sensors ins integration of an inertial navigation system

October 7-8, 2008Return to Session Directory

SENSORS

INS Integration of an Inertial Navigation System and Dynamic Positioning

Richard Stephens, François Crétollier, Pierre-Yves Morvan, Andy Chamberlain

Converteam/IXSEA

Integration of INS and DP

Richard Stephens

This document contains confidential and proprietary information of Converteam and must not be used for any purpose other than that for which it is supplied by Converteam. Its contents must not be disclosed to any other

person nor copied in whole or in part without the prior written consent of Converteam

CUSTOMISED TECHNOLOGY FOR CUSTOMER SUCCESS 8 Oct 2008 2© 2008 Converteam UK Ltd. All rights reservedCOMMERCIAL IN CONFIDENCE

TITLE

Richard StephensRichard StephensAndy ChamberlainAndy Chamberlain

François François CrétollierCrétollierPierrePierre--Yves Yves MorvanMorvan

Integration of an inertial navigation system and DP


OUTLINE

INS and acoustics

INS and GPS

Outages

DP architecture


MOTIVATION: ACOUSTICS

Deep or shallow

Noise

Ping rates

Battery life

Outages


GAPS AND PHINS UNITS

Easy to use

Plug and play

Marinized

Quality IMU

Replace 1 gyroand 1 VRU


SEA TRIALS INS + ACOUSTICS


ACOUSTICS TRIALS

Shallow water15 m depth2000 m horizontal89.5o from vertical

Deep water1000 m depth3 sec minimum ping time21 sec ping time into INS


DP ON ACOUSTICS ONLY: POWER

21 s ping time21 s ping time

0 500 1000 1500 2000 25000

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5Simulated relative fuel consumption

Time (s)

Rel

ativ

e fu

el c

onsu

mpt

ion

Acous+PHINSAcoustics 21 sAcoustics 3 s

3 s ping time3 s ping time

INSINS


INS + ACOUSTICS

Save 85 % of battery replacements

…even more?

Or 40 % thruster power on acoustics only


MOTIVATION: (D)GPS

Differential corrections

Jumps

Outages


DIFFERENTIAL CORRECTIONS

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2Differential corrections

Time (s)

Nor

th c

orre

ctio

n (m

)


DGPS JUMP

19:27 19:28 19:29 19:30 19:310.5

1

1.5

2

2.5

3

3.5

4

Time

Raw

Pm

e P

ositi

on N

[m]

DGPS jump


SEA TRIALS INS + GPS


DP ON GPS WITH/WITHOUT INS: POWER

0 100 200 300 400 500 6000

0.2

0.4

0.6

0.8

1

1.2

1.4

Time (s)

Rel

ativ

e fu

el c

onsu

mpt

ion

Estimated relative fuel consumption

DGPS+PHINSDGPS


OUTAGES

How long can INS fill-in for?

…in bad weather?


‘C’ TRIALS


SUPERVISORY FUNCTION


INS DRIFT DURING OUTAGES

0 50 100 150 200 250 3000

5

10

15

20

25INS drift during GPS outages

Drif

t (m

)

Time from loss of GPS (s)


INS DRIFT DISTRIBUTION

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 50

5

10

No.

of o

ccur

renc

es

Drift after 120 s (m)

Frequency distribution of drift during outages

0 5 10 15 20 250

5

10

No.

of o

ccur

renc

es

Drift after 300 s (m)


NORMAL DP ARCHITECTURE WITH INS

DP system

PME1

PME2

PME3

PME4 INS


ALTERNATIVE DP ARCHITECTURE WITH INS

DP system

PME1

PME2

PME3

PME4

INS


FLEXIBLE ARCHITECTURE

DP system

PME1

PME2

PME3

PME4

INS

Patent pendingPatent pending


CONCLUSIONS

Acoustics battery life

GPS jumps

Outages: < 5 metres in 2 mins

Flexible architecture

This document contains confidential and proprietary information of Converteam and must not be used for any purpose other than that for which it is supplied by Converteam. Its contents must not be disclosed to any other

person nor copied in whole or in part without the prior written consent of Converteam

www.converteam.com

Thank you for your attention

sensors ins integration of an inertial navigation system

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