A flight time interval calculation method based on horizontal course and ground speed profile

Abstract

The application provides a kind of aircraft longitudinal time interval calculation method based on horizontal route and ground speed profile. First, calculate the initial horizontal route according to the preset track point, calculate the heading change, turning radius, turning start point, end point and center according to the initial ground speed and inclination angle;Then, according to the track segment model and the speed, height limit, combined with the speed, height, wind and temperature information in the initial horizontal route, calculate the initial ground speed profile and the position of the aircraft along the route;Using the above calculation results, the horizontal route and the ground speed profile are updated iteratively;Finally, the time of the aircraft passing through each flight segment is obtained from the horizontal route and the ground speed profile, and the time interval between different aircrafts is predicted. Through the position and height information of the host and target aircrafts, and considering the influence factors such as wind speed and temperature, the longitudinal interval of the aircraft can be accurately calculated, further realizing the interval management, and improving the precision and continuity of the interval.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of civil aviation surveillance, and in particular to a flight time interval calculation method based on horizontal route and ground speed profile. BACKGROUND

[0002] In the field of civil aviation, the traditional enroute along ground navigation station design, aircraft fly along the navigation station in order, the longitudinal interval between aircrafts on the enroute is set as a fixed value, and the ground controller is responsible for monitoring whether the aircraft interval meets the requirements. The disadvantage of this navigation mode is that the enroute traffic is limited, the enroute is crowded during peak hours, and the controller load is heavy. The regional navigation RNAV (Regional Area Navigation) breaks the limit of fixed enroute, and the RNAV allows the aircraft to fly along any desired route within the coverage of navigation signals or within the working capability range of the onboard navigation equipment. Furthermore, the required performance navigation RNP (Required Navigation Performance) and the performance-based navigation PBN (Performance-Based Navigation) also allow the aircraft to no longer fly along the fixed enroute, and these navigation modes are considered as the core of the next generation navigation system. The new navigation mode establishes an enroute point database, and the controller allocates respective enroute points for each aircraft, and the aircrafts with the same destination fly along different routes to reach the same terminal, and maintaining the interval between aircrafts is the key to safe enroute flight. The role of interval management is to calculate the real-time interval between the host aircraft and the target aircraft through the position and speed of the host aircraft and the target aircraft, as well as the environmental information, and to provide interval operation suggestions for the pilot. The target aircraft is specified by the ground controller, and is the aircraft that may cause interval risk, and the controller also specifies the interval target with the target aircraft, and the interval management system is installed in the cockpit of the aircraft to assist the pilot to operate and reduce the load of the controller.

[0003] Since the aircrafts fly along different routes, the host aircraft and the target aircraft reach the same planned termination point PTP (Planed Termination Point), and the controller specifies one same achieve-by point ABP (Achieve-by Point) for the two aircrafts, and the maintenance stage between the ABP and the PTP is straight flight, and the interval calculation is relatively simple, while the achieve stage before reaching the ABP (Achieve Stage), the aircraft flies along the specified enroute point, the direction of the enroute point involves turning, and the speed of the aircraft is affected by the wind speed, and it is necessary to design an accurate interval calculation algorithm to provide a reliable reference for interval management. SUMMARY

[0004] Therefore, the present application takes the ADS-B information of the target aircraft, the information of the local and environmental sensors as input, comprehensively considers the positions, speeds, wind and temperature of the local and target aircrafts, and the predetermined waypoints of the aircraft, proposes to convert the aircraft route into a horizontal route, the aircraft speed into a ground speed profile, calculates the turning path, and predicts the time for the local and target aircrafts to reach the ABP, so as to obtain the predicted time interval.

[0005] The first aspect of the present application provides a flight time interval calculation method based on a horizontal route and a ground speed profile, the method comprising:

[0006] S1, according to the waypoint sequence defined by the expected flight track information, calculating an initial horizontal route, the initial horizontal route being a horizontal route described according to a series of horizontal route conversion points HPT; according to the initial ground speed and the tilt angle during the turning, calculating the heading change, the turning radius, the start point, the end point, the center of the turning, and the along-route distance between each horizontal route conversion point HPT and the planned end point;

[0007] S2, based on the track segment model and the speed and height limits set by the program, combining the along-route speed, height, wind and temperature information in the initial horizontal route, calculating the initial ground speed profile and the current along-route position of the local aircraft;

[0008] S3, according to the ground speed profile calculated in S2, recalculating the horizontal route using the accurate estimated value of the ground speed at the turning;

[0009] S4, if the along-route speed, height, wind and temperature information changes, recalculating the ground speed profile based on the horizontal route obtained in S3 and the changed speed, height, wind and temperature information to generate an updated ground speed profile; re-executing S3 according to the updated ground speed profile to recalculate the horizontal route;

[0010] S5, calculating the TTG of the local and target aircrafts based on the ground speed profile and the current along-route distance to obtain the predicted time interval.

