminal (305) is fixedly mounted on the upper edge of the front side of the vertical plate (302).

7. The method for ecological monitoring and protection of nature reserves based on drones according to claim 6, characterized in that: The inner bottom of the storage bin (102) is rotatably sleeved with a plurality of No. 3 conveyor belts (401) through a driving roller (107), the inner surface of the abutting plate (403) is rotatably embedded with an auxiliary roller (404), the bottom of the abutting plate (403) is fixedly installed with a connecting plate (405), the connecting plate (405) is slidably mounted in the connecting plate movable groove (402), the connecting plate movable groove (402) is opened at the bottom of the storage bin (102), the upper side opening of the connecting plate movable groove (402) is opened at the interval of each No. 3 conveyor belt (401), a bidirectional screw rod (406) is rotatably installed in the connecting plate movable groove (402), both ends of the bidirectional screw rod (406) are screwed and sleeved with the connecting plate (405), and the middle part of the bidirectional screw rod (406) is fixedly connected to the output shaft of the No. 2 servo motor (407).

8. The method for ecological monitoring and protection of nature reserves based on drones according to claim 7, characterized in that: The inspection drone (5) comprises: The fuselage (501) has wings (502) fixedly mounted on the four side edges; A monitoring head (503) is rotatably mounted on the front lower edge of the fuselage (501) via an electromechanical structure, wherein the monitoring head (503) is embedded with a high-definition visible light camera, a multi-spectral camera, a thermal imaging camera, etc.; Support legs (504) are fixedly mounted on the bottom edges of both sides of the fuselage (501); A contact charging interface (505) is embedded in the rear side of the support leg (504); The connection contact (506) is embedded in the rear side of the fuselage (501).

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