Terminal Area Flight Procedure Limitation Assessment System Based on ARINC424

Abstract

The present invention discloses a terminal area flight procedure height limit assessment system based on ARINC424. The method flow is as follows: making an ARINC424 terminal area original database; making a control operation and graphics related key information database; making a flight procedure assessment related key information database; making a terminal area fusion database; establishing a flight procedure track model; establishing a flight procedure protection area model; establishing a flight procedure height limit assessment model; importing the longitude and latitude information of obstacles into the system to complete the flight procedure height limit assessment. Compared with the prior art, the present invention has a high degree of automation, greatly improves the work efficiency of the airport flight procedure height limit assessment, performs multiple verifications on the runway orientation and key position points through the terminal area fusion database, truly restores the original track and protection area of ​​the flight procedure design, and then realizes accurate assessment of the flight procedure height limit through key height information, thereby improving the accuracy of the flight procedure height limit assessment.

Description

Technical Field

[0001] The present invention relates to the field of aviation, and particularly to a height limit evaluation system for terminal area flight procedures based on ARINC424. Background Art

[0002] In recent years, with the rapid development of the clean energy industry, China's high-voltage / extra-high voltage technology has become an important means for large-scale development and utilization of clean energy. By erecting high-voltage / extra-high voltage transmission lines, clean energy distributed in different regions can be effectively integrated and utilized to achieve large-scale transmission and utilization of clean energy. High-voltage / extra-high voltage lines span many regions and have long lengths, and the same line may enter the clearance protection ranges of multiple airports. High-voltage / extra-high voltage towers are tall, and if professional evaluation is not carried out before planning and construction, it is extremely easy to affect airport operations. Therefore, the Civil Aviation Administration has successively issued corresponding laws, regulations, rules, standards and regulatory documents, and put forward clear requirements for airport clearance management and safe operation. If the high-voltage line planning scheme enters the airport clearance area, it is necessary to consult the opinions of the civil aviation department.

[0003] Airport clearance is the lifeline for the safe operation of airports. Without ensuring airport clearance, flight safety cannot be guaranteed. There are many clearance restriction factors, including airport obstacle limitation surfaces, visual aids protection areas, flight procedures and operating minimum standards, minimum surveillance guidance altitudes, site protection for civil aviation radio stations and civil airport electromagnetic environments, civil aviation meteorological detection environments, etc. Among them, the evaluation of flight procedures and operating minimum standards is the most cumbersome. It is difficult for high-voltage / extra-high voltage line designers, civil aviation management departments, and airport clearance management departments to evaluate in detail the impact of the line on airport flight procedures, and professional flight procedure designers are often required to conduct navigation service evaluations.

[0004] The restricted height of the reference height chart is relatively conservative and has poor adaptability to mountain airports. Moreover, high-voltage / extra-high voltage towers are tall and easily penetrate the airport reference height chart, and detailed evaluations of flight procedures and operating minimum standards are often still required.

[0005] For the height limit evaluation of flight procedures, it is first necessary to determine the location of the airport runway; then draw the nominal flight procedure track and protection area in CAD according to the procedure charts such as departure, arrival, approach, go-around, and holding published by NAIP; finally, according to the relative position of the obstacle to be evaluated and the flight procedure protection area, perform evaluation calculations based on regulations and specifications.

[0006] Chinese invention "A Method and Device for Inspecting and Controlling Flight Procedure Track Data", Publication No.: CN111444174A. This document mentions a method for restoring flight tracks by using ARINC424 encoding, but does not involve the drawing of flight procedure protection areas and the height limit assessment of flight procedures for airspace clearance. In contrast, the present invention uses ARINC424 encoded data to restore flight procedure tracks and protection areas, and based on height limit assessment parameter libraries such as landing standards and segment obstacle clearance heights, it conducts assessment and analysis on obstacles within the protection area.

[0007] Chinese invention "A Method for Converting Flight Procedures into AIXM Data Structures", Publication No.: CN113553049B. This document mentions a method for converting flight procedures into AIXM data structures and generating flight procedure track data that conforms to the GML standard. This is a track restoration based on mathematical logic, and the turning radius is not calculated according to the actual altitude of the aircraft. In contrast, the present invention starts from the perspective of flight procedure design, realizes track restoration and protection area drawing from the perspective of program design, and provides a solution for the rapid and accurate assessment and analysis of obstacles based on height limit assessment parameter libraries such as landing standards and segment obstacle clearance heights, filling the gap in automatically completing the height limit assessment of flight procedures.

[0008] In actual work, for the height limit assessment and analysis of terminal area flight procedures, first use mapping tools such as Auto CAD to draw tracks and protection areas, and then use office software such as Excel for auxiliary height limit calculations. The height limit assessment of terminal area arrival, departure, and approach procedures is highly professional, with cumbersome steps and a large workload. Relying solely on manual drawing is time-consuming and inefficient, and the NAIP data is updated every 28 days. If there are changes, it is necessary to recalculate and analyze.

[0009] Among them, ARINC424 encoding is the data format and encoding of the airborne navigation database, which is the main information source and important basis for the flight control of the aircraft flight management system (FMS) and the automatic flight control system (AFCS), and is one of the important links to ensure the safe operation of the aircraft. ARINC424 encoding contains core data such as navigation facilities, airports, runways, airways, waypoints, approaches, arrival and departure procedures, holding procedures, and restricted airspace that are crucial for navigation operations. The ARINC424 navigation specification format uniformly uses 132-bit plain text records to encode various navigation database elements, from bit 1 to bit 132, and uses every several bits to define a specific attribute of a certain aviation element. ARINC424 encoding contains information such as path termination codes, positioning points, magnetic track / heading, turning direction, altitude, speed, and navigation accuracy.

[0010] Although ARINC 424 provides a way to describe flight procedures in text encoding, since ARINC 424 is mainly oriented towards airborne avionics equipment such as flight management systems (FMS) and automatic flight control systems (AFCS), much information related to air traffic control operations and graphics will be discarded during the encoding process. Key altitude information such as landing criteria and minimum obstacle clearance altitude for flight segments, which is closely related to the height limit assessment of flight procedures, is also discarded. As a result, relying solely on ARINC 424 cannot accurately restore a flight track that conforms to flight procedure design. Without an accurate flight track, it is impossible to draw the correct protected area range. At the same time, without the correct protected area, obstacle clearance altitude information for the corresponding flight segments, and landing criteria for the approach procedure, it is impossible to conduct a reasonable and reliable height limit assessment and analysis of the flight procedure.

[0011] During the flight activities of aircraft in terminal areas such as departure, arrival, approach, go-around, and holding, to ensure flight safety and operation efficiency, it is necessary to design a flight route that conforms to flight altitude and maneuvering areas according to aircraft performance and regulatory requirements, that is, the nominal flight track.

[0012] Due to factors such as path definition error, flight technical error, and navigation system error, when an aircraft flies along a flight track, it cannot strictly maintain the predetermined flight track and will always deviate more or less. To ensure that it does not collide with obstacles such as mountains during the entire flight, the area between the possible positions of the aircraft flying along the predetermined flight track and the predetermined flight track should be protected. The maximum scope of these protections is called the protected area.

[0013] The minimum obstacle clearance altitude (MOCA) specifies the lowest altitude at which the flight segment where the aircraft is flying can provide the required obstacle clearance. It is the lowest safe altitude at which the aircraft is allowed to fly in this flight segment considering factors such as path definition error, flight technical error, and navigation system error.

[0014] The minimum obstacle clearance (MOC) is the minimum vertical separation that ensures the aircraft will not collide with obstacles when the aircraft flies over the obstacle in the protected area. It is the minimum requirement to ensure the safe obstacle clearance of the aircraft, which is affected by weather, equipment, aircraft performance, and pilot ability. There are corresponding minimum obstacle clearance requirements for each flight segment of the flight procedure.

[0015] The height limit assessment of flight procedures mainly includes the obstacle clearance assessment and inspection of flight procedures in terminal areas such as departure, arrival, approach, go-around, and holding. The height limit of a flight procedure is usually the lowest altitude at which the flight segment can provide the required obstacle clearance minus the minimum obstacle clearance. Summary of the Invention

[0016] The object of the present invention is to address the deficiencies and drawbacks of existing height limit assessment methods and means, and to solve the problem of height limit assessment and analysis for flight procedures. From the perspective of flight procedure design, the present invention provides a terminal area flight procedure height limit assessment system based on ARINC424. By supplementing the missing key information related to control operations and graphics in the original ARINC424 data, the flight track based on flight procedure design principles is restored. Then, a complete flight procedure protection area is drawn according to the flight track. Subsequently, by supplementing the missing key height information such as landing criteria and minimum obstacle clearance height for each flight segment in the original ARINC424 data, the accurate restricted height within the flight procedure segment protection area is calculated, providing a solution for the rapid and accurate assessment and analysis of obstacles, and filling the gap in the automatic assessment and analysis of flight procedures driven by ARINC424 data.

[0017] To achieve the above object, the technical solution adopted by the present invention is as follows: A terminal area flight procedure height limit assessment system based on ARINC424, and the method flow is as follows.

[0018] The first step: Decode and analyze the original ARINC424 data to create an original ARINC424 terminal area database, and automatically update it regularly according to the ARINC424 update cycle.

[0019] The second step: Refer to the field rules of the ARINC424 data table, and create a database of key information related to control operations and graphics required for program design for the missing control operation or graphics-related information in the original ARINC424 terminal area database.

