Simulation method for predicting visual approach flight trajectory

Abstract

The present invention discloses a simulation method for predicting a visual approach flight trajectory, the method comprising the following steps: setting environmental parameters and aircraft parameters of a target airport; correcting the landing reference speed of an aircraft based on a steady wind speed and wind direction to obtain an approach reference speed, and obtaining the true airspeed of each section of the track; determining the projection track and flight time of each section of the track according to the true airspeed of each section of the track and the set environmental parameters and aircraft parameters; calculating the altitude change in multiple sections of the track; computer drawing a visual approach flight trajectory sample; traversing all sampled values ​​of the steady wind speed and wind direction within a preset value range, and drawing multiple visual approach flight trajectory samples. According to the simulation method for predicting a visual approach flight trajectory of the present invention, a large number of test points can be simulated efficiently for the verification of the visual approach of an aircraft, greatly improving efficiency and reducing costs.

Description

Technical Field

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

[0002] At present, in the verification work of the aircraft's visual approach, for most mainstream aircraft models, the related work has high experience requirements for the crew members in terms of visual approach timing, wind correction methods, etc. In addition, the visual approach timing and wind correction methods provided by the current mainstream aircraft models are more or less irrational, 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 unfavorable to the relevant verification work.

[0003] In order to optimize the flight trajectory of visual approach and its timing and wind correction methods, it is necessary to verify the rationality of each visual 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 has low time efficiency (one test point takes about 15 minutes) and 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 visual approach flight trajectory, which can assist in the verification of visual approach to at least partially alleviate or solve the above-mentioned problems and defects of 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 visual approach, and to propose a new simulation method for predicting visual approach flight trajectory.

[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 visual approach flight trajectory, wherein the visual approach flight trajectory comprises a plurality of continuous tracks, the plurality of tracks meet predetermined visual approach standards for a target aircraft type, and the terminal segments of the plurality of tracks extend along the runway axis of a target airport to a corresponding runway threshold. The simulation method comprises the following steps:

[0008] Step 1: according to the target airport targeted by the visual approach flight trajectory, setting the environmental parameters and aircraft parameters of the target airport in a computer, wherein the environmental parameters include steady wind speed and wind direction and runway threshold elevation, and wherein the steady wind speed and wind direction are set to initial values ​​within a preset value range;

[0009] Step 2: Correcting the landing reference speed of the aircraft based on the steady wind speed and wind direction to obtain an approach reference speed, and using the approach reference speed to calculate the true airspeed of the multiple flight paths, thereby obtaining the true airspeed of each flight path;

[0010] Step 3: on the basis of the visual approach standard, according to the true airspeed of each flight path and the set environmental parameters and aircraft parameters, determine the projection position of the starting point and the end point of each flight path in the horizontal plane, and thereby determine the projection trajectory and flight time of each flight path;

[0011] Step 4: calculating the altitude change in the multiple flight paths according to the true airspeed of each flight path and the set environmental parameters and aircraft parameters;

[0012] Step 5: using a computer to draw a visual approach flight track sample according to the calculated projection tracks of each track segment and the altitude changes in the multiple tracks;

[0013] The simulation method also includes:

[0014] After executing step five, the values ​​of the steady wind speed and wind direction are changed in sequence within the preset value range with a predetermined step size, and then steps two to five are repeatedly executed to traverse all sampling values ​​of the steady wind speed and wind direction within the preset value range, and draw multiple items of apparent approach flight trajectory samples.

[0015] According to one embodiment of the present invention, the step one further comprises:

[0016] According to the target aircraft model, parameter values ​​of aircraft parameters associated with the target aircraft model are set, wherein the aircraft parameters include a three-way runway distance, a landing reference speed, a visual approach altitude, a stabilized approach altitude, and a recommended descent rate.

[0017] According to one embodiment of the present invention, the multiple flight paths include, in sequence, three sides parallel to the runway axis, a first arc-shaped transition section, four sides perpendicular to the runway axis, a second arc-shaped transition section, and five sides constituting the end of the multiple flight paths and extending along the runway axis to the runway entrance.

[0018] According to one embodiment of the present invention, the aircraft parameters also include an average roll angle of the aircraft in the first arc transition section, an average roll angle of the aircraft in the second arc transition section, and an angle between the descent trajectory of the aircraft in the five sides and the horizontal plane.

[0019] According to one embodiment of the present invention, the step 4 further comprises:

[0020] The time required for the aircraft to descend from the beginning of descent to the stable approach altitude is calculated based on the visual approach altitude, the stable approach altitude, and the recommended descent rate, and the aircraft's descent apex is further determined by calculating the flight time of each segment of the track.

[0021] According to one embodiment of the present invention, the sub-step of drawing the visual approach flight trajectory sample in step five includes drawing the aircraft descent apex.

