Table Of Contentt. !'
&3,
Airport Simulations Using Distributed Computational
Resources
William J. McDermott, David A. Maluf
NASA Ames Research Center, Moffett Field CA
Yuri Gawdiak
NASA Headquarters, Washington D.C.
Peter Tran
QSS Group, Inc.
ABSTRACT and safety of the National Airspace, making proactive
decisions about improvements to aviation safety.
The Virtual National Airspace Simulation (VNAS) will
improve the safety of Air Transportation. In 2001, using Airspace-wide simulation is a distributed computing
simulation and information management software problem. A distributed simulation environment is chosen
running over a distributed network of super-computers, as the preferred approach for several reasons. First, the
researchers at NASA Ames, Glenn, and Langley National Airspace is a large and complex system that is
Research Centers developed a working prototype of a defined by the interaction of many entities. Second,
virtual airspace. This VNAS prototype modeled daily these interactions produce transient effects that can
operations of the Atlanta airport by integrating measured have an impact on safety but are difficult to capture.
operational data and simulation data on up to 2,000 Third, intelligence is decentralized. A distributed system
flights a day. The concepts and architecture developed of data collection, modeling and simulation captures
by NASA for this prototype are integral to the National information from numerous sources about these many,
Airspace Simulation to support the development of complex interactions. Fourth, research teams are
strategies improving aviation safety, identifying located across the country. A whole aircraft simulation
precursors to component failure. comprised of multidisciplinary simulations requires
bringing together applications and data that are
INTRODUCTION developed by research teams in different locations.
Domain experts plug in models and simulations that will
Air Transportation studies require an airspace-wide
be integral parts of the VNAS, incorporating them into a
simulation environment that maintains information about
system-wide model. This article presents a working
baseline operations and estimates the impact of any
distributed simulation environment for a VNAS [1].
change before it is introduced. To extend the fidelity of
safety simulation to the highest achievable degree and
Because of the complexity of the domain building the
provide seamless, user-transparent access to Air
VNAS is a gradual process. VNAS prototypes described
Transportation safety information, a revolutionary
in this article were developed incrementally over two
technology leap in Intelligent Information Management.
years. After each step the experience gained was
applied to technology evaluation and further concept
The Virtual National Airspace Simulation is an enabling
definition.
architecture that is both extensible and scalable to a
national level. The VNAS infrastructure consists of a
distributed network of supercomputers connected VIRTUAL NATIONAL AIRSPACE SIMULATION
through secure, high-speed ground and satellite links. PROTOTYPE
Smart simulation and intelligent information-integration
tools support the management of information and Building the initial distributed simulation environment
provide the capability to continuously monitor and included the integration of a supercomputing grid,
measure operational performance against expected providing opportunities to identify underlying
performance. From this National Airspace-wide technological issues such as extensibility and scalability.
simulation environment the FAA, airlines, and other Early on, security and network communications were
service providers will have a continuously generated addressed. Data, models and simulations required
performance baseline of the National Airspace. They will compartmentalized views, and data and applications
be able to extract insightful interpretations of the health were distributed across the United States. Also,
integration of monitoring and simulation data and
applicationswere addressed.Object models of If,.'Monitoring. _ [ DomeinEx_'IseJ
componentsoftheairport/airspacbeecamenumerous
andcomplexm, adeupofmultidisciplinasryimulators.
(Surface/Airborne Inputs _ "_
The prototypeVNAS'MilestoneRequirementwsere
twofold:
• Developa batchcapabilityrunningonadistributed
networkof super-computerlsocatedat Ames,
Glenn,and LangleyResearchCenters.Perform
nightlybatchrunsofengine,landing-geaar,ndwing I;'_:'._......i._.". _4
simulations.
• Establishinfra-structurefor processingreal-time
input.
