A waiting state refueling route calculation method based on parallel rendezvous

Abstract

The application provides a parallel rendezvous-based waiting state refueling route calculation method, and belongs to the technical field of route planning, which comprises the following steps: obtaining input refueling route key parameters, including a rendezvous starting point, a rendezvous control point, a refueling speed, a refueling height, a turning roll angle and the like; then, calculating refueling entry headings, turning radii and refueling offsets, turning starting points, turning ending points and the like key points according to the obtained input refueling route key parameters, so as to generate a complete waiting state refueling route. The application can calculate the refueling route according to the position of a receiver aircraft at any time, reduces the waiting time of the receiver aircraft, and improves the refueling efficiency.

Description

Technical Field

[0001] This application belongs to the field of route planning technology, and specifically relates to a method for calculating waiting-state refueling routes based on parallel rendezvous. Background Technology

[0002] With the widespread application of aircraft in fields such as aerial reconnaissance and emergency rescue, the frequency of aircraft performing long-distance or long-duration missions is increasing, which places high demands on the aircraft's endurance in the air, making aerial refueling a necessary means.

[0003] However, during aerial refueling, due to the difference in routes between the tanker and the receiver aircraft, the receiver aircraft often needs to fly slowly in the air to wait for the tanker, which reduces the efficiency of the receiver aircraft in carrying out its mission.

[0004] Therefore, a method is needed to calculate the aerial refueling path for tanker aircraft to reduce the waiting time of the receiving aircraft, increase the flexibility of the refueling route, thereby improving the mission execution efficiency of the aircraft and extending its endurance. Summary of the Invention

[0005] The purpose of this application is to provide a method for calculating waiting refueling routes based on parallel rendezvous, in order to solve or alleviate at least one of the problems in the background art.

[0006] The technical solution of this application is: a method for calculating waiting-state refueling routes based on parallel rendezvous, comprising:

[0007] Step S1: Obtain the current flight plan status of the aircraft and the wind speed and direction of the aircraft. Determine whether to calculate the waiting refueling route based on the flight plan status. If the waiting refueling route is to be calculated, proceed to the next step; otherwise, do not calculate the waiting refueling route.

[0008] Step S2: Obtain the rendezvous start point, rendezvous control point, and refueling altitude during parallel rendezvous; calculate the route distance between the rendezvous start point and the refueling entry heading.

[0009] Step S3: Obtain the refueling speed and calculate the ground speed of the aircraft based on the refueling altitude and the refueling heading.

[0010] Step S4: Obtain the turning roll angle, and calculate the turning radius and refueling offset based on the aircraft's ground speed.

[0011] Step S5: Obtain the length of the waiting refueling route and the entry and exit points of the refueling route. Calculate the center of the first turning circle used for waiting and hovering, as well as its starting and ending points, and the center of the second turning circle, as well as its starting and ending points. By combining the refueling route entry point, rendezvous control point, the center of the first turning circle, as well as its starting and ending points, the center of the second turning circle, as well as its starting and ending points, and the refueling route exit point, the waiting refueling route is obtained.

[0012] In a preferred embodiment of this application, step S1 involves obtaining the aircraft's current flight plan status and the aircraft's wind speed and direction. Based on the flight plan status, it is determined whether to calculate a waiting-for-refueling route. If the waiting-for-refueling route is to be calculated, the next step is executed; otherwise, the waiting-for-refueling route is not calculated. This includes:

[0013] If the flight plan status is determined to be valid, the waiting refueling route is calculated; if the flight plan status is invalid, the waiting refueling route is not calculated.

[0014] In a preferred embodiment of this application, step S2, obtaining the rendezvous start point, rendezvous control point, and refueling altitude during parallel rendezvous, and calculating the route distance between the rendezvous start point and the refueling entry heading, includes:

[0015] Step S21: Determine whether the rendezvous control point is in the navigation database. If it is, proceed to the next step; otherwise, do not proceed to the next step.

[0016] Step S22: When the rendezvous control point is in the navigation database, determine whether the route distance between the rendezvous starting point and the rendezvous control point meets the requirements. If the requirements are met, proceed to the next step; otherwise, do not proceed to the next step.

[0017] Step S23: Calculate the distance between the two points and the refueling heading based on the rendezvous starting point and the rendezvous control point.

