September 16-17, 2003Houston, Texas
Session Chair – Steve Browne, Thales Geo Solutions
SENSORS
HAINAn Integrated Acoustic Positioning and
Inertial Navigation System
Hans Petter Jacobsen and Jan Erik FaugstadmoKongsberg Simrad
Kongsberg Simrad
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HAIN
Hydroacoustic Aided Inertial Navigation
HAIN
Integrated acoustic positioning and inertial navigations system
Jan Erik Faugstadmo
Hans Petter Jacobsen
Kongsberg Simrad AS
Dynamic Positioning Conference, Houston, September 16-17 2003
arranged by
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HAIN
Benefits
Survey:
Increase accuracy
Increase update rate
Dynamic Positioning:
Extend both SSBL and LBL operation limits
Use slow acoustic update rate -> Save batteries
Position update during acoustic drop-out
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HAIN
Acoustic positioning: Relativ high and evenly distributed noise No position drift
Inertial positioning: Very low short term noise. Relativ large position drift
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HAIN – Inertial Navigation
Navigation calculations
acc xacc y acc z
Attitude calculations
gyro xgyro y gyro z
Velocity
Position
Attitude(Roll, pitch, heading)
The IMU measurements are relative to inertial space.
Integrate accelerometers 1x gives velocity, 2x gives position
Integrate gyros 1x gives attitude
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HAIN – INS classes
INS systems are usually classified by the standard deviation
of the position error growth of their free unaided performance
≈1mg≈1°/hRLG, FOGTactical systems
>10nmi/h
≈50µg≈0.01°/hRLG, FOGMarine, air and land navigation
1nmi/h
Accelerometer bias
Gyro biasGyro technology
Traditional application
Class
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HAIN – Kalman Filter Structure
INS
IMU
NavigationEquations
~,ω IB gyro
B
~,fIB acc
B
DVL
Decomposein LGyros
Accelero-meters
$,RLB naveq
~,vEB DVL
B
$ ,vEB DVLL
$ ,vEB naveqL
DGPS +HiPAP
Pressuresensor
Compass
Find .
Error stateKalman
filter
(Attitude)
(Velocity)
$znaveq (Depth)
ψ north
~zdepthm
~,ψ north cmps
Reset
$,REL naveq
(Position)
Estimates(of errors innavigationequations
and coloredsensorerrors)
-$ ,ψ north naveq
~,REL posm
-
-
-
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HAIN
VesselPos
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HAIN
Acoustic Pos.Lat/lon
Aided Inertial Pos.& Status
Acoustic Pos. &Aided Inertial Position
VesselPos
INC 10
IMU
APOS
HiPAPTransceiver
Td
Acousticsignals
DP System
Roll&Pitch
Heading
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HAIN - Simulations
Simulation parameters:
HiPAP SSBL angle accuracy: 0.1° in x and y
dGPS position white/coloured noise: 0.15m/0.1m North and EastReturn to Session Directory
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HAIN - Simulations
HiPAP SSBL 1000 m
Black : Correct positionBlue : HiPAP “Green : HAIN “
Vessel accelerates duringa HiPAP dropout between1240s and 1250s
Drop-out during vessel move
IMU:1nmi/h Drop-out AccelratesRecover pos.
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HAIN - Simulations
VesselPos accuracy during HiPAP dropout.1nmi/h IMU
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The measurements in the trials are:
HiPAP positions relative to a TP on the seabead with known lat long position.The waterdepth is 200m.
Known depth (The vessel is at the surface)
Readings with 100 Hz from the IMU 90.
HAIN - Seatrials
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-80 -60 -40 -20 0 20 40 60 80 100
-60
-40
-20
0
20
40
60
East.
Nor
th.
B61. AL15.txt. 49 positions.
Start
Reduces HiPAP update rate
Blue crosses: Vessel position from HiPAP updates, 1.5 to 20 second.
Green crosses: Vessel positions from real time HAIN estimates every second
HAIN - Seatrials
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HAIN - Seatrials
1550 1600 1650 1700 1750 1800 1850 1900 1950 2000-60
-40
-20
0
20
40
60
80
Time [s] since 15:00:00
Eas
t.
B61. AL15.txt. 49 positions.
The time plots show the same circles as the scatter plot on the previous slide.
1550 1600 1650 1700 1750 1800 1850 1900 1950 2000-80
-60
-40
-20
0
20
40
60
80
Time [s] since 15:00:00N
orth
.
B61. AL15.txt. 49 positions.
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HAIN - Seatrials
1750 1800 1850 1900 1950
0.4
0.5
0.6
0.7
0.8
0.9
Time [s] since 15:00:00
Hor
izon
tal 1
-Sig
ma
B61. AL15.txt. 49 positions.
HAIN 1-sigma accuracy before HiPAP measurement
HAIN 1-sigma accuracy after HiPAP measurement
Blue crosses: Estimated HiPAP 1-sigma accuracy, based on Signal to Noise level, distance and geometry
Green line: HAIN 1-sigma estimated accuracy.
Based on these values we should expect 0.90m difference between HiPAP measurement and HAIN estimate.
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HAIN - Seatrials
It is not possible to distinguish between HiPAP error and HAIN error.
The average difference 0.64 m in the horizontal plane corresponds to a HiPAP angle error of 0.13º in X and Y.
The difference is less than expected, which is 0.9m.
The average of the difference in the horizontal plane is 0.64m.
1830 1830.5 1831 1831.5-8
-7.5
-7
-6.5
-6
-5.5
-5
-4.5
Time [s] since 15:00:00
Eas
t.
B61. AL15.txt. 49 positions.
East difference for one measurement
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HAIN – Seatrials with offshore DP vessel
DP used HAIN as the position reference during the test
Vessel position during the test as logged with dGPS
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HAIN – Seatrials with offshore DP vessel
Timeplot North co-ordinate
HAIN green, HiPAP blue, dGPS red
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HAIN
SubseaPos
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ROV
HCS 10
DVL IMU Depth
HiPAPOperator Station
HiPAPTransceiver
Td
Acousticsignals
DP System
Survey
Roll&Pitch
Heading
dGPS
Aided Inertial Pos.& Status
dGPSAcoustic Pos.Lat/lon
Acoustic Pos. &Aided Inertial Position
HAIN
SubseaPos
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HAIN - Simulations
Simulation parameters:
HiPAP angle accuracy 0.1° in x and y
dGPS position white/coloured noise: 0.15m/0.1m North and East
DVL speed white/coloured noise: 0.02m/s / 0.015m/s Return to Session Directory
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HAIN Pipeline route survey - Depth 650m
Sceen dump, real-time dataHiPAP SSBL – grey line, HAIN – blue line
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HAIN Pipeline route survey - Depth 650m
HiPAP SSBL blue , HAIN real-time green, post processed red
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HAIN Seabed Survey – Depth 4000m
Survey lines – post processed
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HAIN Seabed Survey – Depth 4000m
LBL blue , HAIN real-time green, post processed red
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HAIN Seabed Survey – Depth 4000m
LBL blue , HAIN real-time green, post processed red
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