Method for evaluating signal coverage of directional beacon for aviation accident investigation

Abstract

The application discloses a heading beacon station signal coverage evaluation method for aviation accident investigation, which comprises the following steps: S1, constructing a geographical map containing an airport and a surrounding area, the airport comprising a runway and a heading beacon station, and constructing a signal evaluation sector A with the heading beacon station as a center and R1 as a radius on both sides of a center line of the runway; S2, constructing a ray with the heading beacon station as a starting point as a sampling path in the signal evaluation sector A; S3, acquiring elevation profile data in a vertical ground direction of the sampling path in the signal evaluation sector A and constructing an elevation profile graph, and acquiring a signal coverage minimum height corresponding to the sampling path by using the elevation profile graph; and S4, performing signal coverage evaluation based on the signal coverage minimum height. The application can realize rapid evaluation of the signal coverage of the heading beacon station under the condition of limited on-site investigation data, and provides technical support for cause investigation and direction analysis of the accident investigation.

Description

Technical Field

[0001] This invention relates to the field of signal coverage assessment in aviation accident investigations, and more particularly to a method for assessing the signal coverage of a heading beacon for aviation accident investigations. Background Technology

[0002] In civil aviation accident investigations, accidents involving airport flight area technical standards require compliance analysis and assessment of airport navigation equipment. Signal coverage assessment of localizers (LOCs) and glide slope (GPs) is a crucial component, essential for analyzing the causes and identifying risks associated with runway overruns and other accident types. Currently, localizer signal assessments require specialized verification and analysis by professional organizations, employing a scientific assessment process that is time-consuming and costly, significantly hindering preliminary accident investigation direction analysis, factor elimination, and improving investigation efficiency. Assessments based on professional signal analysis software have high technical barriers, requiring sophisticated spatial data creation and professional parameter tuning, making them difficult for accident investigators to implement. For example, the high technical barriers to operating professional simulation software limit investigator proficiency. Therefore, aviation accident investigations require a user-friendly and quickly applicable localizer signal coverage analysis method to assess navigation beacon signal coverage using key indicator calculations and comparisons, even with limited on-site survey data. Summary of the Invention

[0003] The purpose of this invention is to provide a method for assessing the signal coverage of a heading beacon for aviation accident investigation. The method involves constructing a signal assessment sector, extracting sampling paths within the sector according to assessment density requirements, obtaining elevation profile data and terrain features in the vertical direction of the sampling path, constructing an elevation profile map including the heading beacon, calculating and analyzing the minimum signal coverage height corresponding to the sampling path, and using this height for signal coverage assessment. This method ensures data reliability while also considering assessment efficiency.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A method for assessing the signal coverage of a heading beacon for aviation accident investigation, the method comprising:

[0006] S1. Construct a geographic map including the airport and its surrounding area. The airport includes the runway and the localizer beacon. Construct signal evaluation sectors A with the localizer beacon as the origin and a radius of R1 on both sides of the runway centerline.

[0007] S2. Construct a ray starting from the heading beacon station as the sampling path within the signal evaluation sector A;

[0008] S3. Obtain the elevation profile data of the sampling path in the vertical direction of the ground in signal evaluation sector A and construct an elevation profile map including the heading beacon. The elevation profile map includes the obstacle elevation information from the heading beacon to the boundary of signal evaluation sector A. Draw a critical line on the elevation profile map that exactly crosses the elevation vertices of all obstacles. The elevation of the critical line intersecting the boundary of signal evaluation sector A with the heading beacon as the starting point is taken as the minimum signal coverage height corresponding to the sampling path.

[0009] S4. Collect the signal coverage height of all sampling paths in sector A and compare it with the set signal coverage height threshold. Select sampling paths that are not greater than the signal coverage height threshold and evaluate them as having adequate signal coverage; select sampling paths that are greater than the signal coverage threshold and evaluate them as having inadequate signal coverage.

