phins, an all-in-one sensor for dp applications · phins, an all-in-one sensor for dp applications...
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ConfidentialIXSEA
[email protected] www.ixsea.com
IXSEA S.A.S.
PHINS, an all-in-one sensor for DP applications
DP conference, HoustonSeptember 28-30, 2004
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INTRODUCTION
Positioning sensor is one of the key elements of DP systemsDGPS is a great positioning system but it may be subject to some interruptions in service:
Scintillation effectsSignal maskingMultipath
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INTRODUCTION
Continuity, integrity and availability are the characteristics needed for the positioning reference system.Complementing DGPS with additional sensors is a solution:
PHINS, an inertial navigation systemGAPS a compact, portable calibration free acoustic position system
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PHINS, a Fiber Gyro Navigation System
Small, lightProvides :
PositionRoll, PitchHeadingHeave, AltitudeRate of turn
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PHINS
Inertialcomputations
Attitude, positions, speeds
Other sensors(DGPS, DVL, USBL,
etc.)
Estimated biases
Navigation errors
Sensor compensation
Estimatedsensor errorsGyroscopes
Accelerometers
Kalman filter
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PHINS
GPS data
DVL data
USBL data
OptimalPositiondata
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PHINS
RTK GPS
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PHINS
GPS data
DVL data
USBL data
OptimalPositiondata
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PHINS TEST RESULTS
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PHINS
GPS data
DVL data
USBL data
OptimalPositiondata
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PHINS test resultsPosition drift in pure inertial mode (no GPS aiding, no DVL aiding)
0
5
10
15
20
25
0 50 100 150 200 250 300
time (s) since beginning of pure inertial mode
posi
tion
drift
(m)
Trial 1Trial 2Trial 3Trial 4Trial 5Trial 6Trial 7Trial 8Trial 9Trial 10
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PHINS
PHINS
DPControl system
DGPS likeinterface
DGPS 1
DGPS 2
DVL
USBL
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PHINS
Detects and rejects any DGPS position jumpAble to maintain 2 meter accuracy for one hour with DVL aidingCan use USBL data and no GPS at all for eliminating common mode errorsProvides data at high rate (up to 100 Hz)
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GAPS
USBL :Contains :
3D acoustic antennaBroadband signal processingFOG based navigation systemKalman filter
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GAPS
Single, minimally sized housing Free of calibration Improved accuracy and higher acoustic position update rate Short time update of subsea positions during acoustic drop-out Complete acoustic coverage with tracking close to surface Robust to GPS outage Cost savings and outstanding value-for-money for hardware and performance
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GAPS
Operates in the 19-30 KHz frequency range4000 meters rangeAccuracy : 0.2 % of slant range
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GAPS TESTS RESULTS
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GAPS TEST RESULTS
GAPS : Transponder Position Error
-10
-8
-6
-4
-2
0
2
4
6
8
10
-10 -8 -6 -4 -2 0 2 4 6 8 10
East Error (m)
Nor
th E
rror
(m)
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GAPS USE
The beacon is mooredWhile DGPS is available, GAPS computes automatically beacon positionWhen DGPS no more available, GAPS computes vessel position using beacon position and acoustimeasurements.
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CONCLUSION
PHINS and GAPS are alternative sensors that would allow enhancing
IntegrityAvailabilityRedundancy
of DP positioning reference systems