Method for constructing a planned path based on a standard navigation database

Abstract

The application provides a planned path construction method based on a standard navigation database, comprising the following steps: step S1: judging whether it is a starting flight section, if not, executing step S2; if yes, directly taking the target flight section data as the planned path data, and executing step S4; step S2: preprocessing and solving the path end point of the target flight section; step S3: solving the planned path; step S4: judging whether it is a terminal flight section, if not, returning to step S1 for cyclic iteration; if yes, combining all the unified output arrays into complete planned path data for output. The application can solve the problems of precision loss caused by low correlation between the front and back flight sections, incomplete understanding of the flight intention caused by not fully utilizing the navigation data defined in the ARINC 424 specification, and low reliability and poor practicability of the planned path solving data of the FMS flight planning function block when solving the overall planned flight path.

Description

Technical Field

[0001] This invention relates to the field of civil aviation technology, and in particular to a method for constructing planned routes based on a standard navigation database. Background Technology

[0002] Planned path calculation is the core algorithm module of the FMS flight plan, an essential component for large civil aircraft in performing flight tasks such as path planning, performance prediction, and flight guidance. As shown in Figure 1, the FMS Horizontal Navigation Vehicle (LNAV) control system's flight plan function block is primarily responsible for tasks such as flight plan editing, special plan management, status management, and planned path calculation. Important flight tasks such as aircraft performance data prediction, flight technical error calculation, and horizontal guidance control all require calculations using reference path data from the planned path calculation. The reliability and accuracy of the planned path calculation data support the safety of the aircraft during automatic flight.

[0003] The planned route calculation is mainly responsible for analyzing and calculating the 23 path-termination segment types (AF, CA, CD, CF, CI, CR, DF, FA, FC, FD, FM, HA, HF, HM, IF, PI, RF, TF, VA, VD, VI, VM, VR) and the transition methods between different segments as defined in ARINC 424. Based on the flight plan formulated by the crew and the relevant data in the corresponding navigation database, the planned data of each segment path and the transition path between segments of the plan are analyzed and calculated to obtain the planned route data of the aircraft from the departure airport to the destination airport and the go-around, which meets the specifications of ARINC 424 and ARINC 661.

[0004] Currently, the research and development of design schemes or products related to planned route calculation mainly focuses on two directions: First, research on overall planned route calculation methods, which uses the position coordinates of the planned route to plan a rough flight path from takeoff to landing in a fuzzy, estimated manner. This method is suitable for cost estimation and control of ground flight plans, but lacks precision and cannot describe the aircraft's flight intent in detail. Second, research on individual segments or transition methods between segments within the planned path, which performs detailed calculations of the aircraft's planned path for a certain interval. However, this does not consider different transition combinations of preceding and following segments based on standard navigation database programs, leading to discrepancies between the calculated interval planned path data and the overall aircraft's planned flight intent. Furthermore, different segment types contain different field types in the navigation database, and existing planned route calculation methods do not utilize the field data defined in the navigation database for calculation, which is detrimental to engineering practice research.

[0005] In conclusion, if a method for constructing a planned flight path based on a standard navigation database can be provided, which can solve the problems of low correlation between segments when the FMS flight planning function block calculates the overall planned flight path, resulting in the loss of accuracy, the inability to fully understand flight intentions due to the lack of full utilization of navigation data defined by the ARINC 424 specification, and the low reliability and poor usability of the planned flight path calculation data, it will have great market value. Summary of the Invention

[0006] To address the problems in the prior art, this invention provides a planned path construction method based on a standard navigation database. This method can solve problems such as the loss of accuracy caused by the low correlation between segments when the FMS flight plan function block calculates the overall planned flight path, the inability to fully understand flight intentions due to the failure to fully utilize the navigation data defined by the ARINC 424 specification, and the low reliability and poor usability of the planned path calculation data.

[0007] To achieve the above objectives, a planned path construction method based on a standard navigation database includes the following steps: Step S1: Determine if it is the starting segment. If not, proceed to step S2. If yes, directly use the target segment data as the planned route data and proceed to step S4. Step S2: Use the data in the standard navigation database as input data for the planned path construction. Based on the combination of the path-terminal segment type of the target segment and its preceding and following segments and the corresponding data defined in the standard navigation database, preprocess and calculate the path termination point of the target segment. Step S21: Determine the segment type of the target segment; Step S22: If the target segment is CA, VA, FA, CD, VD, CR, VR, CI, VI or PI, calculate the location of the end point of the target segment; Step S221: Use the outbound heading of the previous segment of the target segment as the inbound heading of the target segment; if the target segment is CA or VA, proceed to step S222; if the target segment is CR or VR, proceed to step S223; if the target segment is CI, VI, or PI, proceed to step S224; if the target segment is CD or VD, proceed to step S225; if the target segment is FA, proceed to step S226. Step S222: Calculate the climb angle using the predicted airspeed and ground speed, calculate the altitude difference between the predicted altitude of the previous segment and the target altitude of the target segment, and calculate the horizontal distance of the target segment using trigonometric functions; calculate the transition angle, transition radius, and turning amount of the transition radius of the target segment using the inbound and outbound headings of the target segment, and directly execute step S227; Step S223: Calculate the reference point position of the target segment using the departure heading and the end point position of the previous segment. Combine this with the recommended navigation beacon positions in the standard navigation database to calculate the azimuth and distance from the reference point position to the recommended navigation beacon. Calculate the scalar angles of the geometric shape formed by the reference point, recommended navigation beacon, and end point of the target segment using the departure heading and the azimuth of the end point of the target segment at the recommended navigation beacon, as defined in the standard navigation database. Then proceed to step S225. Step S224: Calculate the reference point of the target segment based on the type and information of the next segment of the target segment: If the next segment of the target segment is AF, directly calculate the end point position of the target segment using the specified arc radius and heading of the AF segment; if the next segment of the target segment is IF, skip the IF segment and calculate based on the next-next segment type of the target segment; if the next segment of the target segment is not AF or IF, use the departure heading, overflight marker, end point position of the previous segment of the target segment, as well as the turning direction and target heading of the current target segment to gradually calculate the change angle, transition arc radius, turning amount of the transition arc, and the position of the first reference point of the target segment, and then combine the departure heading and end point position of the next segment of the target segment to calculate the position of the second reference point; Step S225: Calculate the path distance of the target flight segment using a sine function: If the target segment is CD or VD, calculate the change angle from the previous segment to the target segment based on the departure heading of the previous segment and the departure heading of the target segment. Combine this with the target segment reference path length in the standard navigation database and use a sine function to calculate the path distance of the target segment. If the target segment is CR or VR, calculate the path distance of the target segment using the scalar angles of the geometric shape formed by the reference point, recommended navigation beacon, and termination point of the target segment calculated in step S223, combined with the target segment reference path length in the standard navigation database. If the target segment is CI, VI, or PI, calculate the path distance of the target segment using a sine function based on the first reference point position and the second reference point position calculated in step S224, combined with the target segment reference path length in the standard navigation database, and then proceed to step S227. Step S226: Based on the type of the previous segment of the target segment, determine whether the location of the fixed positioning point of the target segment is needed: If the previous segment of the target segment is of type xF (i.e., any segment type with a fixed endpoint), then the endpoint of the previous segment must be the starting point of the target segment. In this case, the horizontal distance required to reach the specified altitude, the transition angle, the radius of the transition arc, and the turning amount of the transition arc are calculated based on the overflight markers and departure heading defined in the previous segment. If the previous segment of the target segment is not of type xF (i.e., any segment type with a fixed endpoint), the climb angle is calculated using the predicted airspeed and ground speed, the altitude difference between the predicted altitude of the previous segment and the target altitude of the target segment is calculated, and the horizontal distance of the target segment is calculated using trigonometric functions. The transition angle, the radius of the transition arc, and the turning amount of the transition arc are calculated using the inbound and outbound headings of the target segment. Step S227: If the target segment is CA or VA, use the calculation result of step S222 and the outbound heading of the target segment as defined in the standard navigation database to calculate the path termination point of the target segment; if the target segment is CD, VD, CR, VR, CI, VI, or PI, use the calculation result of step S225 and the outbound heading of the target segment as defined in the standard navigation database to calculate the path termination point of the target segment; if the target segment is FA, use the calculation result of step S226 and the outbound heading of the target segment as defined in the standard navigation database to calculate the path termination point of the target segment. Step S23: If the target segment is CF, calculate the reference point position of the target segment; if the target segment is FC or FD, calculate the end point position of the target segment. Step S24: If the target route is AF, DF, FM, HA, HF, HM, IF, RF, TF, or VM, then no preprocessing calculation is performed, and the planned route is calculated directly. Step S3: Based on the preprocessed solution information, the corresponding data in the standard navigation database, and the combination of the target segment and subsequent segments, calculate the target segment path data and the subsequent transition segment path data, and perform the planned path solution; Step S4: Determine if it is a terminated flight segment. If not, return to step S1 for loop iteration; if yes, combine all unified output arrays into complete planned path data and output it.