[0010] To better achieve the present invention, the present invention also includes the following methods:

[0011] S5. Within the signal assessment sector A, construct a signal critical profile A by virtually connecting the critical lines of all elevation profiles in method S3; obtain the take-off and landing trajectories of the accident aircraft and plot them on the signal critical profile A according to their position information; assess take-off and landing trajectories that are more than the threshold M away from the heading beacon and located below the signal critical profile A as signal coverage risk trajectories.

[0012] Preferably, in method S1, a signal evaluation sector B with a radius of R2 and a heading beacon as the origin is constructed outside the signal evaluation sector A; the signal evaluation sector B is processed according to methods S2 to S4, and sampling paths in the signal evaluation sector B that are not greater than the signal coverage height threshold are evaluated as having satisfactory signal coverage, while sampling paths in the signal evaluation sector B that are greater than the signal coverage threshold are evaluated as having unsatisfactory signal coverage.

[0013] Preferably, in method S1, the sector angle at the vertex of the signal evaluation sector A is 20°, and the signal evaluation sector A is symmetrically divided into two sector units A with a sector angle of 10° around the runway centerline. L .

[0014] Preferably, in method S2, the sampling path length of signal evaluation sector A is R1, all sampling paths of signal evaluation sector A are uniformly distributed within signal evaluation sector A, and the included angle between two adjacent sampling paths is . .

[0015] Preferably, in method S3, the sampling path of sector A is evaluated using the signal. Draw a perpendicular line to the ground and construct a system containing the perpendicular line and the sampling path. The vertical plane is used to obtain the elevation profile data of the vertical plane as the sampling path. The corresponding elevation profile data was used to construct an elevation profile map including the heading beacon, covering the entire sampling path. Area, sampling path The path of sector A, numbered i, is used to evaluate the signal.

[0016] Preferably, in the sampling path In the corresponding elevation profile, the elevation of the point where the critical line is projected onto the plane of signal evaluation sector A and intersects with the boundary of the sector length R1 of signal evaluation sector A is taken as the minimum signal coverage height corresponding to the sampling path.

[0017] Preferably, in method S3, the critical line is drawn on the elevation profile as follows: on the elevation profile, a diagonal line is drawn passing through the elevation vertex of each obstacle, starting from the heading beacon, and the diagonal line with the largest slope is taken as the critical line.

[0018] Preferably, in method S4, the signal coverage height threshold is the runway entrance elevation plus 600 meters; the runway centerline is selected as the sampling path to obtain the corresponding elevation profile and the minimum signal coverage height. If the following conditions are met:

[0019] ,in The length of the runway. This is the distance from the heading beacon to the near end of the runway. This is the runway entrance elevation;

[0020] Then the signal coverage corresponding to the runway centerline meets the standard.

[0021] Preferably, the signal evaluation sector B is a sector unit B that extends 25° to both sides of the signal evaluation sector A. L Two sector units B L Together they constitute signal evaluation sector B; two sector units B L The sampling path length is R2; in each sector unit B L In the middle, sector unit B L All sampling paths are evenly distributed in sector unit B L Within, the angle between two adjacent sampling paths is .

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] (1) The present invention provides an innovative rapid assessment method for the rapid assessment of the signal coverage of the heading beacon in the investigation of landing aircraft aviation accidents. It can achieve rapid assessment of the signal coverage of the heading beacon under the condition of limited on-site survey data, providing technical support for the investigation of the cause of the accident and the direction analysis, and filling the technical gap in the assessment of signal coverage in aviation accident investigation.