[0020] The third step: Refer to the field rules of the ARINC424 data table, and create a database of key information related to flight procedure assessment required for height limit assessment for the missing height limit assessment-related information in the original ARINC424 terminal area database.

[0021] The fourth step: Integrate the original ARINC424 terminal area database, the database of key information related to control operations and graphics, and the database of key information related to flight procedure assessment to create an improved ARINC424 terminal area integrated database. The specific method is to add corresponding columns after the data information of the corresponding airport, arrival / departure, and approach procedures in the flight procedure data file of the original ARINC424 terminal area database, and then integrate the database of key information related to control operations and graphics and the database of key information related to flight procedure assessment one by one according to the airport, arrival / departure, and approach procedures.

[0022] The fifth step: Based on the ARINC424 terminal area integrated database, perform airport runway drawing, runway azimuth verification, go-around turn radius calculation, determination and correction of key position points, and draw the flight procedure track to establish a flight procedure track model.

[0023] Step 6: Based on the ARINC424 terminal area fusion database, determine the flight technical tolerance C, wind helix parameters, and the earliest turning point for a go-around, and establish a flight procedure protection area model according to the route protection area rules;

[0024] Step 7: Establish a flight procedure height limit assessment model based on the ARINC424 terminal area fusion database;

[0025] Step 8: Import the longitude and latitude information of the obstacles into the system, fuse and compare the geographical information of the obstacle positions and the flight procedure protection areas, determine the specific protection areas of the flight procedures where the obstacles are located, and finally, by calling the height limit assessment model of the specific protection areas, evaluate and analyze the restricted heights of the obstacles, and the flight procedure height limit assessment can be completed.

[0026] Most preferably, the ARINC424 terminal area original database refers to the field requirements of ARINC424 data, makes the header data of various data files, and is in an Excel data format that can be viewed, edited, read, and called, including various data files such as airports, runways, navigation aids, waypoints, and flight procedures.

[0027] Among them, the airport data includes airport code, airport name, airport reference point coordinates, airport elevation, magnetic declination, transition altitude, and transition altitude layer, etc.;

[0028] The runway data includes the airport where it is located, runway number, runway length and width, runway magnetic azimuth, longitude and latitude coordinates and elevation of the runway entrance point, and the maximum aircraft type that can be used, etc.;

[0029] The navigation aid data includes navigation aid code, navigation aid name, airport where it is located, navigation aid type, navigation aid longitude and latitude, frequency and call sign, magnetic declination, elevation of the location where it is located, etc.;

[0030] The waypoint data includes waypoint code, waypoint name, airport where it is located, waypoint type, longitude and latitude, and magnetic declination, etc.;

[0031] The flight procedure data includes path termination code, fix identifier, whether to fly over, magnetic course, turn indication, altitude and altitude type, speed limit, vertical path angle VPA / Touchdown height TCH, navigation performance, airport where it is located, approach and departure and approach procedure numbers, and holding time.

[0032] Most preferably, the key information database related to control operation and graphics adopts an Excel data format that can be viewed, edited, read, and called, including the airport where it is located, the numbers of arrival and departure procedures and approach procedures, the climb gradient of the departure flight segment, the climb gradient of the go-around flight segment, whether the departure specified altitude turn procedure prohibits turning before the departure end of runway (DER), whether the approach specified altitude go-around procedure prohibits turning before the missed approach point (MAPt), etc.

[0033] Most preferably, the key information database related to flight procedure evaluation adopts an Excel data format that can be viewed, edited, read, and called, including the airport where it is located, the numbers of arrival and departure procedures and approach procedures, the single lowest obstacle clearance altitude when there is no step-down fix in the intermediate flight segment, multiple lowest obstacle clearance altitudes when there are step-down fixes in the intermediate flight segment, multiple lowest obstacle clearance altitudes when there are step-down fixes in the final flight segment, decision height / altitude, minimum descent height / altitude, minimum temperature limit, etc.

[0034] Most preferably, in step five, the method for establishing the flight procedure track model is as follows

[0035] A. Airport runway drawing: Extract the longitude and latitude coordinates of the runway entrance point and the runway length from the ARINC424 terminal area original database - runway data, and draw the original airport runway;

[0036] B. Conduct multi-angle cross-checks on the runway azimuth;

[0037] C. Extract and determine the key position points required for track drawing from the ARINC424 terminal area fusion database;

[0038] D. Correct the key position points;

[0039] E. Read data from the ARINC424 terminal area fusion database to calculate the go-around turning radius. The calculation formula is as follows: The go-around turning radius calculation of the RNP APCH approach procedure is related to the indicated airspeed IAS and the altitude H of the turning point

[0040]

[0041] Among them, the indicated airspeed IAS is determined according to the maximum go-around turning speed (a fixed value stipulated by regulations) determined by the aircraft type or the flight procedure design speed limit (read from the flight procedure data);

[0042] The altitude H of the constant altitude turn turning point can be read from the flight procedure data;

[0043] The altitude H of the fixed point turn turning point = the distance from TF to MAPt * 0.1 + decision height

[0044] The distance from TF to MAPt can be calculated from the longitude and latitude of TF and MAPt that can be read from the waypoint data; the decision height can be extracted from the key information database related to flight procedure evaluation;

[0045] F. According to the track termination code, connect the key position points IF, IFSDF, FAF, SDF, MAPt, and TA in sequence to draw the five - side approach track and the straight - line segment of the missed approach track. Draw the missed approach turning arc according to the turning radius r, and make the turning arc tangent to the end - point TA of the straight - line segment of the missed approach track to form the missed approach turning arc track. Draw the track from the turning arc to the turning end - point according to the turning end - point and the tangent of the turning arc, and establish a flight procedure track model for the drawn flight procedure track.

[0046] Most preferably, in step B, the following three methods are adopted to cross - check the runway azimuth:

[0047] a. Check with the true azimuth GEO. Extract the runway magnetic azimuth MAG from the ARINC424 terminal area original database - runway data, and extract the magnetic declination VAR from the ARINC424 terminal area original database - airport data. The check formula is:

[0048] GEO = MAG + VAR

[0049] b. Check with the longitude and latitude coordinates of the two ends of the runway entrance. Extract the longitude and latitude coordinates THR1 and THR2 of the two ends of the runway entrance from the ARINC424 terminal area original database - runway data. First, convert the format of longitude and latitude from degrees - minutes - seconds format to decimal degrees format, and then use the following algorithm to calculate the angle of the runway entrance point. The azimuth formula of THR1 is as follows:

[0050] The angle of runway entrance point 1

[0051]

[0052] where,

[0053]

[0054] With the same logic, the azimuth THR2_GEO of THR2 can be calculated. The azimuth of the runway can be calculated by taking the average of the azimuths of the two ends of the runway to obtain the angle GEO that most closely fits the true runway azimuth:

[0055] GEO=(THR1_GEO + THR2_GEO + 180) / 2

[0056] c. Use the image layer

[0057] Extract the longitude and latitude coordinates of the runway entrance points at both ends from the ARINC424 terminal area original database - runway data, draw the runway entrance points at both ends in the geographic information system based on the longitude and latitude, then connect the two entrance points with a line segment to construct the runway entity, fit the constructed runway entity with the actual runway in the image map, calculate the azimuth error, and adjust it based on the runway in the image map;

[0058] When cross-checking the runway azimuth, first perform mean processing on the runway azimuths calculated by method a and method b to obtain the first optimized runway azimuth GEO 1 ; then draw the runway according to the azimuth GEO 1 and compare and fit the drawn runway with the runway in the image layer. If the deviation is less than 0.01°, then determine GEO 1 as the optimal runway azimuth, otherwise, the runway azimuth GEO 1 needs to be rotated and adjusted according to the runway azimuth in the image map.

[0059] Most preferably, in step D, the method for correcting the key position points is to check the key position points located on the straight segments of the downwind approach and go-around based on the verified runway azimuth. First, draw rays outward along the opposite direction of the runway at both ends of the runway. If the waypoint position determined by the longitude and latitude is on the ray, then the waypoint position does not need to be adjusted; if the waypoint position determined by the longitude and latitude is on both sides of the ray, then move the waypoint position to the foot position closest to the ray, and this position is the key position point for the downwind or upwind side finally determined for drawing the flight procedure track and protection area.

[0060] Most preferably, in step six, the method for drawing the flight procedure protection area model is as follows,

[0061] A. Determine the flight technical tolerance C;

[0062] The flight technical tolerance C for the go-around turning point, and its calculation formula is as follows

[0063] C = [171233×(303 - 0.006496H) 0.5 ÷(288 - 0.006496H) 2.628 ·IAS + 15.56]×6

[0064] where the variables are the indicated airspeed IAS and the go-around turning height H;

[0065] B. Determine the wind spiral parameters

[0066] The influence value E of the wind on the aircraft when turning through an angle θ θ , can be calculated based on the indicated airspeed IAS and the go-around turning height H, and its calculation formula is as follows

[0067]

[0068] C. Before drawing, it is necessary to retrieve the information in the key information data of control operation and graphics related to whether the missed approach specified altitude missed approach procedure prohibits turning before the missed approach point (MAPt), determine the earliest turning point of the missed approach, and if this information is yes, the connection point of the inner boundary of the missed approach turning protection area is the MAPt point; if it is no, the connection point of the inner boundary of the missed approach turning protection area is the FAF point;

[0069] D. Draw the flight procedure protection area according to the rules of the sector protection area.

[0070] Most preferably, in step D, the rules for drawing the sector protection area are as follows.

