VNAV vertical deviation calculation method meeting vertical side cutting

Abstract

The invention discloses a VNAV vertical deviation calculation method satisfying vertical side cutting, and the method comprises the steps: obtaining the position of an aircraft, the position of each waypoint of a flight plan, horizontal path data, vertical path data, the ground speed of the aircraft, and the air pressure altitude of the aircraft, and calculating the distance between the aircraft and the end point of the flight plan, and the vertical path segment of the aircraft; the method comprises the following steps: determining whether an aircraft is in a vertical path transition section, and when the aircraft is in the vertical path transition section, calculating a virtual vertical path transition path constructed at a constant vertical acceleration, and calculating the vertical deviation based on the path, so as to achieve the purpose of VNAV vertical deviation calculation meeting vertical side cutting. According to the method, engineering implementation is easy, the guiding target of the VNAV can be optimized into a vertical bypass path with the constant vertical acceleration in the vertical path transition section under the condition that the calculation load is small, and the flight quality and the comfort level of passengers are guaranteed while the vertical path is accurately tracked.

Description

Technical Field

[0001] This invention relates to a method for calculating the vertical deviation of VNAV that satisfies vertical tangency, belonging to the field of civil aviation technology. Background Technology

[0002] Modern passenger aircraft's Flight Management System (FMS), through human-machine interaction and its integration with the automated flight system, supports the automatic execution of route planning and terminal procedures, thereby significantly reducing crew workload and improving flight quality. It is a core system supporting RNP (Required Navigation Performance) operation. Vertical Navigation (VNAV) capability is an important function of the FMS. If the FMS lacks VNAV capability, it can only descend to the LNAV MDA (Minimum Descent Altitude) as a non-precision approach during RNP operations; conversely, it can descend to a lower LNAV / VNAV DA (Decision Altitude) as a precision approach. Therefore, the introduction of VNAV capability enhances landing capabilities in low-visibility conditions and further improves flight safety and operational efficiency.

[0003] The Virtual Navigation Vehicle (VNAV) function has been used in the Flight Management System (FMS) of Boeing and Airbus commercial aircraft since the 1990s. According to the minimum operational performance standards of RNP equipment, the accuracy requirements of the VNAV function are mainly focused on the path descent process, i.e., the typical VNAV PATH mode. Its characteristic is that in this mode, the FMS controls the aircraft to track a predefined vertical path and calculates the aircraft's vertical deviation relative to that path in real time. This deviation is displayed in the crew's main field of view, providing path descent guidance and further contributing to the automatic control law that drives the aircraft's descent. Since the vertical path constructed by the FMS is a segmented straight line of varying lengths composed of different VPAs (Vertical Path Angles), the VNAV control law needs to ensure a smooth transition between different vertical path segments; this process is called Vertical Fly-By. Specifically, the FMS should maintain a relatively constant vertical acceleration during the transition between different vertical path segments to ensure good flight quality and passenger comfort while accurately tracking the vertical path.

[0004] Flight management, as a dual-use technology, is subject to foreign technological embargoes, resulting in a significant gap between domestic and international practices. Domestic universities and research institutions have been catching up with international technological developments, conducting a series of technical studies on VNAV (Vehicle Navigation Vehicle) functions. Currently, related research and inventions mainly focus on methods for allocating vertical errors, defining descent paths and their basic construction processes in mainstream aircraft models, and automated verification systems for vertical navigation guidance modes. However, there are still no related inventions or research on specific vertical navigation command calculation methods, especially methods for implementing vertical lateral tangents. This invention is proposed against this backdrop, designing a VNAV vertical deviation calculation method that satisfies constant vertical acceleration and vertical lateral tangents. Summary of the Invention

[0005] The purpose of this invention is to provide a method for calculating the vertical deviation of VNAV that satisfies vertical tangentiality. The method calculates the vertical deviation of VNAV based on a virtual vertical path transition path with constant vertical acceleration, thereby solving the problem of vertical tangentiality transition between vertical path segments of different VPAs with constant vertical acceleration.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A method for calculating the vertical deviation of VNAV that satisfies vertical tangency includes the following steps:

[0008] Step 1: Obtain the aircraft's position, the positions of all waypoints in the flight plan, the aircraft's ground speed (GS), and the aircraft's barometric altitude (H). A / C Number of horizontal path segments N, length of each horizontal path segment S k (k=0...N), number of vertical path segments M, distance D from the end of each vertical path segment to the destination of the flight plan i (i = 0...M), elevation H at the end of each vertical path segment i (i = 0...M), vertical path angle γ of each vertical path segment i (i = 0...M);

[0009] Step 2, calculate the distance from the aircraft's current position to the planned flight destination:

[0010]

[0011] Step 3: Determine the current vertical path segment of the aircraft based on the distance to the planned flight destination. If S is found... A / C ∈(D i-1 D i If the plane is in the vertical path segment of number i, then the aircraft is in the vertical path segment of number i.