[0022] According to an embodiment of the present invention, in step 3, 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 visual approach altitude based on the runway threshold elevation and the visual approach altitude;

[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 a predetermined judgment standard, determining the approach quality of the drawn visual approach flight trajectory sample, 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 flight paths;

[0028] Among them, the visual approach flight trajectory samples that exceed the upper and lower limits are marked as unselectable samples, and the visual approach flight trajectory samples that meet the optimal value range are marked as preferred samples suitable for achieving good fuel economy and stable approach safety.

[0029] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0030] The positive and progressive effects of the present invention are:

[0031] According to the simulation method for predicting the visual approach flight trajectory of the present invention, a large number of test points can be simulated efficiently through computer simulation technology for the verification of the aircraft visual approach, which can greatly improve time efficiency and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The diagram is an example of a visual approach flight trajectory including multiple continuous flight paths involved in the simulation method for predicting a visual approach flight trajectory according to the present invention.

[0033] Figure 2 The figure is a flow chart of a simulation method for predicting a visual approach flight trajectory according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings of the specification. The following description is exemplary and not limiting of the present invention. Any other similar situations also fall within the protection scope of the present invention.

[0035] In the following detailed 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 used for illustrative purposes rather than limiting.

[0036] According to a simulation method for predicting a visual approach flight trajectory according to a preferred embodiment of the present invention, the visual approach flight trajectory includes multiple continuous tracks, the multiple tracks meet the predetermined visual approach standards for the target aircraft type, and the terminal segments of the multiple tracks extend along the runway axis of the target airport to the corresponding runway entrance.

[0037] It should be understood that the simulation method according to the following preferred embodiment of the present invention can be generally considered as a computer simulation scheme for the approach flight trajectory of the final approach phase (also known as final approach, final approach or final approach, etc.) of the aircraft, and specifically for visual approach. The final approach phase can generally be understood as the last part of the flight from the aircraft approach to 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 generally referred to as final approach in aviation radio communications.

[0038] By visual approach, it is generally understood that in a common airport traffic pattern under visual meteorological conditions, the aircraft needs to turn from four-way to final-way, for example, 1.5 to 2 miles from the airport.

[0039] refer to Figure 1 An example of a trajectory that meets visual approach standards is shown, wherein the multiple tracks include, in sequence, three sides parallel to the runway axis, a first arc transition section, four sides perpendicular to the runway axis, a second arc transition section, and five sides that constitute the terminal section of the multiple tracks and extend along the runway axis to the runway entrance.

[0040] Specifically, refer to Figure 1 As shown, the entire predicted trajectory according to the simulation method of the following preferred embodiment of the present invention can be divided into the following five tracks: the first track L1 is also called the three sides, which is parallel to the runway axis and extends from the tangent runway head point to the three turning points; the second track L2 is the transition from L1 to L3, which is a quarter circle in calm wind and not an arc in steady wind; the third track L3 is a track perpendicular to the runway axis, also called the four sides; the fourth track L4 is the transition from L3 to L5, which is a quarter circle in calm wind and not an arc in steady wind; the fifth track L5 is a track extending along the runway axis to the runway entrance. Among them, the names of three sides to five sides are well known to technicians in the relevant technical field and conform to the conventions or regulations of the existing civil aviation standard manual.

[0041] refer to Figure 2 Combined with Figure 1 As shown, the simulation method according to the preferred embodiment of the present invention comprises the following steps:

[0042] Step 1: according to the target airport targeted by the visual approach flight trajectory, setting the environmental parameters and aircraft parameters of the target airport in a computer, wherein the environmental parameters include steady wind speed and wind direction and runway threshold elevation, and wherein the steady wind speed and wind direction are set to initial values ​​within a preset value range;

[0043] Step 2: Correcting the landing reference speed of the aircraft based on the steady wind speed and wind direction to obtain an approach reference speed, and using the approach reference speed to calculate the true airspeed of the multiple flight paths, thereby obtaining the true airspeed of each flight path;

[0044] Step 3: on the basis of the visual approach standard, according to the true airspeed of each flight path and the set environmental parameters and aircraft parameters, determine the projection position of the starting point and the end point of each flight path in the horizontal plane, and thereby determine the projection trajectory and flight time of each flight path;

[0045] Step 4: calculating the altitude change in the multiple flight paths according to the true airspeed of each flight path and the set environmental parameters and aircraft parameters;

[0046] Step 5: using a computer to draw a visual approach flight track sample according to the calculated projection tracks of each track segment and the altitude changes in the multiple tracks;

[0047] The simulation method also includes:

[0048] After executing step five, the values ​​of the steady wind speed and wind direction are changed in sequence within the preset value range with a predetermined step size, and then steps two to five are repeatedly executed to traverse all sampling values ​​of the steady wind speed and wind direction within the preset value range, and draw multiple items of apparent approach flight trajectory samples.

