Simulation method for predicting spiral approach flight trajectory

Abstract

The present invention discloses a simulation method for predicting the flight trajectory of a circling approach. The method includes the following steps: setting environmental parameters and aircraft parameters according to the target aircraft type and the target airport; correcting the landing reference speed of the aircraft based on the steady wind speed and direction and the landing headwind limit value to obtain the approach reference speed, and obtaining the true airspeed of each flight path segment; determining the projected trajectory and flight time of each flight path segment according to the true airspeed of each flight path segment and the set environmental parameters and aircraft parameters; calculating the altitude change in multiple flight path segments; plotting a sample of the circling approach flight trajectory; traversing the steady wind speed and direction within the preset value range and all sampled values of the circling approach MDH, and plotting multiple samples of the circling approach flight trajectory. According to this method of the present invention, a large number of test points can be efficiently simulated for the verification work of the aircraft circling approach, and the cost can be reduced.

Description

Technical Field

[0001] The invention relates to the field of aviation, in particular to flight trajectory verification of a circling approach of an aircraft, and in particular to a simulation method for predicting a circling approach flight trajectory. Background Art

[0002] At present, in the verification work of the aircraft's circling approach, for most mainstream aircraft models, the related work has high experience requirements for the crew members in terms of circling approach timing, wind correction methods, etc. In addition, the circling approach timing and wind correction methods provided by the current mainstream aircraft models are more or less unreasonable, which leads to certain scenarios within the aircraft's flight envelope. The crew needs to make further corrections based on the recommended correction method and flight experience, which further leads to greater uncertainty. All of these are not conducive to the relevant verification work.

[0003] In order to optimize the flight trajectory of the circling approach and its timing and wind correction methods, it is necessary to verify the rationality of each circling approach timing and wind correction method. The traditional verification method is verified through a flight simulator, which requires the participation of a qualified flight instructor. This traditional method is time-inefficient (one test point takes about 15 minutes) and has high labor costs / equipment usage fees. However, since a large number of test points need to be verified, the traditional verification method cannot meet actual needs due to its low efficiency and high cost.

[0004] Therefore, there is an urgent need to provide a new simulation method for predicting the flight trajectory of a circling approach, which can assist in the verification of the circling approach, so as to at least partially alleviate or solve the above-mentioned problems and defects of the existing solutions. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defect in the prior art that there is a lack of simulation schemes that can effectively assist verification work related to circling approaches, and to propose a new simulation method for predicting the flight trajectory of circling approaches.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] The present invention provides a simulation method for predicting a circling approach flight trajectory, wherein the circling approach flight trajectory comprises a plurality of continuous tracks, the plurality of tracks conforming to a predetermined circling approach standard for a target aircraft type, the plurality of tracks are divided into a front half and a rear half connecting an instrument approach track, wherein the rear half includes a terminal track extending along a runway axis of a target airport to a corresponding runway threshold, and the simulation method comprises the following steps:

[0008] Step 1. Set the environmental parameters and aircraft parameters of the target airport according to the target aircraft model and the target airport for the circling approach flight trajectory, where the environmental parameters include the steady wind speed and direction, and the steady wind speed and direction are set to initial values within a preset value range; the aircraft parameters include the landing reference speed, landing downwind limit, and circling approach MDH (i.e., circling approach minimum descent height) associated with the target aircraft model, and the circling approach MDH is set to an initial value within a preset value range;

[0009] Step 2. Correct the landing reference speed of the aircraft based on the steady wind speed and direction and the landing downwind limit to obtain the approach reference speed, and calculate the true airspeed of each segment of the multi-segment track using the approach reference speed, so as to obtain the true airspeed of each segment of the track;

[0010] Step 3. Based on the circling approach standard, determine the projected positions of the starting and ending points of each segment of the multi-segment track in the horizontal plane according to the true airspeed of each segment of the track and the set environmental parameters and aircraft parameters, and thereby determine the projected track and flight time of each segment of the track;

[0011] Step 4. Calculate the altitude change in the multi-segment track according to the true airspeed of each segment of the track and the set environmental parameters and aircraft parameters;

[0012] Step 5. Use a computer to draw a sample of the circling approach flight trajectory according to the projected trajectory of each segment of the track obtained by calculation and the altitude change in the multi-segment track;

[0013] Step 6. After performing Step 5, change the values of the steady wind speed and direction and the circling approach MDH in sequence at a predetermined step size within the preset value range, and then repeatedly execute Steps 2 to 5, so as to traverse all the sampled values of the steady wind speed and direction and the circling approach MDH within the preset value range, and draw multiple samples of the circling approach flight trajectory.

