ebird control of marine seismic streamers

KONGSBERG PROPRIETARY: This document contains KONGSBERG information which is proprietary and confidential. Any disclosure, copying, distribution or use is prohibited if not otherwise explicitly agreed with KONGSBERG in writing. Any authorised reproduction in whole or in part, must include this legend. © 2014 KONGSBERG – All rights reserved.

eBird – control of marine seismic streamersITK/NTNU 60 år - Kybernetisk fagdag 7.november 2014

Dr.ing. Ola Erik Fjellstad

Ola Erik Fjellstad, PhD

IPR Manager

Kongsberg Seatex AS

• PhD Engineering cybernetics, NTH 1994

– 6 DOF control of autonomus underwater vehicles

– Professor dr.ing. Thor Inge Fossen supervisor

– Professor dr.h.c. Jens Glad Balchen advisor

• Principal Engineer R&D, Kongsberg Seatex 1994 - 2013

– Seapath - Integrated GNSS/IMU navigation system for pos/vel estimation

– MRU - Inertial sensor system for motion measurement and RPH estimation

– eBird – Steering device system for positioning of towed streamer spread

• IPR Manager, Kongsberg Seatex 2014 – today

– Coordination of and participation in all IPR activities18.11.2014Page 2 WORLD CLASS - through people, technology and dedication.

Marine seismic survey

18.11.2014 WORLD CLASS - through people, technology and dedication Page 3

Streamers need steering

Conventional operation

è/ 4 /è18-Nov-14

Worlds biggest controlled structure

18.11.2014 WORLD CLASS - through people, technology and dedication Page 5

eBird - Streamer steering device

• Mounted inline, low vibration noise

• Typically 300m separation

• Power and communication through streamer

• Wing profile optimized for maximum lift and minimum acoustic noise

• Batteries in wings autonomous operation for several days

• 3 wings independently rotatable

• Decoupled roll, depth and lateral control

• Provides ~400 N at 4.5 kt through water

• 3 degrees feather angle

è/ 6 /è18-Nov-14

eBird body

• Length 370 mm Ø 74 mm titanium tube

• Inline mounting – stored on reel

• Sensors for roll angle and depth estimation

• CPU running bird local motion control loops

• Calculated wing deflection transferred to wings

• Wireless connections to wings

• 3 wing docking slots

è/ 7 /è18-Nov-14

eBird wing

• Attached/detached at deployment/retrieval

• Contains CPU, motor/gear and batteries

• Shaft coupling for motor/gear protection

• Wireless power/comms

• Batteries charged in sea in normal operation

• Provides power to body when loss of streamer power

• Stored in charging station onboard vessel

è/ 8 /è18-Nov-14

Wireless connection body-wing

• Wireless connection between body and wing

• No electrical parts exposed to water

• Easy snap on/off mechanism

• Identical iron cores surrounded by coils in body and wing

• Inductive energy transfer utilizing electro-magnetic resonance

• Radio communication: connector = antennae

• Two-way power and communication

•Back-deck operations: body and wing operated using hand-held radio-unit

è/ 9 /è18-Nov-14

Challenges

• Robust control - sea current, waves, objects in sea

• Low acoustic noise – wing profile

• Power distribution over 10 km – voltage drop

• Noise free power – constant load

• Noise free communication – modem

• Loss of power/comms – autonomous operation

• Multicomponent interactions

è10è11/18/2014

Hydrophone RMS noise

èConventional bird

èeBird

èNo bird

è/ 11 /è18-Nov-14

How many eBirds in one flock?

è/ 12 /è18-Nov-14

There have been issues..

è13è11/18/2014

Lift envelope

è11/18/2014 èContract MAR-2008-0080 è14

Clever choice of roll angle reference will enhance stability capacity

Control system

è/ 15 /è18-Nov-14

Robust control

è/ 16 /è18-Nov-14

Rapid depth change

0 20 40 60 80 100 120 140 160 180 2004

6

8

10

Depth [m] and lateral force [%] step response at 4.5 kt

Depth

[m

]

0 20 40 60 80 100 120 140 160 180 200

0

20

40

60

80

100

Forc

e [

%]

Time [sec]

è/ 17 /è18-Nov-14

Lateral control

è/ 18 /è18-Nov-14

Feather angle capability: >3º

0 minutes

40 minutes

100% lateral force portside300 m inline separation

è/ 19 /è18-Nov-14

eBird – The movie

è20è11/18/2014

AcuWing

• Acoustics integrated in eBird wing = AcuWing

• Bi-directional acoustic transducers in wing tip

• Acoustic source attached to stabilized platform

• Cross-line and in-line range measurements

è/ 21 /è18-Nov-14

Magnetic compass

• Heading estimation from 3-axis magnetometer

• Located in wing tip - redundancy

• Magnetic field compensation:

– wing angle

– wing slot position

– roll and pitch

• Calibration in 3-axis Helmholz coil

• Algorithms for bird magnetic signature estimation

/ 22 /18-Nov-14

PosWing

• GNSS receiver and antenna in wing

• GNSS-wing pointing up in surface

mode

• Ephemerides and clock aiding for fast

aquisition (5-10 seconds)

• In combination with– AcuWing sound speed calibration

– Compass streamer shape

– Inertial sensors integrated filter

– Radio aiding data or differential corrections

• No need for tail buoy, fully submerged

streamer spread

• Easy to find from work-boat

/ 23 /18-Nov-14

è/ 24 /è18-Nov-14

Thank you for your attention!