Analysis method of shadow area of ​​civil aviation Doppler omnidirectional beacon reflection network combined with GIS

Abstract

The present invention discloses a method for analyzing the shadow area of ​​a civil aviation Doppler omnidirectional beacon reflection network in combination with GIS, which belongs to the field of civil aviation technology. The analysis method of the present invention comprises the following steps: S1. Determine the maximum distance of the obstacle relative to the station D max Minimum distance D min ; S2. Judgment: If D min > D 0, it is determined that the obstacle does not exceed the shadow area limit of the station reflection network; if D min ≤ D 0, then go to S3; S3. Calculate the angle of the shadow area of ​​the station reflection network; S4. Calculate the range of the shadow area of ​​the station reflection network; S5. Calculate the limit height h , and according to the obstacle altitude h o With height restriction h The difference between △h Determine whether obstacles are beyond the shadow area of ​​the station's reflective network. The method of the present invention can quickly determine whether multiple obstacles meet the Doppler omnidirectional beacon standard requirements, shorten the time of traditional manual review, improve the accuracy and consistency of judgment, and ensure the safe operation of navigation stations.

Description

Technical Field

[0001] The invention belongs to the technical field of civil aviation, and in particular relates to a method for analyzing a shadow area of ​​a civil aviation Doppler omnidirectional beacon reflection network combined with GIS. Background Art

[0002] Protecting the electromagnetic environment around air traffic control (ATC) communication, navigation, and surveillance equipment is crucial for ensuring air traffic control operations, directly impacting flight safety and operational efficiency. In recent years, with the development of new infrastructure, airport-related economic zones, and the "civil aviation + ecosystem," construction demand around airports has increased significantly, posing significant challenges to protecting the electromagnetic environment at ATC stations. According to existing technical specifications, electromagnetic compatibility (EMC) assessments are required before site selection for new airports. For existing airports, analysis of new tall buildings and facilities surrounding them should be conducted to ensure interference-free operation. National standards GB6364 and civil aviation standards MH / T4003.1-2, among others, clearly define electromagnetic environmental protection zones for aviation ATC stations, aiming to strengthen electromagnetic environmental protection at airports and surrounding stations. Furthermore, to further standardize the clearance review process for construction projects within civil airport clearance zones and ensure flight safety, a clearance review is required for construction projects within these zones within a 55-kilometer radius, centered on the airport reference point. A clearance review opinion must be issued within 15 working days.

[0003] Doppler omnidirectional beacons can work in conjunction with airborne receivers to provide aircraft with all-round guidance information to guide aircraft along predetermined routes (lines), takeoffs, and approaches. Since the terrain and objects around the omnidirectional beacon reflect and re-radiate the radio wave signals it transmits, the resulting multipath interference will cause its radiation field pattern to be distorted, resulting in channel bending, swinging, and jittering, threatening flight safety. Therefore, MH / T4003.1 "Civil Aviation Communication, Navigation, and Surveillance Station Installation Site Specifications Part 1: Navigation" makes clear provisions for the protection of Doppler omnidirectional beacon sites, which requires that the reflection path from the sideband antenna phase center through the edge of the reflective net to the ground should not be blocked by obstacles. This area is called the reflective net shadow area.

[0004] Omnidirectional beacons consist of a central antenna, sideband antennas, and a reflector grid. The parameters of each station vary, and the resulting shadow areas are also distinct and abstract. This makes it difficult for auditors to determine whether obstacles meet the protection requirements for omnidirectional beacon sites. Currently, manual calculations are primarily relied upon, which is not only inefficient but also prone to errors. With the increasing number of construction projects, the workload for auditors continues to increase.