[0008] In the preferred technical solution, the specific process of step S3 is as follows: Step S31: Determine the segment type of the target segment; Step S32: Calculate the path of the segment itself according to the segment type of different target segments; Step S33: Determine the segment type of the next segment after the target segment; Step S34: Calculate the transition path for the next segment based on the segment type of the next segment after the target segment.

[0009] In the preferred technical solution, the detailed process of calculating the route for the flight segment itself in step S32 is as follows: Step S321: If the target segment is AF or RF, use the segment data defined in the standard navigation database for the target segment, combined with the path termination point of the previous segment and the transition to the next segment, to calculate the entry tangent, turning direction, radius of arc, and central angle data of the target segment. Step S322: If the target segment is CA or CD or CF or CI or CR or DF or FA or FC or FD or TF or VA or VD or VI or VR, use the longitude and latitude information stored in the standard navigation database or calculated through preprocessing as the output data of the corresponding target segment. Step S323: If the target segment is IF, FM, or VM, where, if the IF target segment is the starting segment of the planned path, the IF segment is omitted and no processing is performed; if the IF target segment is not the starting segment and connects to the CF segment, the IF segment is omitted and no processing is performed; if the IF target segment is not the starting segment and connects to the TF segment, the TF segment is converted to a CF segment and processed as a CF segment, the waypoint of the IF target segment is used as the reference point of the converted CF segment, and the FM or VM segment is processed with a fixed heading and a 640NM line segment starting from the location point, and the longitude and latitude of the location point are used as the output data of the corresponding target segment. Step S324: If the target segment is HA, HF, or HM, calculate the turning radius using the corresponding waiting time or waiting distance defined in the standard navigation database, combined with the current airspeed predicted by the flight management system or the air traffic control speed, solve the position data of each line segment and arc of the waiting procedure, and use the longitude, latitude, arc radius, arc turning direction, arc central angle, and arc entry tangent of the combined data of multiple path termination points and arcs as the output data of the corresponding target segment; Step S325: If the target segment is PI, use the outbound heading information of the previous segment of the PI target segment, and combine it with the specified parameters of the PI target segment in the standard navigation database to calculate an array of multiple path termination points and arcs as the output data of the corresponding target segment.

[0010] In the preferred technical solution, the detailed process of calculating the transition path for the flight segment in step S34 is as follows: Step S341: If the next segment of the target segment is HA, HF, or HM, use the outbound heading of the target segment, combined with the outbound heading and turning direction of the corresponding HA, HF, or HM defined in the standard navigation database, to calculate the transition to the next segment. Step S342: If the next segment of the target segment is CA, CD, CI, CR, DF, PI, VA, VD, VI, or VR, then the transition method of switching to the specified heading after overflight is always adopted. Step S343: If the next segment of the target segment is CF, FC, FD, or FA, calculate the transition method to the next segment based on the path termination point of the target segment and the reference positioning point of the next segment. Step S344: If the next segment type of the target segment is AF or RF, then according to the overflight marker of the target segment, the center position and radius of the AF or RF segment, the transition path from the target segment to the next segment is calculated by using a side-cut transition or a transition method of cutting to the designated route after overflight. Step S345: If the next segment type of the target segment is FM, IF, TF or VM, then the transition method of side-cutting or cutting to the designated route after the overflight is adopted according to the overflight identifier of the target segment.

[0011] In the preferred technical solution, the detailed steps for transitioning the solution to the next flight segment in step S341 are as follows: The airspace is divided into four sectors using the straight line where the departure course of the next segment is located and the straight line at a 70-degree angle to it. The sector and entry method for the next segment are calculated using the departure course of the target segment. The transition arc radius is calculated using a specified airspeed, and a series of path termination point positions and arc data are calculated and used as the output data for the corresponding segment transition path solution.

[0012] In the preferred technical solution, the specific process of step S342, which involves a transition from overflight to a designated heading, is as follows: The outbound heading of the DF segment is calculated using a sine function in the preprocessing step, while the CA, CD, CI, CR, PI, VA, VD, VI, or VR segments are defined from the standard navigation database. By using the departure heading, target airspeed, and predicted wind of the target segment, as well as the departure heading of the next segment of the target segment, the central angle, turning direction, turning radius, and inbound tangent of the transition arc are calculated and used as the output data for the corresponding segment transition path calculation.

