remote airfield lighting: modeling sequential tasks using

© 2008 Rensselaer Polytechnic Institute. All rights reserved.© 2006 Rensselaer Polytechnic Institute. All rights reserved.

1

Remote Airfield Lighting: Modeling Sequential Tasks Using the

Unified System of Photometry

Mark S. Rea1, Zongjie Yuan2, Andrew Bierman1

CORM 2008

1 Lighting Research Center, 2 W.A.C. Lighting

Sponsor: Federal Aviation Administration

© 2008 Rensselaer Polytechnic Institute. All rights reserved.

2

Problem(FAA Cooperative Agreement No. 04-C-GA-ERAU)

Develop technical specifications for remote airfield lighting systems

› Nighttime operations

› General, non-commercial aircraft

Consortium of universities formed to find solution

› Embry-Riddle Aeronautical University

› University of North Dakota – Aerospace

› University of Alaska

› Rensselaer Polytechnic Institute


3

Tasks

Locate the runway

Determine the runway’s orientation

Orient the aircraft to the runway and approach

Land the aircraft

Stop the aircraft


4

Assumptions and constraints

Visual identification of runway from a 5-mile radius

Pilots would have been to the airfield previously in the daytime

No blue or red lights or flash frequencies lower than 1.5 Hz› Possible confusion with emergency vehicle lights or

hazard identification on the ground

Use response times and confidence ratings as dependent variables› Confidence ratings considered more important than

response times


5

Experimental apparatus


6

Assembly of ground scene

Integrating sphere with LED sources


7

View of ground scene and computer monitor


8

Normalized spectral power distributions


9

Locate runway and determine runway orientation

Experiment 1: Detection and identification

› SPDs

Experiment 2: Detection only

› SPDs


› Flicker rates (1, 2 and 4.2 Hz)

› SPDs


10

Response times (Exp. 1)


11

How is mesopic luminous efficiency characterized?

Starlight Moonlight Dim interiors Office lighting Daylight

Scotopic Mesopic Photopic

Radiant Energy

x


12

Introducing the Unified System of Photometry

The relative proportion of photopic and scotopic luminous efficiency for peripheral vision at a given (mesopic) light level (He et al. 1997, 1998)

At high light levels, X = 1

At very low levels, X = 0


13

0.00

0.25

0.50

0.75

1.00

400 500 600 700

Wavelength (nm)

Luminous efficiency

Mesopic luminous efficiency functions

X = 0.09

L = 0.02 cd/m²


14

0.00

0.25

0.50

0.75

1.00

400 500 600 700

Wavelength (nm)

Luminous efficiency


X = 0.16

L = 0.05 cd/m²


15

0.00

0.25

0.50

0.75

1.00

400 500 600 700

Wavelength (nm)

Luminous efficiency


Vmes = (X)V(λ) + (1-X)V’(λ)

(mesopic = cones + rods) X = 0.40

L = 0.22 cd/m2


16


X = 0.12


17



18

Confidence ratings (Exp. 1)

X = 0.22


19



20



› SPDs


› SPDs



› SPDs


21


X = 0.0


22



23


X = 0.0


24



25



› SPDs


› SPDs



› SPDs


26


X = 0.12


27



28


X = 0.22


29



30

Prototypes


32

Final product


33

Summary

Unified System of Photometry developed from data on performing a single visual task› Different data sets used different tasks

These results support the inference that sequential tasks can be successfully modeled by the Unified System of Photometry› Sequential tasks: locate airport, then determine orientation

Results imply that the two visual tasks rely on different visual mechanisms but the stimuli for these complex visual tasks can be rectified additively by the Unified System of Photometry

Unified System of Photometry used as basis for specifying remote airfield landing lights

© 2008 Rensselaer Polytechnic Institute. All rights reserved.© 2006 Rensselaer Polytechnic Institute. All rights reserved.

34

Thank you.

Acknowledgements:

Don Gallagher, FAA

Dennis Guyon, LRC

Howard Ohlhous, LRC

Martin Overington, LRC

remote airfield lighting: modeling sequential tasks using

Documents