[0005] Given the strict requirements of the Doppler omnidirectional beacon site protection zone on the shadow area limit, there is an urgent need for an efficient method that can help auditors quickly determine whether multiple obstacles meet the standards. Summary of the Invention

[0006] The purpose of the present invention is to provide a civil aviation Doppler omnidirectional beacon reflection network shadow area analysis method combined with GIS, which can simplify the audit process, improve judgment accuracy, enhance audit efficiency, effectively alleviate audit pressure, and provide guarantee for the safe and stable operation of navigation stations.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] The present invention discloses a method for analyzing the shadow area of ​​a civil aviation Doppler omnidirectional beacon reflection network in combination with GIS, comprising the following steps:

[0009] S1. Determine the maximum distance of obstacles relative to the station D max Minimum distance D min ;

[0010] S2. Determine the minimum distance of obstacles relative to the station D min Maximum distance from the shadow area of ​​the reflective net D 0 relationship:

[0011] (1) If D min > D If it is 0, it is determined that the obstacle does not exceed the shadow area limit of the station reflection network;

[0012] (2) If D min ≤D 0, then go to step S3;

[0013] S3. Calculate the angle of the shadow area of ​​the station reflection network;

[0014] S4. Calculate the shadow area of ​​the station reflection network based on the included angle of the station reflection network shadow area;

[0015] S5. Calculate the limit altitude h , and according to the obstacle altitude h o With height restriction h The difference between Determine whether the obstacle is beyond the shadow area of ​​the station reflection network.

[0016] In some embodiments of the present invention, in step S1, the shortest distance between the station and each coordinate point of the obstacle is calculated, and the following operations are performed on each coordinate point of the obstacle: first, the current point is projected, and then the distance between the point and the center of the station and the shortest distance between the point and the line segment connecting the center of the station and the previous projection point are calculated; then, if the distance between the current point and the center of the station is greater than the current point, the shortest distance between the current point and the center of the station is calculated. D max , then update D max ; If the shortest distance from the point to the line segment is less than the current D min , then update D min ; Loop through all points until there are no remaining points; Finally, the maximum distance of the obstacle relative to the station can be determined D max Minimum distance D min , to achieve accurate quantitative analysis of the spatial distance relationship between obstacles and stations.

[0017] In some embodiments of the present invention, the maximum distance of the shadow area of ​​the reflective net is D 0=100 meters.

[0018] In some embodiments of the present invention, the following formula is used to calculate the angle of the shadow area of ​​the station reflection network:

[0019] ;

[0020] in i deg is the angle of the shadow area of ​​the reflection net, in degrees; d is the diameter of the reflection network, in m; h a is the height of the central antenna and the sideband antenna, in meters; r is the distance from the sideband antenna to the central antenna, in meters.

[0021] In some embodiments of the present invention, the radius of the shadow area is calculated using the following formula: r t , thus obtaining the shadow area range of the reflection net;

[0022] ;

[0023] ;

[0024] r t is the radius of the shadow area, in m; h r is the height of the reflection network, in meters;d is the diameter of the reflection network, in m, i deg It is the included angle of the shadow area of ​​the reflection net, in degrees.

[0025] In some embodiments of the present invention, the height is limited h The calculation formula is as follows:

[0026] ;

[0027] in h a is the height of the central antenna and the sideband antenna (i.e. the height from the central antenna and the sideband antenna to the reflector), in meters; r is the distance from the sideband antenna to the central antenna, in meters; d is the diameter of the reflection network, in m; h r is the height of the reflection net (i.e. the height of the reflection net from the ground), in meters; h s is the station altitude, in m;

[0028] x is the distance corresponding to the height limit, and its value is determined by the following formula:

[0029] ;

[0030] r t is the radius of the shadow area, in m; D max is the maximum distance of the obstacle relative to the station, in meters.

[0031] Obstacle altitude h o With height restriction h The difference between △h ,

[0032] In some embodiments of the present invention, the obstacle altitude h o With height restriction h The difference between △h The calculation formula is:

[0033] △h = h 0 -h ;

[0034] In some embodiments of the present invention, when △hWhen ≥0, it indicates that the altitude of the obstacle exceeds the restricted altitude, and the obstacle is judged to be beyond the restricted range of the shadow area of ​​the station reflection network. In this case, the obstacle may block the reflection path from the phase center of the sideband antenna along the edge of the reflection network to the ground, affecting the signal transmission of the station.

