USE OF SYNTHETIC VISION TO ENHANCE AIRPORT CAPACITY

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USE OF SYNTHETIC VISION TO ENHANCE AIRPORT
CAPACITY

• J. David Powell, Stanford University
• Professor (emeritus)
• Aero/Astro Dept.
• Presented at the Lockheed Martin
• Palo Alto Colloquia
• October 5, 2006

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AIR TRAFFIC GROWTH

• Recent Eurocontrol study
• Flights could double by 2025
• Biggest 20 airports will be saturated 8 to 10
  hours per day
• Biggest 60 airports will be congested
• There is a 15 to 20 year lead time required to
  develop infrastructure
• Problem is similar in the USA
• Need to start now to avoid severe problems in 20
  years

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Airspace System Capacity

• For enroute, is determined today by
• Radar accuracy
• Altimeter accuracy
• For the airports, is determined by
• Usable number of runways
• Total number of runways that are usable
• Parallel runway spacing
• Weather

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Landing capacity of airports (1)

• To increase capacity with current technology
• Add runways at existing airports
• Parallel runways must be 3400 - 4300 ft apart
• Requires a lot of land area
• Very difficult to acquire land (or fill the Bay)
• Make more use of secondary airports
• Add new airports
• Very difficult to acquire land

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Example SFO
3400 to 4300
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Worldwide Runway Expansion Projects
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14
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5
1
33 Parallel Runways under Development or
Construction
Source www.airport-technology.com
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Lambert Field, St. Louis 2006
http//www.lambert-pmo.org/about/phase1/map/id42.a
sp?m4
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Lambert Field Land Acquisition
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Landing capacity of airports (2)

• This talk will describe technology that
• Allows much closer spacing of parallel runways
  therefore
• uses much less land area
• easier to expand existing airports
• easier to obtain land for new airports
• Allows more use of existing parallel runways in
  bad weather

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Technology Available

• Global Navigation Satellite Systems (GNSS)
• GPS (U.S.), Galileo (Europe), and Glonass
  (Russia)
• Satellites in 20,200 km orbits, some elliptical
• 10 15 m position accuracy - standard
• 2 - 3 m 95 position accuracy differential
  (WAAS and EGNOS)
• Automatic Dependent Surveillance Broadcast
  (ADS-B)
• Air-to-Air and Air-to-Ground Datalink
• Broadcasts aircraft position velocity, etc
• Synthetic Vision shows
• neighboring traffic
• wake vortices from neighboring traffic

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Wide Area Augmentation System (WAAS)
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Automatic Dependent Surveillance-Broadcast (ADS-B)

• Aircraft / vehicle broadcasts known GPS
  position and additional data with reception rate
  of once per second

• ADS-B Message now includes
• Lat/Lon, Altitude
• Velocity
• Intent
• Call sign
• Heading
• Aircraft category

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Comparision - Radar ADS-B

• Courtesy FAA Air Traffic Organization

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Long Range Radar vs. ADS-B
Courtesy FAA Air Traffic Organization
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WAAS/EGNOS ADS-B Benefits

• Compared to radar surveillance
• Much greater accuracy
• Faster update rate
• Coverage requires a simple antenna
• Much lower cost
• Available to pilots as well as controllers
• Traffic separation can be partly accomplished by
  pilots

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Why 3400 -4300 ft runway separation now in bad
weather?

• Accuracy of guidance from Instrument Landing
  System (ILS)
• Accuracy and update rate of radar surveillance
• Response time to alert pilot of a problem
• Time for controller to recognize problem
• Time to communicate to pilot via radio
• Time for pilot to react to ATC instructions
• Time for pilot and aircraft to execute escape
  maneuver

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Design Principle

• Pilots are able to land on very closely spaced
  runways in good weather now
• at San Francisco, pilots routinely land on
  parallel runways separated by 750 ft
• Therefore, make instrument flying like visual
  flying by highlighting the critical features of
  the outside scene on a cockpit display

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Some Design Features

• Use a perspective (pictorial) display of approach
  and traffic (Synthetic Vision)
• Modify ADS-B for approach use so that
• 1 sec update is guaranteed
• Roll angle is broadcast
• Add a depiction of the wake vortices of
  neighboring traffic
• A feature not available in any weather now