[0024] (2) The present invention constructs a signal evaluation sector. Within the signal evaluation sector, sampling paths are extracted according to the evaluation density requirements. The elevation profile data and terrain features of the sampling path in the vertical direction of the ground are obtained and an elevation profile map including the heading beacon is constructed. The minimum signal coverage height corresponding to the sampling path is calculated and analyzed, and the signal coverage is evaluated accordingly. The reliability of the data is guaranteed while the evaluation efficiency is taken into account. The present invention has been successfully tested in the navigation beacon performance analysis of a case of runway overrun at an airport. The results are the same as those of professional simulation software analysis. It has also been verified in the survey analysis of multiple airports. The application efficiency is high and easy to master. It has achieved good application benefits in accident investigation.

[0025] (3) The present invention obtains the sampling path by slicing the sampling within the signal evaluation sector, extracts complex terrain feature data, improves efficiency while ensuring data credibility, and reduces the difficulty of operation. The steps of terrain feature extraction and signal coverage evaluation are carried out under the premise of ensuring credibility, realizing the rapid analysis of the localizer signal coverage. The method is easy to master and implement, greatly reducing time and personnel costs. Attached Figure Description

[0026] Figure 1 This is a flowchart of the method in Example 1;

[0027] Figure 2 This is a flowchart of the method in Example 2;

[0028] Figure 3 This is a schematic diagram illustrating the principle of selecting a sampling path for half of the signal evaluation sectors A and B in the embodiment.

[0029] Figure 4 For example, a schematic diagram of a signal evaluation sector for studying an airport runway is selected as an example;

[0030] Figure 5 This is a schematic diagram of a sampling path elevation profile after a critical line has been drawn, as an example. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to embodiments:

[0032] Example 1

[0033] like Figure 1As shown, a method for assessing the signal coverage of a heading beacon for aviation accident investigation includes the following steps:

[0034] S1. Construct a geographic map including the airport and its surrounding area. The airport includes the runway and the localizer (LOC). On both sides of the runway centerline, construct signal evaluation sectors A with a radius of R1, centered at the localizer (LOC). The vertex of signal evaluation sector A (i.e., the localizer (LOC)) corresponds to a sector-shaped angle. In some embodiments, such as... Figure 3 As shown, the sector angle at the vertex of signal assessment sector A (i.e., the localizer beacon LOC) is 20°. Signal assessment sector A is symmetrically divided into two sector units A with a sector angle of 10° along the runway centerline. L (See) Figure 3 (The angle to the right of the runway centerline is 10°, and the angle to the left of the runway centerline is also 10°.) Figure 3 In this case, the radius R1 is chosen to be 25 NM (i.e., 25 nautical miles).

[0035] S2. Construct a ray originating from the heading beacon within signal evaluation sector A as the sampling path. In some embodiments, the sampling path length for signal evaluation sector A is R1 (see...). Figure 3 (With radius R1 set to 25 nautical miles), all sampling paths in signal evaluation sector A are uniformly distributed within signal evaluation sector A (i.e., all sampling paths uniformly divide the sector angle of signal evaluation sector A), and the angle between two adjacent sampling paths is... (angle) The example is selected as 1°, 0.1°, or 0.01°, which is the angle of the sector in signal evaluation sector A at each interval. (Extract a sampling path). If this invention is directly used in aviation accident investigation, then the sampling path in the area involved in the landing of the aircraft and located in signal assessment sector A is selected (the sampling path in the area related to the aviation accident investigation of the aircraft landing can be collected more densely for subsequent assessment of the localizer beacon signal coverage), as shown in the following example: If the landing track of the aircraft in the accident investigation is in signal assessment sector A... Figure 3 If the distance is 5° to 8° to the right of the runway centerline, then a denser sampling path will be used within this range. For example... Figure 4 As shown, if the aircraft landing track in the accident investigation is in signal assessment sector A... Figure 4 If the sampling path is 0° to 5° to the left of the runway centerline, then sampling will be conducted more densely within this range.