Theinitialprototypeofa NationaAl irspaceSimulation Figure 1.Engine simulator driven by measured operational data
runson NASAcomputerslocatedacrossthe United
The VNAS prototype is comprised of the following: 1)
States.Operationadlatafromupto2,000dailyflights
Intelligent Information Management Concepts,
were batch processedby the aircraft component
Architecture, and Technologies [2], 2) distributed, large-
simulatorsT. heresultisa virtualmodelof aircraftat
scale computational resources, and 3) simulation and
Atlanta'sHartsfieldInternationaAlirport.Theobjectives
application/data integration components. Together they
werefourfold:1) identifyandunderstandunderlying
produce a model of airport operations. New concepts
technologicailssues,2) understandmanagemenotf a
and tools called Intelligent Information Management
complexdistributedsimulationprocessandintegration
support the integration of both applications and data.
of measuredoperationadlataandsimulationdata,3)
design,implementa,ndtestsimulationmiddlewarethat
INTELLIGENT INFORMATION MANAGEMENT
will supportdataintegrationandinteroperabilitwyith
CONCEPTS, ARCHITECTURE, AND TECHNOLOGIES
distributedsimulationsystems,and4) evaluategrid-
Intelligent Information Management involves locating,
services such as single-pointauthenticationand
organizing, and adding value and access to data
authorizationr,emotejobsubmissiona,ndsecurefile-
throughout its life in an enterprise. For the prototype
transfer.
VNAS, it consists of three major parts: 1) an advanced
communication network, 2) the Intelligent Information
TheVNASprototypeusesmeasuredoperationadlata
Management Architecture, and 3) Intelligent Information
aboutindividuaal ircraftwhenit exists.Whereaircraft
Management Services. Network communication is
operationsarenotmeasuredsimulationdataisusedto
provided by NASA Research and Education Network [3].
completeaircraftmodels.At HartsfieldAirportlarge
The Intelligent Information Management Architecture,
amountsof operationadlataarecollectedeveryday.
which is adaptable to common needs of DOD and
Radar,airlineschedulesF,AAflight-plansa,ndweather
NASA's other Enterprises, supports the management of
dataareexamplesofthedata-collectiopnrogramsthat
complex operational environments. It is represented in
providemonitoringdatatotheVNASprototypeI.nthe
Figure 2.
air,FAATerminalRadarApproachControl(TRACON)
tracks every takeoff,approachand landing.Local
weather conditionsare constantlymonitoredand
recorded by the National Weather Service.
Subassemblsyimulatorsaredrivenby thisdataand
producesimulationparametersthatdepictstatesand
conditionwsithinkeyaircraftsubassemblies.
Measuremenatndsimulationdataareinsertedintoflight
equationsandcombinedwithgraphicimagingsoftware.
The resultis a computersimulationthatprovidesa
compositeviewof the aircraftthat reflectsmultiple I'Engine8im. I ILandinGgearSim:i [_'_ngSimT?:::!t
disciples. Representativeoperations data and
Figure 2. Architecture for VNAS Prototype
parametersfromenginesimulationsare depictedin
Figure1. Because the secure, adaptable bus-like architecture
accommodates a wide range of network-communication
and processing needs, it is the key enabling technology
that will allow full use of Air Transportation safety
information. Intelligent Information Management's suite
of smart services collaborate with each other and
communicate with users via this network.
Theseconceptsand technologies,developedand engine manufacturers worked together on NPSS. It
implementedin the prototype,are representedby a provides shaft speed and inlet/outlet temperatures and
suiteofmanagemenatndintegrationservicesthatare pressures at each stage. There is a high level of
connected through a distributed network of confidence in NPSS and engine manufacturers are
supercomputervsia secure,high-speedlinks.These using it in designing new engines. Landing gear
servicescontroltheexecutionofdistributedsimulations simulation is provided by a 737 simulator• NASA and
andintegratioonfoperationaalndsimulationdata. Boeing worked together on this simulator which provides
forces and moments for landing-gear. It has been
DISTRIBUTECDOMPUTATIONARLESOURCES validated and used for a number of years.
Large-scalceomputationarel sourcesarerequiredbya
VNAS.Theyareneededtosupporttheintegrationof The wing simulation is a simple wing model which
hundreds of aircraft performance models. produces aerodynamic coefficients, such as lift and
Computationaclapabilitiesthat will be requiredfor drag, and forces and moments. Graphs of lift-
NationaAl irspace-widseimulationaresuggestedbythe coefficients are illustrated in Figure 1. The solid line
currenat ndfuturerequirementlsistedinTable1. represents a baseline curve for arrivals at Hartsfield
International Airport. The broken lines represent lift
Current Capability Capability coefficients for two arrivals• The wing simulator has not
Capability Needed By 2010 Needed by 2020 been validated.