[0035] when △h When <0, it indicates that the altitude of the obstacle does not exceed the restricted altitude, and it is judged that the obstacle does not exceed the restricted range of the shadow area of ​​the station reflection network and will not cause obvious obstruction to the reflection path.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The method of the present invention can quickly determine whether multiple obstacles meet the Doppler omnidirectional beacon standard requirements. This method not only greatly shortens the time required for traditional manual review, but also significantly improves the accuracy and consistency of judgments, thus providing a stronger guarantee for the safe operation of navigation stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Attachment Figure 1 is a flow chart of the analysis method of the present invention;

[0039] Attachment Figure 2 is the minimum distance of the obstacle relative to the station D min Schematic diagram;

[0040] Attachment Figure 3 is the maximum distance of the obstacle relative to the station D max Schematic diagram;

[0041] Attachment Figure 4 Schematic diagram of the shadow area of ​​the reflection net;

[0042] Attachment Figure 5 Schematic diagram of the relationship between obstacles and the shadow area of ​​the reflective net. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all 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.

[0044] The present invention discloses a method for analyzing the shadow area of ​​a civil aviation Doppler omnidirectional beacon reflection network in combination with GIS. The process is shown in the attached figure. Figure 1 As shown, the specific steps include:

[0045] S1. Determine the maximum distance of obstacles relative to the station D max Minimum distance D min ;

[0046] As attached Figure 2 and attached Figure 3 As shown in the figure, the shortest distance between the station and each coordinate point of the obstacle is calculated respectively. For each coordinate point of the obstacle, the following operations are performed: first, the current point is projected and transformed, and then the distance between the point and the center of the station and the shortest distance between the point and the line segment connecting the center of the station and the previous projection point are calculated respectively; then, if the distance between the current point and the center of the station is greater than the current point, the shortest distance between the current point and the center of the station is calculated respectively. D max , then update D max ; If the shortest distance from the point to the line segment is less than the current D min , then update D min ; Loop through all points until there are no remaining points; Finally, the maximum distance of the obstacle relative to the station can be determined D max Minimum distance D min , to achieve accurate quantitative analysis of the spatial distance relationship between obstacles and stations.

[0047] S2. Determine the minimum distance of obstacles relative to the station D min Maximum distance from the shadow area of ​​the reflective net D 0 relationship:

[0048] (1) If D min > D If it is 0, it is determined that the obstacle does not exceed the shadow area limit of the station reflection network;

[0049] According to MH4003.1-2021 "Civil Aviation Communication Navigation Monitoring Station (Station) Installation Site Specification Part 1: Navigation" "8.4.2 With the center of the Doppler omnidirectional beacon antenna as the reference point and the plane of the antenna reflection net as the reference plane, there should be no obstacles exceeding the reference plane height within a radius of 100m, and the reflection path from the sideband antenna phase center through the edge of the reflection net to the ground should not be blocked by obstacles", the maximum distance of the reflection net shadow area is D 0=100 meters; when the minimum distance between the obstacle and the station D min > D At 0 o'clock, the obstacle is considered to be 100 meters away from the center of the station, and it can be determined that the obstacle does not exceed the shadow area limit of the station reflection network.

[0050] (2) If D min ≤D 0, then go to step S3;

[0051] S3. Calculate the angle of the shadow area of ​​the station reflection network; the calculation formula is as follows:

[0052] ;

[0053] in i deg is the angle of the shadow area of ​​the reflection net, in degrees; d is the diameter of the reflection network, in m; h a is the height of the central antenna and the sideband antenna, in meters; r is the distance from the sideband antenna to the central antenna, in meters.

[0054] The reasoning process of step S3 is as follows:

[0055] The following station intrinsic parameters are known: (1) The distance from the sideband antenna to the central antenna r ; (2) Reflection net diameter d ; (3) Height of central antenna and sideband antenna yes ; (4) Altitude of the reflection network h 1.

[0056] The antenna is located on a vertical plane, the reflector is a circle, and the sideband antennas are distributed around the reflector. A shadow area is formed from the top of the sideband antenna to the edge of the reflector platform and extends to the ground. Figure 4 shown.

