Free Flight

航空

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航空

Free Flight
JM Alliot
Sources : FAA / Eurocontrol /
CENA
OCD(Europe)
NAS(USA)
z National Airspace modernization plan
z The main objective of NAS modernization is
moving the NAS towards a new type of
operating environment known as Free Flight as
defined by RTCA.
RTCA
z Organized in 1935 as the Radio Technical Commission
for Aeronautics,
z Not-for-profit corporation that develops consensusbased
recommendations
z Recommendations used by the Federal Aviation
Administration (FAA) as the basis for policy, program,
and regulatory decisions and
z Recommendations used by the private sector as the
basis for development, investment, and other business
decisions.
z Includes over 200 government, industry, and academic
organizations.
Free Flight NAS/RTCA
definition
z A safe and efficient operating capability under
instrument flight rules in which the operators have the
freedom to select their paths and speed in real time. Air
Traffic restrictions are imposed only to ensure
separation, to preclude exceeding airport capability, to
prevent unauthorized flights through special use of
airspace, and to ensure safet of flights. Restrictions are
limited in extent and duration to correct the identified
problem. Any activity which removes restrictions
represents a step toward Free Flight.
Free Flight
z One word / many different concepts :
y Free Route
y Free Flight / centralized control
y Free Flight / Autonomous Aircraft
Free Route
z No more Standard Routing Scheme
z Aircraft can freely choose their route, but still fly
from waypoint to waypoint
ICARUS and the
mechanical bird
Source : Face à l'automate Alain Gras et al.
z ICARUS
y Pilot sees and is
aware of his
environmentv -
He chooses his
flightpath : route,
flight level, and
speed
y Pilot maintains
separation
z Mechanical bird
y Flightpath :
routes, flight
level, time are
dictated by the
ground
y separations are
maintained by
ground
Tubes 4D and Free Flight
Free Flight / Centralized
control
z Planes can take a direct route from origin
to destination
z Responsability of control remains on the
ground
Centralized control /
Ancestors
z AERA III :
y US 1980, FAA / MITRE Corporation
y Automatic Control with extremely primitive solvers
(Gentle-Strict algorithm)
z ARC 2000 :
y Eurocontrol, 1990
y Automatic control with 4D tubes
y Solvers based on the rubber band algorithm, a multilocal
optimization algorithm
Free Flight / Autonomous
Aircraft
z Planes can take a direct route from origin to
destination
z Planes have to maintain separation themselves
Autonomous Aircraft /
Ancestors
z VFR rules
z ACAS / ASAS concept : 1950 !
z TCAS : 1981
ACAS
z Self contained system, independent of groundbased
system. Provides advice to pilots on
potential conflicting, transponding traffic.
z ACAS is the ICAO, generic term for the
Airborne Collision Avoidance System based on
secondary surveillance radar (SSR) transponder
signals
z Operates independently of ground based
equipment.
ACAS
z ACAS I : utilises interrogations of, and replies
from, airborne radar beacon transponders.
Provides Traffic Advisories (TAs) only.
z ACAS II : ACAS I + Resolution Advisories (RAs)
in the vertical plane.
z ACAS III : ACAS II + Resolution Advisories in
the horizontal plane.
TCAS
z Traffic Alert And Collision Avoidance System
z US commercial (and only) implementation of the
ACAS concept
z TCAS I : implements ACAS I
z TCAS II : implements ACAS II
z TCAS III : development has ceased
z TCAS IV : should implement ACAS III.
Development in stasis.
TCAS
z TCAS II v7 complies with the ICAO ACAS II
standards
z Mandatory for all civil fixed-wing turbineengined
aircraft with mass > 15t or more than
30 passenger seats since 1/1/2000
z Will be mandatory for all civil fixed-wing turbineengined
aircraft with mass > 5.7t or more than
19 passengers seats the 1/1/2005
ACAS not so well-known
facts
z Non-transponding aircraft, and aircraft equipped
with non-altitude reporting transponders, are
not detected by an ACAS
z ACAS cannot resolve all possible collisions and
may even cause some risk of collision
z Performance of ACAS depends on the design
and management of the airspace
ACAS Fundamental
Principle
z ACAS is not intended to replace the
functions of the air traffic controller and
the provision of separation between
aircraft, operating in compliance with air
traffic control clearances, remains the
primary responsibility of air traffic control.
The Free-R project
z 1996/1998 : Autonomous aircraft with Extended
Flying Rules (EFR), an extension of Visual Flying
Rules
z Problem : EFR was not able to solve multiple
conflicts situations
z 1998-> now : Limited Delegation Concept. Free
Flight is postponed until 2015 (?)
Limited Delegation
z The controler delegates to the pilot some tasks
related to separation assurance.
z Target : near term applications (2005)
z Goals : reduction of the controler workload
z Limited delegation is NOT related to (and will
not implement) Free Routing or Free Flight.
NASA DAG/TM
z DAG/TM : Distributed Air Ground Traffic
Management
z NASA concept
z Discusses lot of different issues, but does not
present any single algorithm to implement safely
the concepts presented
NASA DAG/TM
Trafic density in Europe
200 NM
From VFR to Free Flight
Separation
mode
Freedom Capacity
Density
Technology
VFR *** ** 0
rocedures 0 0 *
RADAR * * *
ASAS ** **? **
4D Tubes * ***? ***
Free Flight *** **? ***
Misconception : global and
local optimization
z Many local optima don’t make a global optimum
Autonomous Aircraft / Ideology?
Simulations results
z Free Routing : reduction of 5 to 10% max of
fuel burning and route length
z Autonomous aircraft : short term solution,
inefficient in high density area, less capacitive
than organized traffic

xinlunll

非常需要，谢谢楼主！