Method and system for searching airport clearance and electromagnetic shielding objects

Abstract

The present invention relates to the technical field of airport clearance management, and provides a method and system for searching airport clearance and electromagnetic shielding objects, including obtaining airport runway basic data and station basic data, and constructing an airport model based on the airport runway basic data and station basic data; establishing a clearance allowed shielding area model and an electromagnetic allowed shielding area model based on the airport model, and establishing a clearance shielding object search model based on the clearance allowed shielding area model; fusing three-dimensional digital elevation data and satellite image data to find out the shielding objects and verify the shielding objects. The present invention innovatively uses the shielded objects as a benchmark, and uses the shielded objects located in each area of ​​the clearance allowed shielding area model as a reference object for reverse deduction, quickly determines the search range of the shielding objects, and then uses the three-dimensional terrain data and image data to accurately and quickly search and verify the shielding objects, thereby improving the compliance of the power department with the clearance and electromagnetic requirements of civil aviation airports during the transmission line design process.

Description

Technical Field

[0001] The invention relates to the technical field of airport clearance management, and in particular to a method and system for searching airport clearance and electromagnetic shielding objects. Background Art

[0002] At present, my country is facing the problem of imbalance between energy resources and energy demand. In order to optimize resource allocation and meet the needs of social development and ecological protection, the country has implemented the West-to-East Power Transmission and New Infrastructure UHV Projects. These projects have effectively integrated and utilized energy resources in the western region by building high-voltage or UHV transmission lines. However, these high-voltage lines pose a potential threat to the clearance and electromagnetic environment of civil aviation airports, especially around airports in mountainous areas in the western region. Due to the undulating terrain, transmission lines are more likely to affect the airport clearance and electromagnetics. In order to reduce these effects, shielding analysis is required, that is, to find existing, non-removable shielding objects within a specific range to shield transmission lines. Although shielding analysis helps solve clearance and electromagnetic compliance problems, how to quickly and accurately find these shielding objects has become a technical problem. In the prior art, there is a method that relies on mapping tools such as AutoCAD and high-precision map data to perform on-map pre-selection to find shelters, and then combines it with on-site manual measurement. However, the above solution is time-consuming, inefficient, and prone to errors when the terrain is complex. When the altitude deviation between the pre-selected shelter and the measured shelter is large, and the measured shelter cannot meet the clearance and electromagnetic shielding requirements, it is necessary to re-preselect on the map and re-measure on-site, which greatly reduces the efficiency of finding shelters. Summary of the invention

[0003] The present invention aims at the technical problems of low efficiency and low accuracy in searching for airport clearance and electromagnetic shielding in the prior art, and provides a method and system for searching for airport clearance and electromagnetic shielding. Through shielding analysis, the compliance design of transmission lines to civil aviation airport clearance and electromagnetic is achieved, so as to improve the economy and availability of transmission line design.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A method for searching airport clearance and electromagnetic shielding objects, comprising:

[0006] S1. Obtain airport runway basic data and station basic data, and build an airport model based on the airport runway basic data and station basic data;

[0007] S2. Establishing a clearance allowable shielding area model and an electromagnetic allowable shielding area model according to the airport model, respectively, for dividing the clearance allowable net shielding area and the electromagnetic allowable shielding area;

[0008] S3, establishing a clearance shielding object search model based on the clearance allowed shielding area model, and establishing an electromagnetic shielding object search model based on the electromagnetic allowed shielding area model, so as to determine the search range of the shielding object;

[0009] S4. Based on the clearance shielding object search model, a clearance search surface of shielding objects at an elevation is constructed. Based on the electromagnetic shielding object search model, an electromagnetic search surface of shielding objects at an elevation is constructed. The three-dimensional digital elevation data and satellite image data in the clearance allowed shielding area model and the electromagnetic allowed shielding area model are respectively obtained. The three-dimensional digital elevation data and satellite image data are integrated to find out the shielding objects and verify the shielding objects.

[0010] S5. Export the verified shielding information file.

[0011] A system for finding airport clearance and electromagnetic shielding objects, comprising:

[0012] A construction module is used to obtain airport runway basic data and station basic data, and to construct an airport model based on the airport runway basic data and station basic data;

[0013] The allowed shielding area module is used to establish a clearance allowed shielding area model and an electromagnetic allowed shielding area model according to the airport model, and to divide the clearance allowed net shielding area and the electromagnetic allowed shielding area respectively;

[0014] A shielding object search module is used to establish a clearance shielding object search model based on the clearance allowed shielding area model, and to establish an electromagnetic shielding object search model based on the electromagnetic allowed shielding area model, so as to determine the search range of the shielding object;

[0015] A search and verification module is used to construct a clearance search surface for shielding objects at an elevation based on a clearance shielding object search model, and to construct an electromagnetic search surface for shielding objects at an elevation based on an electromagnetic shielding object search model, respectively obtaining three-dimensional digital elevation data and satellite image data within a clearance allowed shielding area model and an electromagnetic allowed shielding area model, fusing the three-dimensional digital elevation data and satellite image data to find shielding objects and verify the shielding objects;

[0016] The export module is used to export the verified shielding information file.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0018] (1) The present invention focuses on improving the economy and availability of power transmission line design in the power sector, and ensures that line design meets the clearance and electromagnetic requirements of civil aviation airports through intelligent methods. By accurately delineating the clearance-allowed shielding area and the electromagnetic-allowed shielding area, a clear scope definition is provided for subsequent analysis. The present invention can determine whether the area where the shielding object is located is suitable for shielding analysis. After confirming that the shielding object is located in the applicable area, it innovatively uses the shielded object as a benchmark and the shielded objects located in each area of ​​the clearance-allowed shielding area model as reference objects for reverse deduction, quickly determining the search range of the shielding object, and finding suitable shielding objects within the largest applicable range, reducing the possibility of omissions. After having a clear search range, the three-dimensional terrain data and image data are used to accurately and quickly search and verify the shielding object.

[0019] (2) The innovation of the present invention also lies in that it realizes automatic judgment of shielding analysis areas and automatic drawing of shielding object search areas by constructing a clearance-allowed shielding area model and an electromagnetic-allowed shielding area model, as well as a clearance shielding object search model and an electromagnetic shielding object search model, thereby providing a unified data model and solution for automatic search and analysis of shielding objects at airports across the country, greatly improving the compliance of the power sector with the clearance and electromagnetic requirements of civil aviation airports during the transmission line design process, and at the same time improving the economy and availability of the design.

[0020] (3) The present invention improves the automation level of the shelter search work, significantly saves costs, and significantly improves the efficiency and accuracy of the search work. Through in-depth analysis of the indicators of the airport flight zone and the types of electromagnetic stations, a clear air shelter search model and an electromagnetic shelter search model applicable to airports and stations across the country were established. Combined with three-dimensional terrain data and image data, automatic and accurate search and verification of shelters are achieved, effectively reducing the errors that may be caused by human factors in the measurement and calculation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A flow chart of a method for searching for airport clearance and electromagnetic shielding objects according to an embodiment of the present invention;

[0022] Figure 2 A schematic diagram of a system for searching for airport clearance and electromagnetic shielding objects according to an embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of an obstacle limitation surface of an airport model according to an embodiment of the present invention;

[0024] Figure 4 A schematic diagram of the distribution of the clearance-allowed net shielding area and the electromagnetic-allowed shielding area according to an embodiment of the present invention;

[0025] Figure 5A schematic diagram of an electromagnetically permitted net shielding area according to an embodiment of the present invention;

[0026] Figure 6 A schematic diagram of a shielding area allowed by a slide platform according to an embodiment of the present invention;

[0027] Figure 7 It is a schematic diagram of the search ranges corresponding to the side clearance allowing shielding first area shielding search model and the side clearance allowing shielding second area shielding search model according to an embodiment of the present invention;

[0028] Figure 8 It is a schematic diagram of the search ranges corresponding to the end clearance allowing shielding first area shielding search model and the end clearance allowing shielding second area shielding search model according to an embodiment of the present invention;

[0029] Fig. 9 A schematic diagram of a third search range of an electromagnetic shielding object search model according to an embodiment of the present invention;

[0030] Fig.10 FIG. 4 is a schematic diagram of a fourth search range of an electromagnetic shielding object search model according to an embodiment of the present invention.

