Passive optical monitor for atmospheric turbulence and windspeed

ABSTRACT

Keywords:

1. INTRODUCTION

σβ

L

DCn

βσ=

Free-Space Laser Communication and Active Laser Illumination III,edited by David G. Voelz, Jennifer C. Ricklin, Proc. of SPIE Vol. 5160

(SPIE, Bellingham, WA, 2004) · 0277-786X/04/$15 · doi: 10.1117/12.508051

422

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4. TITLE AND SUBTITLE Passive optical monitor for atmosperic turbulence and windspeed

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2. EXPERIMENTAL SET-UP

CCD camera

VIDEOTRACKER

5” Diameter Celestron and/or OrionTelescope with 1.3 m focal length

Laptop with NI-DAQ card

Existing Light Source

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σx2

σy2

σβ = σx2 + σy

2

σβ σx2

σβ σy2

3. DATA AND RESULTS

3.1 Calibration at site 1 – over land at Fort AP Hill, VA

3.2 Data from site 2 – across the Potomac River

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µ µ

µ µ

NRL

3.5 km

2 km

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3.3 Data from site 3 – across the Chesapeake Bay

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1 E -1 5 1 E -1 40 .0 0

0 .0 1

0 .0 2

0 .0 3

0 .0 4

0 .0 5P

roba

bilit

y D

ensi

ty

Cn

2 (m -2 /3)

M e d ia n Cn

2 = 2 .9 x 1 0 -15

6 2 2 M b p s la se rco m lin kc lo s e d w ith ~ 1 0 -10 B E Ra t th is C

n

2 o f 5 x 1 0 -15

3.4 Frequency analysis and wind measurement

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=+

+ −•+

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−≡centfreq

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0

5

10

15

20

25

10/3/2002 12:00 10/4/2002 12:00 10/5/2002 12:00 10/6/2002 12:00 10/7/2002 12:00 10/8/2002 12:00

Tra

nsv

erse

Win

d S

pee

d m

easu

red

at

Rea

gan

Nat

ion

al (

mp

h)

4

6

8

10

12

14

16

18

Freq

uen

cy Cen

troid

(Hz)

Transverse Wind SpeedFrequency Centroid

Average Transverse Wind Speed (mph)

Fre

quen

cy C

entr

oid

(Hz)

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4. CONCLUSIONS

REFERENCES

Proceedings of the SPIE. 4821

Proceedings of the SPIE This issue

Proceedings of the SPIE This issue

Proceedings of the SPIE This issue

Proceedings of the SPIE, This issue

Proceedings of the SPIE, This issue

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