[0014] According to an embodiment of the present invention, the aircraft parameters associated with the target aircraft model set in Step 1 further include the stable approach altitude and the recommended descent rate.

[0015] According to an embodiment of the present invention, the first half of the multi-segment track sequentially includes a first arc transition segment connecting the instrument approach track and turning from the extension direction of the runway axis of the target airport to a predetermined angle with the runway axis, a first straight-line track segment, a second arc transition segment turning to align with the tangent runway point in a direction parallel to the runway axis, and a second straight-line track segment further extending to the tangent runway point;

[0016] The second half of the multiple flight paths includes, in sequence, three sides parallel to the runway axis and extending from the tangent runway point, a third arc transition section, four sides perpendicular to the runway axis, a fourth arc transition section, and five sides constituting the last section of the multiple flight paths and extending along the runway axis to the runway entrance.

[0017] According to one embodiment of the present invention, the aircraft parameters also include the predetermined angle, the first average roll angle of the aircraft in the first arc transition section and the second arc transition section, the second average roll angle of the aircraft in the third arc transition section and the fourth arc transition section, and the angle between the descent trajectory of the aircraft and the horizontal plane in the five sides.

[0018] According to one embodiment of the present invention, the step 4 further comprises:

[0019] The time required for the aircraft to descend from the beginning to the stable approach altitude is calculated based on the circling approach MDH, the stable approach altitude, and the recommended descent rate, and the aircraft descent apex is further determined by calculating the flight time of each segment of the track.

[0020] According to one embodiment of the present invention, the sub-step of drawing the circling approach flight trajectory sample in step six includes drawing the aircraft descent apex.

[0021] According to one embodiment of the present invention, the environmental parameters further include a runway entrance elevation and a protection zone, and the boundary of the protection zone is defined by an arc line centered at the runway entrance and having a predetermined radius.

[0022] According to one embodiment of the present invention, the sub-step of calculating the true airspeed of the multiple flight paths includes:

[0023] determining the indicated airspeed for each segment of the track based on the approach reference speed;

[0024] Estimate the air density at the circling approach MDH based on the runway threshold elevation and the circling approach MDH;

[0025] The corresponding true airspeed is calculated based on the dynamic pressure corresponding to the indicated airspeed and the air density.

[0026] According to an embodiment of the present invention, the simulation method further includes a verification step, and the verification step includes:

[0027] Based on the relative position of the circling approach flight trajectory sample drawn in step 6 relative to the protected area and the length of the last segment of the track therein, the approach quality of the circling approach flight trajectory sample is determined.

[0028] According to an embodiment of the present invention, the verification step includes:

[0029] Based on a predetermined determination criterion, determine the approach quality of the drawn spiral approach flight trajectory sample, wherein the predetermined determination criterion includes the optimal value range and upper and lower limits of the length of the last segment of the multi-segment flight path, and the relative position of the multi-segment flight path with respect to the protected area;

[0030] Among them, mark the spiral approach flight trajectory sample that exceeds the upper and lower limits as an unselectable sample, and also mark the spiral approach flight trajectory sample whose multi-segment flight path exceeds the protected area as an unselectable sample, and mark the spiral approach flight trajectory sample that is always within the boundary of the protected area and meets the optimal value range as a preferred sample.

[0031] On the basis of conforming to the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0032] The positive and progressive effects of the present invention are as follows:

[0033] According to the simulation method for predicting the spiral approach flight trajectory of the present invention, through computer simulation technology, a large number of test points can be efficiently simulated for the verification work of aircraft spiral approach, which can greatly improve the time efficiency and reduce the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is an example diagram of a spiral approach flight trajectory including continuous multi-segment flight paths involved in the simulation method for predicting the spiral approach flight trajectory according to the present invention.

[0035] Figure 2 It is a schematic flowchart of the simulation method for predicting the spiral approach flight trajectory according to the preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The following further describes in detail the preferred embodiments of the present invention with reference to the accompanying drawings of the specification. The following description is exemplary and not a limitation to the present invention. Any other similar situations also fall within the protection scope of the present invention.