[0011] Further, the S5, calculating the TTG of the local and target aircrafts based on the ground speed profile and the current along-route distance to obtain the time interval, comprises:

[0012] Before the target aircraft passes through the arrival point, the predicted time interval PSI(t) refers to the time interval difference between the time TTG O (t) of the local aircraft passing through the arrival point from the current along-route position and the TTG T (t) of the target aircraft, and is expressed as:

[0013] PSI(t)=TTG O (t)-TTG T (t)

[0014] After the target aircraft passes the arrival point, but before the local aircraft passes the arrival point, the prediction time interval PSI(t) at time t is the local aircraft's TTG. O The difference between (t) and the target aircraft's actual arrival time (ATA) at the arrival point is expressed as:

[0015] PSI(t) = (TTG O (t)+t)-ATA T .

[0016] Furthermore, S1 includes:

[0017] S11, Determine the waypoint sequence: First, convert the IFPI (Intended Flight Path Information) data from the navigation database into a waypoint sequence. Waypoints are represented using wpt. i Let i = 1, ..., N; the horizontal route transition points are calculated using HPT. j Let j = 1, ..., M, M = 2m + 2, where m is the number of turns; the waypoints at the turns are represented by two HPTs, indicating the start and end points of the turns.

[0018] S12, Calculate the heading change between waypoints: The coordinates of each waypoint are (x, y), and the heading θ between two waypoints is... i :

[0019]

[0020] The heading angle is measured counterclockwise along the x-axis, defined as ranging from 0 to 2π; the heading change Δθ is wpt. i+1 and WPT i The heading θ between i and WPT i and WPT i-1 The heading θ between i-1 The difference; the heading change Δθ is defined as [-π, π] to prevent the heading change from exceeding 180 degrees;

[0021] S13, Calculate the turning radius: If a fixed radius RF (Radius-to-Fix) segment is used, the turning radius R is the distance from the turning center to the end point. For other segments, the turning radius is a function of ground speed and the assumed turning angle.

[0022]

[0023] Among them, V GS Here, g is the assumed ground speed, g is the acceleration due to gravity, and φ is the assumed lean angle during the turn; assuming the maximum lean angle is 23°, the lean angle φ is:

[0024]

[0025] S14, calculate the start, end and center of the turn: if RF leg is used, the turn center and turn end are determined in the navigation database, the turn start is the end of the previous leg, otherwise the start and end of the turn are calculated according to the waypoint, turn radius and heading change;

[0026] S15, calculate the distance to go (DTG) of each HPT to the planned end point: for two consecutive straight legs, the DTG of the jth HPT is the along-track distance from the (j-1)th HPT plus the distance between the jth and (j-1)th HPT; for a non-RF turn leg, there are two HPTs marked as the start and end of the turn; the along-track distance at the start of the turn is the along-track distance from the next HPT to the end of the turn plus the along-track distance of the previous HPT; the along-track distance at the turn is the arc length derived from the turn radius and the change in track angle.

[0027] Further, the S2 comprises:

[0028] S21, trajectory segment modeling: perform trajectory segment modeling according to different leg types, the output of each trajectory segment is the derivative of the along-track position (ds / dt), height (dh / dt) and true airspeed (da / dt) as a function of time, then integrate them with respect to time;

[0029] S22, calculate wind speed information: the wind speed information is divided into two components V w，x，i and V w，y，i , which represent the wind speed in the x and y directions at the height h i ; use a sample fitting algorithm to calculate the predicted wind speed at the specified height and , where the parallel wind and the vertical wind relative to the aircraft wind speed are represented as:

[0030]

[0031]

[0032] where θ represents the heading, are the wind speed fitting values in the x and y directions, respectively;

[0033] S23, calculate temperature information: use the International Standard Atmosphere (ISA) model to determine the relationship between temperature and altitude, and use the following equation to define the ISA model:

[0034] T(H p ​)=T0+ΔT+β*H trop H p ≥H trop

[0035] T(H p )=T0+ΔT+β*H p H p ≤H trop

[0036] Where, T0 = 288.15 K, β = -0.0065 K / m, H p The potential height is expressed in meters, ΔT is the ISA deviation, and H... trop =11000m is the geopotential height of the tropopause;

[0037] S24, Calculate height and speed limits: Determine height and speed limits based on the IFPI element or the default height and speed limit settings;

[0038] S25, Calculate the position along the flight path of the current position: The position along the flight path of the aircraft and the target aircraft is determined by projecting their current horizontal position onto the horizontal flight path.