[0018] In a preferred embodiment of this application, step S23, calculating the distance between the rendezvous starting point and the rendezvous control point and the refueling entry heading, includes:

[0019] The longitude, latitude, and altitude coordinates of the rendezvous point are ( , The longitude, latitude, and altitude coordinates of the rendezvous control point are (H). , The altitudes of both points (H) are refueling altitudes; the coordinate system used is WGS-84, with the Earth's major axis as the coordinate system. Flatness Earth's short axis Longitude difference ;

[0020] 1. When the rendezvous starting point and the rendezvous control point are at the same longitude, iterative calculation is not required; the flight path distance between the two points is calculated. ;

[0021] 2. When the rendezvous starting point and the rendezvous control point are at different longitudes, iterative processing is required using the following method:

[0022] 1) First iteration:

[0023] The first auxiliary latitude u1 satisfies: ;

[0024] The second auxiliary latitude u2 satisfies: ;

[0025] First iteration starting azimuth angle , Quadrant needs to be determined:

[0026] if : ,but ; ,but ;

[0027] The first iteration central angle of the rendezvous starting point and the rendezvous control point on the sphere ,

[0028] if R is the average radius of the Earth, H t The height threshold;

[0029] but First auxiliary angle , Quadrant needs to be determined;

[0030] First iteration longitude correction ;

[0031] 2) Second iteration:

[0032] make The starting azimuth angle of the second iteration , Quadrant needs to be determined;

[0033] if : ,but ; ,but ;

[0034] The second iteration central angle between the rendezvous starting point and the rendezvous control point on the sphere ;

[0035] if ;

[0036] but ;

[0037] Second auxiliary role , Quadrant needs to be determined;

[0038] Second iteration longitude correction ;

[0039] 3) Third iteration:

[0040] make The starting azimuth of the third iteration , Quadrant needs to be determined:

[0041] if : ,but ; ,but ;

[0042] The central angle of the third iteration on the sphere between the starting point and the control point of the rendezvous ;

[0043] Find ,if ;

[0044] but ;

[0045] Third auxiliary role , Quadrant needs to be determined;

[0046] Third iteration longitude correction ;

[0047] Fourth auxiliary angle , Quadrant needs to be determined;

[0048] make:

[0049] Angle conversion constant ;

[0050] orbital eccentricity satisfies ;

[0051] First correction factor A * satisfy:

[0052] ;

[0053] Second correction factor B* satisfy:

[0054] ;

[0055] Distance parameter S3:

[0056] ;

[0057] After three iterations:

[0058]

[0059]

[0060] For the desired heading angle, This represents the desired flight path distance.

[0061] In a preferred embodiment of this application, step S3, obtaining the refueling speed, and calculating the ground speed of the aircraft based on the refueling altitude and refueling approach heading in step S2, includes:

[0062] Step S31: Determine whether the refueling speed and refueling altitude are both within the predetermined range. If either the refueling speed or the refueling altitude is not met, the corresponding ground speed of the aircraft will not be calculated. If both the refueling speed and the refueling altitude meet the requirements, the corresponding ground speed of the aircraft will be calculated.

[0063] Step S32: When the obtained refueling speed and refueling altitude meet the requirements, calculate the corresponding ground speed V of the aircraft based on the refueling speed, refueling altitude, and refueling entry heading. G :

[0064]

[0065]

[0066] Where: VG is the ground speed of the aircraft;

[0067] V t For the aircraft's vacuum speed;

[0068] V w Wind speed;

[0069] β refuels the aircraft and enters the heading;

[0070] α represents the wind direction;

[0071] H p To refuel at altitude;

[0072] V c To speed up refueling;

[0073] Cn is a sound speed-related parameter;

[0074] R is the air drying ratio;

[0075] Gn is the standard gravitational acceleration.

[0076] In a preferred embodiment of this application, step S4, obtaining the turning roll angle and calculating the turning radius and refueling offset based on the aircraft's ground speed, includes:

[0077] Step S41: Determine whether the obtained turning roll angle is a predetermined angle. If it is a predetermined angle, calculate the turning radius and acceleration offset. If it is not a predetermined angle, do not calculate the turning radius and acceleration offset.

[0078] Step S42, based on the turning roll angle φ and the corresponding ground speed V of the aircraft. G Calculate the turning radius and the acceleration offset, where:

[0079] Turning radius R=(V G / 3.6)*2*1.08 / (1000*g*tanφ), where g is the acceleration due to gravity;

[0080] Refueling offset = 2 * R;

[0081] Step S43: Compare the refueling offset with the offset threshold range. If the refueling offset is within the offset threshold range, proceed to the next step. If the refueling offset is not within the offset threshold range, re-acquire the refueling speed and refueling height, and recalculate.

[0082] In a preferred embodiment of this application, step S5 involves obtaining the length of the waiting refueling route and the refueling route entry and exit points. It also involves calculating the center of the first turning circle used for waiting and circling, along with its starting and ending points, and the center of the second turning circle, along with its starting and ending points. The waiting refueling route is obtained by combining the refueling route entry point, rendezvous control point, the center of the first turning circle, its starting and ending points, the center of the second turning circle, and the refueling route exit point. This includes:

[0083] Step S51: Determine whether the obtained waiting refueling route length is within the refueling route length threshold range. If it is, proceed to the next step; otherwise, re-obtain the waiting refueling route length.