[0037] In the following specific description, directional terms, such as "left", "right", "up", "down", "front", "rear", etc., are used with reference to the directions described in the drawings. The components of the embodiments of the present invention can be placed in a variety of different directions, and the directional terms are for illustrative purposes and not restrictive.

[0038] A simulation method for predicting a circling approach flight trajectory according to a preferred embodiment of the present invention, wherein the circling approach flight trajectory includes a plurality of consecutive flight paths that conform to a predetermined circling approach standard for a target aircraft type, and the plurality of flight paths are divided into a first half and a second half that connect to an instrument approach flight path, wherein the last flight path included in the second half extends along the runway axis of the target airport to a corresponding runway entrance.

[0039] It should be understood that the simulation method according to the following preferred embodiment of the present invention can generally be considered as a solution for simulating the approach flight trajectory of an aircraft during the final approach phase (which can also be referred to as the final approach, the five-sided approach, or the five sides, etc.), and specifically for the circling approach mode. The final approach phase can generally be understood as the last part of the flight path of the aircraft before landing, during which the aircraft needs to align with the runway and descend. This process is stipulated or agreed upon in the relevant aviation standards in this field, and this process is also commonly abbreviated as the five sides in aviation radio communication.

[0040] Figure 1 An example of a segmented flight path of a flight trajectory that conforms to the circling approach standard is shown. Specifically, referring to Figure 1 As shown, the entire predicted trajectory targeted by the simulation method according to the following preferred embodiment of the present invention can be divided into two major parts: a first half and a second half.

[0041] Specifically, referring to Figure 1 As shown, the first half of the entire trajectory may sequentially include a first arc transition section (the first flight path in the first half of the trajectory described herein) L1 that connects to the instrument approach flight path and turns from the extension direction of the runway axis of the target airport to a predetermined angle θ1 with the runway axis, a first straight-line flight path (the second flight path in a straight-line shape) L2, a second arc transition section (the third flight path) L3 that turns to align with the tangent runway point along a direction parallel to the runway axis, and a second straight-line flight path (the fourth flight path) L4 that further extends to the tangent runway point.

[0042] The latter half of the entire trajectory successively includes the following five sections of flight paths: In the latter half of the trajectory, the first section of flight path L5, also known as the downwind leg, is parallel to the runway axis and extends from the tangent runway head point to the three - turn point; the second section of flight path L6 is the transition from L5 to L7, which is a 1 / 4 circle under calm wind conditions and not an arc under steady - wind conditions; the third section of flight path L7 is a section of flight path perpendicular to the runway axis and is also known as the base leg; the fourth section of flight path L8 is the transition from L7 to L9, which is a 1 / 4 circle under calm wind conditions and not an arc under steady - wind conditions; the fifth section L9 is a flight path that extends along the runway axis all the way to the runway entrance. Among them, the names of the downwind leg to the final approach leg are well - known to those skilled in the relevant technical field and conform to the conventions or regulations of existing civil aviation standard manuals.

[0043] Reference Figure 2 And in combination with Figure 1 As shown, according to the simulation method for predicting a circling approach flight trajectory according to a preferred embodiment of the present invention, the circling approach flight trajectory includes a plurality of consecutive sections of flight paths, and the simulation method may include the following steps:

[0044] Step 1: Set the environmental parameters and aircraft parameters of the target airport according to the target aircraft type and the target airport for which the circling approach flight trajectory is targeted. Among them, the environmental parameters include the steady - wind speed and direction, and the steady - wind speed and direction are set as initial values within a preset value range; the aircraft parameters include the landing reference speed, landing headwind limit, and circling approach MDH (i.e., circling approach minimum descent height) associated with the target aircraft type, as well as optionally the steady - approach altitude and recommended descent rate, and the circling approach MDH is set as an initial value within a preset value range;

[0045] Step 2: Correct the landing reference speed of the aircraft based on the steady - wind speed and direction and the landing headwind limit to obtain the approach reference speed, and calculate the true airspeed of the plurality of sections of flight paths using the approach reference speed, thereby obtaining the true airspeed of each section of flight path;