[0036] In some embodiments, if the LOC antenna coordinates of the heading beacon are used Starting from the azimuth angles along the runway (The angle between the runway centerline and magnetic north), where Extending forward 25 NM (i.e., 25 nautical miles), a great circle path is drawn, which determines a slice sampling path for terrain features. The endpoint of the path can be calculated using the following formula:

[0037] (1)

[0038] in, The length of the great circle path is 25 NM (which can be converted from straight-line distance to Earth radians). for coordinate, If the endpoint coordinates are given, then the sampling path is a straight line. .

[0039] S3. Obtain elevation profile data of the sampling path in the vertical direction of the ground (i.e., the vertical plane in which the sampling path is perpendicular to the ground) in signal evaluation sector A, and construct an elevation profile map including the heading beacon (e.g., the elevation profile map of a certain sampling path is shown in the figure). Figure 5 As shown), the elevation profile contains obstacle elevation information from the heading beacon (LOC) to the boundary of signal assessment sector A (i.e., the arc-shaped boundary formed by signal assessment sector A at the edge of radius R1) (see [reference]). Figure 5 , Figure 5 The blue area represents terrain undulation and elevation information; draw a critical line on the elevation profile that exactly crosses the elevation apex of all obstacles (see...). Figure 5 The elevation profile of the example sampling path has the critical line as follows: Figure 5 The red line represents the minimum signal coverage height corresponding to the sampling path. Specifically, the sampling path of signal evaluation sector A is defined by the elevation of the intersection of the critical line (starting from the heading beacon) and the boundary of the critical line. Draw a perpendicular line to the ground and construct a system containing the perpendicular line and the sampling path. The vertical plane is used to obtain the elevation profile data of the vertical plane as the sampling path. The corresponding elevation profile data was used to construct an elevation profile map including the heading beacon, covering the entire sampling path. Area, sampling path For signal evaluation, consider the path of sector A, numbered i. Specifically, in the sampling path... In the corresponding elevation profile, the elevation of the point where the critical line intersects the plane of signal evaluation sector A and the boundary of the sector length R1 of signal evaluation sector A is taken as the minimum signal coverage height corresponding to the sampling path. In this embodiment, the terrain and buildings on the elevation profile of the sampling path may cause reflection and path interference to signal propagation, thus forming a complex propagation path. To reduce the difficulty of assessment, improve assessment efficiency and operability, and meet the application scenario of on-site assessment in aviation accident investigation, this embodiment simplifies and assumes that the signal propagates in a straight line while meeting the requirements of navigation station signal coverage indicators.

[0040] In some embodiments, the method for drawing critical lines on the elevation profile is as follows: Select the elevation vertices (relative vertices of the region) of each obstacle on the elevation profile, and draw a diagonal line passing through the elevation vertices of each obstacle (i.e., the diagonal line connecting the LOC of the localizer and the elevation vertices of the obstacles) starting from the localizer beacon on the elevation profile, and take the diagonal line with the largest slope as the critical line.

[0041] In some embodiments, the critical line of the sampling path elevation profile is a propagation constraint point that can restrict and determine the signal's arrival at the end of the path (i.e., ...). Figure 5 Taking the sampling path elevation profile as an example, the propagation constraint point (Elevation 13.244) is determined, so the minimum signal coverage height can be quickly calculated using the propagation constraint point; the method is as follows:

[0042] According to the signal from the LOC antenna coordinates of the heading beacon The sampling path, using a linear propagation pattern, has 512 uniformly distributed elevation points along its path. The propagation constraint points must satisfy the following: The slope of the line connecting the corresponding point and the constraint point is the largest, therefore:

[0043] The coordinates of the constraint point are , Coordinates are .

[0044] In simplified transfer mode, the calculation is performed by traversing the set of localizer signals along the sampling path. The listed paths (i.e.) Reaching the listed height profile Minimum height of sector boundary, set along sampling path arrive The minimum height of the sector boundary is equivalently described as the height at which the signal reaches the sector boundary after crossing the propagation constraint point. The calculation method is as follows:

[0045] (3)

[0046] in, In order to be in The lowest coverage height value reaching the sector edge along the elevation profile sampling path allows for the rapid determination of the localizer signal at [location missing]. The lowest relative height reaching the sector on the sampling path.