[0031] 1-conical surface, 2-inner horizontal surface, 3-takeoff climb surface, 4-approach surface, 5-transition surface, 6-liftoff strip, 7-first auxiliary line, 8-second auxiliary line, 9-side clearance allows shielding the first area, 10-side clearance allows shielding the second area, 11-end clearance allows shielding the first area, 12-end clearance allows shielding the second area, 13-electromagnetic allows net shielding area, 14-down slide allows shielding area, 15-first search range, 16-second search range, 17-first area of ​​the runway centerline extension line, 18-first outer expansion area, 19-second area of ​​the runway centerline extension line, 20-second outer expansion area, 21-runway, 23-third search range, 24-fourth search range, 25-station. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with embodiments:

[0033] In one embodiment, if Figure 1 As shown, a method for searching for airport clearance and electromagnetic shielding objects comprises:

[0034] S1. Obtain the airport runway basic data and station basic data, and build an airport model based on the airport runway basic data and station basic data; the airport model includes a runway model and an electromagnetic station model. The runway model and the electromagnetic station model can provide a basis for subsequent simulation analysis. The airport runway basic data usually includes the length, width, magnetic heading, true azimuth (the direction angle of the runway), longitude and latitude coordinates, and surface type (such as concrete, asphalt, etc.) of the runway, etc., and the appropriate data type can be selected according to actual needs; the station basic data refers to the basic data of the communication navigation monitoring station, including the location, operating frequency, power, coverage range, etc. of the station, and the appropriate data type can be selected according to actual needs. In this embodiment, an airport containing only one runway is taken as an example to illustrate the subsequent clearance and electromagnetic shielding search. It can also be a multi-runway airport, and reference can be made to traverse each runway for modeling and search. When building the airport model, it is necessary to ensure the accuracy and completeness of the data, and update the airport model regularly to maintain its accuracy.

[0035] In one embodiment, constructing a runway model comprises the following steps:

[0036] S11. Determine the plan and direction of the airport runway based on the basic data of the airport runway: The basic data of the airport runway includes the latitude and longitude coordinates of the entrances at both ends of the airport runway, the true direction of the airport runway and the length of the airport runway. Use the longitude and latitude coordinates to draw the plan of the airport runway in the geographic information system (GIS), and adjust the direction of the airport runway according to the true direction of the airport runway. Understandably, GPS equipment, professional measurement and survey equipment, drone aerial photography and image processors can be used to collect high-precision longitude and latitude coordinates, true direction and length data, select suitable geographic information system (GIS) software, such as ArcGIS, QGIS, etc., import the collected longitude and latitude coordinates into the GIS software as point features, use the drawing tools of the GIS software to draw the plan of the airport runway according to the two-point coordinates, ensure that the runway length is consistent with the collected data, and then adjust the runway direction on the plan according to the true direction of the runway to make it consistent with the actual direction.

[0037] S12. Assign runway attribute information: determine the altitude of the entrances at both ends of the runway, measure and record the slope information of the runway, determine the approach type of the runway according to the flight procedure, and determine the flight zone indicators according to the length, width and strength of the runway; understandably, use high-precision measuring equipment such as GPS receivers or lidar to measure the altitude of the entrances at both ends of the runway, perform multi-point measurements along the length of the runway, calculate and record the slope information, determine the approach type of the runway according to the flight procedures and airport design standards, such as instrument landing system ILS, microwave landing system MLS, etc., and determine the flight zone indicators such as 4C, 4E, 4F, etc. according to the length, width and strength of the runway and with reference to the specifications of the International Civil Aviation Organization (ICAO).

[0038] S13. Integrated terrain and obstacle data: Integrate terrain data around airport runways, including height information of natural terrain and man-made buildings, and collect obstacle data around runways that affect flight safety. Among them, terrain data around airport runways can be obtained through geographic information systems, satellite remote sensing, aerial photography, etc., and obstacle data around runways that affect flight safety, such as the location, height and type of towers, antennas, power lines, etc., can be collected through GIS data, aeronautical charts and obstacle maps, drone aerial photography, etc.

[0039] S14. Based on the altitude and slope information, a GIS software is used to build a three-dimensional model of the runway, and the physical form of the runway and the surrounding terrain are marked in the runway model. The data collected in steps S11 and S12 are organized into a format recognizable by the GIS software, and the three-dimensional modeling function of the GIS software is used to build a three-dimensional model of the airport runway based on the length, width, altitude and slope information of the runway; in the three-dimensional model, different colors, textures or labels are used to mark the physical form of the runway, such as the runway number, center line, sideline, and surrounding terrain, such as mountains, rivers, buildings, etc.

[0040] In one embodiment, in order to determine the specific location of each station and provide basic data for subsequent model building, building an electromagnetic station model includes the following steps:

[0041] A11. Collect the latitude and longitude coordinate information of airport communication, navigation and surveillance stations; the latitude and longitude coordinate information can be obtained through global positioning system GPS technology, satellite signal reception and calculation of online map services, such as Google Maps, Baidu Maps, etc.

[0042] A12. Determine the geographical location of the station and use GIS software to mark the geographical location of each station on the map based on the longitude and latitude coordinate information. In order to intuitively display the location of the station on the map and facilitate the subsequent integration of terrain data and electromagnetic environment analysis, it is necessary to determine the geographical location of the station and import the collected longitude and latitude coordinate information into the GIS software. The location of the station can be marked on the map through the corresponding functions of the GIS software. Different symbols or colors can be used to represent different types of stations.

[0043] A13. Collect height information. Collect corresponding height data according to different types of stations:

[0044] Collect the antenna reflection network altitude of the omnidirectional beacon station VOR, the antenna center bottom altitude of the non-directional beacon station NDB, the antenna altitude of the primary radar (PAPI) and secondary radar SSR, and the antenna altitude of the meteorological radar station.

[0045] A14. Use GIS software to build a dedicated station model for each station, integrate the terrain data around all stations, and analyze the electromagnetic environment around the station based on the terrain data of all stations. Specifically, build a dedicated model for each station in the GIS software, including the location, height, antenna type and other information of each station, integrate the terrain data around the station, such as altitude, terrain undulation, vegetation cover, etc., and use the spatial analysis function of GIS software to simulate and analyze the electromagnetic environment around the station.

[0046] S2. According to the airport model, a clearance shielding area model and an electromagnetic shielding area model are established to divide the clearance net shielding area and the electromagnetic shielding area respectively; shielding analysis is usually conducted in a specific area around the airport, and shielding analysis is not allowed in all areas of the airport clearance protection range. By establishing the airport clearance shielding area model and the electromagnetic shielding area model, it is possible to clearly define which areas are suitable for shielding analysis, avoiding shielding analysis in unsuitable areas, resulting in incorrect application of shielding principles, and thus ensuring the safety of the airport clearance and electromagnetic environment. With a clear shielding area model, relevant departments can make decisions faster when approving new buildings or facilities, reducing delays and errors caused by unclear information.

[0047] In one embodiment, according to the airport model, a clearance allowed shielding area model is established respectively for dividing the clearance allowed net shielding area, and step S2 further includes the following steps:

[0048] S21. Obtain the restriction surfaces of airport obstacles based on the runway model, including the conical surface, inner horizontal surface, take-off and climb surface, approach surface, transition surface, and lift strip; calculate the boundaries of the conical surface, inner horizontal surface, take-off and climb surface, approach surface, transition surface, and lift strip based on the basic runway data collected by the airport runway model and in accordance with the regulations of ICAO or local civil aviation departments, and mark the boundaries of these restriction surfaces on the airport model for subsequent analysis. It can be understood that if Figure 3As shown, the basic data of the airport runway is obtained from the runway model, and the type of obstacle limitation surface to be calculated is determined according to the regulations of the International Civil Aviation Organization (ICAO) or the local civil aviation department. The limitation surface includes a conical surface 1, an inner horizontal surface 2, a take-off climb surface 3, an approach surface 4, a transition surface 5, and a lift strip 6. For each type of obstacle limitation surface, its boundary is calculated according to its definition and calculation formula, combined with the basic runway data, and the boundaries of each obstacle limitation surface calculated are marked on the airport model, and different colors or line types can be used to distinguish them. Among them, airport obstacles and shields play an important role in airport operations. Airport obstacles are objects that need to be avoided and managed because they may pose a direct threat to flight safety; while shields are objects that can be accepted under certain conditions. They can reduce the impact on the surrounding environment and residents while ensuring flight safety.