[0084] Step S52: Determine whether the refueling route entry point and the refueling route exit point are both waypoints within the flight plan, and whether the refueling route entry point is located before the refueling route exit point. If the conditions are met, proceed to the next step; otherwise, reacquire the refueling route entry point and the refueling route exit point.

[0085] Step S53: Based on the rendezvous control point, refueling entry heading, turning radius, and length of the holding refueling route, calculate the center of the first turning circle after the rendezvous control point and its starting and ending points, as well as the center of the second turning circle and its starting and ending points. Combine the refueling route entry point, rendezvous control point, center of the first turning circle and its starting and ending points, center of the second turning circle and its starting and ending points, and refueling route exit point to obtain the holding refueling route, which is used for aircraft flight guidance.

[0086] In a preferred embodiment of this application, the process of calculating the center of the first turning circle after the convergence control point, its starting and ending points, and the center of the second turning circle, its starting and ending points, is as follows:

[0087] The starting point of the first turning circle is the rendezvous control point;

[0088] When determining the center of the first turning circle, the following points are defined: rendezvous control point; heading angle: entry heading -90°; route distance: R.

[0089] When determining the end point of the first turning circle, the following points are defined: rendezvous control point; heading angle: entry heading -90°; route distance: 2R.

[0090] When determining the starting point of the second turning circle, the following points are defined: the ending point of the first turning circle; the heading angle is -180° upon entry; and the route distance is the route length.

[0091] When determining the center of the second turning circle, the following points are defined: the starting point of the second turn; the heading angle is +90° upon entry; and the route distance is R.

[0092] When determining the end point of the second turning circle, the following points are defined: rendezvous control point; heading angle: entry heading -180°; and route distance: route length.

[0093] The calculation process is as follows:

[0094] Given the coordinates of a fixed point Given the heading angle ψ and the route distance S, calculate the coordinates of the target point. ;

[0095] Assuming target point Point and Determined Point Elevation, that is ;

[0096] Establish a spherical model and first estimate the target point. The position is determined, and then the position is continuously corrected using position correction methods until the required accuracy is achieved. The specific process is as follows:

[0097] Step 1: Select the north direction for the model, with east as positive. Decomposed into northward-oriented and along the east The distances are respectively , ,in:

[0098] ,

[0099] ,

[0100] Latitude change R is the average radius of the Earth.

[0101] Longitude change ;

[0102] All parameters satisfy:

[0103]

[0104] , , That is, to find the target point The initial location;

[0105] Step 2: Calculate the following in polar coordinates using the method described in step S23. Preliminary estimated route distance and the preliminary estimated heading angle Then, the distance from the given flight path. and heading angle By comparing, we can find point B. Arrival at point A The heading angle and route distance that need to be corrected, and the corrected distance. ;

[0106] Transform the polar coordinate system in the due north direction into the polar coordinate system in the due east direction. ;

[0107] In the due east polar coordinate system, the coordinates of point A are: The coordinates of point B are Let the angle of inclination of line segment AB be... , , ;

[0108] ;

[0109] 1) When point B is to the right of point A, , ;

[0110] 2) When point B is to the left of point A, , ;

[0111] 3) When point B is due north of point A, , , ;

[0112] 4) When point B is due south of point A, , , ;

[0113] Step 3: Longitude Correction

[0114] 1) , ;

[0115] 2) , ;

[0116] Step 4: The correction vector was obtained from step 2. heading angle and corrected distance Substitute back to the first step and then calculate the corrected longitude change. Latitude change , , , To obtain a new target point Then continue with the second step, repeating this process five times until the target point's position is equal to point [missing information]. The location.

[0117] The parallel rendezvous-based waiting-state refueling route calculation method proposed in this application is applicable to in-flight refueling of aircraft, which can improve refueling flexibility, reduce manual intervention, and provide effective support for aircraft to perform refueling missions. Attached Figure Description

[0118] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0119] Figure 1 This is a schematic diagram of the waiting-state refueling route calculation method based on parallel rendezvous in this application.

[0120] Figure 2 A schematic diagram of the refueling route in the waiting state in this application. Detailed Implementation

[0121] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0122] This application proposes a method for calculating refueling routes in a waiting state based on parallel rendezvous. For the calculation of aerial refueling routes for tanker aircraft, the method introduces the position of the receiver aircraft as a coordination mechanism. While meeting mission requirements, it can calculate the refueling route at any time by combining the current position of the receiver aircraft with the relative position relationship between the receiver aircraft and the tanker aircraft. This reduces the waiting time of the receiver aircraft, increases the flexibility of the refueling route, and thus improves the mission execution efficiency of the aircraft and extends its endurance.

[0123] Firstly, as Figure 1 As shown, the method for calculating the waiting refueling route based on parallel rendezvous provided in this application includes the following process:

[0124] Step S1: Obtain the current flight plan status of the aircraft (i.e., the tanker) as well as the aircraft's wind speed and direction. Based on the flight plan status, determine whether to perform the waiting refueling route calculation. If the waiting refueling route calculation is performed, proceed to the next step; otherwise, do not perform the waiting refueling route calculation.