[0046] Step 3: Based on the circling approach standard, according to the true airspeed of each section of flight path and the set environmental parameters and aircraft parameters, determine the projected positions in the horizontal plane of the starting and ending points of each section of flight path in the plurality of sections of flight paths, and thereby determine the projected trajectory and flight time of each section of flight path;

[0047] Step 4: Calculate the altitude change in the plurality of sections of flight paths according to the true airspeed of each section of flight path and the set environmental parameters and aircraft parameters;

[0048] Step 5: Use a computer to draw a sample of the circling approach flight trajectory according to the calculated projected trajectory of each section of flight path and the altitude change in the plurality of sections of flight paths;

[0049] Step 6. After executing step 5, the values ​​of the steady wind speed and wind direction and the circling approach MDH are sequentially changed with a predetermined step length within the preset value range, and then steps 2 to 5 are repeatedly executed, thereby traversing all sampling values ​​of the steady wind speed and wind direction and the circling approach MDH within the preset value range, and drawing a plurality of circling approach flight trajectory samples.

[0050] refer to Figure 1 As shown, according to some more specific embodiments, the aircraft parameters also include the predetermined angle, the first average roll angle θ2 of the aircraft in the first arc transition section and the second arc transition section, the second average roll angle θ3 of the aircraft in the third arc transition section and the fourth arc transition section, and the angle θ4 between the descent trajectory of the aircraft and the horizontal plane in the fifth side.

[0051] According to some more specific implementations of the present invention, in step 1, the input stable wind size is also adjusted to ensure that the tailwind component in the landing runway direction does not exceed the landing tailwind limit corresponding to the aircraft type while keeping the wind direction unchanged. The processed stable wind is called the corrected stable wind, and the wind component in the landing runway direction is calculated using the corrected stable wind speed and wind direction. Subsequently, the landing reference speed is corrected using the landing runway direction wind component and the approach wind correction method to obtain the approach reference speed.

[0052] For example, the corrected stable wind size = Min (input stable wind, landing tailwind limit corresponding to the aircraft type / cos (angle between wind direction and runway)), the wind component in the landing runway direction = corrected stable wind size * cos (angle between wind direction and runway). On this basis, the corrected stable wind size (i.e. wind speed) can be used to calculate the stable wind component that affects each section of the flight path.

[0053] According to some preferred embodiments of the present invention, the step 4 further comprises:

[0054] The time required for the aircraft to descend from the beginning to the stable approach altitude is calculated based on the circling approach MDH, the stable approach altitude, and the recommended descent rate, and the aircraft descent apex is further determined by calculating the flight time of each segment of the track.

[0055] Further preferably, the sub-step of drawing the circling approach flight trajectory sample in step six includes drawing the aircraft descent apex.

[0056] Further preferably, in the step 3, the sub-step of calculating the true airspeed of the multiple flight paths comprises:

[0057] determining the indicated airspeed for each segment of the track based on the approach reference speed;

[0058] Estimate the air density at the MDH of the circling approach according to the runway threshold elevation and the MDH of the circling approach;

[0059] Calculate the corresponding true airspeed based on the dynamic pressure corresponding to the indicated airspeed and the air density.

[0060] For example, in the relevant calculations from step two to step four, the indicated airspeeds of the first to fourth segments L1, L2, L3, L4 of the first half of the approach track connected to the instrument approach track, the average indicated airspeed of the three-sided track L5, and the indicated airspeeds of the second to fifth segments L6, L7, L8, L9 of the second half of the approach track can be determined first according to the approach reference speed. It should be understood that the numerical relationships between these segmented tracks L1-L9 and the approach reference speed are different and can be determined according to the operating techniques corresponding to the aircraft type (such as relevant specifications or manuals). For example, for a certain aircraft type, the indicated airspeeds corresponding to tracks L1, L2, L3, L4 = Max(approach reference speed, 160), and the average indicated airspeed corresponding to track L5 = (indicated airspeed of L4 + indicated airspeed of L6) / 2.

[0061] Moreover, specifically according to the runway threshold elevation and the MDH of the circling approach, the air density corresponding to the standard atmosphere at the circling approach height can be calculated using the interpolation method, the dynamic pressures corresponding to the indicated airspeeds of the segmented tracks L1-L9 can be calculated, and then the corresponding true airspeeds can be calculated by combining the above dynamic pressures with the air density at the current height.

