Space Indexed Flight Guidance - PowerPoint Presentation

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Space Indexed Flight Guidance

along Air Streams

Mastura Ab Wahid, Hakim Bouadi, Felix Mora-CaminoMAIA/ENAC, Toulouse

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SITRAER20142 OutlineIntroductionDefinition of Air StreamAir Stream Reference TrackFlight Guidance ModelSpace Indexed Guidance PerformanceNonlinear Inverse Control LawStandard Manoeuver within an Air StreamTraffic Management within an Air Stream

ConclusionSlide3

SITRAER20143The

Air transportation traffic has known a sustained increase over the last decades leading to airspace near saturation in some large areas of developed and emerging countries. The global air traffic has doubled in size once every 15 years and it will continue to do so. The design of new navigation and guidance systems with improved accuracy for spatial and temporal trajectory tracking has turned possible

free flight which has appeared as an appealing opportunity for airlines. However, in the case of high traffic density regions, the adoption of free flight should result, even through a 3D+T trajectory negotiation process with ATM, into an increasing number of conflicts which are solved by modifying these aircraft trajectories and losing flight efficiency .

INTRODUCTIONSlide4

SITRAER20144Then, new concepts such as air corridors and time-based flow management (TBFM) are under development and early implementation in United States. TBFM should meters aircraft through speed adjustments with discrete metering points through all flight phases in order to monitor the level of traffic demand in airspace sectors and deliver traffic down to the runway in a smooth way. Here it is considered that in high traffic density regions, air traffic can be organized along main air streams using the full navigation and guidance capability of modern on-board systems so that a common spatial reference trajectory (ASRT

) can be used by aircraft flying through a high density traffic space to maintain an accurate position within their assigned dynamic slot on a given lane. The adoption of such spatial reference will enforce the efficient use of the available time-space capacity along the air space and ease the on-board traffic separation task for an organized traffic along such fixed 3D reference. INTRODUCTIONSlide5

SITRAER20145An air stream is defined as a set of air lanes organized around and along a common 3D reference trajectory (air stream reference track-ASRT). There aircraft are supposed to adopt the reference speed and flight level of their assigned lane and are guided in a common space index basis to maintain their position in their assigned dynamic slot. Like classical airways, air streams propose a common space for aircraft adopting similar navigation and guidance objectives for a portion of their flights but they can join or quit the air stream at any stage. Contrarily to airways and airspace flow corridors , air streams have no nominal shape (width, height or radius).

DEFINITIONSlide6

SITRAER20146In many situations, the central line of an airway or airspace flow corridor could be adopted as an ASRT, although air stream reference trajectories may present turns and may be changed according to different factors such as traffic demand and next day forecasted weather conditions. Aircraft with different performances or adopted cost indexes and speeds can be present in the same air stream but in different lanes. To be allowed in an air stream, aircraft equipment requirements are similar to that of airspace flow corridors: transportation aircraft must be equipped with required navigation performance (RNP), self-separation capability and on-board automated separation assurance. Self-separation on a lane is performed by

dynamic position adjustments where the ADS-B technology can provide position and speed information. DEFINITIONSlide7

SITRAER20147Lane change manoeuvres within the air stream are performed without intervention of a central controller when an aircraft adopts a new reference airspeed. The on-board automated separation assurance system is supposed to incorporate different levels of protection against a collision, including conflict detection and resolution, where the last protection against a collision is the Traffic Collision Avoidance System (TCAS). In air streams, the pilots will remain responsible in insuring the safe separation with nearby aircraft by maintaining situational awareness, performing standard manoeuvers and reacting to conflict resolution advices.

DEFINITIONSlide8

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Air Stream Reference TrackSlide9

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Air Stream Reference Track

trackSlide10

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Flight Guidance Model

Wind speed

Air speedAngle of attackSideslip angle

Attitude anglesSlide11

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Euler equations

Rotation matrix from B to L

External forcesFlight Guidance ModelSlide12

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Flight Guidance Model

Aerodynamic forcesAcceleration equationswithThrust dynamicsSlide13

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Flight Guidance Model

Position equationsRotation matrix from L to E

withSlide14

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Desired 3D+T trajectory

Space Indexed Guidance PerformanceGuidance errorsSlide15

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Space Indexed Guidance Performance

with

whereare stable polynomialsSpace indexed nominal guidance errors dynamicsSlide16

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First space derivatives

First space derivatives of time

Nonlinear Inverse Control LawSlide17

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Nominal guidance error dynamics

Nonlinear Inverse Control Law

Guidance dynamicsSlide18

SITRAER201418Nonlinear Inverse Control Law

Nominal guidance error dynamics with inputsTheoretical flight guidance lawSlide19

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Standard Manoeuver within an Air Stream

Lane shiftSlide20

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Standard Manoeuver within an Air Stream

Speed evolution

Fly over timesSlide21

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Standard Manoeuver within an Air Stream

Space indexed reference trajectory Slide22

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Standard Manoeuver within an Air Stream

i

Slot selectionSlide23

SITRAER201423Traffic Management within an Air Stream

Case studySlide24

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Traffic Management within an Air Stream

Slot synchronization conditionConflict free conditionsSlide25

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Traffic Management within an Air StreamGreedy assignment algorithmSlide26

SITRAER201426Traffic Management within an Air Stream

Initial traffic configuration and goalsSlide27

SITRAER201427Traffic Management within an Air Stream

First ranking of transient flightsSlide28

SITRAER201428Traffic Management within an Air Stream

Final assignment and scheduling of transient flightsSlide29

SITRAER201429ConclusionIn this study a new approach to traffic organization in dense areas compatible with the current performances of aeronautical communication, navigation and surveillance systems, has been proposed. The objective here has been to complement the free flight and traffic management through trajectory negotiation approaches, by introducing new high density traffic links organized in a way limiting traffic conflicts. Then in this paper it has been proposed to organize traffic in congested airspace along main air streams which are characterized by a central 3D track which acts as a common space indexed reference for the involved aircraft which follow lanes associated with different aircraft performances (preferred speeds and flight levels) . Slide30

SITRAER201430Guidance objectives have been expressed with respect to the common spatial reference offered by an ASRT and the synthesis of guidance control laws based on nonlinear inversion has been considered. Then the case of lane shift along a common air stream has been considered, leading to the complete characterization of the resulting trajectories. This allows to manage the traffic inside the airstream by predicting the duration of lane shift manoeuvers and using the common spatial reference to prevent conflicts.

ConclusionSlide31

SITRAER201431ConclusionThen the assignment of conflict free trajectories to transient flights inside the air stream can be performed using different techniques including heuristics.Preliminary concepts have been introduced in this paper to support this idea and many complementary studies should be developed to prove the effectiveness of the proposed approach.Slide32

SITRAER201432Thank You very much for your attention