[0047] S4. Collect the minimum signal coverage height corresponding to all sampling paths in signal evaluation sector A and compare it with the set signal coverage height threshold (preferably, the signal coverage height threshold is the runway entrance elevation). Comparing the sampling paths (plus 600 meters), those with a height not exceeding the signal coverage height threshold are assessed as having adequate signal coverage; those exceeding the threshold are assessed as having inadequate signal coverage. The minimum height for signal coverage is determined by the sampling path assessment. The path (numbered i) satisfies the following formula:

[0048] .

[0049] If we take into account the height of the localizer antenna itself... Then it should satisfy the following formula,

[0050] .

[0051] In some embodiments, the present invention also performs a signal coverage assessment of the runway centerline as the core area, selects the runway centerline as the sampling path, and obtains the corresponding elevation profile and the minimum signal coverage height. If the following conditions are met, the signal coverage corresponding to the runway centerline will meet the standard.

[0052] ,in The length of the runway. This is the distance from the heading beacon to the near end of the runway. This is the runway entrance elevation;

[0053] Example 2

[0054] like Figure 2 As shown, a method for assessing the signal coverage of a heading beacon for aviation accident investigation includes the following steps:

[0055] S1. Construct a geographic map including the airport and its surrounding area. The airport includes the runway and the localizer (LOC). On both sides of the runway centerline, construct signal evaluation sectors A with a radius of R1, centered at the localizer (LOC). The vertex of signal evaluation sector A (i.e., the localizer (LOC)) corresponds to a sector-shaped angle. In some embodiments, such as... Figure 3As shown, the sector angle at the vertex of signal assessment sector A (i.e., the localizer beacon LOC) is 20°. Signal assessment sector A is symmetrically divided into two sector units A with a sector angle of 10° along the runway centerline. L (See) Figure 3 (The angle to the right of the runway centerline is 10°, and the angle to the left of the runway centerline is also 10°.) Figure 3 In this case, the radius R1 is chosen to be 25 NM (i.e., 25 nautical miles).

[0056] In some embodiments, a signal evaluation sector B with a radius of R2 and originating from the heading beacon is constructed outside the signal evaluation sector A; such as... Figure 3 As shown, signal evaluation sector B is a sector unit B that extends 25° to both sides of signal evaluation sector A. L In the fan-shaped areas on both sides of the runway centerline [-10°, -35°] and [10°, 35°], there are two sector units B. L Together they constitute signal evaluation sector B L ( Figure 3 Only the signal evaluation sector B to the right of the runway centerline is shown); two sector units B. L The sampling path length is R2 in all cases. Figure 3 In this case, the radius R2 is chosen to be 17 NM (i.e., 17 nautical miles).

[0057] S2. Construct a ray originating from the heading beacon within signal evaluation sector A as the sampling path. In some embodiments, the sampling path length for signal evaluation sector A is R1 (see...). Figure 3 (With radius R1 set to 25 nautical miles), all sampling paths in signal evaluation sector A are uniformly distributed within signal evaluation sector A (i.e., all sampling paths uniformly divide the sector angle of signal evaluation sector A), and the angle between two adjacent sampling paths is... (angle) The example is selected as 1°, 0.1°, or 0.01°, which is the angle of the sector in signal evaluation sector A at each interval. (Extract a sampling path). If this invention is directly used in aviation accident investigation, then the sampling path in the area involved in the landing of the aircraft and located in signal assessment sector A is selected (the sampling path in the area related to the aviation accident investigation of the aircraft landing can be collected more densely for subsequent assessment of the localizer beacon signal coverage), as shown in the following example: If the landing track of the aircraft in the accident investigation is in signal assessment sector A... Figure 3 If the distance is 5° to 8° to the right of the runway centerline, then a denser sampling path will be used within this range. For example... Figure 4 As shown, if the aircraft landing track in the accident investigation is in signal assessment sector A... Figure 4If the sampling path is 0°–5° to the left of the runway centerline, then sampling will be performed more densely within this range. In each sector unit B... L In the middle, sector unit B L All sampling paths are evenly distributed in sector unit B L Within, the angle between two adjacent sampling paths is (angle) The example is selected as 1°, 0.1°, or 0.01°, which is the angle of the sector in signal evaluation sector A at each interval. Extract a sampling path.