[0049] S22. Eliminate irrelevant boundary lines, and eliminate the lift strip 6 within the inner horizontal plane 2 and the transition plane 5. The lift strip 6 is part of the runway and does not need to be considered as an obstacle restriction surface. Eliminating the lift strip 6 can simplify subsequent analysis.

[0050] S23, draw auxiliary lines, such as Figure 4 As shown, auxiliary lines parallel to the runway are drawn at 2.5 km on both sides of the runway. The parallel auxiliary lines are the first auxiliary lines 7 and intersect with the conical surface 1; auxiliary lines perpendicular to the runway are drawn at 4 km on both ends of the runway. The vertical auxiliary lines are the second auxiliary lines 8 and intersect with the approach surface 4; the auxiliary lines are drawn to better define the clearance allowed shielding area, and the positions and lengths of the first auxiliary lines 7 and the second auxiliary lines 8 can be adjusted according to actual conditions and regulations.

[0051] S24. Establish a side clearance model that allows for shielding areas, such as Figure 4 As shown, it is used to determine the clearance allowable shielding area on both sides of the runway, specifically:

[0052] Establishing the side clearance allows shading of the first area model:

[0053] The area within the first auxiliary line 7, within the boundary line of the tapered surface 1, and outside the boundary line of the approach surface 4 and the boundary line of the transition surface 5 is the side clearance allowing the shielding of the first area 9;

[0054] Building side clearances allows for shading of the second area model:

[0055] The area outside the first auxiliary line 7 and within the boundary line of the tapered surface 1 is used as the side clearance to allow shielding of the second area 10;

[0056] The first side clearance shielding area 9 and the second side clearance shielding area 10 are areas where shielding objects are allowed to exist on both sides of the runway, respectively. The division thereof takes flight safety and the influence of shielding objects into consideration.

[0057] S25. Establish an end clearance allowable shielding area model to determine the clearance allowable shielding areas at both ends of the runway, specifically:

[0058] Establishing end clearance allows shading of the first region model:

[0059] The area outside the second auxiliary line 8 and within the boundary line of the take-off climb surface 3 is the end clearance allowing the shielding of the first area 11;

[0060] Creating end clearance allows for shading of the second region model:

[0061] The area outside the second auxiliary line 8 and within the boundary line of the approach surface 4 is the end clearance allowed to be shielded second area 12, the end clearance allowed to be shielded first area 11 and the end clearance allowed to be shielded second area 12 are areas where shielding objects are allowed to exist at both ends of the runway. This division method fully considers the safety requirements of the aircraft during takeoff and approach.

[0062] The division of the above four areas fully considers flight safety, calculation of obstacle limitation surfaces, drawing of auxiliary lines and definition of different areas, ensuring rational use of the space around the airport while ensuring flight safety.

[0063] In one embodiment, if Figure 5 As shown in the figure, an electromagnetic permitted shielding area model is established according to the electromagnetic station model to divide the electromagnetic permitted net shielding area 13, and step S2 also includes the following steps:

[0064] B21. Define the inner and outer boundaries: The inner boundary is the area formed by the site protection area of ​​each station and the protection distance L, and the outer boundary is the area formed by the site protection range M of each station or the airport clearance protection range; it can be understood that Figure 5 As shown, based on the station type and voltage level, the inner boundary is drawn according to the protection distance, and the outer boundary is determined based on the station's protection range M or the airport clearance protection range. For different types of stations, their protection ranges are different, so the value of M needs to be determined according to specific regulations or standards. For the airport clearance protection range, reference should be made to relevant aviation regulations and standards. The site protection areas and protection distances L of different stations and different interference sources are different, and the site protection area action distances M of different stations are different. Therefore, the allowable shielding area model of the electromagnetic station varies due to the type of station and the type of shielding interference source.

[0065] B22. Establish a model of the area where omnidirectional beacons are allowed to be shielded:

[0066] The inner boundary takes the position of the omnidirectional beacon as the center of the circle. According to the voltage of the transmission line, different L values ​​are used to draw the circular inner boundary, and the circular outer boundary is drawn with the airport clearance protection range M. When the transmission line voltage is 35kV~110kV, L=200m; when the transmission line is 110kV and above, L=500m; M=55000m.

[0067] B23. Establish a model of the area where non-directional beacons are allowed to be shielded:

[0068] A circle is drawn with the position of the non-directional beacon as the center and the L value set according to the voltage of the transmission line. The outer boundary is drawn with the airport clearance protection range M. When the transmission line voltage is below 110kV, L=150m; when the transmission line voltage is 110kV and above, L=500m; M=55000m.

[0069] B24. Establish a model of the areas where primary and secondary radar stations and weather radar stations are allowed to be shielded:

[0070] With the positions of the primary and secondary radar stations and the meteorological radar station as the center, draw circles according to the L value set according to the transmission line voltage, and the outer boundary is a circle drawn with the effective distance M of the site protection zone of each station; among them, when the transmission line voltage is below 110kV, L=700m; when the transmission line is 220kV~330kV, L=800m; when the transmission line is 500kV, L=1200m; the effective distance of the site protection zone of the primary and secondary radar stations is M=30000m; the effective distance of the site protection zone of the meteorological radar station is M=50000m.

[0071] B25. Establish a model of the area where the glide platform is allowed to be shielded, and divide the area where the glide platform is allowed to be shielded 14:

[0072] like Figure 6 As shown, the inner boundary is the rectangular boundary of the glide platform site protection area, and the outer boundary is the fan-shaped area of ​​the glide platform signal coverage. It can be understood that the inner boundary directly adopts the rectangular boundary of the glide platform site protection area, and the outer boundary is the fan-shaped area of ​​the glide platform signal coverage. Specifically, the short side of the rectangle is perpendicular to the runway, and the glide platform is located on the short side of the rectangle. The length of the short side is determined according to the position of the glide platform, usually 240m, and the long side of the rectangle is parallel to the runway. The long side length of the Class I glide platform is 600m. The long side length of the Class II / III glide platform is 730m. The outer boundary of the glide platform allowed shielding area model is the glide platform signal coverage, that is, 8° on both sides of the glide path centerline, and the fan-shaped range of 10NM.

[0073] S3. A clearance shielding search model is established based on the clearance allowed shielding area model, and an electromagnetic shielding search model is established based on the electromagnetic allowed shielding area model, which are used to determine the search range of the shielding object; the clearance shielding objects and electromagnetic shielding objects of different widths are different in width. The minimum resolution interval size I of the shielding model set by the system is used to illustrate the shielding search model. Shielded objects with a width greater than I need to traverse the model to search for shielding objects. The minimum resolution interval size I of the shielding model can be preset according to actual needs. The search methods and ranges of shielding objects in different clearance allowed shielding areas and electromagnetic allowed shielding areas are different. The present invention takes the shielded object as a reference to establish a shielding search model in different clearance allowed shielding areas and electromagnetic allowed shielding areas.

[0074] In one embodiment, if Figures 7 and 8 As shown, a clearance shielding object search model is established based on the clearance allowed shielding area model. Through the clearance shielding object search model, the search range of shielding objects in the allowed shielding area can be clearly determined, including the following steps:

[0075] S31. Pre-set the minimum resolution interval size I of the clearance obstruction search model according to the size of the obstructed object. It can be understood that the minimum resolution interval size I of the clearance obstruction search model can be determined according to the size of the obstructed object and the search accuracy requirement. This size will determine the minimum resolution of the search model in geographic space. The obstructed objects in all areas are the same, but the types of obstructed objects are not limited. The present invention selects high-voltage line towers as the obstructed objects for illustration.