[0057] According to the basic principles of trigonometric functions, the angle related to the shadow area can be calculated i In this geometric model, we can observe a right triangle with opposite sides of length , the adjacent side length is yes According to the definition of tangent function , we can get:

[0058] ;

[0059] To get the angle i The value of , we need to perform inverse trigonometric operations on the above equation, namely:

[0060] ;

[0061] Convert the angle in radians to degrees. According to the conversion formula between radians and degrees , we can get:

[0062] ;

[0063] angle i This represents the angle between the line of sight from the antenna to the edge of the reflector and the vertical direction. The size of this angle directly determines the starting boundary of the shadow area, thus providing a basis for calculating the range of the shadow area.

[0064] S4. Calculate the shadow area of ​​the station reflection network based on the included angle of the station reflection network shadow area;

[0065] The radius of the shadow area is calculated using the following formula: r t , thus obtaining the shadow area range of the reflection net;

[0066] ;

[0067] ;

[0068] r t is the radius of the shadow area, in m; h r is the height of the reflection network, in meters; d is the diameter of the reflection network, in m, i deg It is the included angle of the shadow area of ​​the reflection net, in degrees.

[0069] The reasoning process of step S4 is as follows:

[0070] Getting the angle After that, the radius of the shadow area is calculated by further using the trigonometric function relationship r t , first change the angle i deg Convert to radians i rad Then, according to the definition of the tangent function, with the antenna as the vertex and the reflection network height as the h r In a right triangle with adjacent sides, the length of the opposite side is .Shadow area radius r t Equal to the reflection net radius Add the length of the opposite side above, that is:

[0071] ;

[0072] S5. Calculate the limit altitude h , and according to the obstacle altitude h o With height restrictionh The difference between △h Determine whether the obstacle is beyond the shadow area of ​​the station reflection network.

[0073] Height restriction h The calculation formula is as follows:

[0074] ;

[0075] in h a is the height of the central antenna and the sideband antenna, in meters; r is the distance from the sideband antenna to the central antenna, in meters; d is the diameter of the reflection network, in m; h r is the height of the reflection network, in meters; h s is the station altitude, in m;

[0076] x is the distance corresponding to the height limit, and its value is determined according to the following formula:

[0077] ;

[0078] r t is the radius of the shadow area, in m; D max is the maximum distance of the obstacle relative to the station, in meters.

[0079] Calculate obstacle altitude h o With height restriction h The difference between △h , △h The calculation formula is:

[0080] △h = h 0 -h ;

[0081] when △h When ≥0, it indicates that the obstacle's altitude exceeds the restricted altitude, and it is judged that the obstacle is beyond the shadow area limit of the station reflection network. In this case, the obstacle may block the reflection path from the phase center of the sideband antenna along the edge of the reflection network to the ground, affecting the signal transmission of the station.

[0082] when △h When <0, it indicates that the altitude of the obstacle does not exceed the restricted altitude. It is judged that the obstacle does not exceed the shadow area limit of the station reflection network and will not cause obvious obstruction to the reflection path.

[0083] The reasoning process of step S5 is as follows:

[0084] First, according to the sideband antenna height h a , reflection net diameter d The distance from the sideband antenna to the center of the reflector r , establish height restrictions h With distance x The linear relationship of change. Assume that the equation of the straight line of the change of the limit height is:

[0085] h = kx+b ;

[0086] k is the slope, b is the intercept. k Reflects the rate of change of height limit with distance, slope k The calculation formula of is as follows:

[0087] k=cot ( i rad );

[0088] ;

[0089] intercept b Indicates when the distance x The height limit is equal to the radius of the reflection net. b Height of reflective net h r and the radius of the reflective net The calculation formula is:

[0090] ;

[0091] Taking into account the actual position of the obstacle and the maximum extension of the shadow area, the maximum distance between the obstacle and the station is D max and the calculated shadow radius r t , determine the distance used to calculate the height limit x The value selection rules are as follows:

[0092] ;

[0093] The distance to be determined x Substitute the height limit straight line equation h = kx+b , and taking into account the station altitude h s , get the height limit of the obstacle location h , and its calculation formula is

[0094] h = kx+b + h s ;

[0095] Right now:

[0096] ;

[0097] Calculate obstacle altitude h 0 and restricted height h The difference between △h , and its calculation formula is:

[0098] △h = h 0 -h ;

[0099] when △h When the value is ≥ 0, the obstacle's altitude exceeds the restricted altitude and is considered outside the shadow area of ​​the station's reflector grid. In this case, the obstacle may block the reflection path from the sideband antenna's phase center along the edge of the reflector grid to the ground, affecting the station's signal transmission.