[0125] In some embodiments of this application, the flight plan status is generally obtained through the flight management system. The flight management system integrates various sensors on the aircraft to achieve functions such as flight planning. When the aircraft is in the flight plan state, the flight management system can output a valid (or activated) signal for the flight plan status. If the flight plan status is determined to be valid, the waiting refueling route is calculated; if the flight plan status is invalid, the waiting refueling route is not calculated.

[0126] Step S2: Obtain the rendezvous start point, rendezvous control point, and refueling altitude during parallel rendezvous; calculate the route distance between the rendezvous start point and the refueling entry heading.

[0127] In this application, the specific process of step S2 includes:

[0128] Step S21: Determine whether the rendezvous control point is in the navigation database. If it is, proceed to the next step; otherwise, do not proceed to the next step.

[0129] like Figure 2 The diagram shown illustrates the rendezvous starting point, rendezvous control point, and rendezvous route in this embodiment of the application. In this application, the rendezvous starting point can be any point on the air route, such as any point on the receiver aircraft's forward route. The rendezvous control point, however, must be a data point in the navigation database. If the rendezvous control point is not in the navigation database, a message will be displayed indicating that the refueling parameters are invalid and the rendezvous control point needs to be reset.

[0130] Step S22: When the rendezvous control point is in the navigation database, determine whether the route distance between the rendezvous starting point and the rendezvous control point meets the requirements. If the requirements are met, proceed to the next step; otherwise, do not proceed to the next step.

[0131] In this embodiment of the application, the route distance threshold between two points is set to 130km. That is, it is determined whether the route distance between the rendezvous start point and the rendezvous control point is less than the distance threshold. If it is less than the distance threshold, it is indicated that the set refueling parameters are invalid and the rendezvous start point and rendezvous control point need to be set again. If it is not less than (i.e. greater than or equal to) the distance threshold, the next step is executed.

[0132] Step S23: Calculate the distance between the two points and the refueling heading based on the rendezvous starting point and rendezvous control point mentioned above. The calculation method is as follows:

[0133] The coordinates of the rendezvous point are (longitude) ,latitude (Help, height H), the coordinates of the rendezvous control point are (longitude H). ,latitude The altitudes of both points (H and H) are refueling altitudes. The coordinate system used is WGS-84 (1984 World Geodetic Coordinate System), with the Earth's major axis... =6378137, flatness =1 / 298.257, Earth's minor axis Longitude difference .

[0134] 1. When the rendezvous starting point and the rendezvous control point are at the same longitude, iterative calculation is not required; the distance between the two points is calculated. ;

[0135] 2. When the rendezvous starting point and the rendezvous control point are at different longitudes, iterative processing is required using the following method:

[0136] 1) First iteration:

[0137] The first auxiliary latitude u1 satisfies: ;

[0138] The second auxiliary latitude u2 satisfies: ;

[0139] First iteration starting azimuth angle , Quadrant needs to be determined:

[0140] if : ,but ; ,but ;

[0141] The first iteration central angle of the rendezvous starting point and the rendezvous control point on the sphere ,

[0142] if R is the average radius of the Earth, H t As a height threshold, in this embodiment of the application, R is set to 6371110m, and H... t The value is 5000m;

[0143] but First auxiliary angle , Quadrant needs to be determined;

[0144] First iteration longitude correction ;

[0145] 2) Second iteration:

[0146] make The starting azimuth angle of the second iteration , Quadrant needs to be determined.

[0147] if : ,but ; ,but ;

[0148] The second iteration central angle between the rendezvous starting point and the rendezvous control point on the sphere ;

[0149] if ;

[0150] but ;

[0151] Second auxiliary role , Quadrant needs to be determined;

[0152] Second iteration longitude correction ;

[0153] 3) Third iteration:

[0154] make The starting azimuth of the third iteration , Quadrant needs to be determined:

[0155] if : ,but ; ,but ;

[0156] The central angle of the third iteration on the sphere between the starting point and the control point of the rendezvous ;

[0157] Find ,if ;

[0158] but ;

[0159] Third auxiliary role , Quadrant needs to be determined;

[0160] Third iteration longitude correction ;

[0161] Fourth auxiliary angle , Quadrant needs to be determined;

[0162] make:

[0163] Angle conversion constant ;

[0164] orbital eccentricity satisfies ;

[0165] First correction factor A * satisfy:

[0166] ;

[0167] Second correction factor B * satisfy:

[0168] ;

[0169] Distance parameter S3 satisfies:

[0170] ;

[0171] After three iterations:

[0172]

[0173]

[0174] For the desired heading angle, This represents the desired flight path distance.

[0175] In this application, heading angle The method for determining the quadrant is as follows:

[0176]

[0177] Step S3: Obtain the refueling speed and calculate the ground speed of the aircraft based on the refueling altitude and refueling heading obtained in Step S2.