[0062] It can also be understood that the step of using a computer to draw a sample of the circling approach flight track includes the prediction of the flight track, which can generally be understood as a sequential derivation calculation of the position of the starting point of track L9 from the start of track L1 based on the segmented tracks, and then further calculating the coordinate position of the aircraft descent vertex.

[0063] For example, use the true airspeed of track L2 and the first average bank angle θ2 to calculate the still-air turning radius and the time required for one turn corresponding to the aircraft turning to track L2 and turning from track L2 to track L4, which can satisfy the following formula:

[0064] True airspeed 2 / Turning radius = gravitational acceleration * tan(q2).

[0065] Calculate the flight times of tracks L2 and L5 using the minimum circling approach height and the wind component along the segmented track direction. This correction calculation varies depending on the aircraft type and will not be described in detail here. Then, use the timing time, true airspeed, wind component of track L2, and the turning radius of the aircraft corresponding to track L3 to calculate the starting point of track L4.

[0066] Among them, the length of flight path L2 = (true airspeed + wind component) * timing time. The trajectories of flight paths L3 and L4 are two arcs respectively under calm wind conditions. Then, by considering the distance the aircraft is blown by the wind during the process of turning through the arcs, the starting coordinates of flight path L4 can be calculated.

[0067] Then, use the average true airspeed at the tangent of the runway threshold, the wind component of flight path L5, and the timing time at the tangent of the runway threshold to calculate the position of the aircraft's third turning point. Use the true airspeed of flight path L6 and the second average bank angle θ3 of the aircraft in flight path L6 (the third arc transition section) and flight path L8 (the fourth arc transition section) to calculate the turning radius in calm wind and the time required to complete one turn corresponding to flight path L6. Subsequently, use the turning radius in calm wind of flight path L6, the time required to complete one turn, the wind component of flight path L5, and the wind component of flight path L7 to calculate the starting point of flight path L9. Among them, flight paths L6 and L8 are two quarter arcs under calm wind conditions. Assuming the length of flight path L7 is zero, by considering the distance the aircraft is blown by the wind during the turning process, the coordinates of the starting point of flight path L9 can be obtained.

[0068] It can be understood that the above calculations for the segmented flight paths L6 - L9 are basically the same as the calculation principles for the segmented flight paths L1 - L4 described above.

[0069] On this basis, the relevant calculations for determining the aircraft's descent vertex by combining the flight times of each segmented flight path in step four can be carried out in the following manner, for example.

[0070] First, the time T required for the aircraft to descend from the start of descent to the stable altitude can be calculated using the circling approach MDH, the stable approach altitude, and the recommended descent rate, that is, T = (MDH - stable approach altitude) / recommended descent rate. Use the position of the starting point of flight path L9 and the position where the aircraft establishes the glide path at the stable approach altitude (associated with the angle q4 between the aircraft's descent trajectory and the horizontal plane in the final approach) to calculate the time T7 of flight path L7 and the time T9 to fly to the stable approach point after turning to the final approach.

[0071] Then, use T, T7, T9, the time T6 required for flight path L6, the time T8 required for flight path L8, and the timing time at the tangent of the runway threshold to calculate the timing time at the tangent of the runway threshold corresponding to the recommended circling approach descent vertex.

[0072] For example, the above calculation process satisfies the following formula:

[0073] T7 = distance from the starting point of L7 to the runway axis / airspeed of flight path L7;

[0074] T9 = (length of the projection of the line connecting the starting point of L9 and the stable approach point on the runway axis) / airspeed of L9;

[0075] Tangent runway head timing for the descending vertex = Tangent runway head timing T5 - (T - T7 - T9 - T6 - T8).

[0076] Based on the above calculation results, the coordinates of the descending vertex of the aircraft are calculated using the tangent runway head timing corresponding to the descending vertex, the true airspeed at the tangent runway head of the aircraft, the true airspeed of track L6, the wind component of track L5, and the wind component of track L7. Moreover, the calculation result of the descending vertex coordinates can further determine the position of the descending vertex coordinates, such as in which section of the segmented tracks L5 - L9 the descending vertex is located.

