SIMOPS
Practical Achievement withFM-CW Based Short Range Relative Positioning
in Multi-Vessel Operations
Jan Petter HøiassArne Rinnan
Kongsberg Seatex
October 9-10, 2007
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WORLD CLASS – through people, technology and dedicationWORLD CLASS – through people, technology and dedication
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Practical Achievement with FM-CW Based short range relative positioning in multi vessel
operations
Dynamic Positioning Conference 2007
by
Jan Petter Høiaas, Kongsberg Seatex AS
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Presentation Outline
Background
The Principles
Considerations
User Experience
Lessons learned
Latest Development
Conclusion
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Background
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Microwave Technology Evolution
Ship Radar- range & Bearing- pulsed radar- Surveye use i.e for anchor position- Rotating Antenna
Artemis- Point-to-Point - High precision- Single User- Rotating Antennas
RADius- Multiple Targets- Multiple users- Unique target id- No moving Parts
Other systems often use combination of above
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Motivation for FM-CW based system
Security issues– 1997 - 2001, 24 Reported Incidents of contact or collision
between supply vessels and offshore installations in North-Sea.
Customer demand– Statoil demands DP class 2 requirements for Supply loading
operations
Legislation issues (IMO)– .2 For equipment classes 2 and 3, at least three position
reference systems should be installed and simultaneously available to the DP-control system during operation.
– .3 When two or more position reference systems are required, they should not all be of the same type, but based on different principles and suitable for the operating conditions.
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Design Drivers
No moving parts– Solid state– Low maintenance cost
Environment– Operates in all weather conditions
Functionality– Complementary to existing GPS
positioning reference system
Availability– Multi user– Multiple transponder capability– License free
Integrity– Unique id
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Operates in ALL Weather..
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The Principles
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Principles for Range Determination
Distance = ½ • Fb/Fs • Ts • c
Velocity = ½ • Fd • λ0
Transmitted signal
time
freq
uenc
y
Reflected signal
time
freq
uenc
y
Fb – beat frequency
Operating frequency : 5.5-5.6 GHzSweep Range 100 MHzSweep Period 0.2 S
Transponder
Add ID Frq
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Principles for Attitude Determination
λπφ 2
•=sd , Phase difference, patch 1 and 2
α
d
Patch 1
Patch 2
Transponder
s = d * s
in(α)
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Relative Azimuth & Distance
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Considerations
Limitations & Constraints
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Different relative operation & dynamics
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Side-by-side operation
Single target– Traditional Follow Target– No relative heading– Eyeball computing
Multiple Targets– Extended Follow Target– Relative heading– separation control
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Vertical situation
TRANSPONDER 1
TRANSPONDER 2
Position of instrument critical
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Horizontal view
Operating in GHz requires line of sight.
Emitting into local structures must be avoided to prevent reflection and false signal
Pre-survey reccomended for optimized operation.
No need for ”top of mast” localization.
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User E
xper
ienc
e
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RADius, some references
Viking Energy, MPSV
Skandi Sotra, MPSV
Skandi Rona, MPSV
Edda Fjord, Accomodation vessel
Normand Clipper, MPSV
MSSAU1, Accomodation rig
Rem Stadt, MPSV
Gazprom1, Drill rig
Bold Endurance, Drill rig
Atlantic Osprey, MPSV
Northern River, MPSV
Viking Avant, MPSV
Åsgard, FPSO
Total Installations Worldwide : >200
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User experience in different operations
Shuttle Tanker operations
FSU Aasgard C
Shuttle TankerNavion Anglia Navion Europa
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User experience in different operations
Pipe laying
Langeled Project
2006Havila Harmony LB 200
2007Normand CarrierAcergy Piper
Follow Track, 12-15 m separation
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User experience in different operations
Accomodation vessel
Uncle John (Thunder Horse)
Edda FjordProsafe – Concordia
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User experience in different operations
Polar Bjørn Heidrun
Extreme operationBarents Sea
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Lessons learned
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Single Transponder
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Redundance
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Transponder Network Utilization
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Complementary with GPS
DGPS
RADius
Accuracy
Distance
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Latest Development
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Radius interrogator Network
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Enhanced Low Power Transponder, RADius 700
259 259.5 260 260.5 261 261.5 262 262.50
2
4
6
8
10
12
TID 160, Range distribution, mu = 260.6094, sigma = 0.089229359803 samples
m
%
353.5 354 354.5 355 355.5 3560
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
TID 230, Bearing distribution, mu = 354.9838, sigma = 0.11928359803 samples
deg
%
258.5 259 259.5 260 260.5 261 261.5 2620
1
2
3
4
5
6
7
8
9
10
TID 230, Range distribution, mu = 260.322, sigma = 0.10576359803 samples
m
%
353 353.5 354 354.5 355 355.50
0.1
0.2
0.3
0.4
0.5
0.6
0.7
TID 160, Bearing distribution, mu = 354.4592, sigma = 0.079597359803 samples
deg
%
Comparison test
New Battery TransponderRange 260 msRange=0.09 msBearing=0.08°
High-Gain ReferenceRange 260 msRange=0.11 msBearing=0.12°
Operating Range:1100m
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Conclusion
FM CW system has been ”Proven in Use” for 4 years with satisfactory results for relative positioning in multi vessel operations.
Robust and precise relative reference for DP operations when close to structures or other vessels
Complementary to DGPS e.g as DGPS tends to have reduced accuracy close to structure or other vessels, RADius increases accuracy
Increasing integrity by tracking multiple transponders and built-in accuracy assessment and performance evaluation
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