100 million 10 billion floating 20 GF, 1 terabyte
floating-point point instructions per simulation 0.3 1
instructions (MF), (GF), 20 gigabytes
100 megabytes per simulation O.Z5
per airport LIF]
simulation
0.2
Navier-Stokes, Multi-discipline Multi-discipline
airframe only, simulation, simulation,
0.15
cruise --> 10 hours airframe only, airframe +
landing/takeoff --> propulsion,
1hour landing/takeoff -->
1minute
Table 1.Current and Future Need for Computational Resources [4]
NASA's Information Power Grid, a high-performance
grid made up of a distributed network of supercomputers
running over advanced networks, is employed in the
VNAS prototype [5].
SIMULATION AND INTEGRATION COMPONENTS A central executive is needed to regulate the simulators
The four major parts of the initial simulation prototype and manage the large amount of data that is generated.
and the NASA centers of expertise responsible for
aircraft subassembly simulation and information Intelligent Information Management services run on a
integration are listed in Table 2. computer at an Intelligent Information Node. They
control automated batch processing of an entire day's
flights. This central site also manages the interactive
ExpertiseNNAS Function/Center of requests for simulations by scheduling and controlling
Component Expertise the execution of engine, landing-gear, and wing
Aero-propulsion: Numerical Engine simulation (NASA simulations•
Propulsion Simulation Glenn Research Center)
System (NPSS) [6] The Intelligent Information Node manages these
Airframe Systems: Boeing Landing-gear simulation requests by disseminating operational data and invoking
737 Simulation [7] (NASA Langley Research engine, landing gear and wing simulations on remote
Center) computers. From a simulation-integration point of view
Aerodynamics: Boeing 747 Aerodynamic simulation
every simulation is similar. First, the Intelligent
Wing Simulation [8] (NASA Ames Research
Information Node sends operational data (i.e., radar-
Center)
tracks and surface data) as input to each simulation site.
Intelligent Information Simulation control and data
Management distribution, retrieval, and The input data is processed by simulation software
integration (NASA Ames running at the remote site. For each flight the simulator
Research Center) produces simulation data that reflects the state and
performance of a particular aircraft subassembly. When
Table 2.Expertise for aircraft subassembly simulations and integration
simulations from multidisciplinary perspectives have
The focus of the initial prototype is on basic simulation.
finished, services manage the retrieval and integration
Engine simulation is provided by the Numerical of simulation and monitoring data. This creates a virtual
Propulsion Simulation System (NPSS). NASA and model of each aircraft.
Thesimulationparametersgeneratedbysubassembly concepts can then be inserted into real-time National
simulationsandintegratedby servicesarestoredfor Airspace-wide simulations. Analyses of performance can
analysis.Monitoringandsimulationdatacanbeviewed be a basis for evaluating proposed methods and
via a visualizationtool,trendedandanalyzedforrisk technologies and making proactive decisions about
exposure.For example,weatherdata, flight-plans, improvements to aviation safety.
radar-tracksand simulationparametersare linked
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technologiessuchasXML-converterasndinterpolation
techniquesto integratedata from heterogeneous
databases,5) testtechnologiesthatenabletwo-way CONTACT
informationflowssuchascapturingandfeedingback
safetyinformationfrommulti-disciplinfelightsimulations William J. McDermott. William McDermott is a senior
to pilots, 6) investigateproposedstandardsand software engineer in the Computational Sciences
technologythat supportAerospace-specifIinctelligent Division at NASA Ames Research Center. He has been
InformationManagemen7t,)continuecollaboratiownith conducting simulation research in several aerospace
groups who are working to create large-scale areas since 1995.
computationaglrids. NASA Ames Research Center,
Code IC, Mail Stop 269-4, Moffett Field CA 94035-1000.
bmcdermott @mail.arc.nasa.qov.
CONCLUSION
Tel: (voice) 650 604-5650 (fax) 650 604-4036
For the National Airspace to increase throughput of Air
David A. Maluf. NASA Ames Research Center, Mail
Transportation requires a nation-wide simulation
Stop 269-4, Moffett Field CA 94035-1000.
environment that has the highest achievable degree of
maluf @email.arc.nasa.qov.
fidelity. The solution described in this paper, Intelligent
Tel: (voice) 650 604-0611 (fax) 650 604-4036
Information Management, provides infrastructure to
support a Virtual National Airspace Simulation. New
Yuri Gawdiak.NASAHeadquartersC,odeR, Room
6K17,WashingtoDn.C.20546
[email protected]
Peter Tran. NASA Ames Research Center, Mail Stop
269-4, Moffett Field CA 94035-1000.
pbtran @mail.arc.nasa.qov.