[0071] a. Rules for drawing the straight-line section protection area of the five-sided approach and missed approach

[0072] The half-width of the protection area at the IF is a fixed value of 2.5 NM, the half-width of the protection area at the FAF is a fixed value of 1.45 NM, the FAF is connected to 2.5 NM by an outward extension line at an angle of 30°, and is inwardly retracted to 0.95 NM at an angle of 30°, maintaining 0.95 NM to 0.24 NM in front of the runway threshold, and then outwardly extending to 2 NM at an angle of 15°, maintaining 2 NM to the TA. One-fourth of the half-width of the protection area on both sides of the nominal track is the main area, and the outer side is the secondary area;

[0073] b. Rules for drawing the missed approach turning protection area

[0074] If the procedure prohibits turning before the MAPt, the earliest turning point of the constant altitude missed approach turn is the MAPt; if the procedure allows turning before the MAPt, the earliest turning point of the constant altitude missed approach turn is the FAF; the latest turning point of the constant altitude missed approach turn is the TA + C tolerance; the wind spirals are drawn from one-fourth of the protection area width on both sides of the latest turning point, and are connected by a common tangent; the boundary of the main area of the upper latest turning track protection area is tangent to the outer boundary of the wind spiral by connecting the end point of the missed approach turn and extending 15° to be tangent to the boundary of the main area of the missed approach turn protection area; the boundary of the secondary area of the upper latest turning track protection area is obtained by translating the boundary of the main area by one-fourth of the protection area width; the boundary of the main area of the lower earliest turning track protection area is connected to the position of the boundary of the main area of the protection area 0.24 NM in front of the FAF / MAPt by the end point of the missed approach turn and extending 15° to be tangent to the boundary of the main area of the missed approach turn protection area; the boundary of the secondary area of the lower earliest turning track protection area is the boundary of the main area translated to the position of the boundary of the secondary area of the protection area 0.24 NM in front of the FAF / MAPt and is tangent to the boundary of the secondary area of the missed approach turn protection area.

[0075] Most preferably, in step seven, the method for establishing the flight procedure height limit assessment model is as follows.

[0076] A. Determine the height limit assessment rules for the secondary area;

[0077] B. Establish the main area height limit assessment calculation model for each flight segment of the RNP APCH LNAV non-precision approach procedure;

[0078] Determination of the position of the start-of-climb point SOC for a missed approach

[0079] Distance of SOC of the RNP APCH LNAV non-precision approach procedure from MAPt:

[0080]

[0081] Main area height limit for the IFSDF flight segment from IF to IFSDF:

[0082] H = MOCA IF至IFSDF航段 - MOC 中间

[0083] Main area height limit for the FAF flight segment from IFSDF to FAF:

[0084] H = MOCA IFSDF至FAF航段 - MOC 中间

[0085] Main area height limit for the SDF flight segment from FAF to SDF:

[0086] H = MOCA FAF至SDF航段 - MOC 最后

[0087] Main area height limit for the SOC1 flight segment from SDF to SOC1:

[0088] H = MDA - MOC 最后

[0089] Main area height limit for the SOC flight segment from SOC1 to SOC:

[0090] H = MDA - MOC 递减

[0091] Main area height limit for the TA flight segment from SOC to TA:

[0092] H = MDA + L 至SOC的距离 · Missed approach gradient - MOC 复飞直线段

[0093] Main area height limit for the flight segment from TA to the end of the missed approach turn:

[0094] H = TA + L 障碍物至直线段保护区边界的最近距离 · Missed approach gradient - MOC 复飞转弯区

[0095] Among them, SOC1 is the minimum obstacle clearance that decreases from MOC 最后 to MOC 复飞直线段Starting position, SOC1 is in front of SOC, the distance between SOC1 and SOC = (MOC 最后 -MOC 复飞直线段 ) / go-around gradient; minimum obstacle clearance altitude MOCA IF至IFSDF航段 、MOCA IFSDF至FAF航段 、MOCA FAF至SDF航段 and minimum descent altitude MDA can be read from the key information database related to flight procedure evaluation; the go-around gradient can be read from the key information database related to air traffic control operation and graphics; MOC 中间 =150m, MOC 最后 =75m, MOC 复飞直线段 =30m, MOC 复飞转弯区 =50m, MOC 递减 is decreased from 75m to 30m; the positioning tolerance of key positioning points is considered for each flight segment;

[0096] C. Establish the main area height limit evaluation calculation model for each flight segment of the RNP APCH VNAV type precision approach procedure;

[0097] The precision approach segment of the RNP APCH VNAV type precision approach procedure is composed of the final approach surface (FAS surface), the horizontal plane (G surface) and the go-around surface (Z surface),

[0098] a. Low temperature correction

[0099] When the aircraft executes the RNP APCH VNAV type precision approach procedure and uses the barometric altimeter for vertical guidance, it will be affected by temperature. To avoid the risk caused by the actual flight of the aircraft being too low in low temperature conditions, low temperature correction is required.

[0100] Δh = (C L / 0.0065 + H 机场标高 -2307.7)ln[1 - h FAF / (44330.8 - H 入口 )

[0101] b. Slope of the FAS surface:

[0102] tanα = (h FAF -Δh - Hi)tanVPA / (h FAF - Hi)

[0103] c. Starting point of the FAS surface:

[0104]

[0105] d. Determination of the position of the starting climb point SOC for go-around

[0106] Distance of the RNP APCH VNAV - type precision approach procedure SOC from the runway threshold:

[0107] SOC VNAV = X Z +(DH - HL) / tanVPA

[0108] Height limit of the main area for the section from IF to the starting point of the FAS surface:

[0109] Considering the RNP APCH VNAV landing standard, height limit of the main area for the section from IF to the starting point of the FAS surface:

[0110] H = min(MOCA IF至IFSDF航段 - MOC 中间 , MOCA IFSDF至FAF航段 - MOC 中间 , max(L FAS ·tan(α)+H 入口 , DA -

[0111] HL))

[0112] Height limit of the main area for the G surface (from the starting point of the FAS surface to the starting point of the Z surface):

[0113] Considering the RNP APCH VNAV landing standard, height limit of the main area for the G surface (from the starting point of the FAS surface to the starting point of the Z surface):

[0114] H = DA - HL

[0115] Height limit of the main area for the Z surface (from the starting point of the Z surface to the TA section):

[0116] Considering the RNP APCH VNAV landing standard, height limit of the main area for the Z surface (from the starting point of the Z surface to the TA section):

[0117] H = max(L Z ·go - around gradient + H 入口 , DA - HL)

[0118] Height limit of the main area for the section from TA to the end point of the go - around turn:

[0119] H = TA + L 障碍物至直线段保护区边界的最近距离 ·go - around gradient - MOC 复飞转弯区

[0120] Among them, L FAS is the distance from the starting point of the FAS surface; L Zis the distance from the starting point of the Z plane; Hi is determined according to the height of the FAS plane at the height evaluation position. When the height is less than 5000 ft, Hi = 75; when the height is between 5000 - 10000 ft, Hi = 105; when the height is greater than 10000 ft, Hi = 120; Xz is the starting position of the Z plane, -1400 m for Category D aircraft. When the airport elevation is higher than 900 m or the glide slope angle is greater than 3.2°, it needs to be corrected according to the regulations. HL is the gradient loss, 49 m for Category D aircraft. When the airport elevation is higher than 900 m or the glide slope angle is greater than 3.2°, it needs to be corrected according to the regulations. The airport elevation (H 机场标高 ) can be extracted from the ARINC424 terminal area original database - airport data; the runway threshold height (H 入口 ) can be extracted from the ARINC424 terminal area original database - runway data; the vertical path angle VPA, the overfly runway threshold height TCH, the FAF height (h FAF ) can be extracted from the ARINC424 terminal area original database - flight procedure data; the go-around gradient can be read from the control operation and graphic related key information database; the decision altitude DA, the decision height DH, the minimum temperature limit C L can be extracted from the flight procedure evaluation related key information database. For the go-around obstacles that penetrate the FAS plane, G plane or Z plane, the equivalent approach obstacle height is used to conduct the operation standard evaluation and analysis.

[0121] Compared with the prior art, the advantages of the present invention are as follows:

[0122] (1) High degree of automation. Through the ARINC424 terminal area fusion database, the flight procedure track is automatically restored, the protection area is drawn, and the height limit is evaluated. The flight procedure track and the protection area can be exported as a.dwg file that can be used by Auto CAD software, the flight procedure height limit evaluation result can be exported as an.xls file that can be used by EXCEL software, and it supports exporting the height limit evaluation report.doc file that can be used by WORD software, greatly improving the work efficiency of the airport flight procedure height limit evaluation.

[0123] (2) High accuracy of the height limit evaluation result. Through the ARINC424 terminal area fusion database, multiple checks are carried out on the runway azimuth and key position points, and the original track and protection area of the flight procedure design are truly restored based on the flight procedure design principle, and then the accurate evaluation of the flight procedure height limit is realized through key height information such as the minimum obstacle clearance height and the decision altitude.