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Cockpit Displays
Current technology
Synthetic Vision
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3D Perspective Display
Roll of Bogey
Ownship Roll
Groundspeed
Altitude
Parallel approach pathway
Horizon Line
Flight path vector
Final approach pathway
Bogey Aircraft
Distance to touchdown
Heading
Logo
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Map Display
Warning Danger Zone
Bogey
Caution Danger Zone
Ownship
Approach Tunnels
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Orthographic Display
Longitudinal Spacing Indicator
Ownship Tunnel
Bogey Tunnel
Ownship Position
Current Bogey Position and Roll
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Mixed Display
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Parallel Approach Flight Testing
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System Architecture
Ownship (Caravan)
Bogey (Saratoga)
Attitude GIA2000
Position WAAS
ADS-B Datalink
Attitude Honeywell INS
Position WAAS
Display Computer Terrain Path- way Databases
ADS-B Datalink
LCD Flight Display
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Longitudinal Station-keeping
Station-Keeping Error (nm)
Out the Window
Display
Approaches
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Monte Carlo Simulation

• Want to evaluate the probability of a Loss of
  Separation due to a blunder during Closely Spaced
  Parallel Approaches (CSPA).
• 10,000 CSPA simulations per configuration of
  longitudinal spacing and reaction time.

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Probability of Loss of Separation on CSPA vs
Longitudinal Spacing and Runway Spacing
FAA Safety Threshold 500 wingtip to wingtip
Probability of Loss of Separation on CSPA
1220
P(LOS) lt 5x10-10 for LS gt 2000
Runway Spacing (feet)
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Sensitivities
Minimum Safe Runway Spacing (feet)
Wake Vortex
Wake Vortex
Longitudinal Spacing (feet) RT 0.4 to 4.4
seconds

• Employ the benefits derived from controlling
  Longitudinal Spacing

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What are wake Vortices?
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Wake vortex effect on spacing
WIND
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Effect of Wake on Safe Zone
Safe Zone
Danger Zones
Wake Vortex
WIND
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Nominal Wake Model
zg
descent profile
xg
zw/g
zlimit
zw/g f(w, t)
w f(Wt, V, b, r)
Zlimit f(vortex instabilities, atm. conditions)
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Wake Uncertainty Model
zg
xg
Flight path
Nominal wake depth
Uncertainty over time
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Wake-Danger Zone Model
wake plane
1 sec
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Piloted Flight Simulations
In-trail Encounter Scenario
KNUQ
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Flight Test Aircraft

• Five Pilots
• Six Flights
• Three Scenarios

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Additional Test Equipment
Caravan (probe)
Video Recording Rack
Saratoga (lead)
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Flight Test
In-trail Same Air Mass
Wake
Ground Track
Air Mass
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Results
In-trail Same Air Mass
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Results
In-trail Same Ground Track
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Wake Vortex Flight Test Results

• Subjective results established a proof of concept
• The image on the display faithfully represented
  the view out the window
• A wake-hazard zone appeared to reliably bound the
  wake hazard
• Pilots reported they could discern no noticeable
  difference between the wake location and the
  display prediction
• The wake display improved the awareness of the
  wake hazard
• The pilots loved it, and wanted it ASAP

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Conclusions (1)

• Showed novel displays and supporting systems to
  solve issues related to airport capacity
• Pilots can view neighboring traffic and its wake
• Coupled with ADS-B, the displays have potential
  to reduce parallel runway spacing from 4300 ft to
• 750 ft if lead aircraft can be positioned on
  downwind side
• 750 ft if cross wind is less than 10 kts
  regardless of positioning
• Allows more use of existing runways in bad
  weather
• Reduces amount of land required for airport
  expansion
• Reduces environmental impact of airport
  expansions
• Improves political climate for airport expansions

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Conclusions (2)

• Much more development is needed
• Implementation will not be easy
• Requires extensive simulation
• Requires extensive flight testing
• Safety must be equal to or better than current
  system and procedures
• Requires acceptance by all stakeholders
• Alternative is to build new airports and/or
  runways with 3400 - 4300 ft separation.

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Domestic Airports with Closely Spaced Runways
Newark Seattle Los Angeles San Francisco San
Jose Las Vegas
Detroit Salt Lake City Phoenix Tampa
Atlanta Houston Dallas-Ft. Worth Pittsburgh St.
Louis
Minneapolis Memphis Kennedy Raleigh-Durham
Boston Detroit Orlando
Data courtesy of C. Haissig, Honeywell
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Acknowledgements
Dr. Sharon Houck Dr. Chad Jennings Dr. Wendy
Holforty
FAA SatNav Program Office

• Flight Test Crew
• Lee, Frank, Mohamad, Skander
• Sky Research
• Moffett Federal Airfield

GPS Lab Andy, Keith, Rodney