[0012] Step 4: Determine whether the aircraft is within the vertical lateral transition segment between vertical path segments i-1, i, and i+1.

[0013] Step 5: Calculate the reference altitude H based on whether the aircraft is in the vertical tangential transition section. ref ;

[0014] Step 6, calculate the vertical deviation: ΔH = H A / C -H ref .

[0015] Preferably, step 4 includes the following steps:

[0016] (4.a) Calculate the length of the vertical path segment i:

[0017] L i =D i-1 -D i

[0018] (4.b) Define the vertical acceleration of the perpendicular tangent:

[0019] a capture =k·g

[0020] (4.c) Calculate the required vertical speeds for vertical path segments i-1, i, and i+1 at the current ground speed:

[0021]

[0022] (4.d) Calculate the transition time from vertical path segment i-1 to i, and from vertical path segment i to i+1, respectively, to the required vertical velocity with vertical acceleration by vertical lateral tangency:

[0023]

[0024] (4.e) Calculate the lengths of the vertical side-cut transition segments from vertical path segment i-1 to i and from vertical path segment i to i+1 respectively:

[0025]

[0026] (4.f) Calculate the distance from the aircraft to the end of the current vertical path segment:

[0027] ΔR=S A / C -D i

[0028] (4.g) If ΔR < ΔR smooth_i Then the aircraft is located in the first half of the vertical lateral transition segment between vertical path segments i and i+1; if L i -ΔR<ΔR smooth_i-1If the aircraft is within the latter half of the vertical side-cut transition segment of vertical path segment i-1 and i, then the aircraft is not within the vertical side-cut transition segment; otherwise, the aircraft is not within the vertical side-cut transition segment.

[0029] Preferably, step 5 includes the following steps:

[0030] (5.a) If the aircraft is in the first half of the vertical tangent transition segment between vertical path segments i and i+1, the reference altitude is calculated as follows:

[0031] (5.ai) Calculate the timing for entering the vertical side-tangent transition segment:

[0032]

[0033] (5.a.ii) Calculate the reference height H ref ;

[0034]

[0035] (5.b) If the aircraft is located in the latter half of the vertical tangent transition segment between vertical path segments i-1 and i, the reference altitude shall be calculated as follows:

[0036] (5.bi) Calculate the timing for entering the vertical side-tangent transition segment:

[0037]

[0038] (5.b.ii) Calculate the reference height H ref ;

[0039]

[0040] (5.c) If the aircraft is not within the vertical tangential transition zone, the reference altitude shall be calculated as follows:

[0041]

[0042] The beneficial effects of this invention are as follows:

[0043] This invention proposes a method for calculating the vertical deviation of a VNAV that satisfies vertical tangentiality. Based on the original vertical path segment, a virtual vertical path transition path constructed with constant vertical acceleration is calculated during the vertical deviation calculation process, and the vertical deviation is then calculated based on this path. This method is easily implemented in engineering and can optimize the VNAV's guidance target into a vertically tangential path with constant vertical acceleration within the vertical path transition segment under relatively low computational load, thereby ensuring accurate vertical path tracking while maintaining flight quality and passenger comfort. Attached Figure Description

[0044] Figure 1 This diagram illustrates the distance from the aircraft's current position to the planned flight destination.

[0045] Figure 2 This is a schematic diagram of a vertical lateral transition section.

[0046] Figure 3 This is a schematic diagram for calculating the reference height within the vertical tangent transition section.

[0047] Figure 4 This is a schematic diagram of the vertical tangent trajectory for different vertical accelerations. Detailed Implementation

[0048] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0049] This embodiment illustrates a method for calculating the vertical deviation of VNAV that satisfies vertical tangency, comprising the following steps:

[0050] Step 1: Obtain aircraft position, waypoint positions in the flight plan, horizontal path data, vertical path data, aircraft ground speed (GS), and aircraft barometric altitude (H). A / C The horizontal path data includes the number N of horizontal path segments (including arcs and straight lines) and the length S of each horizontal path segment. k (k=0...N), the vertical path data includes the number of vertical path segments M, and the distance D from the end of each vertical path segment to the destination of the flight plan. i (i = 0...M), elevation H at the end of each vertical path segment i (i = 0...M), vertical path angle γ of each vertical path segment i (i = 0...M).