[0124] (3) Through the accurate restoration of each specific protection area of the flight procedure and the formulation of height limit rules, the present invention forms a flight procedure height limit evaluation standard model that can be extended to national transport airports, reduces the mapping and calculation errors caused by human factors, and improves the accuracy of the flight procedure height limit evaluation. Brief Description of the Drawings

[0125] Figure 1 It is a flowchart of the height limit evaluation method of the present invention;

[0126] Figure 2 It is a track drawing of the present invention;

[0127] Figure 3 It is a drawing of the protected area where turning is allowed before MAPt;

[0128] Figure 4 It is a drawing of the protected area when turning is not allowed before MAPt;

[0129] Figure 5 It is the measured drawing after importing obstacle data. Detailed Implementation Manner

[0130] To solve the problem of height limit evaluation and analysis of flight procedures, from the perspective of flight procedure design, the present invention first restores the track based on flight procedure design principles by supplementing the missing key information related to control operations and graphics in the original ARINC424 data, and draws a complete flight procedure protected area according to the flight track; then, by supplementing the missing key height information such as landing criteria and minimum obstacle clearance height in the original ARINC424 data, calculates the precise limit height within the protected area of the flight procedure segment, provides a solution for the rapid and precise evaluation and analysis of obstacles, and makes up for the blank of the automatic evaluation and analysis of flight procedures driven by ARINC424 data.

[0131] Among them, during the evaluation and analysis process, the flight procedure track restored based on the ARINC424 terminal area fusion database and the produced protected area can export a dwg file that can be used by AutoCAD software for the display and reporting and communication of the airport flight procedure track and protected area; the flight procedure height limit evaluation result calculated based on the ARINC424 terminal area fusion database can export an.xls file that can be used by EXCEL software for the statistical analysis of the evaluation result; based on the flight procedure track, protected area and height limit evaluation result, a.doc file that can be used by WORD software can be exported to realize the interaction of production operation information and the automatic generation of the height limit evaluation report, meet the actual production needs, and improve production efficiency.

[0132] The following will further describe the present invention. A terminal area flight procedure height limit evaluation system based on ARINC424, see Figure 1 , the method flow is as follows,

[0133] The first step: Decoding and parsing of ARINC424 original data;

[0134] Decode and analyze the ARINC424 original data in text format according to the 132-bit encoding rule, and store it in the ARINC424 terminal area original database after completion. The files stored in the ARINC424 terminal area original database are in Excel data format that can be viewed, edited, read, and called, and the data information uses longitude and latitude as geographical information identifiers.

[0135] The ARINC424 terminal area original database includes various data files such as airports, runways, navigation aids, waypoints, flight procedures, etc. Refer to the field requirements of ARINC424 data to make the header data of various data files.

[0136] Airport data includes airport code, airport name, airport reference point coordinates, airport elevation, magnetic declination, transition altitude, and transition altitude layer, etc.

[0137] Runway data includes the airport where it is located, runway number, runway length and width, runway magnetic azimuth, longitude and latitude coordinates and elevation of the runway entrance point, the maximum aircraft type that can be used, etc.

[0138] Navigation aid data includes navigation aid code, navigation aid name, the airport where it is located, navigation aid type, navigation aid longitude and latitude, frequency and call sign, magnetic declination, elevation of the location where it is located, etc.

[0139] Waypoint data includes waypoint code, waypoint name, the airport where it is located, waypoint type, longitude and latitude, and magnetic declination, etc.

[0140] Flight procedure data includes path termination code, fix identifier, whether to fly over, magnetic course, turn indication, altitude and altitude type, speed limit, vertical path angle VPA / Touchdown height TCH over runway threshold, navigation performance, the airport where it is located, the numbers of arrival / departure and approach procedures, holding time, etc.

[0141] The above-completed ARINC424 terminal area original database can be automatically updated regularly every 28 days according to the ARINC424 update cycle to keep up with the latest navigation basic data in real time.

[0142] Step 2: Production of key information related to control operation and graphics;

[0143] Based on the domestic aeronautical information compilation NAIP data, for the information related to the control operation or graphics of the departure, arrival, and approach standard instrument flight procedures missing in the ARINC424 terminal area original database (such as the climb gradient in the departure segment, the climb gradient in the missed approach segment, whether the turn procedure at the specified altitude in the departure is prohibited from turning before the departure end of the runway (DER), whether the missed approach procedure at the specified altitude in the approach is prohibited from turning before the missed approach point (MAPt), etc.), referring to the field rules of the ARINC424 data sheet, a key information database related to control operation and graphics required for program design is made. The key information database related to control operation and graphics also adopts the Excel data format that can be viewed, edited, read, and called, and the data information uses longitude and latitude as the geographical information identifier.

[0144] The key information database related to control operation and graphics includes the airport where it is located, the numbers of the departure, arrival, and approach procedures, the climb gradient in the departure segment, the climb gradient in the missed approach segment, whether the turn procedure at the specified altitude in the departure is prohibited from turning before the departure end of the runway (DER), whether the missed approach procedure at the specified altitude in the approach is prohibited from turning before the missed approach point (MAPt), etc.

[0145] Step 3: Making key information related to flight procedure evaluation;

[0146] Based on the domestic aeronautical information compilation NAIP data, for the information related to the height limit evaluation of the departure, arrival, and approach standard instrument flight procedures missing in the ARINC424 terminal area original database (such as the single minimum obstacle clearance altitude when there is no step-down fix in the intermediate segment, multiple minimum obstacle clearance altitudes when there are step-down fixes in the intermediate segment, multiple minimum obstacle clearance altitudes when there are step-down fixes in the final segment, decision height / altitude, minimum descent height / altitude, minimum temperature limit, etc.), referring to the field rules of the ARINC424 data sheet, a key information database related to flight procedure evaluation required for height limit evaluation is made. The key information database related to flight procedure evaluation also adopts the Excel data format that can be viewed, edited, read, and called.

[0147] The key information database related to flight procedure evaluation includes the airport where it is located, the numbers of the departure, arrival, and approach procedures, the single minimum obstacle clearance altitude when there is no step-down fix in the intermediate segment, multiple minimum obstacle clearance altitudes when there are step-down fixes in the intermediate segment, multiple minimum obstacle clearance altitudes when there are step-down fixes in the final segment, decision height / altitude, minimum descent height / altitude, minimum temperature limit, etc.

[0148] Step 4: Making the ARINC424 terminal area fusion database.

[0149] The files stored in the ARINC424 terminal area original database are in Excel data format that can be read, viewed, and edited. The key information databases related to air traffic control operations and graphics also use Excel data format that can be viewed, edited, read, and called. The key information databases related to flight procedure evaluation also use Excel data format that can be viewed, edited, read, and called. The three database files are of the same type.

[0150] First, add corresponding columns after the data information of the corresponding airport, arrival and departure procedures, and approach procedures in the flight procedure data file of the ARINC424 terminal area original database. Then, integrate the key information databases related to air traffic control operations and graphics and the key information databases related to flight procedure evaluation one by one according to the airport, arrival and departure procedures, and approach procedures. Finally, complete the production of the improved ARINC424 terminal area integrated database.

[0151] Innovatively, by supplementing the key information related to air traffic control operations and graphics, landing standards, and key altitude information such as the minimum obstacle clearance altitude in the original ARINC424 data, an ARINC424 terminal area integrated database that supports the altitude limit evaluation of flight procedures is produced, providing a data basis for the automatic evaluation and analysis of flight procedures at airports across the country. By supplementing the key information related to air traffic control operations and graphics in the original ARINC424 data, the flight track based on the flight procedure design principle can be restored, and a complete flight procedure protection area can be drawn according to the flight track. Then, by supplementing the key altitude information such as landing standards and the minimum obstacle clearance altitude in the original ARINC424 data, the accurate limit altitude within the flight procedure segment protection area can be calculated.

[0152] Step 5: Establish a flight procedure track model based on the ARINC424 terminal area integrated database.

[0153] In the flight procedure altitude limit evaluation model constructed in the present invention, the points, lines, and planes involved are all vector elements with geographical information attributes modeled based on actual longitude and latitude. Among them, the point model is the runway entrance point, waypoint, etc., which are points determined by longitude and latitude; the line model is the runway, flight procedure track, etc., which are line segments determined by longitude and latitude and track termination codes; the plane model is the protection area of each flight procedure segment, etc., which are areas determined by longitude and latitude and protection area rules. Specifically, refer to the method for converting the longitude and latitude coordinate data of obstacles in 202310491584.6, a method for airport clearance safety assessment and mapping based on ARNIC424 coding. After converting the longitude and latitude coordinate data into a Cartesian two-dimensional plane coordinate system, a rectangular coordinate system with the runway entrance as the origin is re-established, and the calculation process is converted from longitude and latitude coordinates to XY coordinates to simplify the calculation.

[0154] Based on the ARINC424 terminal area fusion database, the present invention can achieve the complete reproduction of the flight procedure track, and the flight procedure track model restored based on the flight procedure design rules is a design nominal track with geographical information attributes.

[0155] However, different parameters are required for the design of different standard instrument approach, departure and approach flight procedures. Taking the RNP APCH approach procedure as an example, the present invention illustrates the drawing of the flight procedure track model.

[0156] 1. Airport runway drawing

[0157] Extract the longitude and latitude coordinates of the runway entrance point and the runway length from the runway data in the ARINC424 terminal area original database to draw the original airport runway.

[0158] 2. Runway azimuth verification

[0159] The drawing of the airport runway is the basis for the drawing of the flight procedure track, the drawing of the protection area and the height limit assessment. In particular, the runway length and runway azimuth have the most critical impact on the results. The runway length can be accurately extracted from the runway data in the ARINC424 terminal area original database and drawn. However, the runway azimuth is prone to deviation during the drawing process. The present invention conducts multi-angle verification of the runway azimuth to lay a good foundation for the accurate assessment of the flight procedure height limit.