[0178] In this application, step S3 specifically includes the following process:

[0179] Step S31: Determine whether the refueling speed and refueling altitude are both within the predetermined range. If either the refueling speed or the refueling altitude is not met, the corresponding ground speed of the aircraft will not be calculated, and the set refueling altitude will be displayed as invalid and need to be re-entered. If both the refueling speed and the refueling altitude meet the requirements, the corresponding ground speed of the aircraft will be calculated.

[0180] In this application, the refueling speed is set between 350km / h and 590km / h, and the refueling altitude is set between 0 and 15000m. That is, when both the refueling speed and refueling altitude are within the corresponding range, the corresponding ground speed of the aircraft is calculated.

[0181] Step S32: When the obtained refueling speed and refueling altitude meet the above requirements, calculate the corresponding ground speed V of the aircraft based on the refueling speed, refueling altitude, and refueling entry heading. G :

[0182]

[0183]

[0184] Where: VG is the ground speed of the aircraft;

[0185] V t For the aircraft's vacuum speed;

[0186] V w Wind speed;

[0187] β refuels the aircraft and enters the heading;

[0188] α represents the wind direction;

[0189] H p To refuel at altitude;

[0190] V c To speed up refueling;

[0191] Cn is a sound speed-related parameter, usually the standard sound speed or the sound speed under specific atmospheric conditions;

[0192] R is the air drying ratio, R = 287.05287m 2 / ks 2 ;

[0193] Gn is the standard gravitational acceleration, Gn = 9.80665 m / s.

[0194] Step S4: Obtain the turning roll angle, and calculate the turning radius and refueling offset based on the aircraft's ground speed obtained in step S30.

[0195] In this application, step S4 specifically includes the following process:

[0196] Step S41: Determine whether the obtained turning roll angle is a predetermined angle. If it is a predetermined angle, calculate the turning radius and refueling offset. If it is not a predetermined angle, do not calculate the turning radius and refueling offset.

[0197] In some embodiments of this application, the predetermined angle of the turning roll angle is 15 degrees or 25 degrees. The turning radius and acceleration offset are calculated only when the input turning roll angle is 15 degrees or 25 degrees; otherwise, the turning radius and acceleration offset are not calculated.

[0198] Step S42: Calculate the aircraft's ground speed V based on the turning roll angle φ and the values ​​obtained in step S3. G Calculate the turning radius and the acceleration offset, where:

[0199] Turning radius R=(V G / 3.6)*2*1.08 / (1000*g*tanφ), where g is the acceleration due to gravity;

[0200] Refueling offset = 2 * R.

[0201] Step S43: Compare the refueling offset with the offset threshold range. If the refueling offset is within the offset threshold range, proceed to the next step. If the refueling offset is not within the offset threshold range, prompt that the set refueling parameters are invalid and you need to re-enter the refueling speed and refueling height and recalculate.

[0202] In some embodiments of this application, the offset threshold range is set to 13km to 37km. That is, if the calculated refueling offset is within the range of 13km to 37km, the next step is performed; otherwise, the refueling speed and refueling height are re-entered.

[0203] Step S5: Obtain the route length of the waiting refueling route and the refueling route entry and exit points. Calculate the center of the first turning circle used for waiting and hovering, as well as its turning start and end points, and the center of the second turning circle, as well as its turning start and end points. By combining the refueling route entry point, rendezvous control point, the center of the first turning circle, as well as its turning start and end points, the center of the second turning circle, as well as its turning start and end points, and the refueling route exit point, the waiting refueling route is obtained.

[0204] In this application, step S5 specifically includes the following process:

[0205] Step S51: Determine whether the obtained waiting refueling route length is within the refueling route length threshold range. If it is, proceed to the next step; otherwise, indicate that the set refueling parameters are invalid.

[0206] In some embodiments of this application, the refueling route length threshold range is set to 1km to 130km. When the input waiting refueling route length is within the above-mentioned refueling route length threshold range, the next step is performed; otherwise, the set refueling parameters are indicated as invalid, and the next step is not performed. The route length of the waiting refueling route needs to be re-entered.

[0207] Step S52: Determine whether the refueling route entry point and the refueling route exit point are both waypoints within the flight plan, and whether the refueling route entry point is located before the refueling route exit point. If the above conditions are met, proceed to the next step. If not, prompt that the set refueling parameters are invalid and that the refueling route entry point and the refueling route exit point need to be re-entered.

[0208] Step S53: Based on the rendezvous control point, the refueling entry heading obtained in step S2, the turning radius obtained in step S4, and the refueling route length in step S5, calculate the center of the first turning circle after the rendezvous control point and its turning start and end points, as well as the center of the second turning circle and its turning start and end points. Combine the refueling route entry point, rendezvous control point, center of the first turning circle and its turning start and end points, center of the second turning circle and its turning start and end points, and refueling route exit point to obtain the waiting refueling route, which is used for guiding the aircraft (tanker) flight.

