Pulsed 1.5 micron Lidar for Wake Vortex Measurements and Monitoring :

CREDOS Trials on Frankfurt Airport

A. DOLFI- BOUTEYRE ; J.P. CARIOU

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Lidar configuration during CREDOS

• CREDOS : Crosswind -Reduced Separations for Departure Operations

• 6th framework programme• Campaign : Frankfurt 03/2007• Scanning plane perpendicular

to the trajectory• Location : 200m from glide path

(to allow good angular resolutionwhile enough field of view)

• Fast scan period to ‘freeze’ thevortices : 4s for 60°

• Observing mostly departureslidar

Scanning angle

lidarScanning angle

lidarScanning angle

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ONERALIDAR

Field tests at Francfort airportCREDOS CAMPAIGN (february –March 2007)

ONERALIDAR

DLRLIDAR

VOLPELIDAR

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SWAN lidar set up for CREDOS campaign at Francfort (february –March 2007)

BPFM

FMQWP

CL

L2

EDFA

FL

SWAN lidar characteristics :- wavelength: 1.55 µm- range : 400m- min distance: 50m- Speed resolution : < 1 m/s- Frame rate : 0.25Hz

• Laser characteristics (made in Onera):- 60 µJ per pulse, PM- 250 ns pulse duration- 15 kHz rep. Rate- < 0,5 MHz linewidth , M2=1.3

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SWAN: lidar processing for wake vortex

• Real time signal processing and display:

• longitudinal spatial resolution: 2.4 m (overlap of range gates)

• lateral spatial resolution: 35 cm@200m(0,1°)

• Velocity resolution: < 1 m/s

High level processing:• core position, • velocity profiles, • circulation vs time/span

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SWAN : wake vortex signal processing

Lidar heterodyne signal

Fourier transform

Velocity spectrum for a line of sight θi or a range gateVortex velocity profil along a diameter

Maximun or minimum velocity extraction for the all scan

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ONERALIDAR

40 50 60 70 80 90

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-5

0

5

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15

vite

sse

s (m

/s)

angle(°)

SWAN : Wake vortex spectra analysis

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CREDOS CAMPAIGN Orly/Francfort 2007B744

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CREDOS CAMPAIGN Orly/Francfort 2007B744

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Signal processing outputs

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Statistical analysis of CREDOS departure measurements

•180 measurements of heavies

•The core position error is about ± 2 m

• The circulation error is about 10%.

• Vortex separations ( at first measurement after overflight ) agree with theoretical value for 90% overfligthts

• Measurement duration > 1 min for 50 % overfligthts .

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From Laboratory to operational product

2005 2006

2007ONERA Lab 2005 Leosphere 2006

...2011+2007

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13

LIDAR

Parallel runway monitoring

400m

400m

If compact, autonomous and reliable,one lidar can monitortwo parallel runways

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Lidar range vs Pulse Energy

10

100

1000

10000

1,00E-07 1,00E-06 1,00E-05 1,00E-04 1,00E-03 1,00E-02

Ran

ge(

m)

energy(J)

1.5 µm pulsed Lidar range as a funtion of laser energy

E…

10 cm apertureextinction coef = 3,4 E -6 m-1

retour

Range resolution 30m (pulses 200ns) – integration time 0.1s

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Conclusions

• Wake vortex detection with fiber laser lidar has been demonstrated during CREDOS campaign.

• Technology is affordable ( telecom components) and now commercially available at Leosphere for wind monitoring applications.

• Fiber laser technology is scalable for longer range or faster application .

• Signal processing hardware is mature and automatic algorithms for operational wake vortex monitoring are to be developed.

• Such compact scanning lidars could be used widely on airports to gather stastistical information on wake vortices trajectories and circulation.

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Wake vortex transversal measurements (SWAN lidar) Conclusions

• Robust & reliable (trip to Frankfurt without adjustment)

• Real time display of velocity map

• Further works :• Automatic & real time wake vortex signal processing • Down sizing• Unattended operation

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40 50 60 70 80 90

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/s)

angle(°)

CREDOS : Analyse spectrale des tourbillons

Le profil de vitesse est obtenu en traitement en temps différé en cherchant, après seuillage, la valeur maximale ou minimale de vitesse dans la porte de mesure. Pour chaque distance de mesure, on trace ces valeurs maximales et minimales en fonction de l’angle de balayage, on obtient le réseau de courbes rouges et bleues

Position du coeur, circulation vs temps/balayage

Développement d’un traitement du signal optimal

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θscan

θ i

Vi

αi

LIDAR

maxVimaxVj

Vradial

θj

θscanθiVi

max

Vimin

Vjmax

Vjmin

θj

VJmaxVJ

min

VImaxVi

min

θi,Z1

PS=TF(i(t)).TF*(i(t))

Vradial ∝ fD

θJ,Z2

i(t)

t

θi

Vradial ∝ fD

Transformée de Fourier

Spectre des vitesses pour un angle et une distance donnéeImage des vitesses pour un balayage et une distance donnée

CREDOS : Traitement du signal des vortex

i(t)

t

θj

z1

Z1

ZZ

Z1

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ONERALIDAR

SWAN : REAL TIME display of velocity map

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Mesure des « Wake –Vortex » sur sites aéroportuaire

• Weather limitations Clear stratified sky, low visibility, heavy rain, very low clouds

• Windline+Weather tower and TDWR : only solution under heavy rain

• LIDAR is adapted to most meteo situations

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Wake Vortex monitoringSWAN Lidar- Credos campaign

LIDAR

Scanner

Lidar

750

630

550

0 450 m

450 m