[0051] As an example, in this embodiment:

[0052] The number of horizontal path segments (including arcs and straight lines) is N = 9, and the length of each horizontal path segment (in nautical miles) is S. k | k＝0...9 = [2.5078, 1.50, 0.9944, 5.8889, 1.1522, 3.3611, 0.9667, 2.6667, 0.7778, 2.1944];

[0053] The number of vertical path segments M = 5, and the distance D from the end of each vertical path segment to the destination of the flight plan. i (i = 0...M), elevation H at the end of each vertical path segment i (i = 0...M), vertical path angle γ of each vertical path segment i (i = 0...M), can be represented by the following table;

[0054]

[0055] The aircraft's ground speed GS = 300kt = 154.33m / s;

[0056] Aircraft pressure altitude H A / C =10000ft.

[0057] Step 2, calculate the distance from the aircraft's current position to the planned flight destination:

[0058]

[0059] See Figure 1 As shown, in this embodiment,

[0060] Step 3: Determine the current vertical path segment of the aircraft based on the distance from the aircraft to the destination of the flight plan.

[0061] The specific method is as follows: if S is found... A / C ∈(D i-1 D i If the plane is in the vertical path segment of index i, then the plane is in the vertical path segment of index i. For example, if S is found... A / C If ∈(D1,D2], then the aircraft is in the vertical path segment with index i=2;

[0062] Step 4, determining whether the aircraft is within the vertical lateral transition segment between vertical path segments i-1, i, and i+1, includes the following steps:

[0063] (4.a) Calculate the length of the vertical path segment i:

[0064] L i =D i-1 -D i

[0065] (4.b) Define the vertical acceleration of the perpendicular tangent:

[0066] a capture =k·g

[0067] (4.c) Calculate the required vertical speeds for vertical path segments i-1, i, and i+1 at the current ground speed:

[0068]

[0069] (4.d) Calculate the transition time from vertical path segment i-1 to i, and from vertical path segment i to i+1, respectively, to the required vertical velocity with vertical acceleration by vertical lateral tangency:

[0070]

[0071] (4.e) Calculate the lengths of the vertical side-cut transition segments from vertical path segment i-1 to i and from vertical path segment i to i+1 respectively:

[0072]

[0073] (4.f) Calculate the distance from the aircraft to the end of the current vertical path segment:

[0074] ΔR=S A / C -D i

[0075] (4.g) If ΔR < ΔR smooth_i Then the aircraft is located in the first half of the vertical lateral transition segment between vertical path segments i and i+1; if L i -ΔR<ΔR smooth_i-1 If the aircraft is within the latter half of the vertical side-cut transition segment of vertical path segment i-1 and i, then the aircraft is not within the vertical side-cut transition segment; otherwise, the aircraft is not within the vertical side-cut transition segment.

[0076] For example, determining whether the aircraft is within the vertical lateral transition section between vertical path segments 1, 2, and 3;

[0077] (4.a) Calculate the length of the vertical path segment i = 2 (in nautical miles):

[0078] L2 = D1 - D2 = 12.8905 NM

[0079] (4.b) Define the vertical acceleration of the perpendicular tangent:

[0080] a capture =k·g=0.03·9.8=0.294m / s 2

[0081] (4.c) Calculate the required vertical velocities for vertical path segments i-1, i, and i+1 (i=2) at the current ground speed:

[0082]

[0083] (4.d) Calculate the transition time from vertical path segment 1 to 2 and from vertical path segment 2 to 3 with vertical tangential acceleration to the required vertical velocity:

[0084]

[0085] (4.e) Calculate the lengths of the vertical side-cut transition segments from vertical path segment i-1 to i and from vertical path segment i to i+1 respectively:

[0086]

[0087] (4.f) Calculate the distance from the aircraft to the end of the current vertical path segment:

[0088] ΔR=S A / C -D2=22.01-21.5841=0.4259NM=778.7668m

[0089] (4.g) See also Figure 3 As shown, ΔR < ΔR smooth_2 Therefore, the aircraft is in the first half of the vertical tangential transition section between vertical path segments 2 and 3.

[0090] Step 5: Calculate the reference altitude H based on whether the aircraft is in the vertical tangential transition section. ref .