[0209] In this application, the points along the aforementioned refueling route are:

[0210] The starting point of the first turning circle is the rendezvous control point;

[0211] When determining the center of the first turning circle, the following points are defined: rendezvous control point; heading angle: entry heading -90°; route distance: R.

[0212] When determining the end point of the first turning circle, the following points are defined: rendezvous control point; heading angle: entry heading -90°; route distance: 2R.

[0213] When determining the starting point of the second turning circle, the following points are defined: the ending point of the first turning circle; the heading angle is -180° upon entry; and the route distance is the route length.

[0214] When determining the center of the second turning circle, the following points are defined: the starting point of the second turn; the heading angle is +90° upon entry; and the route distance is R.

[0215] When determining the end point of the second turning circle, the following points are defined: rendezvous control point; heading angle: entry heading -180°; and route distance: route length.

[0216] The calculation process is as follows:

[0217] Given the coordinates of a fixed point Given the heading angle ψ and the route distance S, calculate the coordinates of the target point. .

[0218] Assuming target point and fixed point Elevation, that is .

[0219] Establish a spherical model and first estimate the target point. The position is determined, and then the position is continuously corrected using position correction methods until the required accuracy is achieved. The specific process is as follows:

[0220] Step 1: Select the north direction for the model, with east as positive. Decomposed into northward-oriented and along the east The distances are respectively , ,in:

[0221] Distance component along due north ,

[0222] Distance component along the due east direction ,

[0223] Latitude change R is the average radius of the Earth.

[0224] Longitude change ;

[0225] All parameters satisfy:

[0226]

[0227] , , ;

[0228] That is, to find Initial location.

[0229] Step 2: Calculate the following in polar coordinates using the method described in step S23. Preliminary estimated route distance and the preliminary estimated heading angle Then, the distance from the given flight path. and heading angle By comparing, we can find point B. Arrival at point A The heading angle and route distance that need to be corrected, and the corrected distance. .

[0230] Transform the polar coordinate system in the due north direction into the polar coordinate system in the due east direction. .

[0231] In the due east polar coordinate system, the coordinates of point A are: The coordinates of point B are Let the inclination angle of the AB route segment be... , , .

[0232] ;

[0233] 1) When point B is to the right of point A, , ;

[0234] 2) When point B is to the left of point A, , ;

[0235] 3) When point B is due north of point A, , , ;

[0236] 4) When point B is due south of point A, , , ;

[0237] Step 3: Longitude Correction

[0238] 1) , ;

[0239] 2) , ;

[0240] Step 4: The correction vector was obtained from step 2. heading angle Distance from flight path Substitute back to the first step and then calculate the corrected longitude change. Latitude change , , , To obtain a new target point Then continue with the second step, repeating this process five times until the target point's position is equal to point [missing information]. The location.

[0241] This application proposes a method for calculating refueling routes in a waiting state based on parallel rendezvous. This method acquires key parameters of the input refueling route, including the rendezvous start point, rendezvous control point, refueling speed, refueling altitude, and turning roll angle. Then, based on these parameters, it calculates key points such as the refueling entry heading, turning radius and refueling offset, turning start point, and turning end point, thereby generating a complete waiting refueling route. This method can calculate the refueling route at any time based on the receiver aircraft's position, reducing receiver aircraft waiting time and improving refueling efficiency. It optimizes the refueling path by utilizing the relative positional relationship between the refueling and receiver aircraft. By designing a complete waiting refueling calculation logic, only key parameters are needed to quickly generate a complete refueling route. It can automatically generate complete waiting refueling routes, reducing manual intervention. This method can be widely applied in avionics systems, providing efficient and reliable refueling route calculation support for flight management systems.

[0242] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for calculating refueling routes in a waiting state based on parallel rendezvous, characterized in that, include: Step S1: Obtain the current flight plan status of the aircraft and the wind speed and direction of the aircraft. Determine whether to calculate the waiting refueling route based on the flight plan status. If the waiting refueling route is to be calculated, proceed to the next step; otherwise, do not calculate the waiting refueling route. Step S2: Obtain the rendezvous start point, rendezvous control point, and refueling altitude during parallel rendezvous; calculate the route distance between the rendezvous start point and the refueling entry heading. Step S3: Obtain the refueling speed and calculate the ground speed of the aircraft based on the refueling altitude and the refueling heading. Step S4: Obtain the turning roll angle, and calculate the turning radius and refueling offset based on the aircraft's ground speed. Step S5: Obtain the length of the waiting refueling route and the entry and exit points of the refueling route. Calculate the center of the first turning circle used for waiting and hovering, as well as its starting and ending points, and the center of the second turning circle, as well as its starting and ending points. By combining the refueling route entry point, rendezvous control point, the center of the first turning circle, as well as its starting and ending points, the center of the second turning circle, as well as its starting and ending points, and the refueling route exit point, the waiting refueling route is obtained.