[0077] It should be understood that the above description of the calculation process is a brief example of the derivation and calculation process between various parameters, and is not intended to limit the protection scope of this application. The protection scope is defined by the claims appended to this disclosure.

[0078] According to the simulation method for predicting the spiral approach flight trajectory according to the above preferred embodiment of the present invention, through computer simulation technology, a large number of test points can be efficiently simulated for the verification work of aircraft spiral approach, which can greatly improve the time efficiency and reduce the cost.

[0079] Based on any of the above-described embodiments, further preferably, the environmental parameters further include the runway threshold elevation and the protected area, and the boundary of the protected area is defined by an arc line centered at the runway threshold and having a predetermined radius.

[0080] Moreover, the simulation method further includes a verification step, and the verification step includes:

[0081] Based on the relative position of the spiral approach flight trajectory sample drawn in Step Six with respect to the protected area and the length of the final section of the track, determine the approach quality of the spiral approach flight trajectory sample.

[0082] Further preferably, the verification step includes:

[0083] Based on a predetermined determination criterion, determine the approach quality of the drawn spiral approach flight trajectory sample, where the predetermined determination criterion includes the optimal value range, upper and lower limits of the length of the final section of the multi-segment track, and the relative position of the multi-segment track with respect to the protected area;

[0084] Among them, the spiral approach flight trajectory samples that exceed the upper and lower limits are marked as non-selectable samples, and the spiral approach flight trajectory samples whose multi-segment tracks exceed the protected area are also marked as non-selectable samples, and the spiral approach flight trajectory samples that are always within the boundary of the protected area and meet the optimal value range are marked as preferred samples.

[0085] Based on the above preferred embodiments, it will not only be able to generate a large number of test points (i.e., flight trajectory samples) through computer simulation to improve the efficiency of the verification work, but also be able to preliminarily automatically evaluate the approach quality of a large number of test points to a certain extent, thereby further reducing the labor cost.

[0086] Moreover, relevant tests on the application examples based on the above preferred embodiments show that, compared with the traditional flight simulator verification method, the above method can greatly improve the time efficiency of relevant work while ensuring the accuracy and effectiveness of a large number of test points and verification results, and at the same time maintain a relatively low cost. Based on relevant tests, using the simulation method described above to assist in the verification of the circling approach, in the case of locked computing power, compared with the traditional flight simulator verification method, the improvement in time efficiency may be as high as tens of thousands of times (reaching 64,800 times in one test). On the other hand, in terms of verification cost, compared with the high personnel labor costs and equipment usage fees included in the flight simulator, using the simulation method described above can greatly save relevant costs. Based on some tests that have been carried out, through the solution of the above embodiments of the present invention, the cost savings for a single test point can reach more than a thousand yuan, which indicates that the cost savings effect that can be achieved for relevant verification work that often involves tens of thousands of test points will be extremely significant.

[0087] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that these are only examples, and the protection scope of the present invention is defined by the appended claims. Without departing from the principles and essence of the present invention, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A simulation method for predicting a circling approach flight trajectory, the circling approach flight trajectory including a plurality of consecutive flight tracks, the plurality of flight tracks conforming to a predetermined circling approach standard for a target aircraft type, the plurality of flight tracks being divided into a first half and a second half that connect to an instrument approach flight track, wherein the last flight track included in the second half extends along the runway axis of the target airport to the corresponding runway entrance. Characterized in that: The simulation method includes the following steps: Step 1: Set the environmental parameters and aircraft parameters of the target airport according to the target aircraft type and the target airport for which the circling approach flight trajectory is targeted. Among them, the environmental parameters include the steady wind speed and direction, and the steady wind speed and direction are set as initial values within a preset value range; the aircraft parameters include the landing reference speed, landing headwind limit, and circling approach MDH associated with the target aircraft type, and the circling approach MDH is set as an initial value within a preset value range. Step 2: Correct the landing reference speed of the aircraft based on the steady wind speed and direction and the landing headwind limit to obtain an approach reference speed, and calculate the true airspeed of the plurality of flight tracks using the approach reference speed, so as to obtain the true airspeed of each flight track. Step 3: Based on the circling approach standard, determine the projected positions in the horizontal plane of the starting and ending points of each flight track in the plurality of flight tracks according to the true airspeed of each flight track and the set environmental parameters and aircraft parameters, and thereby determine the projected trajectory and flight time of each flight track. Step 4: Calculate the altitude change in the plurality of flight tracks according to the true airspeed of each flight track and the set environmental parameters and aircraft parameters. Step 5: Use a computer to draw a sample of a circling approach flight trajectory according to the projected trajectory of each flight track obtained by calculation and the altitude change in the plurality of flight tracks. Step 6: After performing Step 5, change the values of the steady wind speed and direction and the circling approach MDH in sequence at a predetermined step size within the preset value range, and then repeatedly execute Steps 2 to 5, so as to traverse all the sampled values of the steady wind speed and direction and the circling approach MDH within the preset value range, and draw multiple samples of circling approach flight trajectories.

