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
-10
-5
0
5
10
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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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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-5
0
5
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vite
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s (m
/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