[0076] S32, identify the side clearance that allows shielding the first area, the side clearance that allows shielding the second area, the end clearance that allows shielding the first area, and the end clearance that allows shielding the second area; according to step S2, the above four areas can be determined, and according to the location of the shielded object (high-voltage line tower), the clearance area that allows shielding is determined.

[0077] S33, such as Figure 7 As shown, for the side clearance that allows shielding the first area 9, a side clearance that allows shielding the first area shielding object search model is established:

[0078] Taking the location of the obstructed object as a reference, a semicircle with a radius of 300m is established towards the runway and away from the runway as the first search range 15; that is, taking the location of the obstructed object (high-voltage line tower) as the center, a semicircle with a radius of 300m is established towards the runway and away from the runway, and this is achieved through geographic information system (GIS) software or custom geographic calculation tools. According to the specific location and shape of the obstructed object, the search range is fine-tuned to ensure that potential obstructions are fully covered; the adjusted search range is saved as a side clearance allowed to shield the first area obstruction search model, and the side clearance allowed to shield the first area obstruction search model is visualized in the geographic information system (GIS) software.

[0079] S34, such as Figure 7 As shown, for the side clearance that allows shielding of the second area 10, a side clearance that allows shielding of the second area shielding object search model is established:

[0080] In non-mountainous areas, based on the location of the obstruction, a semicircle with a radius of 600m is established in the direction toward the runway, and a semicircle with a radius of 300m is established in the direction away from the runway as the search range in non-mountainous areas;

[0081] In mountainous areas, the horizontal search range is a rectangle with a diameter of 1,200 m and a width centered on the obstructed object, extending to the boundary line of the second area where the side clearance allows obstruction. The search range in the direction away from the runway is a semicircle with a radius of 300 m.

[0082] The above search range corresponding to non-mountainous areas and the search range corresponding to mountainous areas are used as the second search range 16; the second search range 16 is used as the search range of the side clearance allowing shielding the second area shielding search model, and the side clearance allowing shielding the first area shielding search model visualized in the geographic information system GIS software.

[0083] S35, such as Figure 8 As shown, for the end clearance allowing shielding of the first area 11, an end clearance allowing shielding of the first area shielding object search model is established:

[0084] The search range corresponding to the end clearance allowed shielding first area shielding search model includes the first area of ​​the runway centerline extension line and the first outer expansion area, and its division method is as follows:

[0085] The first area 17 of the extended runway centerline is based on the location of the shielded object, and the boundary lines on both sides are parallel to the line connecting the shielded object and the runway endpoint, extending to the boundary line of the first area allowed to be shielded by the end clearance; specifically, the boundary lines on both sides in the direction toward the runway and the direction away from the runway are composed of parallel to the line connecting the shielded object and the runway endpoint, and the boundary line extends from the location of the shielded object to the boundary line of the first area allowed to be shielded by the end clearance.

[0086] The first outward expansion area 18, the boundary line close to the extended line of the runway center is the line between the obstructed object and the runway endpoint, which is extended by 12.5%; the boundary line close to the boundary side and the back of the runway is the parallel line between the obstructed object and the runway endpoint; specifically, based on the location of the obstructed object, the boundary line close to the extended line of the runway center in the runway direction is the line between the obstructed object and the runway endpoint, which is extended by 12.5% ​​and extended to the extended line of the runway centerline, and the clearance along the extended line of the runway centerline to the end is allowed to be blocked. The boundary line of the first area 11 is shielded; the boundary line on one side of the boundary is a parallel line connecting the shielded object and the end point of the runway, and the parallel line extends from the position of the shielded object to the end clearance that allows shielding the boundary line of the first area 11; the boundary lines on both sides in the direction away from the runway are parallel lines connecting the shielded object and the end point of the runway, and the parallel line extends from the position of the shielded object to the clearance that allows shielding the boundary line of the first area 11, and the end clearance that allows shielding the first area shielding search model visualized in the geographic information system GIS software.

[0087] S36, such as Figure 8 As shown, for the end clearance allowed shielding second area 12, an end clearance allowed shielding second area shielding search model is established: the search range corresponding to the end clearance allowed shielding second area shielding search model includes the second area of ​​the runway centerline extension line and the second outer expansion area, and the division method is as follows:

[0088] The second area 19 of the extended runway centerline is based on the location of the shielded object, and the boundary lines on both sides are parallel to the line connecting the shielded object and the runway endpoint, extending to the end clearance allowing the boundary line of the second area to be shielded; specifically, the boundary lines on both sides in the runway direction and the back-to-runway direction are composed of parallel to the line connecting the shielded object and the runway endpoint, and the boundary line extends from the location of the shielded object to the boundary line of the second area allowed to be shielded by the end clearance.

[0089] The second outward expansion area 20, the boundary line on the side close to the extended line of the center of the runway is 15% extended from the line connecting the obstructed object and the end point of the runway; the boundary lines on the side close to the boundary and in the direction away from the runway are also parallel lines; specifically, based on the position of the obstructed object, the boundary line on the side close to the extended line of the center of the runway in the runway direction is 15% extended from the line connecting the obstructed object and the end point of the runway and extended to the extended line of the center line of the runway, and along the extended line of the center line of the runway to the end clearance, the boundary line of the second area 12 is allowed to be shielded; the boundary line on the side close to the boundary is a parallel line to the line connecting the obstructed object and the end point of the runway, and the parallel line extends from the position of the obstructed object to the boundary line of the second area 12 allowed to be shielded by the end clearance; the boundary lines on both sides in the direction away from the runway are parallel lines to the line connecting the obstructed object and the end point of the runway, and the parallel line extends from the position of the obstructed object to the boundary line of the second area 12 allowed to be shielded by the end clearance; the end clearance allows shielding the second area shielding object search model visualized in the geographic information system GIS software.

[0090] S37, processing the overlapping area, the overlapping part of the end clearance allowing shielding the first area 11 and the end clearance allowing shielding the second area 12, if the obstruction penetrates the two end clearance restriction surfaces, then the obstruction search models of the two areas are used simultaneously for search.

[0091] In one embodiment, if Fig. 9 As shown, the electromagnetic shielding area is composed of the shielding area models of each electromagnetic station. Although the shielding areas of different electromagnetic stations are different, the shielding object search models of the shielded objects in different electromagnetic shielding areas are the same. The electromagnetic shielding object search model is established based on the electromagnetic shielding area model, including the following steps:

[0092] C31. According to the electromagnetic shielding area allowed by each electromagnetic station, the starting point and the end point of the corresponding electromagnetic shielding object search model are determined, and the search range is determined by using the starting point and the end point as the third search range 23:

[0093] The starting point is the inner boundary of the electromagnetic permitted shielding area of ​​the electromagnetic station, the end point is the shielded object, and the boundary is composed of parallel lines connecting the station and the shielded object.

[0094] C32. Construct the boundary of the search model. According to the locations of the electromagnetic station and the obscured object, determine one or more connecting lines between the electromagnetic station and the obscured object. Based on the connecting lines, construct boundary lines parallel to the parallel lines. The width of the parallel lines is the preset minimum resolution interval size. All parallel lines will constitute the boundary of the electromagnetic obscured object search model.

[0095] In one embodiment, if Fig.10 As shown, according to the lower slide platform allowed shielding area 14, referring to the above method, the inner boundary and the starting point of the lower slide platform allowed shielding area 14 are determined, and the search range is determined by using the starting point and the end point as the fourth search range 24.

[0096] The clearance shielding search model in the above steps S31-S37 uses the shielded objects located in each area of ​​the clearance allowed shielding area model as reference objects for back-calculation, which can quickly determine the search range of the shielding object and find the appropriate shielding object within the largest applicable range; thereby reducing the possibility of omissions. Since the back-calculation is based on the known position of the shielded object, the search result is more accurate and reliable. The back-calculation method can be applied to the search of different types of shielding objects, whether it is a clearance shielding object or an electromagnetic shielding object, as long as the position of the shielded object can be determined (the position of the shielding object is very easy to determine), the back-calculation method can be used to quickly find possible shielding objects.