2. The simulation method for a circling approach flight trajectory according to claim 1, Characterized in that: The aircraft parameters associated with the target aircraft type set in Step 1 further include a steady approach altitude and a recommended descent rate.

3. The simulation method for a circling approach flight trajectory according to claim 2, Characterized in that: The first half of the plurality of flight tracks sequentially includes a first arc transition section that connects to the instrument approach flight track and turns from the extension direction of the runway axis of the target airport to a predetermined angle with the runway axis, a first straight flight track, a second arc transition section that turns to align with the tangent runway point in a direction parallel to the runway axis, and a second straight flight track that further extends to the tangent runway point. The second half of the multiple flight paths includes, in sequence, three sides parallel to the runway axis and extending from the tangent runway point, a third arc transition section, four sides perpendicular to the runway axis, a fourth arc transition section, and five sides constituting the last section of the multiple flight paths and extending along the runway axis to the runway entrance.

4. The method for simulating a circling approach flight trajectory as claimed in claim 3, It is characterized in that The aircraft parameters also include the predetermined angle, a first average roll angle of the aircraft in the first arc transition section and the second arc transition section, a second average roll angle of the aircraft in the third arc transition section and the fourth arc transition section, and an angle between the descent trajectory of the aircraft and the horizontal plane in the fifth side.

5. The method for simulating a circling approach flight trajectory as claimed in claim 4, It is characterized in that The step 4 also includes: The time required for the aircraft to descend from the beginning to the stable approach altitude is calculated based on the circling approach MDH, the stable approach altitude, and the recommended descent rate, and the aircraft descent apex is further determined by calculating the flight time of each segment of the track.

6. The method for simulating a circling approach flight trajectory as claimed in claim 5, It is characterized in that The sub-step of drawing the circling approach flight trajectory sample in step six includes drawing the aircraft descent apex.

7. The method for simulating a circling approach flight trajectory according to any one of claims 1 to 6, It is characterized in that The environmental parameters also include a runway entrance elevation and a protection zone, wherein the boundary of the protection zone is defined by an arc line with a predetermined radius and the runway entrance as the center.

8. The method for simulating a circling approach flight trajectory as claimed in claim 7, It is characterized in that In step 3, the sub-step of calculating the true airspeed of the multiple flight paths includes: determining the indicated airspeed for each segment of the track based on the approach reference speed; Estimate the air density at the circling approach MDH based on the runway threshold elevation and the circling approach MDH; The corresponding true airspeed is calculated based on the dynamic pressure corresponding to the indicated airspeed and the air density.

9. The method for simulating a circling approach flight trajectory as claimed in claim 7, It is characterized in that The simulation method further comprises a verification step, wherein the verification step comprises: Based on the relative position of the circling approach flight trajectory sample drawn in step 6 relative to the protected area and the length of the last segment of the track therein, the approach quality of the circling approach flight trajectory sample is determined.

10. The method for simulating a circling approach flight trajectory as claimed in claim 9, It is characterized in that The verification step includes: Based on a predetermined judgment standard, the approach quality of the drawn circling approach flight track sample is judged, wherein the predetermined judgment standard includes an optimal value range and upper and lower limits of the length of the last segment of the multiple track segments, and a relative position of the multiple track segments relative to the protection area; Among them, the spiral approach flight trajectory samples exceeding the upper and lower limit values are marked as non-selectable samples, the spiral approach flight trajectory samples of the multi-segment flight track exceeding the protection area are also marked as non-selectable samples, and the spiral approach flight trajectory samples that are always within the boundary of the protection area and meet the best value range are marked as preferred samples.

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