[0160] Since the approach procedures of most airports are for landing on the runway on the final approach side, and the length of the final approach side is usually from more than ten to dozens of kilometers. Therefore, a small error in azimuth will be continuously amplified after a deviation of more than ten to dozens of kilometers. Obstacles that should originally be in the protection area may be outside the protection area due to the deviation, seriously affecting the accuracy of the protection area drawing and height limit assessment.

[0161] The present invention adopts the following several methods to cross-verify the runway azimuth:

[0162] (1) Verify using the true azimuth GEO

[0163] Extract the magnetic azimuth MAG of the runway from the runway data in the ARINC424 terminal area original database, and extract the magnetic declination VAR from the airport data in the ARINC424 terminal area original database.

[0164] GEO = MAG + VAR

[0165] (2) Verify using the longitude and latitude coordinates of the two ends of the runway entrance point

[0166] Extract the longitude and latitude coordinates of the two runway entrance points THR1 (longitude THR1_lon, latitude THR1_lat) and THR2 (longitude THR2_lon, latitude THR2_lat) from the ARINC424 terminal area original database - runway data. First, convert the formats of longitude and latitude from degrees, minutes, and seconds to decimal degrees format (DDD.DDDD°). Then, use the following algorithm to calculate the angle of the runway entrance point. The following is the calculation of the azimuth of THR1.

[0167] The angle of runway entrance point 1

[0168]

[0169] Among them,

[0170]

[0171] Using the same logic, the azimuth of THR2, THR2_GEO, can be calculated. The azimuth of the runway can be calculated by taking the average of the azimuths of the two runway ends to obtain the angle that best fits the true runway azimuth.

[0172] GEO = (THR1_GEO + THR2_GEO + 180) / 2

[0173] (3) Using the image layer

[0174] Extract the longitude and latitude coordinates of the two runway entrance points from the ARINC424 terminal area original database - runway data, and draw the two runway entrance points in the geographic information system based on the longitude and latitude. Then connect the two entrance points with a line segment to construct the runway entity, fit the constructed entity runway with the actual runway in the image map, calculate the azimuth error, and adjust it based on the runway in the image map.

[0175] When cross-checking the runway azimuth based on the above checking method, first take the average of the runway azimuths calculated in (1) and (2) to obtain the first optimized runway azimuth GEO 1 ; then draw the runway according to the azimuth GEO 1 and compare and fit the drawn runway with the runway in the image layer. If the deviation is less than 0.01°, then determine GEO 1 as the optimal runway azimuth, otherwise, the runway azimuth GEO 1 needs to be rotated and adjusted according to the runway azimuth in the image map.

[0176] 3. Determination of key position points

[0177] The key position points required for the track drawing of the RNP APCH approach procedure are: the intermediate approach fix IF, the intermediate approach segment step-down fix IFSDF, the final approach fix FAF, the final approach segment step-down fix SDF, the missed approach point MAPt, the fixed-point missed approach turning point TF, and the constant-altitude missed approach turning point TA.

[0178] Among them, the intermediate approach fix IF, the intermediate approach segment step-down fix IFSDF, the final approach fix FAF, the final approach segment step-down fix SDF, the missed approach point MAPt, and the fixed-point missed approach turning point TF can be extracted from the ARINC424 terminal area original database - waypoint data.

[0179] The constant-altitude missed approach turning point TA = [turning point altitude - threshold elevation] / missed approach segment climb gradient

[0180] Among them, the turning point altitude is read from the flight procedure data, the threshold elevation is read from the runway data, and the missed approach segment climb gradient is read from the air traffic control operation and graphic-related key information data.

[0181] 4. Key position point correction

[0182] The key position points are the key nodes for the track drawing of the flight procedure and the drawing of the protection area, and are the guarantee and basis for correct height limit assessment. There are fuzzy errors in the storage of the longitude and latitude accuracy of the waypoints in the ARINC424 terminal area original database, and there are deviations from the original longitude and latitude of the flight procedure design. It is necessary to correct the key position points in combination with the flight procedure design principles and the actual waypoint positions.

[0183] Since the runway azimuth has been cross-checked, and the key position points on the five-side approach track of the flight procedure and the key position points for takeoff on one side are usually located on the extension line of the runway, the key position points can be corrected based on the corrected runway data.

[0184] Based on the verified runway azimuth, check the key position points located on the five-side approach and the missed approach straight line segments. The specific method is as follows: First, draw rays outward along the runway in the opposite direction at both ends of the runway. If the waypoint position determined by the longitude and latitude is on the ray, the position of this waypoint does not need to be adjusted; if the waypoint position determined by the longitude and latitude is on both sides of the ray, move the position of this waypoint to the foot position closest to the ray. This position is the final key position point for drawing the flight procedure track and the protection area on the five-side or one side.

[0185] 5. Missed approach turning radius calculation

[0186] The calculation of the missed approach turning radius of the RNP APCH approach procedure is related to the indicated airspeed IAS and the turning point altitude H

[0187]

[0188] Among them, the indicated airspeed IAS is determined according to the maximum speed of the go-around turn (a fixed value specified by regulations) determined according to the aircraft type or the flight procedure design speed limit (read from the flight procedure data).

[0189] The altitude H of the turning point of the constant altitude turn can be read from the flight procedure data.

[0190] The altitude H of the turning point of the fixed point turn = the distance from TF to MAPt * 0.1 + the decision altitude

[0191] The distance from TF to MAPt can be calculated from the latitudes and longitudes of TF and MAPt read from the waypoint data; the decision altitude can be extracted from the database of key information related to flight procedure evaluation.

[0192] 6. Draw the flight procedure track according to the track termination code to establish the flight procedure track model

[0193] There is a step-down fix in each of the intermediate approach segment and the final approach segment, and the RNP APCH approach procedure with a constant altitude turn for go-around is adopted. The track termination code for the track of the segment of procedure IF - IFSDF - FAF - SDF - MAPt - TA - end point of go-around turn is IF - TF - TF - TF - TF - CA - DF.

[0194] Connect the key position points IF, IFSDF, FAF, SDF, MAPt and TA in sequence to draw the five-sided approach track and the straight-line segment track of the go-around. Draw the go-around turn circular arc according to the turning radius r, and make the turning circular arc tangent to the TA point at the end of the straight-line segment track of the go-around to form the go-around turn arc-shaped track. Draw the track from the turning circular arc to the turning end point according to the turning end point and the tangent line of the turning circular arc. The drawn flight procedure track is as Figure 2 shown.

[0195] Step 6: Establish the flight procedure protection area model based on the ARINC424 terminal area fusion database

[0196] Based on the ARINC424 terminal area fusion database, the accurate restoration of the flight procedure protection area can be realized, and the restored flight procedure protection area model is a specific area with geographical information attributes.

[0197] The parameters required for different standard instrument departure, arrival and approach flight procedure designs are different. In the present invention, the RNP APCH approach procedure with a constant altitude turn for go-around is taken as an example to illustrate the drawing of the flight procedure protection area model.

[0198] 1. Determination of flight technical tolerance C

[0199] The flight technical tolerance C of the go-around turning point determines the starting point for drawing the outer boundary of the wind spiral protection area. The flight technical tolerance C of the go-around turning point can be calculated according to the following formula.

[0200] C = [171233×(303 - 0.006496H) 0.5 ÷(288 - 0.006496H) 2.628 ·IAS + 15.56]×6

[0201] Where the variables are the indicated airspeed IAS and the go-around turning height H.

[0202] 2. Determination of wind spiral parameters

[0203] During the turning process of the aircraft, the influence of the wind needs to be considered, including the outer boundary of the turning protection area and the maximum turning outer boundary formed under the influence of the wind during the turning process. The influence value E of the wind on the aircraft when it turns through an angle θ θ can be calculated based on the indicated airspeed IAS and the go-around turning height H.

[0204]

[0205] 3. Determination of the earliest go-around turning point

[0206] Before drawing, it is necessary to retrieve the information on whether the approach specified height go-around procedure in the key information data related to air traffic control operations and graphics prohibits turning before the go-around point (MAPt). If the information is yes, the connection point of the inner boundary of the go-around turning protection area is the MAPt point; if it is no, the connection point of the inner boundary of the go-around turning protection area is the FAF point.

[0207] 4. Drawing the flight procedure protection area according to the rules of the sector protection area

[0208] (1) Drawing rules for the straight-line section protection area of the five-sided approach and go-around

[0209] The half-width of the protection area at the IF is a fixed value of 2.5 NM, the half-width of the protection area at the FAF is a fixed value of 1.45 NM. The FAF is connected to 2.5 NM by an outward extension line at an angle of 30°, and then inwardly retracted to 0.95 NM at an angle of 30°, maintaining 0.95 NM to 0.24 NM in front of the runway threshold, and then outwardly extended to 2 NM at an angle of 15°, maintaining 2 NM to the TA. One-fourth of the half-width of the protection area on both sides of the nominal track is the main area, and the outer side is the secondary area.

[0210] (2) Drawing rules for the go-around turning protection area

[0211] If the procedure prohibits turning before the MAPt, the earliest turning point of the constant-altitude go-around turn is the MAPt, as Figure 4 shown; if the procedure allows turning before the MAPt, the earliest turning point of the constant-altitude go-around turn is the FAF, asFigure 3 As shown.