[0091] See Figure 4 As shown, when the aircraft is within the vertical path transition segment, a virtual vertical path transition path constructed with constant vertical acceleration is calculated, i.e., altitude H. ref The vertical deviation is calculated based on this path to achieve the goal of calculating the vertical deviation of VNAV with vertical side tangency. This includes the following steps:

[0092] (5.a) If the aircraft is in the first half of the vertical tangent transition segment between vertical path segments i and i+1, the reference altitude is calculated as follows:

[0093] (5.ai) Calculate the timing for entering the vertical side-tangent transition segment:

[0094]

[0095] (5.a.ii) Calculate the reference height H ref ;

[0096]

[0097] As an example, if the aircraft is in the first half of the vertical tangential transition section between vertical path segments 2 and 3, the reference altitude is calculated as follows:

[0098] (5.ai) Calculate the timing for entering the vertical side-tangent transition segment:

[0099]

[0100] (5.a.ii) Calculate the reference height H ref ;

[0101]

[0102] (5.b) If the aircraft is located in the latter half of the vertical tangent transition segment between vertical path segments i-1 and i, the reference altitude shall be calculated as follows:

[0103] (5.bi) Calculate the timing for entering the vertical side-tangent transition segment:

[0104]

[0105] (5.b.ii) Calculate the reference height H ref ;

[0106]

[0107] (5.c) If the aircraft is not within the vertical tangential transition zone, the reference altitude shall be calculated as follows:

[0108]

[0109] Step 6, calculate the vertical deviation: ΔH = H A / C -H ref .

[0110] In this embodiment, ΔH = H A / C -H ref =10000-9705.89=294.11ft

[0111] It is understood that those skilled in the art can make equivalent substitutions or modifications to the technical solution and inventive concept of the present invention, and all such substitutions or modifications should fall within the protection scope of the appended claims.

Claims

1. A method for calculating the vertical deviation of VNAV that satisfies vertical tangency, characterized in that... Includes the following steps: Step 1: Obtain the aircraft's position, the positions of all waypoints in the flight plan, the aircraft's ground speed (GS), and the aircraft's barometric altitude (H). A / C Number of horizontal path segments N, length of each horizontal path segment S k (k=0...N), number of vertical path segments M, distance D from the end of each vertical path segment to the destination of the flight plan i (i = 0...M), elevation H at the end of each vertical path segment i (i = 0...M), vertical path angle γ of each vertical path segment i (i = 0...M); Step 2, calculate the distance from the aircraft's current position to the planned flight destination: Step 3: Determine the current vertical path segment of the aircraft based on its distance to the planned flight destination. If S is found... A / C ∈(D i-1 D i If the plane is in the vertical path segment of number i, then the aircraft is in the vertical path segment of number i. Step 4: Determine whether the aircraft is within the vertical lateral transition segment between vertical path segments i-1, i, and i+1. Step 5: Calculate the reference altitude H based on whether the aircraft is in the vertical tangential transition section. ref ; Step 6, calculate the vertical deviation: ΔH = H A / C -H ref .

2. The method for calculating the vertical deviation of VNAV satisfying vertical tangency as described in claim 1, characterized in that... Step 4 includes the following steps: (4.a) Calculate the length of the vertical path segment i: L i =D i-1 -D i (4.b) Define the vertical acceleration of the perpendicular tangent: a capture =k·g (4.c) Calculate the required vertical speeds for vertical path segments i-1, i, and i+1 at the current ground speed: (4.d) Calculate the transition time from vertical path segment i-1 to i, and from vertical path segment i to i+1, respectively, to the required vertical velocity with vertical acceleration by vertical lateral tangency: (4.e) Calculate the lengths of the vertical side cut transition segments from vertical path segment i-1 to i and from vertical path segment i to i+1 respectively: (4.f) Calculate the distance from the aircraft to the end of the current vertical path segment: ΔR=S A / C -D i (4.g) If ΔR < ΔR smooth_i Then the aircraft is located in the first half of the vertical lateral transition segment between vertical path segments i and i+1; if L i -ΔR<ΔR smooth_i-1 If the aircraft is within the latter half of the vertical side-cut transition segment of vertical path segment i-1 and i, then the aircraft is not within the vertical side-cut transition segment; otherwise, the aircraft is not within the vertical side-cut transition segment.

3. The method for calculating the vertical deviation of VNAV satisfying vertical tangency as described in claim 1, characterized in that... Step 5 includes the following steps: (5.a) If the aircraft is in the first half of the vertical tangent transition segment between vertical path segments i and i+1, the reference altitude is calculated as follows: (5.ai) Calculate the timing for entering the vertical side-tangent transition segment: (5.a.ii) Calculate the reference height H ref ; (5.b) If the aircraft is located in the latter half of the vertical tangent transition segment between vertical path segments i-1 and i, the reference altitude shall be calculated as follows: (5.bi) Calculate the timing for entering the vertical side-tangent transition segment: (5.b.ii) Calculate the reference height H ref ; (5.c) If the aircraft is not within the vertical tangential transition zone, the reference altitude shall be calculated as follows:

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