[0058] In some embodiments, if the LOC antenna coordinates of the heading beacon are used Starting from the azimuth angles along the runway (The angle between the runway centerline and magnetic north) By drawing a great circle path, a slice sampling path for terrain features can be determined. The endpoint of the path can be calculated using the following formula:

[0059] (1)

[0060] in, The length of the great circle path is 25 NM (which can be converted from straight-line distance to Earth radians). for coordinate, If the endpoint coordinates are given, then the sampling path is a straight line. .

[0061] S3. Obtain elevation profile data of the sampling path in the vertical direction of the ground (i.e., the vertical plane in which the sampling path is perpendicular to the ground) in signal evaluation sector A, and construct an elevation profile map including the heading beacon (e.g., the elevation profile map of a certain sampling path is shown in the figure). Figure 5 As shown), the elevation profile contains obstacle elevation information from the heading beacon (LOC) to the boundary of signal assessment sector A (i.e., the arc-shaped boundary formed by signal assessment sector A at the edge of radius R1) (see [reference]). Figure 5 , Figure 5 The blue area represents terrain undulation and elevation information; draw a critical line on the elevation profile that exactly crosses the elevation apex of all obstacles (see...). Figure 5 The elevation profile of the example sampling path has the critical line as follows: Figure 5 The red line represents the minimum signal coverage height corresponding to the sampling path. Specifically, the sampling path of signal evaluation sector A is defined by the elevation of the intersection of the critical line (starting from the heading beacon) and the boundary of the critical line. Draw a perpendicular line to the ground and construct a system containing the perpendicular line and the sampling path. The vertical plane is used to obtain the elevation profile data of the vertical plane as the sampling path. The corresponding elevation profile data was used to construct an elevation profile map including the heading beacon, covering the entire sampling path. Area, sampling path For signal evaluation, consider the path of sector A, numbered i. Specifically, in the sampling path... In the corresponding elevation profile, the elevation of the point where the critical line intersects the plane of signal evaluation sector A and the boundary of the sector length R1 of signal evaluation sector A is taken as the minimum signal coverage height corresponding to the sampling path. In this embodiment, the terrain and buildings on the elevation profile of the sampling path may cause reflection and path interference to signal propagation, thus forming a complex propagation path. To reduce the difficulty of assessment, improve assessment efficiency and operability, and meet the application scenario of on-site assessment in aviation accident investigation, this embodiment simplifies and assumes that the signal propagates in a straight line while meeting the requirements of navigation station signal coverage indicators.

[0062] Following the same method described above, elevation profile data were collected for the sampling path of signal evaluation sector B in the direction perpendicular to the ground (i.e., the vertical plane where the sampling path is perpendicular to the ground). An elevation profile map including the heading beacon was constructed. The minimum signal coverage height corresponding to the sampling path in signal evaluation sector B was then obtained using the same method. Assume that the sampling paths of signal evaluation sectors A and B are evenly distributed with 512 elevation points. The elevation profile set of signal evaluation sector A is denoted as... ,in It is the set of elevation points within the range of the nth sampling path. , For the nth height sampling point, This corresponds to its elevation value. Similarly, the set of elevation profiles obtained from the sampling path of signal evaluation sector B is denoted as... .

