Practical achievement with FM-CW rev2 B

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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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



Presentation Outline

Background

The Principles

Considerations

User Experience

Lessons learned

Latest Development

Conclusion



Background



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



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.



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



Operates in ALL Weather..



The Principles



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



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)



Relative Azimuth & Distance



Considerations

Limitations & Constraints



Different relative operation & dynamics



Side-by-side operation

Single target– Traditional Follow Target– No relative heading– Eyeball computing

Multiple Targets– Extended Follow Target– Relative heading– separation control



Vertical situation

TRANSPONDER 1

TRANSPONDER 2

Position of instrument critical



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.



User E

xper

ienc

e



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



User experience in different operations

Shuttle Tanker operations

FSU Aasgard C

Shuttle TankerNavion Anglia Navion Europa




Pipe laying

Langeled Project

2006Havila Harmony LB 200

2007Normand CarrierAcergy Piper

Follow Track, 12-15 m separation




Accomodation vessel

Uncle John (Thunder Horse)

Edda FjordProsafe – Concordia




Polar Bjørn Heidrun

Extreme operationBarents Sea



Lessons learned



Single Transponder



Redundance



Transponder Network Utilization



Complementary with GPS

DGPS

RADius

Accuracy

Distance



Latest Development



Radius interrogator Network


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



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



WORLD CLASS – through people, technology and dedicationWORLD CLASS – through people, technology and dedication


Practical achievement with FM-CW rev2 B

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