[0100] when △h <0, indicating that the altitude of the obstacle does not exceed the restricted altitude, and the obstacle is judged to be within the restricted range of the shadow area of ​​the station reflection network, and will not cause obvious obstruction to the reflection path; Figure 5 shown.

[0101] Example 1: Analysis of obstacles in the shadow area of ​​a station reflection network

[0102] Assume that there is a building around the station and the station-related parameters are as follows:

[0103] Distance from sideband antenna to central antenna r =6 meters, diameter of reflection net d =30 meters, height of central antenna and sideband antenna h a =1.4 meters, station altitude h s =512 meters, height of the reflection net h r =4.5 meters, obstacle height above sea level h 0=518 meters.

[0104] S1. Determine the maximum distance of obstacles relative to the station D max Minimum distance D min ;

[0105] Calculate the shortest distance between the station and each coordinate point of the obstacle. Perform the following operations for each coordinate point of the obstacle: first, perform a projection transformation on the current point, then calculate the distance between the point and the center of the station, and the shortest distance between the point and the line segment connecting the center of the station and the previous projection point; then, if the distance between the current point and the center of the station is greater than the current point, D max , then update D max ; If the shortest distance from the point to the line segment is less than the current D min , then update D min ; Loop through all points until there are no remaining points; Finally, the maximum distance of the obstacle relative to the station can be determined D max Minimum distance D min , to achieve accurate quantitative analysis of the distance between obstacles and stations. In this embodiment, the minimum distance D min =40 meters, maximum distance D max =50 meters.

[0106] S2. Calculate the angle of the shadow area of ​​the station reflection network using the following formula:

[0107] ;

[0108] Will r =6 meters, d =30 meters, h a =1.4 meters Substitute i deg The calculation formula is i deg ≈81.13°;

[0109] S3. Calculate the range of the station reflection network shadow area according to the included angle of the station reflection network shadow area; first i deg ≈81.13°Substitute into the following formula and calculate i rad ;

[0110] ;

[0111] Then i rad The calculation results of h r =4.5 meters, d =30m Substitute into the radius of the shaded area rt The calculation formula is:

[0112] ;

[0113] Calculated r t ≈43.93 meters.

[0114] S4. Determine whether the obstacle is beyond the shadow area of ​​the station reflection network.

[0115] Minimum distance of obstacles relative to the station D min =40 meters, radius of shadow area r t ≈43.93 meters; D min < D 0, the obstacle altitude needs to be calculated h o With height restriction h The difference between △h .

[0116] First, calculate according to the following formula x ;

[0117] ;

[0118] D max =50 meters; r t ≈43.93 meters, D max > r t , x =43.93 meters.

[0119] Then r =6 meters, d =30 meters, h a =1.4 meters, x =43.93 meters, h r =4.5 meters, h s =512 meters Substitute into the following formula to calculate the restricted height h :

[0120] ;

[0121] Get the restricted height h =512 meters.

[0122] Recalculate the height difference △h ;

[0123] △h = h 0 -h ;

[0124] △h =518-512=6 meters.

[0125] △h >0, so the building exceeds the shadow area limit of the station reflection network and will block the reflection path of the sideband antenna phase center extending along the edge of the reflection network to the ground.

[0126] The above description is merely a preferred embodiment of the present invention and is intended to be illustrative of the present invention, rather than limiting the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made by those skilled in the art to the technical solution of the present invention should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for analyzing the shadow area of ​​a civil aviation Doppler omnidirectional beacon reflection network in combination with GIS, characterized in that: The steps include: S1. Determine the maximum distance of obstacles relative to the station D max Minimum distance D min ; S2. Determine the minimum distance of obstacles relative to the station D min Maximum distance from the shadow area of ​​the reflective net D 0 relationship: (1) If D min > D If it is 0, it is determined that the obstacle does not exceed the shadow area limit of the station reflection network; (2) If D min ≤ D 0, then go to step S3; S3. Calculate the angle of the shadow area of ​​the station reflection network; S4. Calculate the shadow area of ​​the station reflection network based on the included angle of the station reflection network shadow area; S5. Calculate the limit altitude h , and according to the obstacle altitude h o With height restriction h The difference between Determine whether the obstacle is beyond the shadow area of ​​the station reflection network.