[0039] Furthermore, S25 also includes: the coordinates (x, y) of the waypoint and the HPT when j = 1...M. j The distance between them is calculated using Euclidean distance; the minimum distance d is calculated from this distance. j Starting with the HPT, calculate the cross-track error between the aircraft position and the horizontal path; if the absolute value of the cross-track error is less than 2.5 nmi, determine the downstream HPT; otherwise, use the second minimum value d. j Check the cross-track error of the HPT; continue comparing cross-track errors until an HPT that meets the 2.5 nmi threshold is found, and then use the downstream HPT to calculate the position and distance along the route.

[0040] Furthermore, S14 also includes a turning endpoint (x) turn_end y turn_end The calculation is as follows:

[0041]

[0042]

[0043] Where L is wpt i and WPT i+1 The distance between them, R is the turning radius, θ i The current heading is represented by Δθ, which represents the change in heading.

[0044] If Δθ < 0, the turning center (xturn_center turn_center turn_start turn_start

[0045]

[0046]

[0047]

[0048]

[0049] turn_center turn_center turn_start turn_start

[0050]

[0051]

[0052]

[0053]

[0054] In addition, the second aspect of the present application provides an electronic device, comprising: one or more processors, a memory for storing one or more computer programs; the computer programs are configured to be executed by the one or more processors, and the programs comprise steps for executing the flight time interval calculation method based on the water prediction time interval flat track and the ground speed profile as described above.

[0055] In addition, the third aspect of the present application provides a storage medium, which stores a computer program; the program is loaded and executed by a processor to realize the flight time interval calculation method based on the water prediction time interval flat track and the ground speed profile as described above.

[0056] ​​​​​​​​​In the scheme of the present application, an initial horizontal route is calculated according to a sequence of waypoints defined by expected flight track information, the initial horizontal route being a horizontal route described according to a series of horizontal route transition points HPT; a heading change, a turn radius, a start point, an end point, a center of the turn, and an along-track distance between each horizontal route transition point HPT and a planned end point are calculated according to an initial ground speed during the turn and a tilt angle; an initial ground speed profile and a current along-track position of the aircraft are calculated based on a track segment model and a speed and altitude limit set by a procedure, in combination with along-track speed, altitude, wind and temperature information in the initial horizontal route; the horizontal route is recalculated using a precise estimate of the ground speed at the turn according to the calculated ground speed profile; if the along-track speed, altitude, wind and temperature information changes, a ground speed profile is recalculated based on the horizontal route obtained in S3 and the changed along-track speed, altitude, wind and temperature information to generate an updated ground speed profile; the horizontal route is recalculated according to the updated ground speed profile; the time to go TTG of the aircraft and the target aircraft is calculated based on the ground speed profile and the current along-track distance to obtain a predicted time interval. By comprehensively considering the positions, speeds, wind and temperature of the aircraft and the target aircraft, the planned waypoints of the aircraft, converting the aircraft route into a horizontal route and the aircraft speed into a ground speed profile, the turn path is calculated and iteratively updated, and the time for the aircraft and the target aircraft to reach the ABP is predicted, so that the time interval is accurately predicted. BRIEF DESCRIPTION OF DRAWINGS

[0057] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. Other related drawings can also be obtained by those skilled in the art without creative labor.

[0058] Figure 1 A flowchart of the flight time interval calculation method based on horizontal route and ground speed profile disclosed in the present embodiment;

[0059] Figure 2 A schematic diagram of the horizontal route described based on horizontal route transition HPT points disclosed in the present embodiment;

[0060] Figure 3 A flowchart of the calculation of the horizontal route disclosed in the present embodiment;

[0061] Figure 4 A structure diagram of the track segment type disclosed in the present embodiment;

[0062] Figure 5 A flowchart of the calculation of the shortest along-track position of the current horizontal position disclosed in the present embodiment;

[0063] Figure 6 A flow chart of the principle of iteratively updating the computation interval disclosed in this embodiment;

[0064] Figure 7 A simulated horizontal flight path generated step by step according to a sequence of waypoints disclosed in this embodiment;

[0065] Figure 8 A simulation result of measuring the time interval between the local aircraft and the target aircraft disclosed in this embodiment. DETAILED DESCRIPTION

[0066] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations may, however, be implemented in many different forms and should not be construed as limited to the examples set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of example implementations to those skilled in the art.

