1 Presented by David Wing ([email protected]) Bryan Barmore ([email protected]) NASA Langley...
-
Upload
clement-esmond-davis -
Category
Documents
-
view
253 -
download
5
Transcript of 1 Presented by David Wing ([email protected]) Bryan Barmore ([email protected]) NASA Langley...
1
Presented by David Wing ([email protected])
Bryan Barmore ([email protected])NASA Langley Research Center
NASA Research Results for“4D-ASAS” Applications
ASAS Thematic Network 2 Third Workshop, Glasgow, Scotland 11-13 September 2006
2
Research Premise: Distributing ATM Functions Results in Scalable ATM System
Strategic functions: ATSPTraffic flow management, resource scheduling
Local functions: 4D-ASAS-capable operatorFlight safety, ATSP-issued constraint conformance, trajectory optimization
Presentation is on Two DAG-TM “4D-ASAS” ConceptsEn-Route: Autonomous Flight ManagementTerminal Arrival: Airborne Precision Spacing
ATSP: Air Traffic Service Provider
Aeronautical
Operational
Control A
ir T
raff
ic
Ser
vice
Pro
vide
rFlightCrew
• Information
• Decision making
• Responsibility
Distributed Air
GroundTraffic
Management
Original 4D trajectory
Modified 4D trajectory, same strategic constraints
RTA unchanged
Distributed 4D Trajectory ManagementATSP sets strategic trajectory constraintsOperator manages trajectory to meet them
Distributed 4D Trajectory ManagementATSP sets strategic trajectory constraintsOperator manages trajectory to meet them
Local situations and “no impact” changes are implemented by 4D-ASAS aircraft
Local situations and “no impact” changes are implemented by 4D-ASAS aircraft
Changes impacting NAS resource usage
are coordinated strategically
Changes impacting NAS resource usage
are coordinated strategically
Example local situationExample local situation
4D-ASAS: Four Dimensional Airborne Separation Assistance SystemsRTA: Required Time of Arrival
3
Instrument Flight Rules (IFR) Aircraft
Hazard avoidanceFleet management
Priorityrules
Maneuver restrictions
IFRpriority Distributed
separationassurance
Terminal area
Terminal areaentry constraints
IFR and AFR traffic flow management
IFR trajectory
management
Cost controlPassenger comfort
AFR-managed trajectories
$+
Autonomous Flight ManagementAn En-Route/Transition 4D-ASAS Concept
Levels of 4D-ASASperformance
Integrated Operational Principles• Performance-based operations • 4D trajectory operations• Non-segregated operations
Integrated Operational Principles• Performance-based operations • 4D trajectory operations• Non-segregated operations
Autonomous Flight Rules(AFR) Aircraft
Air Traffic Service Provider
Special Use Airspaceavoidance
David WingNASA Langley Research Center
4
AFM Research Accomplishments
NASA project-level accomplishments• Operational concept description• Feasibility assessment of airborne and integrated air/ground operations• Feasibility assessment of ATSP operations • Human factors assessment • Life-cycle cost-benefit analysis • Safety impact assessment • Flight deck technology for autonomous operations • ATSP decision support technology• Experimental evaluation of integrated air/ground operations
Langley contribution highlights1. Developed flight-deck decision support toolset
and supporting flight deck systems-- Autonomous Operations Planner (AOP)
2. Conducted 3 HITL simulation experiments3. Performed 36-issue assessment of concept
feasibility -- application of research analysis and domain expertise
5
• Strategic & tactical conflict detection & resolution
• Conflict-free maneuvering support
• Flow constraint conformance
• Airspace restriction avoidance
Principal Functions
Autonomous Operations Planner NASA’s Research Prototype of 4D-ASAS En-Route Toolset
Attributes
• Working software prototype w/ ARINC 429 data-bus & 702a FMS integration
• CD&R alerting is RTCA SC186 ACM-WG compliant
• Simultaneously meets traffic, airspace, user, and flow management constraints (RTA)
• Performs trajectory optimization as part of conflict resolution
• Works within and ‘across’ normal autoflight modes, and within aircraft performance limits
Command conflicts
Planning conflicts
Provisional (FMS/MCP)
conflicts
Blunder protection and collision data
Ownship intent
Conflict alerts and
information
Maneuver restriction
information
Conflict resolutionand
trajectory planning
Intent-basedconflict
detection
State-basedconflict
detection
Priorityrules
ATC flow management constraints and airspace
constraints
AOP
Traffic intent
Ownship state
Traffic state
Crew inputs
6
Pilot-Only Simulation Experiments: Study of Tools, Procedures, Hazards
Scenario DesignConventional traffic conflicts
– Lateral & vertical– State & intent
Unconventional traffic conflicts– Blunders– Pop-up separation loss – Meter-fix conflicts
Constraints– ADS-B surveillance limitations– Airspace restrictions– Required Time of Arrival
Variables studied– Traffic density– Use of intent data– Conflict resolution method– Lateral separation standard– Airspace restrictions– Priority rules
Studies resulted in significant gains in understanding of AFR operations feasibility, operational sensitivities, human factors design, and requirements for tools & procedures
7
Pilot-Only Simulation Experiments: Sample Results
Aircraft B
Aircraft A
SUA
SUA
SUA
SUA
Crossing AssignmentRTA <30 seconds
Altitude < 500 ftPosition < 2.5 nm
Identical crossing assignments
Second generation
conflictSecond generation
conflict
Planned conflict
Planned conflict
Ove
r-C
on
stra
ined
T
raje
cto
ries
Co
nfl
ict
Pro
pag
atio
n
0%
20%
40%
60%
80%
100%
Leftaircraft
Co
ns
tra
int
Co
nfo
rma
nc
e
missed multiplemissed onemet all
Rightaircraft
No priority rules With priority rules
Leftaircraft
Rightaircraft
Go
al
Go
al
Res
ult
: B
ett
er
pre
dic
tab
ilit
y
Resolution MethodTactical: open loop
Strategic: closed loopModified: pilot override
No
Eve
nts
59 data runs
Resolution method
Res
ult
: D
om
ino
eff
ec
t p
rev
en
ted
8
Integrated Air-Ground Experiment: Langley-Ames Experimental Evaluation
Addressed 2 key feasibility issues:– Mixed Operations: Investigate safety and efficiency in high density sectors
compared to all managed operations– Scalability: Investigate ability to safely increase total aircraft beyond controller
manageable levels. Number of managed aircraft remains at or below current high-density levels.