2. The method for analyzing the shadow area of ​​a civil aviation Doppler omnidirectional beacon reflection network in combination with GIS according to claim 1, characterized in that: In step S1, the shortest distance between the station and each coordinate point of the obstacle is calculated. For each coordinate point of the obstacle, the following operations are performed: first, the current point is projected, and then the distance between the point and the center of the station and the shortest distance between the point and the line segment connecting the center of the station and the previous projection point are calculated; then, a comparison is made. If the distance between the current point and the center of the station is greater than the current point, the shortest distance between the current point and the center of the station is calculated. D max , then update D max ; If the shortest distance from the point to the line segment is less than the current D min , then update D min ; Loop through all points until there are no remaining points; Finally, the maximum distance of the obstacle relative to the station can be determined D max Minimum distance D min , to achieve accurate quantitative analysis of the spatial distance relationship between obstacles and stations.

3. The method for analyzing the shadow area of ​​a civil aviation Doppler omnidirectional beacon reflection network in combination with GIS according to claim 1, characterized in that: Maximum distance of the shadow area of ​​the reflective net D 0=100 meters.

4. The method for analyzing the shadow area of ​​a civil aviation Doppler omnidirectional beacon reflection network in combination with GIS according to claim 1, characterized in that: In step S3, the angle of the shadow area of ​​the station reflection network is calculated using the following formula: ； in θ deg is the angle of the shadow area of ​​the reflection net, in degrees; d is the diameter of the reflection network, in m; h a is the height of the central antenna and the sideband antenna, in meters; r is the distance from the sideband antenna to the central antenna, in meters.

5. The method for analyzing the shadow area of ​​a civil aviation Doppler omnidirectional beacon reflection network in combination with GIS according to claim 4, characterized in that: In step S4, the radius of the shadow area is calculated using the following formula: r t , thus obtaining the shadow area range of the reflection net; ； ； r t is the radius of the shadow area, in m; h r is the height of the reflection network, in meters; d is the diameter of the reflection network, in m, θ deg It is the included angle of the shadow area of ​​the reflection net, in degrees.

6. The method for analyzing the shadow area of ​​a civil aviation Doppler omnidirectional beacon reflection network in combination with GIS according to claim 5, characterized in that: Height restriction h The calculation formula is as follows: ； in h a is the height of the central antenna and the sideband antenna, in meters; r is the distance from the sideband antenna to the central antenna, in meters; d is the diameter of the reflection network, in m; h r is the height of the reflection network, in meters; h s is the station altitude, in m; x is the distance corresponding to the height limit, and its value is determined according to the following formula: ； r t is the radius of the shadow area, in m; D max is the maximum distance of the obstacle relative to the station, in meters.

7. The method for analyzing the shadow area of ​​a civil aviation Doppler omnidirectional beacon reflection network in combination with GIS according to claim 6, characterized in that: △h The calculation formula is: △h ＝ h 0 -h ； h o is the obstacle altitude, in m; h It is the height restriction, in meters.

8. The method for analyzing the shadow area of ​​a civil aviation Doppler omnidirectional beacon reflection network in combination with GIS according to claim 1, characterized in that: when △h When ≥0, it indicates that the obstacle's altitude exceeds the restricted altitude, and is judged to be outside the shadow area of ​​the station's reflection network. In this case, the obstacle may block the reflection path from the sideband antenna phase center along the edge of the reflection network to the ground, affecting the station's signal transmission. when △h When <0, it indicates that the altitude of the obstacle does not exceed the restricted altitude, and it is judged that the obstacle does not exceed the restricted range of the shadow area of ​​the station reflection network and will not cause obvious obstruction to the reflection path.

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