[0212] The latest turning point for a fixed-altitude missed approach turn is the TA+C tolerance. Wind spirals are drawn from one-fourth of the protection zone width on both sides of the latest turning point, and the two wind spirals are connected by a common tangent. The upper latest turning track main area protection zone boundary is connected to the missed approach turn end point and the tangent of the outer boundary of the wind spiral, and is expanded 15° outward to be tangent to the main area boundary of the protection zone at the end point of the missed approach turn. The upper latest turning track secondary area protection zone boundary is obtained by translating the main area protection zone boundary by one-fourth of the protection zone width. The lower earliest turning track protection zone main area boundary is connected to the missed approach turn end point and the protection zone main area boundary position 0.24NM ahead of FAF / MAPt, and is expanded 15° outward to be tangent to the main area boundary of the protection zone at the end point of the missed approach turn. The lower earliest turning track protection zone secondary area boundary is the main area boundary translated to the protection zone secondary area boundary position 0.24NM ahead of FAF / MAPt, and is tangent to the secondary area boundary of the protection zone at the end point of the missed approach turn.

[0213] Step 7: Establish a flight procedure height limit assessment model based on the ARINC424 terminal area fusion database.

[0214] Based on the ARINC424 terminal area fusion database, a height limit assessment model can be assigned to a specific section of the flight procedure protection zone, thereby achieving an accurate assessment of the flight procedure height limit.

[0215] The flight procedure altitude limit assessment model includes MSA, MVA, holding, visual circling, traditional and PBN departure, RNP ILS / DME precision approach, RNP ILS / DME GP INOP non-precision approach, ILS / DME precision approach, ILS / DME GP INOP non-precision approach, VOR / DME non-precision approach, NDB / DME non-precision approach, RNP APCH VNAV precision approach, RNP APCHLNAV non-precision approach and other models.

[0216] Due to the different parameters required for the design of different standard instrument arrival, departure and approach flight procedures, the present invention takes the RNP APCH approach procedure with a fixed altitude turn for a missed approach as an example to illustrate the flight procedure altitude limit evaluation model. The RNP APCH approach procedure is divided into the RNP APCH LNAV non-precision approach procedure and the RNP APCH VNAV precision approach procedure. The altitude limit evaluation model is described below:

[0217] 1. Determination of the height limit assessment rules for the secondary area

[0218] The inner boundary of the secondary area has the same restricted height as the adjacent primary area. The restricted height of the secondary area increases linearly from the inner boundary to the outer boundary, and the increment is the MOC of the corresponding flight segment. The same evaluation rules for the restricted height of the secondary area apply to both the RNP APCH LNAV non-precision approach procedure and the RNP APCH VNAV precision approach procedure.

[0219] 2. Calculation model for evaluating the restricted height of the primary area in each flight segment of the RNP APCH LNAV non-precision approach procedure

[0220] Determination of the SOC position of the starting climb point during missed approach

[0221] Distance of the SOC of the RNP APCH LNAV non-precision approach procedure from the MAPt:

[0222]

[0223] Restricted height of the primary area for the IF to IFSDF flight segment:

[0224] H = MOCA IF至IFSDF航段 -MOC 中间

[0225] Restricted height of the primary area for the IFSDF to FAF flight segment:

[0226] H = MOCA IFSDF至FAF航段 -MOC 中间

[0227] Restricted height of the primary area for the FAF to SDF flight segment:

[0228] H = MOCA FAF至SDF航段 -MOC 最后

[0229] Restricted height of the primary area for the SDF to SOC1 flight segment:

[0230] H = MDA - MOC 最后

[0231] Restricted height of the primary area for the SOC1 to SOC flight segment:

[0232] H = MDA - MOC 递减

[0233] Restricted height of the primary area for the SOC to TA flight segment:

[0234] H = MDA + L 至SOC的距离 · Missed approach gradient - MOC 复飞直线段

[0235] Restricted height of the primary area for the TA to the end point of the missed approach turn flight segment:

[0236] H = TA + L 障碍物至直线段保护区边界的最近距离 · Missed approach gradient - MOC复飞转弯区

[0237] Among them, SOC1 is the starting position where the minimum obstacle clearance margin decreases from MOC 最后 to MOC 复飞直线段 . SOC1 is located in front of SOC, and the distance between SOC1 and SOC = (MOC 最后 - MOC 复飞直线段 ) / go-around gradient; the minimum obstacle clearance height MOCA IF至IFSDF航段 , MOCA IFSDF至FAF航段 , MOCA FAF至SDF航段 and the minimum descent altitude MDA can be read from the relevant key information database for flight procedure evaluation; the go-around gradient can be read from the relevant key information database for air traffic control operation and graphics; MOC 中间 = 150m, MOC 最后 = 75m, MOC 复飞直线段 = 30m, MOC 复飞转弯区 = 50m, MOC 递减 decreases from 75m to 30m; the positioning tolerances of key positioning points are considered for each flight segment.

[0238] 3. Evaluation of the main area height limit for each flight segment of the RNP APCH VNAV type precision approach procedure

[0239] The precision approach segment of the RNP APCH VNAV type precision approach procedure is composed of the final approach surface (FAS surface), the horizontal plane (G surface) and the go-around surface (Z surface).

[0240] (1) Low temperature correction

[0241] When the aircraft executes the RNP APCH VNAV type precision approach procedure and uses the barometric altimeter for vertical guidance, it will be affected by temperature. To avoid the risk caused by the actual flight of the aircraft being too low in low temperature conditions, low temperature correction is required.

[0242] Δh = (C L / 0.0065 + H 机场标高 - 2307.7) ln[1 - h FAF / (44330.8 - H 入口 )

[0243] (2) Slope of the FAS surface:

[0244] tanα = (h FAF - Δh - Hi) tanVPA / (h FAF - Hi)

[0245] (3) Starting point of the FAS surface:

[0246]

[0247] (4) Determination of the SOC position for the initial climb point of a go-around

[0248] Distance of the SOC for the RNP APCH VNAV type precision approach procedure from the runway threshold:

[0249] SOC VNAV = X Z + (DH - HL) / tanVPA

[0250] Main area height limit for the flight path segment from IF to the starting point of the FAS surface

[0251] Considering the RNP APCH VNAV landing standard, the main area height limit for the flight path segment from IF to the starting point of the FAS surface:

[0252] H = min(MOCA IF至IFSDF航段 - MOC 中间 , MOCA IFSDF至FAF航段 - MOC 中间 , max(L FAS ·tan(α) + H 入口 , DA -

[0253] )

[0254] Main area height limit for the G surface (from the starting point of the FAS surface to the starting point of the Z surface)

[0255] Considering the RNP APCH VNAV landing standard, the main area height limit for the G surface (from the starting point of the FAS surface to the starting point of the Z surface):

[0256] H = DA - HL

[0257] Main area height limit for the Z surface (from the starting point of the Z surface to the TA flight path segment)

[0258] Considering the RNP APCH VNAV landing standard, the main area height limit for the Z surface (from the starting point of the Z surface to the TA flight path segment):

[0259] H = max(L Z · go-around gradient + H 入口 , DA - HL)

[0260] Main area height limit for the flight path segment from TA to the end point of the go-around turn:

[0261] H = TA + L 障碍物至直线段保护区边界的最近距离 · go-around gradient - MOC 复飞转弯区

[0262] Among them, L FAS is the distance from the starting point of the FAS surface; L Zis the distance from the starting point of the Z plane; Hi is determined according to the FAS plane height at the height limit assessment position. When the height is less than 5000 ft, Hi = 75; when the height is between 5000 - 10000 ft, Hi = 105; when the height is greater than 10000 ft, Hi = 120; Xz is the starting position of the Z plane, -1400 m for Category D aircraft. When the airport elevation is higher than 900 m or the glide slope angle is greater than 3.2°, it needs to be corrected according to the regulations. HL is the gradient loss, 49 m for Category D aircraft. When the airport elevation is higher than 900 m or the glide slope angle is greater than 3.2°, it needs to be corrected according to the regulations. The airport elevation (H 机场标高 ) can be extracted from the ARINC424 terminal area original database - airport data; the runway threshold height (H 入口 ) can be extracted from the ARINC424 terminal area original database - runway data; the vertical path angle VPA, the overfly runway threshold height TCH, the FAF height (h FAF ) can be extracted from the ARINC424 terminal area original database - flight procedure data; the missed approach gradient can be read from the air traffic control operation and graphic related key information database; the decision height DA, the decision height DH, the minimum temperature limit C L ) can be extracted from the flight procedure evaluation related key information database. For the missed approach obstacles that penetrate the FAS plane, G plane or Z plane, the equivalent approach obstacle height is used to conduct the operation standard evaluation and analysis.

[0263] Step 8: Flight procedure height limit assessment.

[0264] Based on the flight procedure track and protection area model with geographic information attributes generated from the ARINC424 terminal area fusion database, and the height limit assessment model assigned to specific segments of the flight procedure protection area, the accurate assessment of the flight procedure height limit can be achieved.

[0265] First, import the longitude and latitude information of the obstacles into the system, then through the system, realize the geographic information fusion comparison of the obstacle position and the flight procedure protection area, determine the specific flight procedure protection area where the obstacle is located, and finally, by calling the height limit assessment model of the specific protection area, conduct the assessment and analysis of the obstacle restricted height, and the assessment analysis data and height limit assessment report can be exported. Specific obstacle examples are as follows:

[0266] Import the positions of a set of 29 obstacles (P1 - P29) into the system, such as Figure 5As shown in the figure, the obstacle and the protected area of the RNP APCH VNAV type precision approach flight procedure for Runway 27 of a certain airport are successfully superimposed on the same geographic information system through latitude and longitude information. By comparing the latitude and longitude information of the obstacles with the geographic information of the protected area of the flight procedure, it is found that 13 obstacles (P9 - P14, P23 - P29) are located outside the protected area of the RNP APCH VNAV type precision approach procedure, and 16 obstacles are located inside the protected area of the RNP APCH VNAV type precision approach procedure.