• T0: ≈ current monitor alert parameter• T1: approximate threshold above which managed only
operations will definitely fail (determined by Ames study)• Only overflights were increased (arrivals held constant)
Autonomous
Managed
T1 L2
L3
L1 L1
T0
C1 C2 C3 C4
4 test conditions3 traffic levels
Fort Worth Center (ZFW)
Ghost DFW TRACON
Ghost South
Ghost North
Wichita FallsHigh
Ardmore High
Amarillo High
Bowie Low
OverflightsArrivals
BAMBEFort Worth Center (ZFW)
Ghost DFW TRACON
Ghost South
Ghost North
Wichita FallsHigh
Ardmore High
Amarillo High
Bowie Low
OverflightsArrivalsOverflightsArrivals
BAMBE
• 22 commercial airline pilots (20 single pilots + 2 pilot crew in high fidelity simulator)
• 5 professional air traffic controllers (1 per sector + 1 tracker)
9
Langley Aircraft and Ames ControllerSample Results
• Pilots mainly able to meet constraints• Some pilot entry error (RTA into FMS)• No apparent performance degradation
as traffic level increased
0
20
40
60
80
100
C1 C2 C3 C4
Condition
Per
cen
t C
on
form
ance
Time Altitude Speed
Increasing Traffic
Meter fix conformance for arrivals
• Lower workload for all mixed conditions• Traffic levels at C3 and C4 not considered
manageable if all aircraft IFR
1
2
3
4
5
6
7
Amarillo Ardmore Wichita Falls Bowie
ControllerW
ork
load
Rat
ing
C1 C2 C3 C4
Controller workload assessment
Low
High
10
AFM Feasibility Assessment Activity
• Team analysis of 36 feasibility questions – Distributed operations, air/ground integration, strategic & local TFM, flight crew
responsibilities, airborne equipage, CNS– Evaluations based on literature search, research results, operational experience
and judgment
• Sample questions:– Is the distributed AFR network vulnerable to system-level or cascading component
failures?– Within what limits do AFR aircraft have the ability to adapt to changes in the airport
acceptance?– Can airborne conflict management be performed in all ownship flight guidance
modes?– Can AFR operations accommodate a range of RNP capabilities?