[0097] The application of the back-calculation method in the clearance obstruction search model has brought many significant benefits, not only enhancing the accuracy and efficiency of the search, but also optimizing the operation and management of multiple key areas, as shown in the following aspects:

[0098] Efficiency: The traditional one-by-one investigation method requires a lot of manpower and material resources for extensive searches, while the reverse reasoning method can quickly narrow the search scope through logical analysis and data models, so that resources and time can be allocated more reasonably; it effectively reduces invalid searches, makes the search process more centralized and efficient, and significantly improves work efficiency.

[0099] Risks: The traditional method of first searching for obstructions and then determining their suitability has great uncertainty, resulting in waste of resources. In addition, the obstructions found may not necessarily be suitable for the required obstructions, resulting in excessive redundancy in the early search and increasing the risk of obstruction failure. The reverse method directly analyzes the possibility and demand of obstructions, accurately defines the potential area of ​​obstructions, effectively avoids misjudgment and invalid calculation of non-obstruction areas, and significantly reduces the risk of obstruction failure.

[0100] Applicability: Compared with traditional methods, the inverse model is more flexible and can adjust algorithm parameters according to different environmental conditions and characteristics of shelters. Whether it is terrain changes, vegetation changes caused by seasonal changes, or the height and shape of shelters, this method can maintain efficient and accurate search capabilities through adaptive adjustments. This adaptability makes the model have a wide range of applications and strong vitality.

[0101] In terms of auxiliary decision support: by providing accurate search scope and possibility analysis, the reverse deduction method provides powerful decision support for power planning and design departments; in the planning stage of construction projects, the corresponding model of this method can be used to reasonably predict and avoid future clearance restriction problems, avoid project adjustments or delays, and this support is of great significance to improving the scientificity and rationality of decision-making.

[0102] Data analysis and prediction: Long-term application of the reverse inference model will generate a large amount of valuable data. By analyzing this data, we can gain a deep understanding of the development trend and distribution pattern of obstructions and predict possible future clearance obstacles. This predictive capability provides an important basis for formulating preventive measures and long-term planning, helping to avoid potential risks in advance and optimize resource allocation.

[0103] In summary, the application of the back-calculation method in the clearance shelter search model has significant advantages and broad application prospects. It not only improves the accuracy and efficiency of the search, but also promotes the scientific and modern safety management and planning decision-making, providing strong support for ensuring aviation safety and promoting urban development.

[0104] The electromagnetic shielding object search model in steps C31-C32 is reversed based on the shielded objects in each area of ​​the electromagnetic permissible shielding area model as reference objects, which can quickly determine the search range of the shielding object and find the appropriate shielding object within the largest applicable range.

[0105] S4. Based on the clearance shelter search model, a clearance search surface for shelters at elevation is constructed. Based on the electromagnetic shelter search model, an electromagnetic search surface for shelters at elevation is constructed. The three-dimensional digital elevation data and satellite image data in the clearance allowed shelter area model and the electromagnetic allowed shelter area model are obtained respectively. The three-dimensional digital elevation data and satellite image data are integrated to find shelters and verify the shelters. By assigning a fixed slope shelter search surface to the shelter search model at elevation and combining it with geographic information data, fast and accurate search of shelters can be achieved.

[0106] Step S4 also includes the following steps:

[0107] S41, constructing an obstruction search surface, comprising the following steps:

[0108] S411. In the clearance shielding search model, a clearance shielding search surface is constructed based on the altitude of the shielded object. The search ranges of the shielding search models where the shielded object is located in different clearance allowed shielding areas are different, but the shielding search method at elevation is the same, so the clearance shielding search surfaces in each clearance shielding search model are the same.

[0109] The composition of the clearance shielding search surface is as follows: based on the altitude of the shielded object, a horizontal surface with a reference height constructed toward the runway, and a slope with an upward slope of 10% constructed from the starting height as the reference height in the direction away from the runway.

[0110] S412, in the electromagnetic shielding object search model, constructing an electromagnetic shielding object search surface based on the altitude of the station;

[0111] The composition of the electromagnetic shielding search surface: based on the altitude of the station, a slope with an upward angle of α is constructed towards the direction of the shielded object; the starting point of the vertical slope is the station, and the end point of the slope is the shielded object, where α is the vertical shielding angle of each station; for example, the omnidirectional beacon station is 2.5°, the non-directional beacon station is 3°, the glide path station is 1°, the primary and secondary radar stations are 0.25°, and the meteorological radar station is 1°.

[0112] S42. Obtaining digital terrain data:

[0113] Through satellite remote sensing technology or ground measurement equipment, and through the data acquisition module, the three-dimensional digital elevation data and satellite image data of the clear air allowed net shielding area and the electromagnetic allowed shielding area are obtained. The three-dimensional digital elevation data includes DEM data and DSM data, and the satellite image data includes DOM data and TDOM data; the three-dimensional digital elevation data is used to find shielding points, and the satellite image data is used to check the shielding points.

[0114] S43. A canopy height model is established based on digital terrain data to obtain the height information of the shelter above the ground. The canopy height model is obtained by performing difference calculation between DEM and DSM. The expression of the canopy height model is:

[0115] CHM ij =DSM ij -DEM ij

[0116] Among them, CHM ij Indicates the canopy height at pixel (i, j), DSM ij Indicates the height value of DSM at pixel (i, j), DEM ij Represents the height value of DEM at pixel (i, j); by comparing the height values ​​of DSM data and DEM data, we can get the canopy height, that is, the height above the ground that may become an obstruction. The canopy height model can help us identify potential obstructions more accurately.

[0117] S44. TDOM data and DOM data are superimposed through the fusion model to fuse the satellite image data into one image in order to more comprehensively display the information of the obstruction. The expression of the fusion model is:

[0118] Fusion Image ij =δ·TDOM ij +(1-δ)·DOM ij

[0119] Among them, Fusion Image ij The value of the fused image at the pixel point (i, j), δ value is the weight factor, the contribution ratio of TDOM in the fused image is δ, and the contribution ratio of DOM in the fused image is 1-δ; control the contribution ratio of TDOM and DOM in the final fused image, adjust it according to the actual situation to optimize the visual effect, and the fused satellite image data can more accurately verify the type of shelter found.

[0120] S45. Find out the shielding objects based on the digital terrain data, and find out the possible shielding objects from the three-dimensional digital elevation data through grid processing and extreme point comparison. It can be understood that the grid clearance shielding object search surface, electromagnetic shielding object search surface and three-dimensional terrain data are grid-sized according to the search accuracy and search efficiency, and the extreme points in each grid are found for each grid, and the grid extreme values ​​of the clearance shielding object search surface and the electromagnetic shielding object search surface are compared with the grid extreme values ​​of the three-dimensional terrain data. In the clearance shielding object search model or the electromagnetic shielding object search model, if there are natural mountains and buildings beyond the clearance shielding object search surface and the electromagnetic shielding object search surface, the natural mountains and buildings can be considered as potential shielding objects.

[0121] Specifically, step S45 further includes the following steps:

[0122] Verify the 3D digital elevation model (DEM) data, the clear air shielding search surface data, and the electromagnetic shielding search surface data to cover the same geographic area, in the same coordinate system and resolution. Then adjust the grid size of all data sets to be consistent to facilitate spatial registration and ensure the accurate correspondence of each data set in space.

[0123] S451, gridding the clearance shielding object search surface, electromagnetic shielding object search surface and three-dimensional digital elevation data, and setting the grid size;

[0124] S452, finding the extreme value point in each grid, finding the maximum value in each grid, and comparing the grid extreme value of the clearance shielding search surface and the grid extreme value of the electromagnetic shielding search surface with the grid extreme value of the three-dimensional digital elevation data respectively;

[0125] If the maximum extreme value of the 3D digital elevation data grid is lower than the corresponding maximum extreme value of the clear shielding search surface and the electromagnetic shielding search surface, it means that there are no natural mountains or buildings in the area that can be used for shielding;

[0126] If the maximum extreme value of the three-dimensional digital elevation data grid is higher than the corresponding maximum extreme value of the grid of the clearance shielding search surface and the electromagnetic shielding search surface, it indicates that there are potential shielding objects such as natural mountains or buildings in the area that can be used for shielding.

