ANTARES : Acoustic Positioning System

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ANTARES Acoustic Positioning System
G. Hallewell for
V.Bertin P.Keller A.LeVanSuu V.Niess
VLVnT2 Catania November 2005
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THE POSITIONING OF THE ANTARES DETECTOR
PRINCIPLES

• 1 To do astronomy absolute spatial orientation
  
• 3 geographic coordinates
• ? needs few meters depth and few arc minutes
  for longitude and latitude
• 3 orientation angles for the global orientation
  of detector
• - orientation with respect to Magnetic North
• - tilt with respect to horizontal plane according
  to directions E/W et N/S
• ? angular resolution expected 0.2
• 2 To reconstruct muon trajectories relative
  positioning
• need precise measurement of Cerenkov light
  arrival time on optical
• modules and their relative positions
• ? precision needed on position 10 cm
• ? Performed by 2 complementary systems acoustic
  triangulation
• heading measurement tilts on each OM

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ABSOLUTE POSITIONING ACOUSTIC NAVIGATION

• ? Principle
• low frequency acoustic system (8-16 Khz) between
  boat and acoustic releases located on objects to
  be monitored (MORS/Océano Technologie)
• (l 190-90mm, range 5km, precision 1m)
• differential GPS system
• (geographic position of the boat within few
  meters)
• pressure sensors located on mooring line
  (immersion depth)

• ? Functions
• geographic position and orientation of detector
• monitoring of all detector components during
  deployment
• navigation of submarine during line? JB
  connections

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Long Baseline Acoustic Absolute Positioning (1)
Boat with differential GPS positioning
LBL transponders deployed on seabed for
absolute detector positioning
1km
1km
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Long Baseline Acoustic Absolute Positioning (2)
Placing objects on seabed
Deployment Boat
Descending object with acoustic transponder
1km
1km
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Acoustic TriangulationShort Baseline Transponder
net
Deployment Boat
High frequency 40-60kHz l37?25mm, range
few100m, precision 1-3cm
300m
1km
300m
1km
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ACOUSTIC POSITIONNING SYSTEM PROTOTYPE
Acoustic triangulation system developped by
Genisea for the line5 demonstrator line tested on
demonstrator line 4 distancemeters
(hydrophones) fixed on the line 4 autonomous
(40kHz) transponders on the sea bed around the
line 1 sound velocimeter
4 transponders
Accuracy
measured distances
1 cm
Inter-distancemeters
? good performance of system 3D
positioning of hydrophones along the line
with an average accuracy of 3 cm
1 cm
Inter-transponders
? 3 cm
Dist.Transponders
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BUT WE NEED TO DETERMINE PMT POSITIONS TO
10-20cm ? NEED LINE SHAPE
Acoustic Triangulation
Tiltmeter- Compass
Tilt x ()
Line shape Reconstruction
? 100 sec
Time propagation of acoustic waves gt . Distance
between acoustic modules . Position in space
Tilt and orientation of OMs
Top of the line
bottom of the line
2 m
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TCM2 COMPASS TILTMETER SYSTEM

• Our need to achieve an accuracy of 10 cm on 3D
  space position on optical modules
• Compass 5
• Tiltmeter 0.2

The TCM2 tiltmeter/compass from PNI is integrated
onto a more general instrumental board in the
electronics container of every storey

• Global qualification tilt results on TCM2 cards
  (3) on -55

• Global qualification heading results on TCM2
  cards (3) on -0360

? Performance conforms to what is required
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IMPROVED ANTARES ACOUSTIC POSITIONING SYSTEM
Celerity (sound velocity), Conductivity (salt
ppm) Temperature Depth (from pressure)
Rx Hydrophone
On-shore Acoustic software
Celerity
CCTD
Configuration gains, detection threshold,
listenning window, acoustic cycles synchro
Rx module
Electronics (Emission/Reception)
Synchronisation with general Antares clock
Pressure sensor
Readout via DAQ board
RxTx module
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MILOM ACOUSTIC SETUP

• Since April 14 2005,
• One RxTx emitter module on bottom of MILOM line
• One Rx receiver module on 1rst floor of MILOM
  d(Rx/Tx) 96 m
• One external autonomous mobile  transponder 
  d(RxTx/Transponder84 m)

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ACOUSTIC MEASUREMENT RESULTS
RxTx /Transponder (autonomous line) distances
over a period of 5 hours, variation are due to
movements of the transponder in the autonomous
line
RxTx /Rx distances over 96m fixed acoustic path
over 20 day period
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Orientation/tilts Measurements on PSL
Pitch tilt data in each of the 5 PSL storeys over
one month
Heading data from compasses in each of the 5 PSL
storeys over one month
Roll tilt data in each of the 5 PSL storeys over
one month
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Conclusions

• ? All the features of the acoustic positioning
  system are functional on the MILOM
• their accuracies are within the required
  specifications
• Would needs 2 extra transponders to perform
  acoustic triangulation in order to test the full
  length 3D spacial reconstruction
• will be done with the using the first deployed
  full length line
• Even awaiting the first full length line
  acoustic data, it seems that the specification of
  lt10 cm spacial precision on Optical modules will
  be possible

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Long Baseline Acoustic Triangulation Absolute
Positioning
Boat with differential GPS positioning
LBL transponders deployed on seabed for
absolute detector positioning
1km
1km