[0013] In the preferred technical solution, the specific process of step S343 is as follows: Determine whether the path termination point of the target segment is the same as the reference positioning point of the next segment. If they are the same, then based on the overflight marker of the target segment, use either a side-cut or overflight-to-the-designated-road transition method to calculate the central angle, turning direction, turning radius, and inbound tangent of the transition arc, and use this as the output data for the corresponding segment's transition path calculation. If the path termination point of the target segment is not the same as the reference positioning point of the next segment, then based on the overflight marker of the target segment, use either a side-cut or overflight-to-the-designated-road transition method to fly to the reference positioning point of the next segment, and then use a side-cut transition method to reach the next segment of the target segment. Finally, calculate the central angle, turning direction, turning radius, and inbound tangent of the transition arc, and use this as the output data for the corresponding segment's transition path calculation.

[0014] In the preferred technical solution, the specific process of step S344 is as follows: Both AF and RF segments are circular segments, and their arc data comes from different fields in the standard navigation database. Specifically: the center position of the arc in the AF segment is the recommended navigation beacon position for this segment as defined by the standard navigation database, and the radius of the arc in the AF segment is the distance from the recommended navigation beacon to the end point of the AF segment as defined by the standard navigation database; the center position of the arc in the RF segment is the center positioning point position as defined by the standard navigation database, and the radius of the arc in the RF segment is the radius as defined by the standard navigation database. Based on the end point of the target segment, the departure heading of the target segment, the center position of the arc of the next segment, and the radius of the arc of the next segment, calculate the tangent point between the target segment and the arc of the next segment via a side transition or overflight transition. Use this tangent point to calculate the trajectory change angle of the side transition or overflight transition. Finally, combine the departure heading of the target segment, the target airspeed, and the predicted wind to calculate the central angle, turning direction, turning radius, and entry tangent of the transition arc, and use this as the output data for the corresponding segment transition path calculation. The system determines whether the target segment overflight marker is true. If the marker is false, a lateral transition method is used to calculate the transition path. Based on the tangent point position, tangent heading, and the target segment's departure heading, termination point position, target airspeed, and predicted wind, the central angle, turning direction, turning radius, and inbound tangent of the transition arc are calculated and used as the output data for the corresponding segment's transition path calculation. If the target segment overflight marker is true, a transition method of tackling to the designated route after overflight is used to calculate the transition path. This transition path includes two arc segments and a line segment between them. Based on the target segment termination point position, target airspeed, predicted wind, target segment departure heading, and tangent heading tangent to the next segment, the specific data for the arc segment, line segment, and arc segment are calculated, including the radius, starting position, and arc length of the arc segment, as well as the starting and ending points of the line segment, thus obtaining the output data for the corresponding segment's transition path calculation. The specific process of step S345 is as follows: If the next segment of the target segment is an IF segment, skip that segment and process it according to the segment type of the next segment of the IF segment; For each target segment, if the next segment is FM, TF, or VM, determine if the target segment overflight indicator is true. If the target segment overflight indicator is not true, calculate the transition path using a lateral transition method. Based on the departure heading of the target segment and the change-of-course angle of the transition section at the departure heading of the next segment, combined with the target segment termination point position, target airspeed, and predicted wind, calculate the central angle, turning direction, turning radius, and inbound tangent of the transition arc, and use this as the output data for the corresponding segment transition path calculation; if If the target segment overflight indicator is true, the transition path is calculated using a transition method that switches to the designated route after the overflight. This transition path includes two circular arc segments and a line segment between the two circular arc segments. Based on the target segment termination point position, target airspeed and predicted wind, the target segment departure heading and the next segment departure heading, the specific data of the circular arc segments, line segments, and circular arc segments are calculated, including the radius, starting position, and arc length of the circular arc segments, as well as the starting and ending point positions of the line segments, thus obtaining the output data of the corresponding segment transition path solution.

[0015] Compared with existing technologies, the advantages of the planned path construction method based on a standard navigation database in this invention are: This invention utilizes data specified in the standard navigation database to ensure the reliability and applicability of the planned path construction method and enhance engineering feasibility.

[0016] For different combinations of planned route segment types, corresponding calculation methods for the segments themselves and transition segments are adopted so that the output data obtained can fully reflect the flight intent of the planned route.

[0017] 3. The path construction method covers 23 flight segment types defined in the terminal area, encompasses the flight intent of all planned paths, and meets the relevant path regulations in the civil aviation standard documents. This allows for the expansion of the scenario envelope for path calculation of various flight intents while ensuring the accuracy of the path construction method in solving various flight intents.

[0018] 4. This invention can solve the problems of low accuracy loss caused by the low correlation between segments when the FMS flight plan function block calculates the overall planned flight path, incomplete understanding of flight intentions due to the failure to fully utilize the navigation data defined by ARINC 424, and low reliability and poor usability of the planned path calculation data.

[0019] In summary, this invention utilizes segment data defined in a standard navigation database as input to the planned path construction method, significantly improving its engineering feasibility and ensuring the reliability of the constructed data. Simultaneously, the planned path construction method considers relevant civil aviation regulations, expanding its application scenarios and the actual calculated operational envelope. Furthermore, the path calculation method is divided into preprocessing and path calculation sub-steps, where each sub-step algorithm can be selectively iterated according to different scenarios. This enables path calculation and planned data construction for 23 terminal area path-termination segments and their various combinations, optimizing computational load and improving operational efficiency while fully reflecting the planned flight intent. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the system architecture for a planned path construction method based on a standard navigation database, which can be applied to this invention.

[0021] Figure 2 This is a schematic diagram of the overall process of a planned path construction method based on a standard navigation database according to the present invention.

[0022] Figure 3 This is a schematic diagram of the preprocessing calculation process of the present invention.

[0023] Figure 4 This is a schematic diagram of the planned path calculation process of the present invention. Detailed Implementation

[0024] The relevant terms used in this invention are explained as follows: ARINC: Aeronautical Radio, Inc., an aviation radio communications company; FMS: Flight Management System; NDB: Navigation Database; DME: Distance Measuring Equipment; VOR: VHF Omni-directional Range; IF: Initial Fix, the initial positioning point; TF: Track to Fix; from the track to the fix point. CF: Course to Fix; from the channel to the fix point. DF: Direct to Fix; flying directly to the target location. FA: Track from Fix to Altitude; FC: Track from Fix to Distance, from the fix point to the specified distance; FD: Track from Fix to DME Distance, from the fix point to a specified distance on the DME station; FM: From Fix to Manual Termination; CA: Course to Altitude; CD: Course to DME Distance, the designated distance from the waterway to the DME station; CI: Course to Intercept; from the course to the point of interception of the next leg of the journey. CR: Course to VOR Radial, the point where the waterway intersects with the radial line specified by VOR; RF: Constant Radius Arc to Fix, from a fixed radius arc to the fixing point; AF: Arc to Fix, from the arc to the fixing point; VA: Heading to Altitude; VD: Heading to DME Distance; VI: Heading to Intercept; VM: Heading to Manual Termination; VR: Heading to VOR Radial, from the heading to the intersection of the radial lines specified by VOR; PI: Procedure Turn to Intercept; HA: Holding to Altitude; from waiting to hover to a designated altitude. HF: Holding to Fix, indicating the process of hovering to the designated location. HM: Holding to Manual Termination.