[0049] According to some preferred embodiments of the present invention, the simulation method preferably further comprises a verification step, and the verification step comprises:

[0050] Based on a predetermined judgment standard, determining the approach quality of the drawn visual approach flight trajectory sample, 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 flight paths;

[0051] Among them, the visual approach flight trajectory samples that exceed the upper and lower limits are marked as unselectable samples, and the visual approach flight trajectory samples that meet the optimal value range are marked as preferred samples suitable for achieving good fuel economy and stable approach safety.

[0052] Based on this preferred implementation, not only can a large number of test points (i.e., flight trajectory samples) be generated through computer simulation to improve the efficiency of verification work, but also a preliminary automatic evaluation of the approach quality of a large number of test points can be performed to a certain extent, thereby further reducing labor costs.

[0053] More specifically, the step one also includes:

[0054] According to the target aircraft model, parameter values ​​of aircraft parameters associated with the target aircraft model are set, wherein the aircraft parameters include a three-way runway distance, a landing reference speed, a visual approach altitude, a stabilized approach altitude, and a recommended descent rate.

[0055] In addition, the aircraft parameters also include an average roll angle of the aircraft in the first arc transition section, an average roll angle of the aircraft in the second arc transition section, and an angle between the descent trajectory of the aircraft and the horizontal plane in the fifth side.

[0056] Further preferably, the step 4 further comprises:

[0057] The time required for the aircraft to descend from the beginning of descent to the stable approach altitude is calculated based on the visual approach altitude, the stable approach altitude, and the recommended descent rate, and the aircraft's descent apex is further determined by calculating the flight time of each segment of the track.

[0058] Further preferably, the sub-step of drawing the visual approach flight trajectory sample in step five includes drawing the aircraft descent apex.

[0059] 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.

[0060] According to some preferred embodiments of the present invention, in step 3, the sub-step of calculating the true airspeed of the multiple flight paths includes:

[0061] determining the indicated airspeed for each segment of the track based on the approach reference speed;

[0062] Estimate the air density at the visual approach altitude based on the runway threshold elevation and the visual approach altitude;

[0063] The corresponding true airspeed is calculated based on the dynamic pressure corresponding to the indicated airspeed and the air density.

[0064] For example, in the relevant calculations of step 2 to step 4, the indicated airspeed of the tangent runway head, the average indicated airspeed of track L1, and the indicated airspeeds of segmented tracks L2, L3, L4, and L5 can be determined first according to the approach reference speed. The tangent runway head is defined as follows: a vertical line is drawn through the runway threshold on the horizontal plane, and the intersection of the vertical line and L1 is the tangent runway head point.

[0065] In addition, the air density corresponding to the standard atmosphere at the visual approach altitude can be calculated by interpolation method based on the runway threshold elevation and the visual approach altitude H, and the indicated airspeed at the tangent runway head, the average indicated airspeed of track L1, and the dynamic pressures corresponding to the indicated airspeeds of tracks L2, L3, L4, and L5 can be calculated. Then, the corresponding true airspeed can be calculated by using the above dynamic pressures in combination with the air density at the current altitude.

[0066] It can also be understood that the step of using a computer to draw a visual approach flight trajectory sample includes the prediction of the flight trajectory, which can be generally understood as a sequence of segmented tracks based on the derivation and calculation of the position of the starting point of track L5 starting from track L1, and then further calculating the coordinate position of the aircraft's descent apex.

[0067] For example, the timing wind correction method corresponding to the target aircraft model can be used to calculate the timing time of track L1; the average true airspeed, wind component, and flight time of track L1 can be used to calculate the starting point of track L2; the true airspeed of track L2 and the average turning roll angle θ1 of tracks L2 and L4 (which can be determined by relevant parameters of the aircraft model) can be used to calculate the calm wind turning radius corresponding to track L2 and the time required for a turn; the calm wind turning radius of track L2, the time required for a turn, the wind component of track L1, and the wind component of track L3 can be used to calculate the position of the starting point of L5.

[0068] Then, the visual approach altitude H (which can be a predetermined value, generally set to, for example, 1500 feet), the stable approach altitude, and the recommended descent rate can be further used to calculate the time T required for the aircraft to descend from the beginning to the stable altitude; then, the position of the starting point of L5 and the position of the glide path when the aircraft reaches the stable approach altitude θ2 are used to calculate the flight time T1 of the track L3 and the time T2 to turn to L5 and fly to the stable approach point; then, the time T required to descend to the stable altitude and the flight time of each segmented track, combined with the true airspeed of each segment track and the component of the stable wind, are used to calculate the coordinates of the aircraft's descent apex.

