# US 12,181,286 B2 · Method for determining a trajectory of an aircraft, associated computer program product and determination module

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- Number: US 12,181,286 B2
- Document ID: US12181286B2
- Status: Granted
- Kind: B2
- Application number: 17/637,299
- Filed: 2020-08-20
- Published: 2022-09-08
- Granted: 2024-12-31
- Earliest claimed: 2019-08-22
- Assignees: Thales
- Applicants: Thales
- Inventors: Johan Boyer; Emmanuel Dewas; Geoffrey Durand
- Web page: https://patentgrep.com/patent/US12181286B2

## CPC

- G01C 21/20: Instruments for performing navigational calculations (G01C21/24, G01C21/26 take precedence)
- G01C 21/005: {with correlation of navigation data from several sources, e.g. map or contour matching (G01C21/30 takes precedence)}
- G01C 23/00: Combined instruments indicating more than one navigational value, e.g. for aircraft; Combined measuring devices for measuring two or more variables of movement, e.g. distance, speed or acceleration
- G08G 5/21: located onboard the aircraft
- G08G 5/34: for flight plan modification
- G08G 5/53: for cruising
- G08G 5/55: for a single aircraft
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)
- G08G: TRAFFIC CONTROL SYSTEMS (guiding railway traffic, ensuring the safety of railway traffic B61L; arrangement of road signs or traffic signals E01F9/00; radar or analogous systems, sonar systems, lidar systems specially adapted for traffic control G01S13/91, G01S15/88, G01S17/88; {radar or analogous systems, sonar systems, lidar systems specially adapted for anti-collision purposes G01S13/93, G01S15/93, G01S17/93})

## Abstract

This method comprises a step of determining a reference profile along a lateral trajectory precalculated comprising searching, in the precalculated lateral trajectory, at least one segment of discontinuity comprising a lateral discontinuity, determining a required distance corresponding to a minimum flight distance between the two segments bordering the discontinuity segment and integrating each required distance into the reference profile. This method further comprises a step of determining, on the basis of the reference profile, vertical predictions relating to a vertical trajectory of the aircraft and a step of determining, on the basis of the vertical predictions, a resulting lateral trajectory comprising, for each discontinuity segment, determining a substitution segment connecting the two corresponding bordering segments in a continuous manner.

## Claims

### Claim 1

A method for determining a trajectory of an aircraft and displaying the determined trajectory on a vertical display or navigation display of a flight managements system in a cockpit, wherein the method is implemented by an electronic module connected to the flight management system of the aircraft, comprising steps:
determining a reference profile along a lateral trajectory precalculated based on a plurality of speed or altitude constraints, the precalculated lateral trajectory comprising a plurality of segments, the determining step comprising:
searching in the precalculated lateral trajectory for at least one segment of discontinuity between two segments, called frame segments, the at least one segment of discontinuity comprising a lateral discontinuity;
for the at least one segment of discontinuity, determining a required distance corresponding to a minimum flight distance between the two frame segments, allowing for compliance with the speed or altitude constraints while flying along the frame segments; and
integrating the required distance into the reference profile;
determining, based on the reference profile, vertical predictions related to a vertical trajectory of the aircraft;
determining, based on the vertical predictions, a resulting lateral trajectory comprising for the at least one segment of discontinuity, determining a substitution segment connecting the two frame segments in a continuous manner, a length of the substitution segment being determined as a function of the required distance determined for the at least one segment of discontinuity;
wherein the substitution segment for the at least one segment of discontinuity is displayed on the vertical display or navigation display representing the resultant lateral trajectory of the aircraft;
displaying a graphical symbol on the vertical display or navigation display representing a deselection point for the at least one segment of discontinuity;
wherein the determining the reference profile comprises sub-steps, which are carried out in reverse from an integration starting point and include:
determining an intermediate endpoint and determining a geometric portion of the reference profile delimited by the integration starting point and the intermediate endpoint;
searching on the geometric portion, for the at least one segment of discontinuity between two segments, the two segments including the frame segments; and
when the at least one segment of discontinuity exists:
determining the required distance for the at least one segment of discontinuity; and
integrating the required distance into the portion of the reference profile.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the required distance is greater than or equal to a direct distance is greater than or equal to a direct distance connecting the frame segments.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the required distance is determined as a function of a direct distance between the frame segments of the at least one segment of discontinuity.

### Claim 4 (depends on 3)

The method according to claim 3, wherein the required distance is further determined as a function of a plurality of elementary slopes, each elementary slope being calculated for an elementary interval that is part of the geometric portion on which the at least one of the segment of discontinuity corresponding to the required distance has been identified, as a function of a performance of the aircraft on the elementary interval.

### Claim 5 (depends on 3)

The method according to claim 3, wherein the required distance is further determined as a function of a slop retained for the geometric portion on which the segment of discontinuity corresponding to the required distance has been identified, the retained slope corresponding to one of elements selected from the group including:
a resulting equivalent slope determined using a value of the distance required and an altitude variation over said geometric portion; and
a slope having a smallest absolute value among a plurality of elementary slopes, each elementary slope being calculated for an elementary interval that is part of the geometric portion as a function of performance of the aircraft over the elementary interval.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the required distance is determined as a function of an altitude variation over the geometric portion on which the segment of discontinuity corresponding to the required distance has been identified and of a retained slope, said retained slope being selected from a plurality of elementary slopes, each following elementary slope being obtained by means of an iterative dichotomy technique using an initial elementary slope and a preceding elementary slope.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the at least one segment of discontinuity corresponds to a manual termination leg.

### Claim 8 (depends on 7)

The method according to claim 7, wherein the determination of the substitution segment for the at least one segment of discontinuity in the step of determining the resulting lateral trajectory comprises determining a deselection point of the corresponding manual termination leg as a function of the required distance determined for the at least one discontinuity segment and of a direct distance between the corresponding frame segment.

### Claim 9 (depends on 8)

The method according to claim 8, wherein a graphical symbol representing the deselection point for each manual termination leg is displayed on a screen representing the resultant lateral trajectory of the aircraft.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the substitution segment for the at least one segment of discontinuity is displayed on a screen representing the resultant lateral trajectory of the aircraft.

### Claim 11 (depends on 1)

A non-transitory computer program product including software instructions that, when executed by computer equipment, execute the method according to claim 1.

### Claim 12 (depends on 1)

An assembly comprising a flight management system and a module for determining the trajectory of the aircraft, comprising technical means configured to carry out the method according to claim 1.