[0025] like Figures 1 to 4 As shown, a planned path construction method based on a standard navigation database is proposed. This invention utilizes the data specified in the standard navigation database defined in the ARINC 424 (NAVIGATION SYSTEMS DATA BASE) file. Based on the path planning rules defined in the file, and considering the flight intentions and the preceding and following transitions of 23 path-termination segment types, a planned path construction method is designed. The path planning device constructed according to this method can construct and display planned paths for set flight plans and tasks.

[0026] The specific implementation technical solution is as follows: As shown in Figure 2, the planned path construction method uses the specified data of the standard navigation database as the supporting input data of the technical solution of this invention. According to the combination of the path-terminal segment type of the target segment and its preceding and following segments and the corresponding database definition data, the segment data of the target segment is preprocessed and calculated using the corresponding algorithm. According to the preprocessed and calculated information, the database data, and the combination of the target segment and the subsequent segment, the corresponding path calculation algorithm is used to calculate the path data of the target segment and the path data of the subsequent transition segment. The process is iterated in a loop, and finally the solution is a unified output array of the path termination point & arc combination mode, which is combined into complete planned path data.

[0027] The planned path construction method of the present invention mainly includes two basic algorithm steps: a preprocessing step and a path calculation step.

[0028] Figure 3 shows a flowchart of the preprocessing algorithm. For target segments of 23 segment types where the navigation database does not define the path termination point or requires additional reference point positions (to assist in path calculation), preprocessing is performed to facilitate subsequent path calculation. The preprocessing algorithm utilizes the different types of preceding and following segments and corresponding existing data to calculate the path termination point position and the required reference point positions for the target segment. Specific implementation plans include: The "Segment Type Preprocessing" step is used to preprocess specific segment types; the "Target Segment Type Determination" step is used to determine the target segment type; the steps "(Target Segment: CA / VA)" and "(Target Segment: FA)" represent the algorithm flow for target segments CA / VA, "(Target Segment: CD / VD)" and "(Target Segment: CR / VR)" represent the algorithm flow for target segments CR / VR, "(Target Segment: CI / VI / PI)" represent the algorithm flow for target segments CI / VI / PI, "(Target Segment: CF / FC / FD)" represent the algorithm flow for target segments CF / FC / FD, and "(Target Segment: AF / DF / FM / HA / HF / HM / RF / IF / VM / TF)" indicate that the data remains unchanged according to the standard navigation database definition. The algorithms corresponding to the above steps mainly target the path termination in the 23 segment types. For flight segment types where the endpoint or reference positioning point is unknown, the sub-algorithm steps used are: step (calculate the departure heading of the previous flight segment based on the type and information of the previous flight segment), step (obtain the path distance of the target flight segment), step (keeping the standard navigation database definition data unchanged), step (considering the FIX point position of the target flight segment), step (calculate the change angle from the previous flight segment to the target flight segment), step (construct the geometric angle), step (calculate the reference point position from the next flight segment information), step (calculate the change angle and turning amount from the previous flight segment to the target flight segment; calculate the path distance of the target flight segment), step (calculate the path distance of the target flight segment using a sine function), step (calculate the path termination point position of the target flight segment using the flight intention of the target flight segment), and step (calculate the reference point position (CF) or path termination point position (FC / FD) of the target flight segment). This results in a preprocessed and solved flight segment data array in step (the preprocessed navigation database flight segment data array).

[0029] Step (Segment Type Preprocessing): When the IF segment is not the starting segment and connects to the TF segment, the IF segment needs to be deleted and the TF segment needs to be changed to the CF segment. The distance between the path termination points of the IF segment and the TF segment is calculated as the path distance of the CF segment, and the heading from the IF segment to the TF segment is calculated as the departure heading of the CF segment.

[0030] Step (Calculate the departure heading of the previous segment based on the type and information of the previous segment of the target segment): For the previous segment (AF, RF, DF, TF) of the target segment, if the departure heading is not defined in the standard navigation database, calculate the departure heading of the previous segment based on the segment type of the previous segment and the data defined in the standard navigation database. If the previous segment is an AF segment, the outbound heading of the AF segment is calculated using the positioning point specified in the navigation database (the positioning point is the path termination point of the AF segment under the specified overflight intention, and the positioning point is the starting point of the arc turn before the path termination point of the AF segment under the specified lateral intention), the bearing angle of the recommended navigation beacon, and the turning direction of the segment. If the previous segment is a DF segment, the outbound heading is determined by the previous segment of the DF segment. If the previous segment is an RF segment, the bearing of the positioning point specified in the navigation database at the center point of the RF arc segment is calculated, and the outbound heading of the RF segment is calculated using the specified turning direction. If the previous segment is a TF segment, the outbound heading of the TF segment is calculated using the path termination point position of the previous segment and the path termination point position of the TF segment. If the previous segment is any other segment, the outbound heading is defined in the navigation database, and this value is directly selected.

[0031] The step (Obtaining the Path Distance of the Target Segment) is responsible for obtaining the path distance of the target segment from the reference point to the path termination point. If the target segment is CF or FC, and the navigation database defines a path distance, then the path distance defined in the navigation database is used and remains unchanged. If the target segment is CF or FC, and the navigation database defines a path time, then the path distance is calculated based on the path time and the predicted airspeed. If the target segment is FD, the azimuth and distance from the reference positioning point of the FD segment to the recommended navigation beacon position of the segment are calculated. Combined with the distance from the path termination point to the recommended navigation beacon defined in the navigation database and the defined outbound heading of the segment, the path distance of the FD segment is calculated using the law of sine.

[0032] The steps (standard navigation database definition data remains unchanged) are as follows: For AF / DF / FM / HA / HF / HM / RF / IF / VM / TF segments, no preprocessing or calculation of the segment data is required, and the original navigation database segment data remains unchanged.

[0033] The step (considering the FIX point position of the target segment) mainly addresses the impact of the reference points defined in the navigation database on the steps (calculating the change angle and turn amount from the previous segment to the target segment; calculating the path distance of the target segment) when the target segment is an FA segment. According to the ARINC 424 definition, FA segments have designated positioning points (compared to CA and VA). If the previous segment is of type xF (any segment type where the path termination point is a FIX point), then the path termination point of the previous segment must be the starting point of the target segment. In this case, the processing method is consistent with that of CA and VA in steps (calculating the change angle and turn amount from the previous segment to the target segment; calculating the path distance of the target segment). If the previous segment is not of type xF, then the location point specified by the FA segment is used to replace the path termination point position of the previous segment, and the heading from the previous segment to that location point is calculated as the replacement heading of the previous segment. The replacement path termination point position and heading value of the previous segment are used as the input for calculating the change angle and turn amount in steps (calculating the change angle and turn amount from the previous segment to the target segment; calculating the path distance of the target segment).