[0127] S453, if there is a natural mountain or building beyond the clear space shielding search surface and the electromagnetic shielding search surface in the shielding search model, determine that the natural mountain or building is a potential shielding object;

[0128] Through grid processing and extreme point comparison, the search range of shelters can be effectively narrowed and the search efficiency can be improved. By comparing with the search surface, it can be determined which natural mountains or buildings may constitute potential shelters.

[0129] S46. Check the shielding objects.

[0130] Step S46 also includes the following steps:

[0131] S461. According to the location of the potential obstruction, the satellite image data at the location is obtained to provide visual information of the location of the obstruction, and the satellite image data at the location includes digital orthophoto image data DOM and digital true orthophoto image data TDOM. According to the location of the obstruction that has been found, the image data at the same location in the digital orthophoto image data DOM and the digital true orthophoto image TDOM is obtained to determine whether the obstruction point in the image data is an obstruction that can be used for shielding.

[0132] S462. Determine whether the shielded points in the satellite image data are shielding objects that can be used for shielding through visual interpretation or automatic classification algorithms. It is understandable that the image data at the same position in the digital orthophoto data DOM and the digital true orthophoto image TDOM are preprocessed, such as denoising, radiation calibration, geometric correction, etc., to improve the accuracy of image interpretation. Visual interpretation is to use remote sensing image processing software to directly observe and analyze satellite images, identify and determine whether the shielded points in the remote sensing image are shielding objects that can be used for shielding based on the reflection or radiation characteristics of specific objects and landforms in different bands, and record the interpretation results and related information, which can be recorded in the form of tables, text descriptions, etc.

[0133] The automatic classification algorithm uses satellite images for preprocessing operations, such as denoising, radiation calibration, geometric correction, etc. According to the needs of the automatic classification algorithm, the image is appropriately converted into a data format and feature extracted to extract features related to obstructions, such as shape, size, texture, spectral information, etc. Principal component analysis PCA, linear mixed model LMM and other methods can also be used for feature extraction and dimensionality reduction. According to the specific application scenario and data characteristics, a suitable automatic classification algorithm is selected, such as a classification algorithm based on deep learning, support vector machine SVM, etc. The model is trained using a data set with known labels, and the model parameters are adjusted to optimize the classification performance. The model is evaluated using a test data set to ensure that the model has a high classification accuracy; the trained model is applied to satellite image data to automatically identify the obstruction points in the image, and based on the identification results, the location of the obstruction that can be used for shielding and related information are output.

[0134] S463. If the satellite image data shows that the obstruction point is a natural mountain, then the natural mountain is confirmed as the obstruction.

[0135] S464. If the satellite image data shows that the shielding point is a building, if the building cannot be relocated or adjusted or is a legal and compliant house, then the building is determined to be a shielding object; if the building is a communication base station, high-voltage tower, transmission line, billboard, high pole lamp, smoke tower, wind turbine, control tower, terminal building and temporary building, it cannot be used for shielding.

[0136] S5. Export the verified information file of the shielding object. Export the relevant information of the shielding object that can be used for shielding in the form of a file, the relevant information of the shielding object includes digital terrain data, shielding object type, longitude and latitude, and altitude.

[0137] The present invention also provides a system for searching for airport clearance and electromagnetic shielding objects, comprising:

[0138] The construction module 100 is used to obtain the airport runway basic data and the station basic data, and construct an airport model according to the airport runway basic data and the station basic data;

[0139] The allowed shielding area module 200 is used to establish a clear air allowed shielding area model and an electromagnetic allowed shielding area model according to the airport model, and divide the clear air allowed shielding area and the electromagnetic allowed shielding area respectively;

[0140] The shielding object search module 300 is used to establish a clearance shielding object search model based on the clearance allowed shielding area model, and to establish an electromagnetic shielding object search model based on the electromagnetic allowed shielding area model, so as to determine the search range of the shielding object;

[0141] The search and verification module 400 is used to construct a clearance search surface of the shielding object at the elevation based on the clearance shielding object search model, and to construct an electromagnetic search surface of the shielding object at the elevation based on the electromagnetic shielding object search model, respectively obtain the three-dimensional digital elevation data and satellite image data in the clearance allowed shielding area model and the electromagnetic allowed shielding area model, fuse the three-dimensional digital elevation data and satellite image data to find the shielding object and verify the shielding object;

[0142] The export module 500 is used to export the verified shielding object information file.

[0143] In the airport clearance and electromagnetic shielding search system of the above-mentioned embodiment of the present invention, a clearance allowed shielding area and an electromagnetic allowed shielding area model applicable to airports and stations across the country are established, which provides a basic area definition for subsequent shielding object searches. It innovatively takes the shielded objects as the benchmark, and innovatively establishes a clearance shielding object search model and an electromagnetic shielding object search model, aiming to help the power department design and plan power transmission lines that meet the clearance and electromagnetic requirements of civil aviation airports, and realize the rapid search and verification of shielding objects through automated and precise methods.

[0144] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for searching airport clearance and electromagnetic shielding objects, characterized in that: include: S1. Obtain airport runway basic data and station basic data, and build an airport model based on the airport runway basic data and station basic data; S2. Establishing a clearance allowable shielding area model and an electromagnetic allowable shielding area model according to the airport model, respectively, for dividing the clearance allowable net shielding area and the electromagnetic allowable shielding area; S3, establishing a clearance shielding object search model based on the clearance allowed shielding area model, and establishing an electromagnetic shielding object search model based on the electromagnetic allowed shielding area model, so as to determine the search range of the shielding object; establishing the clearance shielding object search model based on the clearance allowed shielding area model includes the following steps: S31, presetting the minimum resolution interval size I of the clearance obstruction search model according to the size of the obstruction; S32, identifying that the side clearance allows shielding of the first area, the side clearance allows shielding of the second area, the end clearance allows shielding of the first area, and the end clearance allows shielding of the second area; S33, for the side clearance that allows shielding the first area, establish a shielding object search model for the side clearance that allows shielding the first area: Taking the location of the obstructed object as the reference, establish a semicircle with a radius of 300m in the direction towards the runway and in the direction away from the runway as the search range; S34, for the side clearance that allows shielding the first area, establish a side clearance that allows shielding the second area shielding object search model: In general areas, based on the location of the obstruction, a semicircle with a radius of 600m is established in the direction toward the runway, and a semicircle with a radius of 300m is established in the direction away from the runway as the search range in non-mountainous areas; In mountainous areas, the horizontal search range is a rectangle with a diameter of 1,200 m and a width centered on the obstructed object, extending to the boundary line of the second area where the side clearance allows obstruction. The search range in the direction away from the runway is a semicircle with a radius of 300 m. S35. For the end clearance that allows shielding the first area, establish an obstruction search model for the end clearance that allows shielding the first area: The first area of ​​the extended runway centerline is based on the location of the obstructed object, and the boundary lines on both sides are parallel lines connecting the obstructed object and the runway endpoints, extending to the boundary line of the first area where the end clearance allows obstruction; In the first extended area, the boundary line on the side close to the extended line of the runway center is 12.5% ​​extended outward from the line connecting the obstructed object and the end point of the runway; the boundary line on the side close to the boundary and in the direction away from the runway is a line parallel to the line connecting the obstructed object and the end point of the runway; S36: For the end clearance that allows shielding the second area, establish an end clearance that allows shielding the second area shielding object search model: The second area of ​​the extended runway centerline is based on the location of the obstructed object, and the boundary lines on both sides are parallel lines connecting the obstructed object and the runway endpoints, extending to the boundary line of the second area where the end clearance allows obstruction; The second extended area, the boundary line close to the extended line of the runway center is 15% extended from the line connecting the obstructed object and the end point of the runway; the boundary line close to the boundary side and the boundary line in the direction away from the runway are also parallel lines; S37, processing the overlapping area, the end clearance allows the overlapping part of the first area to be shielded and the end clearance allows the overlapping part of the second area to be shielded, if the shielded object penetrates the two end clearance restriction surfaces, then the shielding object search models of the two areas are used simultaneously for search; S4, constructing a clearance search surface for the shielding at an elevation based on the clearance shielding search model, constructing an electromagnetic search surface for the shielding at an elevation based on the electromagnetic shielding search model, respectively obtaining three-dimensional digital elevation data and satellite image data in the clearance allowed shielding area model and the electromagnetic allowed shielding area model, fusing the three-dimensional digital elevation data and satellite image data to find the shielding and verify the shielding; comprising the following steps: S41, constructing an obstruction search surface, comprising the following steps: S411, in the clearance shielding object search model, constructing a clearance shielding object search surface based on the altitude of the shielded object; Taking the altitude of the sheltered object as the reference, the direction toward the runway is composed of a horizontal plane with a height equal to the reference height, and the direction away from the runway is composed of an inclined plane with a starting height equal to the reference height and an upward slope of 10%; S412, in the electromagnetic shielding object search model, constructing an electromagnetic shielding object search surface based on the altitude of the station; Taking the altitude of the station as the reference, the direction toward the shielded object is formed by a slope with an upward angle of α; the starting point of the vertical slope is the station, and the end point of the slope is the shielded object, where α is the vertical shielding angle of each station; S42. Obtaining digital terrain data: The three-dimensional digital elevation data and satellite image data of the clearance allowed net shielding area and the electromagnetic allowed shielding area are obtained through the data acquisition module. The three-dimensional digital elevation data includes DEM data and DSM data, and the satellite image data includes DOM data and TDOM data; S43. A canopy height model is established based on digital terrain data to obtain the height information of the shelter above the ground. The canopy height model is obtained by performing difference calculation between DEM and DSM. The expression of the canopy height model is: CHM ij =DSM ij -DEM ij Among them, CHM ij Indicates the canopy height at pixel (i, j), DSM ij Indicates the height value of DSM at pixel (i, j), DEM ij Indicates the height value of DEM at pixel (i, j); S44. TDOM data and DOM data are superimposed through a fusion model to fuse the satellite image data into one image. The expression of the fusion model is: Fusion Image ij =δ·TDOM ij +(1-d)·DOM ij Among them, Fusion Image ij The value of the fused image at the pixel (i, j), the δ value is the weight factor, the contribution ratio of TDOM in the fused image is δ, and the contribution ratio of DOM in the fused image is 1-δ; S45, finding out shelters based on the digital terrain data; S46. Check shielding objects; S5. Export the verified shielding information file.