[0267] By comparing the latitude and longitude information of the obstacles within the protected area with the geographic information of each segment protected area of the RNP APCH VNAV type precision approach procedure, it is found that obstacles P1 - P8 are located in the main area of the protected area of the TA to the end point of the missed approach turn segment, obstacles P18 and P19 are located in the main area of the protected area of the IF to the starting point of the FAS surface segment, and obstacles P15 - P17, P20 - P22 are located in the secondary area of the protected area of the IF to the starting point of the FAS surface segment.

[0268] After determining the flight procedure segment and the location within the protected area where the obstacle is located, the height limit assessment model for the corresponding segment protected area location is retrieved, and the flight procedure restricted height of the obstacle is evaluated. The evaluation results are shown in the following table.

[0269]

[0270] The present invention innovatively supplements the missing key information related to control operations and graphics, key height information such as landing criteria and minimum obstacle clearance height in the original ARINC424 data, and creates an ARINC424 terminal area fusion database to support the height limit assessment of flight procedures, providing a data basis for the automatic assessment and analysis of flight procedures at airports across the country.

[0271] Moreover, innovatively starting from the perspective of flight procedure design, first, by supplementing the missing key information related to control operations and graphics in the original ARINC424 data, the flight track based on the flight procedure design principle is restored, and the complete flight procedure protected area is drawn according to the flight track; then, by supplementing the missing key height information such as landing criteria and minimum obstacle clearance height in the original ARINC424 data, the precise restricted height within the protected area of the flight procedure segment is calculated.

[0272] The system has a high degree of automation and high accuracy of the height limit assessment results. The assessment results are completely consistent with the actual situation. By accurately restoring each specific protected area of the flight procedure and formulating height limit rules, a height limit assessment standard model for flight procedures at national transport airports that can be extended is formed, reducing the mapping and calculation errors caused by human factors and improving the accuracy of the flight procedure height limit assessment.

[0273] The above has introduced in detail a height limit evaluation system for terminal area flight procedures based on ARINC424. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. It will be possible to make changes and improvements to the present invention without exceeding the concept and scope defined by the appended claims. In summary, the content of this specification should not be construed as a limitation on the present invention.

Claims

1. A terminal area flight procedure height limit assessment system based on ARINC424, characterized by: The method flow is as follows: Step 1: Decode and analyze the ARINC424 original data, create the ARINC424 terminal area original database, and automatically update it regularly according to the ARINC424 update cycle; Step 2: For the information related to control operation or graphics missing from the original database of the ARINC424 terminal area, a database of key information related to control operation and graphics required for procedure design is prepared; the database of key information related to control operation and graphics includes the airport, the number of the approach procedure, the climb gradient of the departure segment, the climb gradient of the missed approach segment, whether the departure designated altitude turning procedure prohibits turning before the runway liftoff end DER, and whether the approach designated altitude missed approach procedure prohibits turning before the missed approach point MAPt; Step 3: Based on the information related to the height restriction assessment that is missing from the original ARINC424 terminal area database, a flight procedure assessment-related key information database required for the height restriction assessment is created; Step 4: Integrate the ARINC424 terminal area original database, the control operation and graphics related key information database, and the flight procedure evaluation related key information database to create an improved ARINC424 terminal area fusion database; Step 5: Based on the ARINC424 terminal area fusion database, the airport runway is drawn, the runway orientation is checked, the go-around turning radius is calculated, the key position points are determined and corrected, and the flight procedure track is drawn to establish the flight procedure track model; Step 6: Based on the ARINC424 terminal area fusion database, determine the flight technical tolerance C and wind spiral parameters. Before drawing, retrieve the information on whether the approach designated altitude missed approach procedure is prohibited from turning before the missed approach point MAPt in the key information data related to control operation and graphics, and determine the earliest turning point for missed approach. If the information is yes, the boundary connection point in the missed approach turning protection area is the MAPt point; if not, the boundary connection point in the missed approach turning protection area is the FAF point, and establish the flight procedure protection area model according to the segment protection area rules; Step 7: Establish a flight procedure height limit assessment model based on the ARINC424 terminal area fusion database; The method for establishing the flight procedure height restriction assessment model is as follows: A. Determine the height limit assessment rules for the secondary area; B. Establish a calculation model for the altitude limit assessment of each segment of the RNP APCH LNAV non-precision approach procedure; C. Establish a calculation model for the altitude limit assessment of each segment of the main area of ​​RNP APCH VNAV precision approach procedures; Step 8: Import the longitude and latitude information of the obstacle into the system, integrate and compare the obstacle location with the geographic information of the flight procedure protection zone, determine the flight procedure specific protection zone where the obstacle is located, and finally evaluate and analyze the obstacle restriction height by calling the height limit assessment model of the specific protection zone to complete the flight procedure height limit assessment.

2. The terminal area flight procedure height restriction assessment system based on ARINC424 according to claim 1, characterized in that: The ARINC424 terminal area original database refers to the field requirements of ARINC424 data to produce the header data of various data files, and is in an Excel data format that can be viewed, edited, read, and called, including various data files of airports, runways, navigation stations, waypoints, and flight procedures. Among them, airport data includes airport code, airport name, airport reference point coordinates, airport elevation, magnetic variation, transition altitude and transition altitude layer; runway data includes the airport, runway number, runway length and width, runway magnetic bearing, latitude and longitude coordinates and elevation of runway entrance point, and the maximum aircraft type that can be used; navigation station data includes navigation station code, navigation station name, airport, navigation station type, navigation station longitude and latitude, frequency and call sign, magnetic variation, and elevation of the location; waypoint data includes waypoint code, waypoint name, airport, waypoint type, longitude and latitude and magnetic variation; flight procedure data includes path termination code, positioning point identification, whether to fly over, magnetic heading, turn instructions, altitude and altitude type, speed limit, vertical path angle VPA / flyover runway threshold height TCH, navigation performance, airport, arrival, departure and approach procedure numbers, and waiting time.

3. The terminal area flight procedure height restriction assessment system based on ARINC424 according to claim 1 is characterized in that: The control operation and graphics-related key information database adopts an Excel data format that can be viewed, edited, read and called, including the airport, the numbers of the entry and departure procedures and the approach procedures, the climb gradient of the departure segment, the climb gradient of the missed approach segment, whether the departure designated altitude turning procedure prohibits turning before the runway liftoff end DER, and whether the approach designated altitude missed approach procedure prohibits turning before the missed approach point MAPt.

4. The terminal area flight procedure height restriction assessment system based on ARINC424 according to claim 1 is characterized in that: The flight procedure evaluation-related key information database adopts an Excel data format that can be viewed, edited, read and called, including the airport, the numbers of the entry and departure procedures and the approach procedures, a single minimum obstacle clearance altitude when there is no step-down fix point in the intermediate segment, multiple minimum obstacle clearance altitudes when there is a step-down fix point in the intermediate segment, multiple minimum obstacle clearance altitudes when there is a step-down fix point in the last segment, decision altitude / height, minimum descent altitude / height, and minimum temperature limit.

5. The terminal area flight procedure height restriction assessment system based on ARINC424 according to claim 1 is characterized in that: In step 5, the method for establishing the flight program trajectory model is: A. Airport runway drawing: extract the latitude and longitude coordinates of the runway entry point and the runway length from the ARINC424 terminal area original database - runway data, and draw the original runway of the airport; B. Carry out multi-angle cross-check on the runway orientation; C. Extract and determine the key location points required for track drawing from the ARINC424 terminal area fusion database; D. Correct key position points; E. Read data from the ARINC424 terminal area fusion database to calculate the missed approach turning radius. The calculation formula is as follows: The missed approach turning radius calculation of the RNP APCH approach procedure is related to the indicated airspeed IAS and the turning point altitude H. The indicated airspeed IAS is determined according to the maximum speed for the missed approach turn determined by the aircraft type or the flight procedure design speed limit; The altitude H of the turning point for a fixed-altitude turn can be read in the flight program data; Fixed-point turn Altitude of turning point H = distance from TF to MAPt * 0.1 + decision altitude The distance from TF to MAPt can be calculated from the longitude and latitude of TF and MAPt read from the waypoint data; the decision altitude can be extracted from the key information database related to flight procedure evaluation; F. According to the track termination code, connect the key position points IF, IFSDF, FAF, SDF, MAPt and TA in sequence to draw the final approach track and the missed approach straight segment track. Draw the missed approach turning arc according to the turning radius r, and make the turning arc tangent to the end point TA of the missed approach straight segment track to form a missed approach turning arc track. Draw the track from the turning arc to the turning end point according to the tangent of the turning arc and the turning arc. Draw the flight procedure track and establish the flight procedure track model.