[0034] Step (Calculate the change angle from the previous segment to the target segment) The calculation of the change angle is mainly for the target segment being CD or VD. The change angle is calculated based on the departure heading of the previous segment and the target segment when the target segment type is CD or VD.

[0035] Step (Constructing Geometric Angles): For target segments of type CR or VR, to calculate the path termination point of the target segment, it is first necessary to calculate the scalar angle values ​​of the geometric shapes constructed by each point in the target segment. Based on the departure heading of the previous segment calculated in step (Calculating the Outbound Heading of the Previous Segment Based on its Type and Information), and the location of the path termination point of the previous segment, the position of the reference positioning point for the target segment is calculated. Combined with the positions of recommended navigation beacons in the navigation database, the azimuth and distance from the reference positioning point to the recommended navigation beacon are calculated. Finally, using the departure heading of the target segment and the azimuth of the path termination point of the target segment at the recommended navigation beacon, as defined in the navigation database, the values ​​of the scalar angles of the geometric shapes formed by the reference positioning point, the recommended navigation beacon, and the path termination point of the target segment are calculated.

[0036] The step (calculating reference point positions from next segment information) primarily targets CI, VI, or PI target segments. It specifies that the path termination point position relies on the types and information of the preceding and following segments. Calculating the path termination point of the target segment requires obtaining the positions of each reference positioning point using existing data. If the next segment of the target segment is AF, due to ARINC... 424 stipulates that when transitioning from a CI or VI segment (PI to AF is illegal, PI can only transition to CF), the heading of this segment must point towards (or be away from) the recommended navigation beacon of the AF segment. Therefore, the influence of the previous segment of the target segment does not need to be considered. The path termination point of the CI segment is directly calculated using the specified arc radius and heading of the AF segment. If the next segment of the target segment is IF, this segment is skipped and the calculation is performed based on the segment type of the next segment of the IF segment. If the next segment of the target segment is not AF or IF, the change angle, transition arc radius, turning amount of the transition arc, and the position of reference positioning point 1 are calculated step by step using the segment type, segment information (departure heading, overflight marker, path termination point position) of the previous segment of the target segment, as well as the flight intention of the current target segment (turning direction, target heading). Then, the position of reference positioning point 2 is calculated by combining the type and information (departure heading, path termination point position) of the next segment of the target segment.

[0037] The steps (calculating the change angle and turn amount from the previous segment to the target segment; calculating the path distance of the target segment) are as follows: Based on the aircraft's performance data, calculate the horizontal distance to the specified altitude in the target segment, the change angle, transition arc radius, and turn amount when switching from the previous segment to the target segment. Calculate the climb (or descent) angle using the predicted airspeed and ground speed, calculate the altitude difference between the predicted altitude of the previous segment and the target altitude of the target segment, and calculate the horizontal distance of the target segment using trigonometric functions. Using the departure heading of the previous segment calculated in step (calculating the departure heading of the previous segment based on its type and information), and combining this with the departure heading of the target segment defined in the navigation database, calculate the change angle, transition arc radius, and turn amount of the transition arc for the segment transition.

[0038] Step (Calculate the path distance of the target segment using a sine function): Based on the path termination point position of the previous segment calculated in the previous loop, the change angle, the geometric angle values ​​constructed by each reference positioning point, the reference point position, and the navigation beacon position recommended by the navigation database for the target segment, calculate the path distance of the target segment using a sine function.

[0039] Step (Calculate the path termination point of the target segment using the flight intent of the target segment): Based on the transition attributes of the previous segment of the planned path target segment (side cut or overflight followed by cut to the prescribed route or overflight followed by cut to the prescribed heading), the departure heading, and the flight intent of the target segment such as the transition attributes and departure heading, combined with the path termination point of the previous segment calculated in the previous cycle, the path distance of the target segment calculated in the previous steps, and the heading of the target segment defined in the navigation database, the path termination point of the target segment is calculated.

[0040] Step (Calculating the Target Segment Reference Point Position (CF) or Path End Point Position (FC / FD)): For CF / FC / FD segments, calculate the target segment reference point position or path end point position. The reference point for the CF segment is calculated in reverse from the path distance defined or calculated by the navigation database, the path end point position, and the target segment departure heading. The reference point for the FC and FD segments is defined by the navigation database and remains unchanged. The path end point position for the CF segment is defined by the navigation database and remains unchanged. The path end point position for the FC and FD segments is calculated forward from the calculated or defined path distance, the navigation database-defined reference point position, and the target segment departure heading.

[0041] The step (preprocessed navigation database segment data array) integrates the data calculated in the previous steps with the standard navigation database segment data, filling in undefined or invalid fields in the navigation database to facilitate subsequent path calculation algorithms. The segment data array contains: segment number, segment termination point name, segment path termination point location (longitude, latitude), segment reference point location (longitude, latitude), segment speed limit, segment altitude limit, segment predicted altitude, segment predicted speed, path-termination segment type, overflight marker, turning direction, forced turn marker, recommended navigation beacon name and location, azimuth of the path termination point at the recommended navigation beacon, distance between the path termination point and the recommended navigation beacon, segment departure heading, segment path distance, segment center location, and segment arc radius.

[0042] As shown in Figure 4, the path calculation algorithm flowchart is divided into two parts according to the transition type of the target flight segment and the subsequent transition flight segment, with a total of 10 steps. Using the flight segment information and path termination point location information output by the preprocessing step, different methods are used to calculate according to the situation of the target flight segment and the subsequent transition flight segment. Through iterative loops, the path calculation of the target flight path is performed to obtain the path calculation data of the path termination point and the arc.

[0043] The path calculation algorithm for the target segment itself is divided into five categories based on the commonalities of the 23 segment types.

[0044] Segment planning scheme 1: For AF segment and RF segment, the characteristic of this target segment is that the path itself is a circular arc segment. Using the segment data defined in the navigation database for the target segment, combined with the path termination point of the previous segment and the transition method to the next segment (side cut or two overflights), the entry tangent, turning direction, arc radius and central angle data of the circular arc segment are calculated.

[0045] Segment 2: For CA / CD / CF / CI / CR / DF / FA / FC / FD / TF / VA / VD / VI / VR segments, the characteristic of this target segment is that the path itself is a linear segment. Using the location of the path termination point stored in the navigation database or calculated through preprocessing steps, the longitude and latitude information are placed in the output array.

[0046] Segment Planning Scheme 3: For IF / FM / VM segments, the characteristic of this target segment is that the path itself does not have a specified line segment or arc. Therefore, its location information needs to be placed in the longitude and latitude fields of the output array. The IF segment is generally the planned starting segment, but it can also be used to transition to CF / TF segments. If the IF segment is not used as the starting segment and is connected to a CF segment, the IF segment is omitted, i.e., no processing is done. If the IF segment is not used as the starting segment and is connected to a TF segment, the TF segment is converted to a CF segment and processed as a CF segment, with the IF waypoint serving as the reference point for this converted CF segment. FM / VM segments start from the location of the positioning point and are processed as a 640NM line segment with a fixed heading, thus being placed in the longitude and latitude fields of the output data.