[0067] Moreover, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the application. One skilled in the relevant art will recognize, however, that the

[0068] The block diagrams in the drawings show only the functionality of the embodiments and do not necessarily imply a physical structure or organization. That is, the functionality can be implemented in software, hardware, or a combination of the two. For example, the functionality can be implemented in software executed by one or more hardware processors or microcontrollers.

[0069] The flow diagrams depicted in the figures are merely exemplary and do not necessarily include all of the steps or operations, nor do they necessarily indicate the order in which the steps or operations can be performed. For example, some operations can be performed in parallel, some operations can be omitted, and some operations can be performed in a different order than depicted in the figures. Furthermore, the flow diagrams can be implemented in software, hardware, or a combination of the two.

[0070] The following describes in detail the implementation of the technical solutions of the embodiments of the application:

[0071] This embodiment proposes a flight time interval calculation method based on horizontal flight lines and ground speed profiles for flight interval management of aircraft in a flight path. The method uses horizontal flight lines and ground speed profiles to represent the flight path of the aircraft and the segment speed, and uses the time TTG O (t) of the local aircraft from the current position along the flight path to the arrival point and the TTGT The difference between the time intervals (t) represents the predicted spacing interval (PSI). The initial horizontal path is calculated according to the pre-set waypoints. The initial ground speed profile is calculated according to the flight path segment model and the speed, height, wind and temperature information in the initial horizontal path. Through dynamic iteration, more accurate horizontal path and ground speed profile are obtained to calculate the time-to-go (TTG) of the aircraft to the arrival point.

[0072] Referring to Figure 1 , Figure 1 is a flowchart of a flight time interval calculation method based on a horizontal path and a ground speed profile according to an embodiment of the present application. As shown in Figure 1 , the flight time interval calculation method based on a horizontal path and a ground speed profile according to an embodiment of the present application comprises:

[0073] S1, according to the waypoint sequence defined by the expected flight path information, calculate the initial horizontal path, which is a horizontal path described according to a series of horizontal path transition points (HPT); according to the initial ground speed and the inclination angle during the turn, calculate the heading change, the turn radius, the start point, the end point, the center of the turn, and the along-path distance between each horizontal path transition point (HPT) and the planned end point.

[0074] Specifically, the embodiment performs horizontal path projection. The flight path of the aircraft is determined by the four-dimensional flight path information of ADS-B, including the horizontal position and height changing over time. In order to determine the time-to-go (TTG) of the home or target aircraft to the arrival point (ABP) at time t, the horizontal position of the corresponding aircraft at time t is orthogonally projected onto its horizontal path to obtain the position along the horizontal path at that time.

[0075] Further, the input for calculating the initial horizontal path is the ground speed estimate value of the aircraft during the turn, the waypoint sequence and the assumption of the turn inclination angle. The output is a horizontal path described by a series of horizontal path transition (HPT) points, as shown in Figure 2 The horizontal path described by the horizontal path transition (HPT) points is shown in the figure, and the HPT is represented by a circle point, representing the start and end points of the turn and straight line segment. The dashed line represents the straight line path connecting the waypoints, and the dashed line represents the continuous horizontal path passing through the HPT, as shown in Figure 3 The flowchart of the calculation of the horizontal path of the embodiment is shown. Wherein, the S1 comprises:

[0076] S11, determine the waypoint sequence: first convert the IFPI data in the navigation database into a waypoint sequence, and the waypoint is represented by wpt iLet i = 1, ..., N; the horizontal route transition points are calculated using HPT. j Let j = 1, ..., M, M = 2m + 2, where m is the number of turns; the waypoints at the turns are represented by two HPTs, indicating the start and end points of the turns.

[0077] S12, Calculate the heading change between waypoints: The coordinates of each waypoint are (x, y), and the heading θ between two waypoints is... i :

[0078]

[0079] The heading angle is measured counterclockwise along the x-axis, defined as ranging from 0 to 2π; the heading change Δθ is wpt. i+1 and WPT i The heading θ between i and WPT i and WPT i-1 The heading θ between i-1 The difference; the heading change Δθ is defined as [-π, π] to prevent the heading change from exceeding 180 degrees;

[0080] S13, Calculate the turning radius: If a fixed radius RF (Radius-to-Fix) segment is used, the turning radius R is the distance from the turning center to the end point. For other segments, the turning radius is a function of ground speed and the assumed turning angle.