2. The method for calculating refueling routes in a waiting state based on parallel rendezvous as described in claim 1, characterized in that, Step S1: Obtain the aircraft's current flight plan status and wind speed and direction. Based on the flight plan status, determine whether to calculate the refueling route while waiting. If the refueling route calculation is performed, proceed to the next step; otherwise, do not perform the calculation. This includes: If the flight plan status is determined to be valid, the waiting refueling route is calculated; if the flight plan status is invalid, the waiting refueling route is not calculated.

3. The method for calculating refueling routes in a waiting state based on parallel rendezvous as described in claim 2, characterized in that, Step S2: Obtain the rendezvous start point, rendezvous control point, and refueling altitude during the parallel rendezvous; calculate the route distance between the rendezvous start point and the refueling entry heading, including: Step S21: Determine whether the rendezvous control point is in the navigation database. If it is, proceed to the next step; otherwise, do not proceed to the next step. Step S22: When the rendezvous control point is in the navigation database, determine whether the route distance between the rendezvous starting point and the rendezvous control point meets the requirements. If the requirements are met, proceed to the next step; otherwise, do not proceed to the next step. Step S23: Calculate the distance between the two points and the refueling heading based on the rendezvous starting point and the rendezvous control point.

4. The method for calculating refueling routes in a waiting state based on parallel rendezvous as described in claim 3, characterized in that, Step S23, calculating the distance between the rendezvous starting point and the rendezvous control point and the refueling entry heading based on the rendezvous starting point and the rendezvous control point, including: The longitude, latitude, and altitude coordinates of the rendezvous point are ( , The longitude, latitude, and altitude coordinates of the rendezvous control point are (H). , The altitudes of both points (H) are refueling altitudes; the coordinate system used is WGS-84, with the Earth's major axis at . Flatness Earth's short axis Longitude difference ; 1. When the rendezvous starting point and the rendezvous control point are at the same longitude, iterative calculation is not required; the flight path distance between the two points is calculated. ; 2. When the rendezvous starting point and the rendezvous control point are at different longitudes, iterative processing is required using the following method: 1) First iteration: The first auxiliary latitude u1 satisfies: ; The second auxiliary latitude u2 satisfies: ; First iteration starting azimuth angle , Quadrant needs to be determined: if : ,but ; ,but ; The first iteration central angle of the rendezvous starting point and the rendezvous control point on the sphere , if R is the average radius of the Earth, H t The height threshold; but First auxiliary angle , Quadrant needs to be determined; First iteration longitude correction ; 2) Second iteration: make The starting azimuth angle of the second iteration , Quadrant needs to be determined; if : ,but ; ,but ; The second iteration central angle between the rendezvous starting point and the rendezvous control point on the sphere ; if ; but ; Second auxiliary role , Quadrant needs to be determined; Second iteration longitude correction ; 3) Third iteration: make The starting azimuth of the third iteration , Quadrant needs to be determined: if : ,but ; ,but ; The central angle of the third iteration on the sphere between the starting point and the control point of the rendezvous ; Find ,if ; but ; Third auxiliary role , Quadrant needs to be determined; Third iteration longitude correction ; Fourth auxiliary angle , Quadrant needs to be determined; make: Angle conversion constant ; orbital eccentricity satisfies ; First correction factor A * satisfy: ； Second correction factor B * satisfy: ； Distance parameter S3 satisfies: ； After three iterations: ； ； For the desired heading angle, This represents the desired flight path distance.

5. The method for calculating refueling routes in a waiting state based on parallel rendezvous as described in claim 4, characterized in that, Step S3: Obtain the refueling speed. Based on the refueling altitude and refueling approach heading obtained in Step S2, calculate the aircraft's ground speed, including: Step S31: Determine whether the refueling speed and refueling altitude are both within the predetermined range. If either the refueling speed or the refueling altitude is not met, the corresponding ground speed of the aircraft will not be calculated. If both the refueling speed and the refueling altitude meet the requirements, the corresponding ground speed of the aircraft will be calculated. Step S32: When the obtained refueling speed and refueling altitude meet the requirements, calculate the corresponding ground speed V of the aircraft based on the refueling speed, refueling altitude, and refueling entry heading. G : Where: V G This represents the ground speed of the aircraft. V t For the aircraft's vacuum speed; V w Wind speed; β refuels the aircraft and enters the heading; α represents the wind direction; H p To refuel at altitude; V c To speed up refueling; Cn is a sound speed-related parameter; R is the air drying ratio; Gn is the standard gravitational acceleration.