[0047] Segment 4: For the HA / HF / HM segment, the characteristic of this target segment is a waiting procedure (a special path plan that is essential during flight). Using the corresponding waiting time (or waiting distance) defined in the navigation database, combined with the current airspeed predicted by the flight management system (or the speed specified by air traffic control), the turning radius is calculated. This allows for the calculation of the position data of each line segment and arc of the waiting procedure. The data is then placed in the fields of longitude, latitude, arc radius, arc turning direction, arc central angle, and arc ingress tangent in the output array in the form of multiple path termination points and arcs.

[0048] Segment 5: For the PI segment, this target segment is designed to meet the flight intent of a standard procedure turn (U-turn). By using the outbound heading information of the previous segment of the target segment and combining it with the specified parameters for the target segment in the navigation database, an array of multiple path termination points and arcs is calculated and placed in the corresponding fields of the output array.

[0049] Figure 4 shows the transition path calculation process between the target segment and the next segment after the path calculation for the target segment itself is completed. There are generally three transition methods: lateral transition, overflight followed by a transition to a specified heading, and overflight followed by a transition to a specified route. However, different combinations of segment types and flight intentions result in different transition methods being used; in fact, transitioning to a certain type of segment may involve a combination of two transition methods. Therefore, the planned path construction method of this invention analyzes the transition methods required for subsequent transitions to various segment types, classifying segment transition situations and solutions into five categories.

[0050] Segment Transition Planning Scheme 1: If the next segment after the target segment is a HA / HF / HM (holding procedure) segment, the transition method to the next segment is determined using the target segment's departure heading, combined with the defined departure heading and turning direction of the HA / HF / HM segment in the navigation database. There are four ways to transition from the target segment to a holding procedure segment. The airspace is divided into four sectors by the straight line containing the holding procedure departure heading and two straight lines forming a 70-degree angle with it. The sector to enter the holding procedure and the entry method are calculated using the target segment's departure heading. The specific entry methods for the four sectors are specified in RTCA DO-283B. Segment Transition Planning Scheme 1 uses the above data to determine which entry method to use (not controlled by the target segment overflight markers). By calculating the transition arc radius using a specified airspeed, a series of path termination point positions and arc data are calculated and placed into the corresponding fields in the output data.

[0051] Segment Transition Planning Scheme 2: Segment Transition Planning Scheme 2 shares the same characteristic as Segment 1: it is also not controlled by the target segment overflight marker. If the next segment of the target segment is one of CA / CD / CI / CR / DF / PI / VA / VD / VI / VR, then a transition method of cutting to the specified heading after overflight is always adopted. The outbound heading of the DF segment is calculated using a sine function in the preprocessing step. Segment Transition Planning Scheme 2 uses the transition method of cutting to the specified heading after overflight. Using parameters such as the outbound heading of the target segment, target airspeed, predicted wind, and the outbound heading of the next segment of the target segment, it calculates the central angle, turning direction, turning radius, and inbound tangent of the transition arc, and places these data in the corresponding fields of the output array.

[0052] Segment Transition Planning Scheme 3: If the next segment of the target segment is a CF / FC / FD / FA segment, then Transition Planning Scheme 3 is used to calculate the transition path. CF / FC / FD / FA segments, in addition to the path termination point, also have a reference positioning point. The defined path is a line segment from the reference positioning point to the path termination point. Segment Transition Planning Scheme 3 determines whether the path termination point of the target segment and the reference positioning point of the next segment are the same point, and selects different transition methods accordingly. If this condition is true, then a side-cut or overflight-to-the-designated-line transition method is used based on the overflight marker of the target segment; if this condition is false, then a side-cut or overflight-to-the-designated-heading transition method is used based on the overflight marker of the target segment to fly to the reference positioning point of the next segment, and then another side-cut transition method is used to reach the next segment of the target segment, i.e., two transitions are required. A series of output fields for the transition path are calculated using this scheme.

[0053] Segment Transition Planning Scheme 4: If the next segment after the target segment is an AF / RF segment, the transition method will be determined based on the overflight marker of the target segment, either by lateral traversal or by traversing to the designated route after overflight. Since AF / RF segments are circular segments, during the transition calculation between the target segment and the next segment, if the outbound heading of the target segment is not tangent to the inbound heading of the next segment, the position of the transition segment needs to be iteratively calculated to ensure accuracy. This scheme is used to calculate a series of output fields for the transition path.

[0054] Segment Transition Planning Scheme 5: If the above logic is not followed, transition planning scheme 5 is used to calculate the transition segment data. By determining whether the target segment has an overflight indicator, a side-cut or overflight followed by a cut to the designated route transition method is adopted. The output fields of the transition path are calculated using this scheme.

[0055] This invention obtains planned path data with complete flight intent from takeoff to landing based on a standard navigation database through a path construction method consisting of a preprocessing step and a path calculation step.

[0056] This invention utilizes data specified in a standard navigation database to ensure the reliability and applicability of the planned path construction method, enhancing its engineering feasibility. For different combinations of planned path segment types, corresponding calculation methods for the segments themselves and transition segments are employed, ensuring that the output data fully reflects the flight intent of the planned path. The path construction method is designed to consider the 23 segment types defined in the terminal area, covering the flight intent of all planned paths and satisfying relevant path specifications in the documentation. This expands the scenario envelope for path calculation of various flight intents while ensuring the accuracy of the path construction method. The planned path construction method based on a standard navigation database proposed in this invention uses segment data defined in the navigation database as input for the planned path construction steps, significantly improving the engineering feasibility of the method and ensuring the reliability of the planned path construction data. Simultaneously, the planned path construction method considers the definitions of relevant specifications, expanding the applicable scenarios and broadening the actual calculation operation envelope. Furthermore, the path calculation method is divided into a preprocessing sub-step and a path calculation sub-step. Each sub-algorithm can be selectively iterated according to different scenarios to realize path calculation and plan data construction for 23 terminal area paths-termination segments and their various combinations of transition methods. This optimizes the computational load and improves the operational efficiency of path calculation while fully reflecting the flight intent of the planned path.

[0057] In summary, this invention is the first to propose decoding and calculating 23 path-termination segment types and their transition methods, and considering all legal segment transition combinations to construct a planned path with a clear flight intention and a combination of path termination points and arcs. Furthermore, by analyzing the ARINC 424 specification, the algorithm categories in the preprocessing and path calculation steps are standardized, reducing algorithm complexity and demonstrating strong engineering practicality. The final path termination point and arc combination array calculated by this method conforms to the ARINC 661 specification, and its standardized interface has high compatibility, adapting to airborne cockpit display and control systems.