[0081]

[0082] Among them, V GS Here, g is the assumed ground speed, g is the acceleration due to gravity, and φ is the assumed lean angle during the turn; assuming the maximum lean angle is 23°, the lean angle φ is:

[0083]

[0084] S14, Calculate the start, end, and center of the turn: If the RF segment is used, the turn center and end point are determined in the navigation database, and the turn start point is the end point of the previous segment; otherwise, the turn start and end point will be calculated based on the waypoint, turning radius, and heading change.

[0085] Furthermore, S14 also includes a turning endpoint (x) turn_end y turn_end The calculation is as follows:

[0086]

[0087]

[0088] Where L is wpti and wpt i+1 between the distance, R is the turning radius, θ i is the current heading, Δθ is the heading change;

[0089] If Δθ < 0, the turning center (x turn_center , y turn_center ), the turning start point (x turn_start , y turn_start ) are expressed as:

[0090]

[0091]

[0092]

[0093]

[0094] If Δθ > 0, the turning center (x turn_center , y turn_center ), the turning start point (x turn_start , y turn_start ) are expressed as:

[0095]

[0096]

[0097]

[0098]

[0099] S15, calculate the distance of each HPT to the planned end point DTG: for two consecutive straight line segments, the DTG of the jth HPT is the along-track distance from the (j-1)th HPT plus the distance between the jth and (j-1)th HPTs; for a non-RF turning segment, there are two HPTs marked as the turning start point and end point; the along-track distance at the turning start point is the along-track distance from the latter HPT to the turning end point plus the along-track distance of the former HPT; the along-track distance at the turning is the arc length derived from the turning radius multiplied by the change in heading.

[0100] S2, based on the track segment model and the speed and altitude limits set by the program, combined with the initial along-track speed, altitude, wind and temperature information in the horizontal flight line, calculate the initial ground speed profile and the current along-track position of the local machine.

[0101] Specifically, in this embodiment, the ground speed profile is the velocity along a horizontal flight path mapped from the aircraft's airspeed, taking into account the effects of wind speed and temperature. It is generated by integrating a set of ordinary differential equations relating path position, altitude, and true airspeed as a function of time. The ground speed profile is constructed by combining trajectory segments defined using fundamental kinematic relationships, thus adhering to programmed altitude and speed limits, as well as adjustable speed limits.

[0102] Furthermore, S2 includes:

[0103] S21, Path segment modeling: Path segment modeling is performed according to different path segment types. The output of each path segment is the position (ds / dt), altitude (dh / dt), and true airspeed along the path as a function of time. The derivatives are then integrated with respect to time.

[0104] Specifically, in this embodiment, the flight segment type is as follows: Figure 4 As shown, there are 6 types. The output of each track segment is the position (ds / dt), altitude (dh / dt), and true airspeed along the flight path as a function of time. The derivatives are then integrated with respect to time. Along the track position s, altitude h, and calibrated airspeed V... CAS , ground speed The flight path angle (γ) and vertical speed dh / dt are both functions of time t. In the ground speed equation, V w⊥ It is the wind component perpendicular to the aircraft's heading, V w|| It is the wind component parallel to the aircraft's heading.

[0105] Type 1: Constant Calibration Airspeed Descent Segment. Assume the flight path angle is constant at γ during descent. If γ = 2.9° below 10,000 feet and γ = 3.1° above 10,000 feet, the output will be:

[0106]

[0107]

[0108]

[0109] Type 2: Deceleration and Descent Segment. Assuming a constant real airspeed deceleration of 0.50 knots / second and a constant flight path angle γ = 1.0°, the output will be:

[0110]

[0111]

[0112]

[0113] Type 3: Constant track descent, constant airspeed leg. The airspeed is held constant, and the flight track angle γ of the aircraft is determined from the ground speed. The output is:

[0114]

[0115]

[0116]

[0117] where γ - represents the flight track angle γ updated with the previous state.