2. The method for searching airport clearance and electromagnetic shielding objects according to claim 1, characterized in that: The airport model includes a runway model and an electromagnetic station model. Constructing the runway model includes the following steps: S11. Determine the plane map and direction of the airport runway based on the basic data of the airport runway: the basic data of the airport runway includes the latitude and longitude coordinates of the entrances at both ends of the airport runway, the true orientation of the airport runway, and the length of the airport runway. The plane map of the airport runway is drawn in the geographic information system GIS using the latitude and longitude coordinates, and the direction of the airport runway is adjusted according to the true orientation of the airport runway; S12. Assigning runway attribute information: determining the altitude of the entrances at both ends of the runway, measuring and recording the slope information of the runway, determining the approach type of the runway according to the flight procedure, and determining the flight zone index according to the length, width and strength of the runway; S13. Integrated terrain and obstacle data: Integrate terrain data around the airport runway, including the height information of natural terrain and man-made buildings, and collect obstacle data around the runway that affects flight safety; S14. Based on the altitude and slope information, use GIS software to build a three-dimensional model of the runway, and mark the physical form of the runway and the surrounding terrain in the runway model.

3. The method for searching airport clearance and electromagnetic shielding objects according to claim 2, characterized in that: Building an electromagnetic station model includes the following steps: A11. Collect the latitude and longitude coordinate information of airport communication, navigation and surveillance stations; A12. Determine the geographical location of the stations and use GIS software to mark the geographical location of each station on the map based on the latitude and longitude coordinate information; A13. Collect height information. Collect corresponding height data according to different types of stations: Collect the antenna reflection network altitude of the omnidirectional beacon station VOR, the antenna center bottom altitude of the non-directional beacon station NDB, the antenna altitude of the primary radar (PAPI) and secondary radar SSR, and the antenna altitude of the meteorological radar station; A14. Use GIS software to build a dedicated station model for each station, integrate the terrain data around all stations, and analyze the electromagnetic environment around the stations based on the terrain data of all stations.

4. The method for searching airport clearance and electromagnetic shielding objects according to claim 2, characterized in that: Establishing a clearance allowable shielding area model based on the airport model includes the following steps: S21. Obtain the restriction surfaces of airport obstacles based on the runway model, including conical surface, inner horizontal surface, take-off and climb surface, approach surface, transition surface and lift strip; S22, remove irrelevant boundary lines, remove the lift belts within the inner horizontal plane and transition plane; S23. Draw auxiliary lines. Draw auxiliary lines parallel to the runway at 2.5 km on both sides of the runway and intersect with the conical surface. Draw auxiliary lines perpendicular to the runway at 4 km on both ends of the runway and intersect with the approach surface. S24. Establish a side clearance permissible shielding area model to determine the clearance permissible shielding areas on both sides of the runway, specifically: Establishing the side clearance allows shading of the first area model: The area within the parallel auxiliary lines, within the boundary line of the tapered surface, and outside the boundary line of the approach surface and the boundary line of the transition surface is the first area of ​​side clearance that is allowed to be shielded; Building side clearances allows for shading of the second area model: The area outside the parallel auxiliary lines and inside the boundary line of the tapered surface is used as the side clearance to allow shielding of the second area; S25. Establish an end clearance allowable shielding area model to determine the clearance allowable shielding areas at both ends of the runway, specifically: Establishing end clearance allows shading of the first region model: The area outside the vertical auxiliary line and within the boundary line of the take-off climb surface is the first area that is allowed to be shielded by the end clearance; Creating end clearance allows for shading of the second region model: The area outside the vertical auxiliary line and within the approach surface boundary line is the end clearance, which allows the second area to be shielded.

5. The method for searching airport clearance and electromagnetic shielding objects according to claim 3, characterized in that: The electromagnetic permissible shielding area model is established according to the electromagnetic station model, including the following steps: B21. Define the inner boundary and outer boundary: the inner boundary is the area formed by the site protection area of ​​each station and the protection distance L, and the outer boundary is the area formed by the site protection range M of each station or the airport clearance protection range; B22. Establish a model of the area where omnidirectional beacons are allowed to be shielded: The inner boundary is drawn with the position of the omnidirectional beacon as the center, and a circle is drawn with different L values ​​set according to the voltage of the transmission line. The outer boundary is drawn with the airport clearance protection range M. When the transmission line voltage is 35kV~110kV, L=200m; when the transmission line voltage is 110kV and above, L=500m; M=55000m; B23. Establish a model of the area where non-directional beacons are allowed to be shielded: With the location of the non-directional beacon as the center, a circle is drawn according to the L value set according to the voltage of the transmission line, and the outer boundary is drawn with the airport clearance protection range M. Among them, when the transmission line voltage is below 110kV, L = 150m; when the transmission line voltage is 110kV and above, L = 500m; M = 55000m; B24. Establish a model of the areas where primary and secondary radar stations and weather radar stations are allowed to be shielded: With the positions of the primary and secondary radar stations and the meteorological radar station as the center of the circle, a circle is drawn according to the L value set according to the voltage of the transmission line, and the outer boundary is a circle drawn with the effective distance M of the site protection zone of each station; among them, when the voltage of the transmission line is below 110kV, L = 700m; when the transmission line is 220kV ~ 330kV, L = 800m; when the transmission line is 500kV, L = 1200m; the effective distance of the site protection zone of the primary and secondary radar stations is M = 30000m; the effective distance of the site protection zone of the meteorological radar station is M = 50000m; B25. Establish a model of the area where the glide path allows for shielding: The inner boundary is the rectangular boundary of the glide platform site protection area, and the outer boundary is the fan-shaped area of ​​the glide platform's signal coverage range.