[0058] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. It should be noted that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for constructing planned paths based on a standard navigation database, characterized in that: It includes the following steps: Step S1: Determine if it is the starting segment. If not, proceed to step S2. If yes, directly use the target segment data as the planned route data and proceed to step S4; Step S2: Use the data in the standard navigation database as input data for the planned path construction. Based on the combination of the path-terminal segment type of the target segment and its preceding and following segments and the corresponding data defined in the standard navigation database, preprocess and calculate the path termination point of the target segment. Step S21: Determine the segment type of the target segment; Step S22: If the target segment is CA, VA, FA, CD, VD, CR, VR, CI, VI or PI, calculate the location of the end point of the target segment; Step S221: Use the outbound heading of the previous segment of the target segment as the inbound heading of the target segment; if the target segment is CA or VA, proceed to step S222; if the target segment is CR or VR, proceed to step S223; if the target segment is CI, VI, or PI, proceed to step S224; if the target segment is CD or VD, proceed to step S225; if the target segment is FA, proceed to step S226. Step S222: Calculate the climb angle using the predicted airspeed and ground speed, calculate the altitude difference between the predicted altitude of the previous segment and the target altitude of the target segment, and calculate the horizontal distance of the target segment using trigonometric functions; calculate the transition angle, transition radius, and turning amount of the transition radius of the target segment using the inbound and outbound headings of the target segment, and directly execute step S227; Step S223: Calculate the reference point position of the target segment using the departure heading and the end point position of the previous segment. Combine this with the recommended navigation beacon positions in the standard navigation database to calculate the azimuth and distance from the reference point position to the recommended navigation beacon. Calculate the scalar angles of the geometric shape formed by the reference point, recommended navigation beacon, and end point of the target segment using the departure heading and the azimuth of the end point of the target segment at the recommended navigation beacon, as defined in the standard navigation database. Then proceed to step S225. Step S224: Calculate the reference point of the target segment based on the type and information of the next segment of the target segment: If the next segment of the target segment is AF, directly calculate the end point position of the target segment using the specified arc radius and heading of the AF segment; if the next segment of the target segment is IF, skip the IF segment and calculate based on the next-next segment type of the target segment; if the next segment of the target segment is not AF or IF, use the departure heading, overflight marker, end point position of the previous segment of the target segment, as well as the turning direction and target heading of the current target segment to gradually calculate the change angle, transition arc radius, turning amount of the transition arc, and the position of the first reference point of the target segment, and then combine the departure heading and end point position of the next segment of the target segment to calculate the position of the second reference point; Step S225: Calculate the path distance of the target flight segment using a sine function: If the target segment is CD or VD, calculate the change angle from the previous segment to the target segment based on the departure heading of the previous segment and the departure heading of the target segment. Combine this with the target segment reference path length in the standard navigation database and use a sine function to calculate the path distance of the target segment. If the target segment is CR or VR, calculate the path distance of the target segment using the scalar angles of the geometric shape formed by the reference point, recommended navigation beacon, and termination point of the target segment calculated in step S223, combined with the target segment reference path length in the standard navigation database. If the target segment is CI, VI, or PI, calculate the path distance of the target segment using a sine function based on the first reference point position and the second reference point position calculated in step S224, combined with the target segment reference path length in the standard navigation database, and then proceed to step S227. Step S226: Based on the type of the previous segment of the target segment, determine whether the location of the fixed positioning point of the target segment is needed: If the previous segment of the target segment is of type xF (i.e., any segment type with a fixed endpoint), then the endpoint of the previous segment must be the starting point of the target segment. In this case, the horizontal distance required to reach the specified altitude, the transition angle, the radius of the transition arc, and the turning amount of the transition arc are calculated based on the overflight markers and departure heading defined in the previous segment. If the previous segment of the target segment is not of type xF (i.e., any segment type with a fixed endpoint), the climb angle is calculated using the predicted airspeed and ground speed, the altitude difference between the predicted altitude of the previous segment and the target altitude of the target segment is calculated, and the horizontal distance of the target segment is calculated using trigonometric functions. The transition angle, the radius of the transition arc, and the turning amount of the transition arc are calculated using the inbound and outbound headings of the target segment. Step S227: If the target segment is CA or VA, use the calculation result of step S222 and the outbound heading of the target segment as defined in the standard navigation database to calculate the path termination point of the target segment; if the target segment is CD, VD, CR, VR, CI, VI or PI, use the calculation result of step S225 and the outbound heading of the target segment as defined in the standard navigation database to calculate the path termination point of the target segment. If the target segment is FA, the path termination point of the target segment is calculated using the calculation result of step S226 and the outbound heading of the target segment as defined in the standard navigation database. Step S23: If the target segment is CF, calculate the reference point position of the target segment; if the target segment is FC or FD, calculate the end point position of the target segment. Step S24: If the target route is AF, DF, FM, HA, HF, HM, IF, RF, TF, or VM, then no preprocessing calculation is performed, and the planned route is calculated directly. Step S3: Based on the preprocessed solution information, the corresponding data in the standard navigation database, and the combination of the target segment and subsequent segments, calculate the target segment path data and the subsequent transition segment path data, and perform the planned path solution; Step S4: Determine if it is a terminated flight segment. If not, return to step S1 for iterative looping. If yes, combine all the unified output arrays into complete planned path data for output.

2. The method for constructing a planned path based on a standard navigation database according to claim 1, characterized in that: The specific process of step S3 is as follows: Step S31: Determine the segment type of the target segment; Step S32: Calculate the path of the segment itself according to the segment type of different target segments; Step S33: Determine the segment type of the next segment after the target segment; Step S34: Calculate the transition path for the next segment based on the segment type of the next segment after the target segment.

3. The method for constructing a planned path based on a standard navigation database according to claim 2, characterized in that: The detailed process of calculating the route for the flight segment itself in step S32 is as follows: Step S321: If the target segment is AF or RF, use the segment data defined in the standard navigation database for the target segment, combined with the path termination point of the previous segment and the transition to the next segment, to calculate the entry tangent, turning direction, radius of arc, and central angle data of the target segment. Step S322: If the target segment is CA or CD or CF or CI or CR or DF or FA or FC or FD or TF or VA or VD or VI or VR, use the longitude and latitude information stored in the standard navigation database or calculated through preprocessing as the output data of the corresponding target segment. Step S323: If the target segment is IF, FM, or VM, where, if the IF target segment is the starting segment of the planned path, the IF segment is omitted and no processing is performed; if the IF target segment is not the starting segment and connects to the CF segment, the IF segment is omitted and no processing is performed; if the IF target segment is not the starting segment and connects to the TF segment, the TF segment is converted to a CF segment and processed as a CF segment, the waypoint of the IF target segment is used as the reference point of the converted CF segment, and the FM or VM segment is processed with a fixed heading and a 640NM line segment starting from the location point, and the longitude and latitude of the location point are used as the output data of the corresponding target segment. Step S324: If the target segment is HA, HF, or HM, calculate the turning radius using the corresponding waiting time or waiting distance defined in the standard navigation database, combined with the current airspeed predicted by the flight management system or the air traffic control speed, solve the position data of each line segment and arc of the waiting procedure, and use the longitude, latitude, arc radius, arc turning direction, arc central angle, and arc entry tangent of the combined data of multiple path termination points and arcs as the output data of the corresponding target segment; Step S325: If the target segment is PI, use the outbound heading information of the previous segment of the PI target segment, and combine it with the specified parameters of the PI target segment in the standard navigation database to calculate an array of multiple path termination points and arcs as the output data of the corresponding target segment.