6. The terminal area flight procedure height restriction assessment system based on ARINC424 according to claim 5 is characterized in that: In step B, the runway orientation is cross-checked in the following three ways: a. Use the true azimuth GEO to calibrate, extract the runway magnetic azimuth MAG from the ARINC424 terminal area original database - runway data, and extract the magnetic variation VAR from the ARINC424 terminal area original database - airport data. The calibration formula is: GEO=MAG+VAR b. Use the longitude and latitude coordinates of the runway entry points at both ends to check, extract the longitude and latitude coordinates THR1 and THR2 of the runway entry points at both ends from the ARINC424 terminal area original database-runway data, first convert the longitude and latitude formats from degree, minute, and second format to decimal degree format, and then use the following algorithm to calculate the angle of the runway entry point. The azimuth calculation formula of THR1 is as follows: Angle of runway entry point 1 in, The same logic can be used to calculate the azimuth angle THR2_GEO of THR2. The azimuth angles of the runways at both ends can be used to calculate the average value to obtain the angle GEO that best fits the actual runway azimuth: GEO=(THR1_GEO+THR2_GEO+180) / 2 c. Using image layers Extract the longitude and latitude coordinates of the runway entry points at both ends from the ARINC424 terminal area original database - runway data, and draw the runway entry points at both ends in the geographic information system based on the longitude and latitude. Then connect the entry points at both ends with line segments to construct the runway entity. Fit the constructed entity runway with the actual runway in the image map, calculate the azimuth error, and make adjustments based on the runway in the image map. When cross-checking the runway orientation, firstly average the runway orientations calculated by methods a and b to obtain the first optimized runway orientation GEO1; then draw the runway according to orientation GEO1, and compare and fit the drawn runway with the runway on the image layer. If the deviation is less than 0.01°, GEO1 is determined to be the optimal runway orientation. Otherwise, the runway orientation GEO1 needs to be rotated and adjusted according to the runway orientation on the image map.

7. The terminal area flight procedure height restriction assessment system based on ARINC424 according to claim 5 is characterized in that: In step D, the method for correcting the key position points is to verify the key position points located on the final approach and missed approach straight segments based on the verified runway orientation. First, a ray is drawn from both ends of the runway in the opposite direction of the runway. If the position of the waypoint determined by the longitude and latitude is on the ray, the position of the waypoint does not need to be adjusted; if the position of the waypoint determined by the longitude and latitude is on both sides of the ray, the waypoint position is moved to the position of the foot of the ray closest to the ray. This position is the key position point of the final five sides or one side for drawing the flight procedure track and the protection area.

8. The terminal area flight procedure altitude restriction assessment system based on ARINC424 according to claim 1, characterized in that: In step 6, the flight technical tolerance C and wind spiral parameters are determined. A. Determine the flight technical tolerance C; The flight technical tolerance C of the missed approach turning point is calculated as follows: C=[171233×(303-0.006496H) 0.5 ÷(288-0.006496H) 2.628 ·IAS+15.56]×6 Among them, the variables are indicated airspeed IAS and go-around turn altitude H; B. Determine wind spiral parameters The wind impact value E of the aircraft when it turns at angle θ θ , can be calculated based on the indicated airspeed IAS and the go-around turn altitude H. The calculation formula is as follows 9. The terminal area flight procedure altitude restriction assessment system based on ARINC424 according to claim 8, characterized in that: In step 6, the rules for drawing the flight protection zone are as follows: a. Rules for drawing protection zones for final approach and missed approach straight lines The half-width of the protection zone at IF is a fixed value of 2.5NM, and the half-width of the protection zone at FAF is a fixed value of 1.45NM. At FAF, the expansion line is connected to 2.5NM at an angle of 30°, and is retracted to 0.95NM at an angle of 30°, maintaining 0.95NM to 0.24NM before the runway entrance, and then expanding to 2NM at an angle of 15°, maintaining 2NM to TA. One quarter of the half-width of the protection zone on both sides of the nominal track is the main zone, and the outer side is the secondary zone; b. Rules for drawing the flying turn protection area If the procedure prohibits turning before MAPt, the earliest turning point of the fixed-altitude missed approach turn is MAPt; if the procedure allows turning before MAPt, the earliest turning point of the fixed-altitude missed approach turn is FAF; the latest turning point of the fixed-altitude missed approach turn is TA+C tolerance; the wind spiral is drawn from one-fourth of the width of the protection zone on both sides of the latest turning point, and the two wind spirals are connected by a common tangent line; the upper side of the latest turning track main area protection zone boundary is connected by the tangent line of the wind spiral outer boundary at the end point of the missed approach turn, and expands 15° outward to be tangent to the main area boundary of the protection zone at the end point of the missed approach turn; the upper side The boundary of the protection zone of the secondary zone of the latest turning track is obtained by translating the boundary of the main zone protection zone by one-fourth of the width of the protection zone; the main zone boundary of the protection zone of the earliest turning track on the lower side is connected to the main zone boundary of the protection zone at the end point of the missed approach turn and 0.24NM in front of FAF / MAPt, and expands 15° outward to be tangent to the main zone boundary of the protection zone at the end point of the missed approach turn; the secondary zone boundary of the protection zone of the earliest turning track on the lower side is the main zone boundary translated to the secondary zone boundary of the protection zone at 0.24NM in front of FAF / MAPt, and is tangent to the secondary zone boundary of the protection zone at the end point of the missed approach turn.

10. The terminal area flight procedure altitude restriction assessment system based on ARINC424 according to claim 1, characterized in that: In step 7, the altitude limit evaluation calculation model of each segment of the RNP APCH LNAV non-precision approach procedure mainly performs the following altitude limit evaluation calculations: SOC position determination of the initial climb point for missed approach RNP APCH LNAV non-precision approach procedure SOC distance from MAPt: Main area altitude limit from IF to IFSDF: H=MOCA IF至IFSDF航段 -POWER 中间 Main area altitude limit for IFSDF to FAF segment: H=MOCA IFSDF至FAF航段 -POWER 中间 Main area altitude limit for FAF to SDF segment: H=MOCA FAF至SDF航段 -POWER 最后 Main area altitude restrictions for the SDF to SOC1 segment: H=MDA-MOC 最后 SOC1 to SOC main area altitude limit: H=MDA-MOC 递减 Main area altitude limit from SOC to TA: H=MDA+L 至SOC的距离 Go-around gradient-MOC 复飞直线段 The main area altitude limit from TA to the end point of the missed approach turn: H=TA+L 障碍物至直线段保护区边界的最近距离 Go-around gradient-MOC 复飞转弯区 Among them, SOC1 is the minimum obstacle clearance margin determined by MOC 最后 Descending to MOC 复飞直线段 The starting position of SOC1 is in front of SOC, and the distance between SOC1 and SOC = (MOC 最后 -MOC 复飞直线段 ) / go-around gradient; minimum obstacle clearance altitude MOCA IF至IFSDF航段 、MOCA IFSDF至FAF航段 、MOCA FAF至SDF航段 The minimum descent altitude (MDA) can be read from the flight procedure evaluation related key information database; the missed approach gradient can be read from the control operation and graphics related key information database; MOC 中间 =150m, MOC 最后 =75m, MOC 复飞直线段 =30m, MOC 复飞转弯区 =50m, MOC 递减 It decreases from 75m to 30m; the positioning tolerance of key positioning points is considered in each flight segment; In step 7, the RNPAPCH VNAV precision approach procedure main area height limit evaluation calculation model for each segment of the RNPAPCH VNAV precision approach procedure is composed of the final approach surface, the horizontal surface and the missed approach surface, and the following height limit evaluation calculation is mainly performed: a. Low temperature correction Δh=(C L / 0.0065+H 机场标高 -2307.7)·ln[1-h FAF / (44330.8-H 入口 ] b. Slope of FAS surface: tanα=(h FAF -Δh-Hi)·tanVPA / (h FAF -Hi) c. Starting point of FAS surface: d. Determine the SOC position of the initial climb point for missed approach RNP APCH VNAV precision approach procedure SOC distance from the runway threshold: SOC VNAV =X Z +(DH-HL) / tanVPA The main area height limit from IF to FAS surface starting point segment: Considering the RNP APCH VNAV landing standard, the main area height limit from IF to the FAS surface starting point is: H=min(MOCA IF至IFSDF航段 -MOC 中间 ,MOCA IFSDF至FAF航段 -MOC 中间 ,max(L FAS ·tan(α)+H 入口 ,YES -HL)) Height limit of main area of ​​G surface: Considering the RNP APCH VNAV landing standard, the height limit of the main area of ​​the G plane is: H=DA-HL Z-plane main area height limit: Considering the RNP APCH VNAV landing standard, the Z plane main area height limit is: H=max(L Z Go-around gradient + H 入口 , DA-HL) The main area altitude limit from TA to the end point of the missed approach turn: H=TA+L 障碍物至直线段保护区边界的最近距离 Go-around gradient-MOC 复飞转弯区 Among them, L FAS is the distance from the starting point of the FAS surface; L Z is the distance from the starting point of the Z plane; Hi is determined according to the height of the FAS plane at the height limit assessment position. When the height is less than 5000ft, Hi=75; when the height is between 5000-10000ft, Hi=105; when the height is greater than 10000ft, Hi=120; Xz is the starting position of the Z plane, which is -1400m for Class D aircraft. When the airport elevation is higher than 900m or the glide path angle is greater than 3.2°, it needs to be corrected according to regulations; HL is the gradient loss, which is 49m for Class D aircraft. When the airport elevation is higher than 900m or the glide path angle is greater than 3.2°, it needs to be corrected according to regulations; When the glide path angle is greater than 3.2°, it needs to be corrected according to regulations; the airport elevation can be extracted from the ARINC424 terminal area original database-airport data; the runway threshold height can be extracted from the ARINC424 terminal area original database-runway data; the vertical path angle VPA, the runway threshold height TCH, and the FAF height can be extracted from the ARINC424 terminal area original database-flight procedure data; the missed approach gradient can be read from the control operation and graphics related key information database; the decision altitude DA, decision height DH, and the minimum temperature limit C L It can be extracted from the key information database related to flight procedure evaluation; for missed approach obstacles that penetrate the FAS surface, G surface or Z surface, the equivalent approach obstacle height is evaluated and analyzed for operational standards.

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