6. The method for calculating refueling routes in a waiting state based on parallel rendezvous as described in claim 5, characterized in that, Step S4: Obtain the turning roll angle, and calculate the turning radius and refueling offset based on the aircraft's ground speed, including: Step S41: Determine whether the obtained turning roll angle is a predetermined angle. If it is a predetermined angle, calculate the turning radius and acceleration offset. If it is not a predetermined angle, do not calculate the turning radius and acceleration offset. Step S42, based on the turning roll angle φ and the corresponding ground speed V of the aircraft. G Calculate the turning radius and the acceleration offset, where: Turning radius R=(V G / 3.6)*2*1.08 / (1000*g*tanφ), where g is the acceleration due to gravity; Refueling offset = 2 * R; Step S43: Compare the refueling offset with the offset threshold range. If the refueling offset is within the offset threshold range, proceed to the next step. If the refueling offset is not within the offset threshold range, re-acquire the refueling speed and refueling height, and recalculate.

7. The method for calculating refueling routes in a waiting state based on parallel rendezvous as described in claim 6, characterized in that, Step S5: Obtain the length of the waiting refueling route and the entry and exit points of the refueling route. Calculate the center of the first turning circle used for waiting and circling, along with its starting and ending points, and the center of the second turning circle, along with its starting and ending points. By combining the refueling route entry point, rendezvous control point, the center of the first turning circle, its starting and ending points, the center of the second turning circle, and the refueling route exit point, the waiting refueling route is obtained, including: Step S51: Determine whether the obtained waiting refueling route length is within the refueling route length threshold range. If it is, proceed to the next step; otherwise, re-obtain the waiting refueling route length. Step S52: Determine whether the refueling route entry point and the refueling route exit point are both waypoints within the flight plan, and whether the refueling route entry point is located before the refueling route exit point. If the conditions are met, proceed to the next step; otherwise, reacquire the refueling route entry point and the refueling route exit point. Step S53: Based on the rendezvous control point, refueling entry heading, turning radius, and length of the holding refueling route, calculate the center of the first turning circle after the rendezvous control point and its starting and ending points, as well as the center of the second turning circle and its starting and ending points. Combine the refueling route entry point, rendezvous control point, center of the first turning circle and its starting and ending points, center of the second turning circle and its starting and ending points, and refueling route exit point to obtain the holding refueling route, which is used for aircraft flight guidance.

8. The method for calculating refueling routes in a waiting state based on parallel rendezvous as described in claim 7, characterized in that, The process of calculating the center of the first turning circle after the rendezvous control point, as well as its starting and ending points, and the center of the second turning circle, as well as its starting and ending points, is as follows: The starting point of the first turning circle is the rendezvous control point; When determining the center of the first turning circle, the following points are defined: rendezvous control point; heading angle: entry heading -90°; route distance: R. When determining the end point of the first turning circle, the following points are defined: rendezvous control point; heading angle: entry heading -90°; route distance: 2R. When determining the starting point of the second turning circle, the following points are defined: the ending point of the first turning circle; the heading angle is -180° upon entry; and the route distance is the route length. When determining the center of the second turning circle, the following points are defined: the starting point of the second turn; the heading angle is +90° upon entry; and the route distance is R. When determining the end point of the second turning circle, the following points are defined: rendezvous control point; heading angle: entry heading -180°; and route distance: route length. The calculation process is as follows: Given the coordinates of a fixed point Given the heading angle ψ and the route distance S, calculate the coordinates of the target point. ; Assuming target point and fixed point Elevation, that is ; Establish a spherical model and first estimate the target point. The position is determined, and then the position is continuously corrected using position correction methods until the required accuracy is achieved. The specific process is as follows: Step 1: Select the north direction and east direction as positive for the model. Decomposed into northward-oriented and along the east The distances are respectively , ,in: Distance component along due north , Distance component along the due east direction , Latitude change R is the average radius of the Earth. Longitude change ; All parameters satisfy: , , That is, to find the target point The initial location; Step 2: Calculate the following in polar coordinates using the method described in step S23. Preliminary estimated route distance and the preliminary estimated heading angle Then, the distance from the given flight path. and heading angle By comparing, we can find point B. Arrival at point A The heading angle and route distance that need to be corrected, and the corrected distance. ; Transform the polar coordinate system in the due north direction into the polar coordinate system in the due east direction. ; In the due east polar coordinate system, the coordinates of point A are: The coordinates of point B are Let the angle of inclination of line segment AB be... , , ; ； 1) When point B is to the right of point A, , ; 2) When point B is to the left of point A, , ; 3) When point B is due north of point A, , , ; 4) When point B is due south of point A, , , ; Step 3: Longitude Correction 1） ， ； 2） ， ； Step 4: The correction vector was obtained from step 2. heading angle and corrected distance Substitute back to the first step and then calculate the corrected longitude change. Latitude change , #imgpt124#, #imgpt125#, #imgpt126#, to get the new target point #imgpt127#, then continue to the second step, repeating this correction 5 times, the position of the target point is equal to the position of point #imgpt128#.

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