Using STK To Visualize Air Traffic - AGI

Introduction• Aeronautics BlueprintLangley Research Center–Summer 2001• NASA Langley Research Center was asked to participate in theproduction of a multimedia presentation designed to supplementNASA’s Aeronautics Blueprint for the 21 st Century.–Premise• One of the arguments presented by the Aeronautics Blueprintwas that the national airspace is not as congested as originallybelieved. It is suggested that current airspace is abundant andunderutilized.www.stk.comPg 2 of 26

GoalLangley Research CenterTo illustrate that airspace is not congested, theAeronautics Blueprint team wanted a realistic 3-Dillustration of actual aircraft flights within the periodof a day.• Task–The Data Visualization and Analysis Lab at NASALangley began the process of acquiring the informationand tools necessary to develop this illustration.www.stk.comPg 3 of 26

Client’s Minimum RequirementsLangley Research Center• Restrict data to public-use airports only• Domestic flights only• No military flights• No helicopter flights• 9 seconds of animation content• 5 hours of flight datawww.stk.comPg 4 of 26

HardwareLangley Research Center• SGI Onyx2• Infinite Reality2 Graphics• 8 R12000 CPUs• 8GB RAMwww.stk.comPg 5 of 26

SoftwareLangley Research Center• STK/VO 4.2– Accurate– Interactive 3D– Easily integrated Off-the-Shelf software• STK/Connect• STK Face of the Earth Imagery• Perl– Excellent regular expression capability for processing ASCII data– Easily adaptable– Quick prototypingwww.stk.comPg 6 of 26

Data Process FlowRaw dataLangley Research CenterFAA flight data:Extracted flight infoNIMA DAFIF files:Extracted airport &waypoint locationsPerl scriptPre-processed dataPerl scriptPerl scriptPerl scriptSTK formatted flight files(1 .ga for each flight)STK/Connectcommand script (*.cc)www.stk.comPg 7 of 26

Airport & Waypoint DataLangley Research Center• Extracted relevant data from NIMA DAFIF databases–Restricted airport data to domestic public-use facilities–Lat-Long position for each airport/waypoint• Processed 5000+ airports• Processed 56800+ waypointsAirportsWaypointswww.stk.comPg 9 of 26

TRX_Mar18.to Format• Raw FAA flight data– 54798 flights– 24 hrs Mar 18, 2001• 2 lines per flight– First Line• Start time• Flight ID• Aircraft model• Assigned altitude• Air speed– Second Line• Takeoff airport ID• Consecutive waypoints• Landing airport IDLangley Research Centerwww.stk.comPg 10 of 26

Automate .ga File GenerationLangley Research Center• Created perl script to process flight data, airports,and waypoints for each of 43000 flightswww.stk.comPg 11 of 26

Define Great Arc File• Create new great arc (.ga) file for each flightLangley Research Center• Define header including flight start time and number ofwaypointswww.stk.comPg 12 of 26

Extract Position InformationLangley Research Center• Get airport lat-longs• Get waypoint lat-longswww.stk.comPg 13 of 26

Complete Great Arc (.ga)• Add flight waypoints to file• Save great arc (.ga) file for current flight definitionLangley Research Centerwww.stk.comPg 14 of 26

Create STK/Connect Script• ConnectImportData.cc– Define new aircraft class– Define model for new aircraft– Assign great arc (.ga) file to new aircraft class– Repeat process for all aircraftLangley Research Centerwww.stk.comPg 15 of 26

Create Base Scenario• Set scenario epoch to match flight dataLangley Research Center• Set aircraft flight path Route display to simulate anapproximate airspace clearance for each flight–Lead Type None–Trail Type Time = 80 sec• Load Face of the Earth imagery for North America• Create camera animation• Set animation start and end time• Set SoftVTR render environmentwww.stk.comPg 16 of 26

Run Simulation• Load base scenario in STK• Load data into STK via AgiPCExp (*.cc)Langley Research Center• Send STK/Connect command to start sequentialimage renderwww.stk.comPg 17 of 26

Unexpected Input Termination• STK/Connect terminated prematurelyLangley Research Center–.cc file explicitly imported empty.mdl aircraft model foreach flight• AGI Tech Support recommended that we defineempty.mdl as the default model and remove themodel assignment from the .cc scripts–Effectively cut the number of script commands by a thirdwww.stk.comPg 18 of 26

Still Could Not Import DataLangley Research Center• Discovered IRIX command line buffer bottleneck– AgiPCExp would consistently fail after about 2000 STK/Connectcommands• Partitioned .cc file into smaller .cc files to import 1000aircraft each• Created a shell script that called each of the partitioned .ccfiles with a 3 minute pause between each group of 1000aircraft to allow IRIX time to execute all commands in thebuffer• Workaround succeeded. Successive tests indicated thatwe could now import as many files as requiredwww.stk.comPg 19 of 26

Refine Scenario Parameters• 9 seconds of animation required 270 framesLangley Research Center–Of the 43000 flights available, only 19000 flights, or 5.5hours of flight activity, were required• Pre-loaded the airspace with 2 hours of flight databefore beginning animation• Restricted animation window to daylight hourswww.stk.comPg 20 of 26

Run Time Issues• STK browser window would not display theenormous number of aircraft loadedLangley Research Center• STK/Connect would stall due to interface refreshrequirements at each STK/Connect commandwww.stk.comPg 21 of 26

Tech Support Recommendations• Interface issuesLangley Research Center–Instruct STK browser to ignore display of aircraft class• Setenv AGI_EXCLUDECLASSES Aircraft• STK/Connect issues–Instructed interface to not refresh during STK/Connectcommands• BatchGraphics * On–Instructed STK/Connect to operate at maximum speed• ConControl / HighSpeedOnwww.stk.comPg 22 of 26

Abundant Airspace VariationLangley Research Center• San Francisco• New Imagery– AirPhoto USA• STK/Terrainwww.stk.comPg 24 of 26

ConclusionLangley Research Center• The animation was included in the AeronauticsBlueprint video and was presented to thePresident’s Blue Ribbon Commission onAeronautics.• This process has served as template for otherrelated STK projects–Use Stk.pm for more efficient STK/Connect processingwww.stk.comPg 25 of 26