[0118] Type 4: Constant track descent, decelerating airspeed leg. The flight track angle γ and the deceleration along the track are set. The output is:

[0119]

[0120]

[0121]

[0122] Type 5: Level flight, constant airspeed leg. The airspeed and altitude are held constant, and the output is:

[0123]

[0124]

[0125]

[0126] Type 6: Level flight, decelerating airspeed leg. The altitude is held constant, and the output is:

[0127]

[0128]

[0129]

[0130] S22, compute wind information: The wind information is split into the vector V w，x，i and V w，y，i represent the wind in the x and y directions at the altitude h i ; the predicted wind at the specified altitude is computed using a sample fitting algorithm and where the parallel wind and the perpendicular wind to the aircraft wind velocity are given by:

[0131]

[0132]

[0133] where θ denotes the heading, are the wind speed fit values in x and y directions respectively;

[0134] S23, calculate temperature information: ISA (International Standard Atmosphere) model is used to determine the relationship between temperature and altitude, and the ISA model is defined using the following equation:

[0135] T(H p ) = T0 + ΔT + β * H trop , H p ≥ H trop

[0136] T(H p ) = T0 + ΔT + β * H p , H p ≤ H trop

[0137] where T0 = 288.15 K, β = -0.0065 K / m, H p is the potential height in meters, ΔT is the ISA deviation, and H trop = 11000 m is the potential height of the tropopause;

[0138] S24, calculate height and speed limits: determine the height and speed limits according to the settings of the IFPI elements or the default height and speed limits;

[0139] Specifically, in this embodiment, the height and speed limits are the inputs of the ground speed calculation function, which are used to calculate the vertical and airspeed profiles of the host and target aircrafts. It is assumed that there are height and speed limits at each waypoint of the waypoint sequence, and the limit information comes from the IFPI elements or the default height and speed limits. Some waypoints may not have program limits, such as the planned terminal point, and the default height and airspeed limits must be used, as shown in Table 1, which is a comparison table of the default speed and height limits in this embodiment.

[0140] Table 1

[0141]

[0142] S25, calculate the along-track position of the current position: the along-track positions of the host and target aircrafts are determined by projecting their current horizontal positions onto the horizontal track. Specifically, as shown in Figure 5 , which is a flowchart of calculating the shortest along-track position of the current horizontal position in this embodiment.

[0143] Further, the S25 further comprises: when j = 1…M, the distance between the coordinate (x, y) position of the waypoint and the HPT is calculated using the Euclidean distance; the cross-track error between the aircraft position and the horizontal route is calculated from the HPT with the minimum distance d j j The cross-track error between the aircraft position and the horizontal route is calculated from the HPT with the minimum distance d j The cross-track error of the HPT is checked; continue to compare the cross-track error until the HPT that meets the threshold of 2.5 nmi is found, and then calculate the along-route position and along-route distance using the downstream HPT.

[0144] S3, according to the ground speed profile calculated in S2, the horizontal route is recalculated using the accurate estimated value of the ground speed at the turn.

[0145] Specifically, in this embodiment, the TTG of the aircraft along the route from the current position is calculated, which requires calculating the distance of each track segment of the aircraft passing through the arrival point along the route, calculating the passing time of each segment using the ground speed profile of the aircraft, and finally adding up.

[0146] S4, if the along-route airspeed, altitude, wind, and temperature information changes, the horizontal route obtained in S3 is used to recalculate the ground speed profile based on the changed airspeed, altitude, wind, and temperature information to generate an updated ground speed profile; S3 is re-executed according to the updated ground speed profile to recalculate the horizontal route.

[0147] It should be noted that the waypoint sequence is the basis for constructing the horizontal route. First, it is assumed that the aircraft flies at a fixed speed, and the along-route distance of the host aircraft and the target aircraft to the terminal point is calculated from the expected flight waypoints, and then the interval between the host aircraft and the target aircraft is obtained. Due to the influence of wind speed and temperature, as well as the inconsistency between the flight speed of the aircraft and the assumed speed, the along-route distance calculated from the first step of assumed data has changed, and it is necessary to continue to return to the first step for calculation, and the interval is updated by iteration to ensure the reliability of the interval, as Figure 6 is the principle flowchart for iteration and updating of the interval in this embodiment. Further, according to the horizontal route of the host aircraft and the target aircraft, the along-route distance to the planned terminal point, the TTG, and the measured time interval can be calculated.

[0148] S5, based on the ground speed profile and the current along-route distance, the TTG of the host aircraft and the target aircraft is calculated to obtain the predicted time interval.