• Conclusion: – Feasible at the integrated-system / laboratory-simulation maturity level– Further technical progress requirements identified– Sample challenges:
Accommodating prediction uncertainties Flow-constrained descents Convective weather interaction Failure modes Traffic complexity management Complex AFR/IFR interactions
Dr. Bryan BarmoreNASA Langley Research Center
A Terminal Arrival 4D-ASAS Concept
Airborne Precision Spacing
12
Airborne Precision Spacing
ADS-B-enabled operation in which the ATSP assigns speed management for spacing to the aircraft
Goal is to increase runwaycapacity by increasing the precision and predictability of runway arrivals
ATSP manages traffic flow, ensures separation and determines the landing sequence
Pilots precisely fly their aircraft to achieve ATSP-specified spacing goal
A single strategic clearance reduces radio congestion and workload for both ATSP and pilots
13
APS Flight Deck Automation
Computes relative ETA at threshold Provides speed guidance to
achieve desired relative ETASafe merging is a consequence of
beginning spacing operations early
Spacing interval can be customized pair-wise to account for wake vortex hazard and other constraints
Adjusts for dissimilar final approach speeds
Corrects speed if necessary to prevent separation violations
Gain scheduling to enhance stability of a aircraft stream
Respects aircraft configuration limits for speed changes
Ownship:time to go = 23:15
Lead:time to go = 22:15
30 seconds early at threshold
Slow down 5 knots
Target: 90 secs
14
Human-in-the-Loop Evaluation of APS
Chicago O’Hare Flight Evaluation
Three equipped aircraft including NASA B757
Wind shifts of 230º or more seen on base and final
Flight performance – 8 sec
Simulation performance – 2 sec
Medium fidelity simulation Merging and in-trail operations
9 aircraft stream (6 subject pilots)
No dependence on airspace design, type of operation or location in stream
15-20 minute flight times
Medium fidelity simulation results
15
Fast-time Simulations
DFW airspace with three merging streams
Each data run had a stream of 100 aircraft / 40 repetitions per condition
Wide range of aircraft types and performance (BADA model)
Precision of approximately 2 sec under nominal conditions
Challenges for significant initial spacing deviation; wind forecast errors and limited ADS-B range
Knowing final approach speed gives significant improvement in spacing precision
Improvements being made for wind updating and setting initial spacing requirements
16
CDA with Spacing
Continuous Descent Approaches offer a fuel and time efficient descent while reducing ground noise and environmental pollutants
However, ATSP must be largely “hands-off” resulting in loss of capacity to maintain safety
By including airborne spacing we can realize the majority of the CDA benefits while maintaining capacity levels
The ability to make only minor speed adjustments during the procedure allows the flight crew to stay close to the optimal CDA while maintaining spacing with other aircraft
NASA is currently working with the FAA, other research organizations, a major airline and avionics vender to develop and implement merging & spacing
This is seen as a first step to implementing airborne spacing in large, complex terminal environments
17
Preliminary Merging and Spacing Simulation Results
Separation at merge point
Four CDA routes into DFW350 nm routesMerges at cruise, downwind, baseNominal winds, initial spacing deviationStudied several disruptive events
(not presented here)Results for nominal case: 0.21.3 sec
for disturbances: -0.94.3 sec
18
Current and Future NASA ResearchRelated to 4D-ASAS
• Safety assessments of distributed airborne separation– Batch study on distributed strategic conflict management
• Traffic complexity management through distributed control of trajectory flexibility– Development of flexibility metric, preservation function– Trajectory constraint minimization
• Early implementation applications– Oceanic In Trail Procedure– Merging and spacing with continuous descents
• Airborne Precision Spacing in super-density terminal arrival operations
19
Thanks for your attention.
(Back-up charts follow)
20
En-RouteSafety Impact Assessment
• Study performed by Volpe National Transportation Systems Center, Oct. 2004– To provide NASA with information on potential safety impacts and risks that can be
addressed during concept development, simulation, and testing– Approach: (1) Task-based analysis and (2) Simulation results analysis
• Findings– Identified no safety showstoppers, several positive safety impacts, and several safety issues
recommended for further research– Concept at early stages of R&D, too soon to determine safety relative to the current system – Ultimate assessment requires iterative safety analyses, determination of safety and
performance requirements for systems and operators, and extensive testing
• Safety Issues Recommended for Further Research (highlights)– Roll of automation: Need stringent criteria for availability, integrity, and accuracy– Unambiguous identification (air & ground) of AFR vs. IFR status– Determine need for ATSP awareness of AFR traffic, AFR-IFR conflicts– AFR awareness of AFR-IFR conflicts; AFR/ATSP coordination for short-term alerts– Upper limit of distributed authorities (AFR) for safe operations – complexity management*– AFR-to-IFR transition in non-normal situations; significant rates of metering non-
conformance– Impact of degraded or erroneous intent information– Flight crew workload in descent– Preclusion of conflict propagation* * New R&D activities currently in progress
or planned to address these issues
21
L2 alert(conflict alert)
L3 alert(NMAC alert)
Display filteringConflict prevention
Flexibility preservation L1 alert(low level alert)
Additional Protective Factors• Long look-ahead time horizon• On-condition intent-change broadcast• Intent-based automated conflict detection• Alert-based procedures• Rapid-update state surveillance• Human/automation redundancy
L0 alert(traffic point out)
XXXX
Safety DesignAOP’s Layered Approach to Distributed Separation Assurance
Level 1 (L1) alert(low level alert)
L2 alert(conflict alert)
L3 alert(NMAC alert)
Continuoussurveillance
Right-of-wayrules
Strategic & tactical CR
ACAS
Maneuver restriction alerting
Protection layers
Implicit coordination
Nearby aircraft
Pre-alert
Pre-alert
22
4D-ASAS Issues of Concern For Discussion and Possible Study
• Socio-political acceptability– Social acceptance that a distributed-authority system is safe regardless of technical proof? – Political resistance to implementation of distributed system (users and service providers)?
• Destabilization from gaming– Can this be mitigated using slot management?
• Performance-achievement incentive– Is there sufficient incentive for users to always want to equip for higher ATM performance?
• Short-distance flight benefits– Are there sufficient degrees of freedom?
• Departure constraints impact on performance– Will users have sufficient departure-time control to achieve benefits?
• Retrofit potential– Does forward-fitting meet the demand?– Are retrofit options technically feasible, cost-effective, and beneficial?
• Mandate impact– What is the user cost/benefit impact if 4D-ASAS is mandated?