6. The method for searching airport clearance and electromagnetic shielding objects according to claim 5, characterized in that: The electromagnetic shielding object search model is established based on the electromagnetic allowed shielding area model, including the following steps: C31. According to the electromagnetic shielding area allowed by each electromagnetic station, determine the starting point and end point of the corresponding electromagnetic shielding object search model, and use the starting point and end point to determine the search range: The starting point is the inner boundary of the electromagnetic permissible shielding area of ​​the electromagnetic station, the end point is the shielded object, and the boundary is composed of parallel lines connecting the station and the shielded object; C32. Construct the boundary of the search model. According to the locations of the electromagnetic station and the obscured object, determine one or more connecting lines between the electromagnetic station and the obscured object. Based on the connecting lines, construct boundary lines parallel to the parallel lines. The width of the parallel lines is the preset minimum resolution interval size. All parallel lines will constitute the boundary of the electromagnetic obscured object search model.

7. The method for searching airport clearance and electromagnetic shielding objects according to claim 6, characterized in that: Step S45 also includes the following steps: S451, gridding the clearance shielding object search surface, electromagnetic shielding object search surface and three-dimensional digital elevation data, and setting the grid size; S452, finding out the extreme value points in all the grids, and comparing the grid extreme values ​​of the clearance shielding search surface and the grid extreme values ​​of the electromagnetic shielding search surface with the grid extreme values ​​of the three-dimensional digital elevation data respectively; S453, if there is a natural mountain or building beyond the clear space shielding search surface and the electromagnetic shielding search surface in the shielding search model, determine that the natural mountain or building is a potential shielding object; Step S46 also includes the following steps: S461, according to the location of the potential shielding object, obtaining satellite image data at the location of the potential shielding object to provide visual information of the location of the shielding object, wherein the satellite image data at the location of the potential shielding object includes digital orthophoto data DOM and digital true orthophoto data TDOM; S462, judging whether the shielding point in the satellite image data is a shielding object that can be used for shielding by visual interpretation or automatic classification algorithm; S463. If the satellite image data shows that the obstruction point is a natural mountain, the natural mountain is confirmed as the obstruction object; S464. If the satellite image data shows that the shielding point is a building, if the building is a legal and compliant house that cannot be relocated, then the building is determined to be a shielding object; if the building is a communication base station, a high-voltage tower, a transmission line, a billboard, a high-pole lamp, a smoke tower, a wind turbine, a tower, a terminal building, or a temporary building, then it cannot be used for shielding; Step S5 includes the following steps: exporting the relevant information of the shielding object that can be used for shielding in the form of a file, the relevant information of the shielding object includes digital terrain data, shielding object type, longitude and latitude, and altitude.

8. A system for searching for airport clearance and electromagnetic shielding objects, characterized in that: include: A construction module is used to obtain airport runway basic data and station basic data, and to construct an airport model based on the airport runway basic data and station basic data; The allowed shielding area module is used to establish a clearance allowed shielding area model and an electromagnetic allowed shielding area model according to the airport model, and to divide the clearance allowed net shielding area and the electromagnetic allowed shielding area respectively; A shielding object search module is used to establish a clearance shielding object search model based on the clearance allowed shielding area model, and to establish an electromagnetic shielding object search model based on the electromagnetic allowed shielding area model, so as to determine the search range of the shielding object; The search and verification module is used to construct a clearance search surface for the shielding object at an elevation based on the clearance shielding object search model, and to construct an electromagnetic search surface for the shielding object at an elevation based on the electromagnetic shielding object search model, respectively obtain the three-dimensional digital elevation data and satellite image data in the clearance allowed shielding area model and the electromagnetic allowed shielding area model, fuse the three-dimensional digital elevation data and satellite image data to find the shielding object and verify the shielding object; establishing the clearance shielding object search model based on the clearance allowed shielding area model includes the following steps: S31, presetting the minimum resolution interval size I of the clearance obstruction search model according to the size of the obstruction; S32, identifying that the side clearance allows shielding of the first area, the side clearance allows shielding of the second area, the end clearance allows shielding of the first area, and the end clearance allows shielding of the second area; S33, for the side clearance that allows shielding the first area, establish a shielding object search model for the side clearance that allows shielding the first area: Taking the location of the obstructed object as the reference, establish a semicircle with a radius of 300m in the direction towards the runway and in the direction away from the runway as the search range; S34, for the side clearance that allows shielding the first area, establish a side clearance that allows shielding the second area shielding object search model: In general areas, based on the location of the obstruction, a semicircle with a radius of 600m is established in the direction toward the runway, and a semicircle with a radius of 300m is established in the direction away from the runway as the search range in non-mountainous areas; In mountainous areas, the horizontal search range is a rectangle with a diameter of 1,200 m and a width centered on the obstructed object, extending to the boundary line of the second area where the side clearance allows obstruction. The search range in the direction away from the runway is a semicircle with a radius of 300 m. S35. For the end clearance that allows shielding the first area, establish an obstruction search model for the end clearance that allows shielding the first area: The first area of ​​the extended runway centerline is based on the location of the obstructed object, and the boundary lines on both sides are parallel lines connecting the obstructed object and the runway endpoints, extending to the boundary line of the first area where the end clearance allows obstruction; In the first extended area, the boundary line on the side close to the extended line of the runway center is 12.5% ​​extended outward from the line connecting the obstructed object and the end point of the runway; the boundary line on the side close to the boundary and in the direction away from the runway is a line parallel to the line connecting the obstructed object and the end point of the runway; S36: For the end clearance that allows shielding the second area, establish an end clearance that allows shielding the second area shielding object search model: The second area of ​​the extended runway centerline is based on the location of the obstructed object, and the boundary lines on both sides are parallel lines connecting the obstructed object and the runway endpoints, extending to the boundary line of the second area where the end clearance allows obstruction; The second extended area, the boundary line close to the extended line of the runway center is 15% extended from the line connecting the obstructed object and the end point of the runway; the boundary line close to the boundary side and the boundary line in the direction away from the runway are also parallel lines; S37, processing the overlapping area, the end clearance allows the overlapping part of the first area to be shielded and the end clearance allows the overlapping part of the second area to be shielded, if the shielded object penetrates the two end clearance restriction surfaces, then the shielding object search models of the two areas are used simultaneously for search; The search and verification module also includes the following steps: S41, constructing an obstruction search surface, comprising the following steps: S411, in the clearance shielding object search model, constructing a clearance shielding object search surface based on the altitude of the shielded object; Taking the altitude of the sheltered object as the reference, the direction toward the runway is composed of a horizontal plane with a height equal to the reference height, and the direction away from the runway is composed of an inclined plane with a starting height equal to the reference height and an upward slope of 10%; S412, in the electromagnetic shielding object search model, constructing an electromagnetic shielding object search surface based on the altitude of the station; Taking the altitude of the station as the reference, the direction toward the shielded object is formed by a slope with an upward angle of α; the starting point of the vertical slope is the station, and the end point of the slope is the shielded object, where α is the vertical shielding angle of each station; S42. Obtaining digital terrain data: The three-dimensional digital elevation data and satellite image data of the clearance allowed net shielding area and the electromagnetic allowed shielding area are obtained through the data acquisition module. The three-dimensional digital elevation data includes DEM data and DSM data, and the satellite image data includes DOM data and TDOM data; S43. A canopy height model is established based on digital terrain data to obtain the height information of the shelter above the ground. The canopy height model is obtained by performing difference calculation between DEM and DSM. The expression of the canopy height model is: CHM ij =DSM ij -DEM ij Among them, CHM ij Indicates the canopy height at pixel (i, j), DSM ij Indicates the height value of DSM at pixel (i, j), DEM ij Indicates the height value of DEM at pixel (i, j); S44. TDOM data and DOM data are superimposed through a fusion model to fuse the satellite image data into one image. The expression of the fusion model is: Fusion Image ij =δ·TDOM ij +(1-d)·DOM ij Among them, Fusion Image ij The value of the fused image at the pixel (i, j), the δ value is the weight factor, the contribution ratio of TDOM in the fused image is δ, and the contribution ratio of DOM in the fused image is 1-δ; S45, finding out shelters based on the digital terrain data; S46. Check shielding objects; The export module is used to export the verified shielding information file.

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