[0149] ​Further, the S5, based on the ground speed profile and the current along-track distance, calculates the ownship and the target aircraft TTG, obtaining the time interval, including, before the target aircraft passes the arrival point, the predicted time interval PSI(t) is the time TTG that the ownship passes the arrival point from the current along-track position O (t) and the TTG of the target aircraft T (t). The difference between the time intervals is expressed as:

[0150] PSI(t) = TTG O (t) - TTG T (t)

[0151] After the target aircraft passes the arrival point, but before the ownship passes the arrival point, the predicted time interval PSI(t) at time t is the TTG of the ownship O (t) and the actual arrival time ATA of the target aircraft at the arrival point. The difference between the time intervals is expressed as:

[0152] PSI(t) = (TTG O (t) + t) - ATA T .

[0153] In particular, the embodiment uses time intervals to represent the real-time intervals between aircrafts. The time interval is the sum of the intervals of each segment of the route, and each segment of the time interval is calculated by the horizontal track distance ratio and the real-time ground speed of the segment. Further, the reference horizontal track is composed of a series of straight segments and turning segments, and the continuous track of the aircraft is described by these combinations. The reference horizontal track data is shown in Table 2, and the horizontal route map generated step by step according to the sequence of track points is shown in Figure 7 .

[0154] Table 2

[0155]

[0156] The wind and temperature test data is shown in Table 3, the ownship travels from HPT1 at a speed of 200 knots, and the target aircraft travels from HPT2 at a speed of 230 knots. The time interval of the ownship and the target aircraft passing HPT4 is measured. The simulation results are shown in Figure 8 .

[0157] Table 3

[0158]

[0159] In addition, the second aspect of the embodiment provides an electronic device, the electronic device comprising: one or more processors, a memory for storing one or more computer programs; the computer programs are configured to be executed by the one or more processors, the programs include steps for executing the flight time interval calculation method based on the horizontal track and the ground speed profile as described above.

[0160] In addition, the third aspect of the embodiment provides a storage medium storing a computer program; the program is loaded and executed by a processor to implement the flight time interval calculation method based on horizontal flight path and ground speed profile as described above.

[0161] Those skilled in the art can appreciate that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware, computer software or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been described in the above description in general terms. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0162] The units described as separate components can or can not be physically separated. As a unit, those skilled in the art can appreciate that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware, computer software or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been described in the above description in general terms. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0163] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or software functional unit.

[0164] The integrated unit, if implemented in the form of a software function unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art, or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a grid device, etc.) to execute all or part of the steps of the method described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0165] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A flight time interval calculation method based on horizontal track and ground speed profiles, characterized in that, The method comprises: S1, calculating an initial horizontal route according to a sequence of waypoints defined by the intended flight track information, the initial horizontal route being a horizontal route described according to a series of horizontal route transition points HPTs; calculating a heading change, a turn radius, a start point, an end point, and a center of the turn, and an along-route distance between each HPT and a planned end point according to an initial ground speed during the turn and a tilt angle; S2, calculating an initial ground speed profile and a current along-route position of the aircraft based on a track segment model and a speed and altitude limit set by a procedure, in combination with along-route speed, altitude, wind, and temperature information in the initial horizontal route; S3, recalculating the horizontal route using a precise estimate of the ground speed at the turn according to the ground speed profile calculated in S2; S4, if the along-route speed, altitude, wind, and temperature information changes, recalculating a ground speed profile based on the horizontal route obtained in S3 and the changed along-route speed, altitude, wind, and temperature information to generate an updated ground speed profile, and recalculating the horizontal route according to S3 based on the updated ground speed profile; S5, calculating the time-to-go (TTG) of the aircraft and the target aircraft based on the ground speed profile and the current along-route distance to obtain a predicted time interval, comprising: the time interval before the target aircraft passes the point of arrival is the time from the current position along the route to the time the own aircraft passes the point of arrival and the time interval of the of the target aircraft, expressed as: ； the difference between the actual time of arrival of the target aircraft at the arrival point and the predicted time of arrival of the home aircraft at the arrival point, expressed as: the difference between the actual time of arrival of the target aircraft at the arrival point and the predicted time of arrival of the home aircraft at the arrival point, expressed as: 。 2. The flight time interval calculation method based on water predicted time interval flat route and ground speed profile according to claim 1, wherein S1 comprises: S11, determining the sequence of waypoints: first, according to the IFPI data in the navigation database, the sequence of waypoints is converted, the waypoint is represented by , wherein ; the calculated horizontal flight path conversion point is represented by , wherein , M=2m+2, m is the number of turns; the waypoint at the turn is represented by two HPTs representing the start point and the end point of the turn; S12, calculate the heading change between waypoints: the coordinates of each waypoint are (x, y), the heading between two waypoints is : ； The heading angle is measured along the x-axis in a counterclockwise direction, with a defined range of 0 to 360 degrees ; the heading change is the difference in heading between and and ; the heading change is defined as the difference between the heading of the vehicle at the start of the time interval and the heading of the vehicle at the end of the time interval, to prevent the heading change from exceeding 180 degrees; S13, calculate turn radius: if a Radius-to-Fix leg is used, the turn radius is the distance from the turn center to the end of the leg, and the other leg turn radius is a function of ground speed and an assumed turn bank angle: ； wherein is the assumed ground speed, g is the acceleration due to gravity, is the assumed bank angle during a turn; the maximum turn bank angle is assumed to be 23°, the turn bank angle : ； S14, calculating a start point, an end point, and a center of the turn: if an RF segment is used, the turn center and the turn end point are determined in a navigation database, and the turn start point is the end point of the previous segment, otherwise the turn start point and the turn end point are calculated according to the waypoints, the turn radius, and the heading change; S15, calculating a distance to go (DTG) of each HPT to the planned end point: for two consecutive straight line segments, the DTG of the jth HPT is the along-route distance from the (j-1)th HPT plus the distance between the jth and the (j-1)th HPTs; for a turn segment that is not an RF, there are two HPTs marked as the start point and the end point of the turn; the along-route distance at the turn start point is the along-route distance from the next HPT to the turn end point plus the along-route distance of the previous HPT; the along-route distance at the turn is the arc length obtained by multiplying the turn radius by the route change angle.