[0069] It should be understood that the above description of the calculation process is a brief example of the derivation calculation process between the various parameters therein, and is not intended to limit the scope of protection of the present application, which is defined by the claims attached to the present disclosure.

[0070] According to the simulation method for predicting the visual approach flight trajectory of the above-mentioned preferred embodiment of the present invention, a large number of test points can be efficiently simulated through computer simulation technology for the verification of the aircraft visual approach, which can greatly improve time efficiency and reduce costs.

[0071] Moreover, the relevant tests based on the application examples of the above preferred embodiments show that compared with the traditional flight simulator verification method, the above method can greatly improve the time efficiency of related work while maintaining relatively low costs while ensuring the accuracy and effectiveness of a large number of test points and verification results. Based on relevant tests, the simulation method described above is used to assist in the verification of visual approaches. Under the condition of locked computing power, the improvement in time efficiency may be as high as tens of thousands of times (up to 64,800 times in one test) compared with the traditional flight simulator verification method. On the other hand, in terms of verification costs, compared with the high manpower hours and equipment usage fees included in flight simulators, the use of the simulation method described above can save related costs.

[0072] Although the specific embodiments of the present invention are 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. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A simulation method for predicting a visual approach flight trajectory, wherein the visual approach flight trajectory comprises a plurality of continuous tracks, the plurality of tracks conforming to a predetermined visual approach standard for a target aircraft type, and the terminal segment of the plurality of tracks extends along a runway axis of a target airport to a corresponding runway threshold, characterized in that: The multiple flight paths sequentially include three sides parallel to the runway axis, a first arc transition section, four sides perpendicular to the runway axis, a second arc transition section, and five sides constituting the end of the multiple flight paths and extending along the runway axis to the runway entrance. The simulation method includes the following steps: Step 1: according to the target airport targeted by the visual approach flight trajectory, setting the environmental parameters and aircraft parameters of the target airport in a computer, wherein the environmental parameters include steady wind speed and direction and runway threshold elevation, wherein the steady wind speed and direction are set to initial values ​​within a preset value range, and wherein, according to the target aircraft model, setting the parameter values ​​of the aircraft parameters associated with the target aircraft model, wherein the aircraft parameters include the runway distance from the third leg, the landing reference speed, the visual approach altitude, the stable approach altitude, the recommended descent rate, the average roll angle of the aircraft in the first arc transition section, the average roll angle of the aircraft in the second arc transition section, and the angle between the descent trajectory of the aircraft and the horizontal plane in the fifth leg; Step 2: Correcting the landing reference speed of the aircraft based on the steady wind speed and wind direction to obtain an approach reference speed, and using the approach reference speed to calculate the true airspeed of the multiple flight paths, thereby obtaining the true airspeed of each flight path; Step 3: on the basis of the visual approach standard, according to the true airspeed of each flight path and the set environmental parameters and aircraft parameters, determine the projection position of the starting point and the end point of each flight path in the horizontal plane, and thereby determine the projection trajectory and flight time of each flight path; Step 4: calculating the altitude change in the multiple flight paths according to the true airspeed of each flight path and the set environmental parameters and aircraft parameters; Step 5: using a computer to draw a visual approach flight track sample according to the calculated projection tracks of each track segment and the altitude changes in the multiple tracks; The simulation method also includes: After executing step five, the values ​​of the steady wind speed and wind direction are changed in sequence within the preset value range with a predetermined step size, and then steps two to five are repeatedly executed to traverse all sampling values ​​of the steady wind speed and wind direction within the preset value range, and draw multiple items of apparent approach flight trajectory samples.

2. The simulation method for visual approach flight trajectory according to claim 1, characterized in that: The step 4 also includes: The time required for the aircraft to descend from the beginning of descent to the stable approach altitude is calculated based on the visual approach altitude, the stable approach altitude, and the recommended descent rate, and the aircraft's descent apex is further determined by calculating the flight time of each segment of the track.

3. The simulation method for visual approach flight trajectory according to claim 2, characterized in that: The sub-step of drawing the visual approach flight trajectory sample in step 5 includes drawing the aircraft descent apex.

4. The simulation method for visual approach flight trajectory according to claim 1, 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 visual approach altitude based on the runway threshold elevation and the visual approach altitude; The corresponding true airspeed is calculated based on the dynamic pressure corresponding to the indicated airspeed and the air density.

5. The method for simulating a visual approach flight trajectory according to any one of claims 1 to 4, characterized in that: The simulation method further comprises a verification step, wherein the verification step comprises: Based on a predetermined judgment standard, determining the approach quality of the drawn visual approach flight trajectory sample, 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 flight paths; Among them, the visual approach flight trajectory samples that exceed the upper and lower limits are marked as unselectable samples, and the visual approach flight trajectory samples that meet the optimal value range are marked as preferred samples suitable for achieving good fuel economy and stable approach safety.

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