4. The method for constructing a planned path based on a standard navigation database according to claim 2, characterized in that: The detailed process of calculating the transition path for flight segments in step S34 is as follows: Step S341: If the next segment of the target segment is HA, HF, or HM, use the outbound heading of the target segment, combined with the outbound heading and turning direction of the corresponding HA, HF, or HM defined in the standard navigation database, to calculate the transition to the next segment. Step S342: If the next segment of the target segment is CA, CD, CI, CR, DF, PI, VA, VD, VI, or VR, then the transition method of switching to the specified heading after overflight is always adopted. Step S343: If the next segment of the target segment is CF, FC, FD, or FA, calculate the transition method to the next segment based on the path termination point of the target segment and the reference positioning point of the next segment. Step S344: If the next segment type of the target segment is AF or RF, then according to the overflight marker of the target segment, the center position and radius of the AF or RF segment, the transition path from the target segment to the next segment is calculated by using a side-cut transition or a transition method of cutting to the designated route after overflight. Step S345: If the next segment type of the target segment is FM, IF, TF or VM, then the transition method of side-cutting or cutting to the designated route after the overflight is adopted according to the overflight identifier of the target segment.

5. The method for constructing a planned path based on a standard navigation database according to claim 4, characterized in that: The detailed steps for transitioning the solution to the next flight segment in step S341 are as follows: The airspace is divided into four sectors using the straight line where the departure course of the next segment is located and the straight line at a 70-degree angle to it. The sector and entry method for the next segment are calculated using the departure course of the target segment. The transition arc radius is calculated using a specified airspeed, and a series of path termination point positions and arc data are calculated and used as the output data for the corresponding segment transition path solution.

6. The method for constructing a planned path based on a standard navigation database according to claim 5, characterized in that: The specific process of step S342, which involves a transition from overflight to a designated heading, is as follows: The outbound heading of the DF segment is calculated using a sine function in the preprocessing step, while the CA, CD, CI, CR, PI, VA, VD, VI, or VR segments are defined from the standard navigation database. By using the departure heading, target airspeed, and predicted wind of the target segment, as well as the departure heading of the next segment of the target segment, the central angle, turning direction, turning radius, and inbound tangent of the transition arc are calculated and used as the output data for the corresponding segment transition path calculation.

7. The method for constructing a planned path based on a standard navigation database according to claim 6, characterized in that: The specific process of step S343 is as follows: Determine whether the path termination point of the target segment is the same as the reference positioning point of the next segment. If they are the same, then based on the overflight marker of the target segment, use either a side-cut or overflight-to-the-designated-road transition method to calculate the central angle, turning direction, turning radius, and inbound tangent of the transition arc, and use this as the output data for the corresponding segment's transition path calculation. If the path termination point of the target segment is not the same as the reference positioning point of the next segment, then based on the overflight marker of the target segment, use either a side-cut or overflight-to-the-designated-road transition method to fly to the reference positioning point of the next segment, and then use a side-cut transition method to reach the next segment of the target segment. Finally, calculate the central angle, turning direction, turning radius, and inbound tangent of the transition arc, and use this as the output data for the corresponding segment's transition path calculation.

8. The method for constructing a planned path based on a standard navigation database according to claim 7, characterized in that: The specific process of step S344 is as follows: Both AF and RF segments are circular segments, and their arc data comes from different fields in the standard navigation database. Specifically: the center position of the arc in the AF segment is the recommended navigation beacon position for this segment as defined by the standard navigation database, and the radius of the arc in the AF segment is the distance from the recommended navigation beacon to the end point of the AF segment as defined by the standard navigation database; the center position of the arc in the RF segment is the center positioning point position as defined by the standard navigation database, and the radius of the arc in the RF segment is the radius as defined by the standard navigation database. Based on the end point of the target segment, the departure heading of the target segment, the center position of the arc of the next segment, and the radius of the arc of the next segment, calculate the tangent point between the target segment and the arc of the next segment via a side transition or overflight transition. Use this tangent point to calculate the trajectory change angle of the side transition or overflight transition. Finally, combine the departure heading of the target segment, the target airspeed, and the predicted wind to calculate the central angle, turning direction, turning radius, and entry tangent of the transition arc, and use this as the output data for the corresponding segment transition path calculation. The system determines whether the target segment overflight marker is true. If the marker is false, a lateral transition method is used to calculate the transition path. Based on the tangent point position, tangent heading, and the target segment's departure heading, termination point position, target airspeed, and predicted wind, the central angle, turning direction, turning radius, and inbound tangent of the transition arc are calculated and used as the output data for the corresponding segment's transition path calculation. If the target segment overflight marker is true, a transition method of tackling to the designated route after overflight is used to calculate the transition path. This transition path includes two arc segments and a line segment between them. Based on the target segment termination point position, target airspeed, predicted wind, target segment departure heading, and tangent heading tangent to the next segment, the specific data for the arc segment, line segment, and arc segment are calculated, including the radius, starting position, and arc length of the arc segment, as well as the starting and ending points of the line segment, thus obtaining the output data for the corresponding segment's transition path calculation. The specific process of step S345 is as follows: If the next segment of the target segment is an IF segment, skip that segment and process it according to the segment type of the next segment of the IF segment; For each target segment, if the next segment is FM, TF, or VM, determine if the target segment overflight indicator is true. If the target segment overflight indicator is not true, calculate the transition path using a lateral transition method. Based on the departure heading of the target segment and the change-of-course angle of the transition section at the departure heading of the next segment, combined with the target segment termination point position, target airspeed, and predicted wind, calculate the central angle, turning direction, turning radius, and inbound tangent of the transition arc, and use this as the output data for the corresponding segment transition path calculation; if If the target segment overflight indicator is true, the transition path is calculated using a transition method that switches to the designated route after the overflight. This transition path includes two circular arc segments and a line segment between the two circular arc segments. Based on the target segment termination point position, target airspeed and predicted wind, the target segment departure heading and the next segment departure heading, the specific data of the circular arc segments, line segments, and circular arc segments are calculated, including the radius, starting position, and arc length of the circular arc segments, as well as the starting and ending point positions of the line segments, thus obtaining the output data of the corresponding segment transition path solution.

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