[0063] In some embodiments, the method for drawing critical lines on the elevation profile is as follows: Select the elevation vertices (relative vertices of the region) of each obstacle on the elevation profile, and draw a diagonal line passing through the elevation vertices of each obstacle (i.e., the diagonal line connecting the LOC of the localizer and the elevation vertices of the obstacles) starting from the localizer beacon on the elevation profile, and take the diagonal line with the largest slope as the critical line.

[0064] In some embodiments, the critical line of the sampling path elevation profile is a propagation constraint point that can restrict and determine the signal's arrival at the end of the path (i.e., ...). Figure 5 Taking the sampling path elevation profile as an example, the propagation constraint point (Elevation 13.244) is determined, so the minimum signal coverage height can be quickly calculated using the propagation constraint point; the method is as follows:

[0065] According to the signal from the LOC antenna coordinates of the heading beacon If the sampling path is uniformly distributed with 512 elevation points, and the propagation pattern propagates in a straight line, the propagation constraint point should satisfy the following: The slope of the line connecting the responding point and the constraining point is the largest, therefore:

[0066] The coordinates of the constraint point are , Coordinates are .

[0067] In simplified transfer mode, the calculation is performed by traversing the set of localizer signals along the sampling path. The listed paths (i.e.) Reaching the listed height profile Minimum height of sector boundary, set along sampling path arrive The minimum height of the sector boundary is equivalently described as the height at which the signal reaches the sector boundary after crossing the propagation constraint point. The calculation method is as follows:

[0068] (3)

[0069] in, In order to be in The lowest coverage height value reaching the sector edge along the elevation profile sampling path allows for the rapid determination of the localizer signal at [location missing]. The lowest relative height reaching the sector on the sampling path.

[0070] S4. Collect the minimum signal coverage height corresponding to all sampling paths in signal evaluation sector A and compare it with the set signal coverage height threshold (preferably, the signal coverage height threshold is the runway entrance elevation). Comparing with a distance of 600 meters, sampling paths not exceeding the signal coverage height threshold are evaluated as having satisfactory signal coverage; sampling paths exceeding the signal coverage threshold are evaluated as having inadequate signal coverage. Following methods S2 to S4, signal evaluation sector B is processed, and sampling paths in sector B not exceeding the signal coverage height threshold are evaluated as having satisfactory signal coverage, while sampling paths exceeding the signal coverage threshold are evaluated as having inadequate signal coverage. The minimum height of the sampling path that is evaluated as having satisfactory signal coverage is determined by the minimum signal coverage height. The path (numbered i) satisfies the following formula:

[0071] .

[0072] If we take into account the height of the localizer antenna itself... Then it should satisfy the following formula,

[0073] .

[0074] S5. Within the signal assessment sector A, construct a signal critical profile A by virtually smoothing the critical lines of all elevation profiles in method S3; obtain the take-off and landing trajectories of the accident aircraft and plot them on the signal critical profile A according to their position information; assess take-off and landing trajectories that are more than M away from the heading beacon and located below the signal critical profile A as signal coverage risk trajectories.

[0075] 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 within the protection scope of the present invention.

Claims

1. A method for evaluating signal coverage of a directional beacon for an aviation accident investigation, characterized by: The method comprises the following steps: S1, constructing a geographic map comprising an airport and a surrounding area, the airport comprising a runway and a localizer beacon, and constructing a signal evaluation sector A with the localizer beacon as the origin and a radius of R1 on both sides of the center line of the runway; S2, constructing a ray with the localizer beacon as the starting point in the signal evaluation sector A as a sampling path; S3, obtaining elevation profile data in the vertical ground direction of the sampling path in the signal evaluation sector A and constructing an elevation profile map comprising the localizer beacon, the elevation profile map comprising obstacle elevation information from the localizer beacon to the boundary of the signal evaluation sector A; drawing a straight line through the localizer beacon and just over all the obstacle elevation points as a critical line on the elevation profile map, and the elevation of the critical line corresponding to the intersection point of the signal evaluation sector A boundary in the elevation profile map corresponding to the sampling path is the lowest signal coverage height corresponding to the sampling path; S4, comparing the lowest signal coverage height corresponding to all sampling paths in the signal evaluation sector A with the set signal coverage height threshold, and screening the sampling paths not greater than the signal coverage height threshold as signal coverage degree meeting the standard; screening the sampling paths greater than the signal coverage threshold as signal coverage degree not meeting the standard.