3. The flight time interval calculation method based on water predicted time interval flat route and ground speed profile according to claim 2, wherein S2 comprises: S21, flight segment modeling: flight segment modeling is performed according to different flight segment types, the output of each flight segment is the derivatives of along-track position (ds / dt), altitude (dh / dt) and true airspeed as a function of time, which are then integrated with respect to time ; S22, calculate wind speed information: component vectors of wind speed information and representing the height of the wind speed in the x and y directions, respectively; Using a sample fitting algorithm to calculate a predicted wind speed for a specified height and where the parallel wind relative to the aircraft wind speed and the perpendicular wind is expressed as: ； wherein represents a heading, , are the fitted values of the wind speed in the x and y directions, respectively; S23, calculating temperature information: using an International Standard Atmosphere (ISA) model to determine the relationship between temperature and altitude, and using the following equation to define the ISA model: ； wherein, = 288.15 K, β = -0.0065 K / m, is the geopotential height in meters, is the ISA bias, and = 11000 m is the geopotential height of the tropopause; S24, calculating altitude and speed limits: determining the altitude and speed limits according to the IFPI element or a default setting of the altitude and speed limits; S25, calculating the along-route position of the current position: the along-route positions of the aircraft and the target aircraft are determined by projecting their current horizontal positions onto the horizontal route.

4. The flight time interval calculation method based on water predicted time interval flat route and ground speed profile according to claim 3, wherein S25 further comprises: The distance between the coordinates (x, y) position of the waypoint and is calculated using the Euclidean distance; from the calculation of the minimum distance the cross-track error between the aircraft position and the horizontal leg is calculated starting from the HPT If the absolute value of the cross-track error is less than 2.5 nmi, the downstream HPT is determined, otherwise, the second minimum is used Check the cross-track error of the HPT; Continue the cross-track error comparison until an HPT is found that satisfies the 2.5 nmi threshold, then use the downstream HPT to calculate the along-track position and along-track distance.

5. The flight time interval calculation method based on water predicted time interval flat track and ground speed profile according to claim 2, wherein the S14 further comprises: Turn end point (Tep) , ) is calculated as follows: ； wherein L is and the distance between, is the turning radius, is the current heading, is the change in heading; If the turning center (Ct) and the turning start point (Cst) are expressed as: , , , ​ ； If the center of the turn (Ct) and the start point of the turn (St) are expressed as: , , , ​ 。 6.An electronic device comprising: one or more processors, a memory for storing one or more computer programs; characterized in that the computer programs are configured to be executed by the one or more processors, the programs comprising steps for executing the flight time interval calculation method based on water predicted time interval flat track and ground speed profile according to any one of claims 1-5.

7. A storage medium storing a computer program; the program is loaded and executed by a processor to implement the steps of the flight time interval calculation method based on water predicted time interval flat track and ground speed profile according to any one of claims 1-5.

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