2. The heading beacon station signal coverage assessment method for aviation accident investigation according to claim 1, characterized in that: The method further comprises the following steps: S5, virtually connecting the critical lines of all the elevation profile maps in the signal evaluation sector A to construct a signal critical profile A in the signal evaluation sector A; obtaining the take-off and landing trajectory of the accident aircraft and drawing it on the signal critical profile A according to the position information, and evaluating the take-off and landing trajectory located below the signal critical profile A and having a distance greater than a threshold M from the localizer beacon as a signal coverage risk trajectory.

3. The heading beacon station signal coverage assessment method for aviation accident investigation according to claim 1, characterized in that: In method S1, a signal evaluation sector B with the localizer beacon as the origin and a radius of R2 is constructed outside the signal evaluation sector A; methods S2-S4 are used to process the signal evaluation sector B, and the sampling paths in the signal evaluation sector B not greater than the signal coverage height threshold are screened as signal coverage degree meeting the standard, and the sampling paths in the signal evaluation sector B greater than the signal coverage threshold are screened as signal coverage degree not meeting the standard.

4. The heading beacon station signal coverage assessment method for aviation accident investigation of claim 1, wherein: In the method S1, the signal evaluation sector A has a sector angle of 20° at the vertex, and the signal evaluation sector A is symmetrically divided into two sector units A with a sector angle of 10° with respect to the runway center line L .

5. The heading beacon station signal coverage assessment method for aviation accident investigation according to claim 4, characterized in that: In the method S2, the sampling path length of the signal evaluation sector A is R1, all the sampling paths of the signal evaluation sector A are uniformly distributed in the signal evaluation sector A, and the included angle between two adjacent sampling paths is .

6. The heading beacon station signal coverage assessment method for aviation accident investigation according to claim 5, characterized in that: In method S3, the signal evaluation sector A is evaluated for the sampling path A perpendicular line to the ground is made and a vertical plane is constructed containing the perpendicular line, the sampling path The vertical plane is acquired as elevation profile data for the sampling path The corresponding elevation profile data and a construction containing the heading beacon tower is constructed as an elevation profile map, which covers the entire sampling path region, the sampling path for the signal evaluation sector A, the path with the number i.

7. The heading beacon station signal coverage assessment method for aviation accident investigation according to claim 1, characterized in that: In method S3, the critical line on the elevation profile map is drawn as follows: draw an inclined line through each obstacle elevation point with the localizer beacon as the starting point on the elevation profile map, and take the inclined line with the largest slope as the critical line.

8. The heading beacon station signal coverage assessment method for aviation accident investigation of claim 1, wherein: In the method S4, the signal coverage height threshold is the runway entrance elevation plus 600 meters; the runway centerline is selected as the sampling path and the corresponding elevation profile and signal coverage minimum height are obtained if the following conditions are met: wherein L is the runway length, D is the distance from the directional beacon to the runway threshold, E is the runway entrance elevation; The signal coverage degree corresponding to the center line of the runway meets the standard.

9. The heading beacon station signal coverage assessment method for aviation accident investigation according to claim 3, characterized in that: The signal evaluation sector B is composed of two sector units B which are respectively extended 25° on both sides of the signal evaluation sector A L The sampling path length of each sector unit B L is R2 L In each sector unit B L , all the sampling paths of the sector unit B L are uniformly distributed in the sector unit B L , and the included angle between two adjacent sampling paths is .

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