Aset Notes Flashcards
What is the DP Final setup settling period?
30 minutes.
What is surge and sway measured by?
Position Reference Systems (PRS).
What is yaw measured by?
Gyro.
What is pitch and roll measured by?
-Motion Reference Unit (MRU).
-Vertical Reference System (VRS).
What is the Max operating angle of a Taut wire?
30 Degrees.
What is the range of the Taut wire system dependent on?
The water depth due to the max angle.
What happens if the taut wire exceeds its max operating angle?
Exceeding the operating angle may result in the weight “skipping” along the seabed.
What is ‘Bilge Keeling’?
When the Taut wire touches the hull of the vessel.
What is ARTEMIS used for?
Shuttle tankers off take.
What frequency does ARTEMIS use?
‘X’ Band 3cm.
What are the disadvantages of using ARTEMIS?
-Interference can occur when there are other vessels in the vicinity who are also using ‘X’ Band radars.
-It is a 1:1 system.
What is the accuracy of ARTEMIS?
-5-6NM.
-5000m.
How accurate are Tube Reflectors?
150-200m.
How accurate are Prism Reflectors?
1000m.
What are the disadvantages of Fanbeam/CyScan?
-Lenses need routine cleaning.
-Bright lights can confuse the system.
-Target swap can occur (boiler suit reflectors).
-Precipitation can cause range errors to occur.
What does FMCW stand for?
Frequency, Modulated, Continuous, Wave
What frequency does FMCW use?
‘X’ Band 3cm.
What is the range of FMCW?
1000m.
What is the advantage of using FMCW
Multi-user system with no interference.
What is the Horizontal Beam Length of RADASCAN?
360 Degrees.
What is the Vertical Beam Length of RADASCAN?
22 Degrees.
What is the Horizontal Beam Length of RADIUS?
90 Degrees.
What is the Vertical Beam Length of RADIUS?
90 Degrees.
How many PRS systems should be used for Class 2/3 vessels?
3 or more.
What do follow track and follow sub mean?
The same thing.
What happens when there is a system failure?
The system will give thrust inputs based upon the historic data of the model 30 minutes prior to the failure.
Who determines what class is required for the project?
The charterer.
Can a vessel degrade its class?
No
What are CyScan/Fanbeam
Laser Opticals
Which DP class must operate with all bus ties open?
Class 3.
When should wind sensors be taken out of the system?
When conducting Heli Ops
What is PDOP?
Position, Dilution, of Precision
How many satellites are needed for global coverage?
24 satellites.
How many satellites are required for position fixing?
4 satellites.
What is GPS accuracy?
5-10m.
What are included in paid GNSS corrections?
-1m
-0.2/0.3m
-0.1m
Transmitted via INMARSAT or Spotbeam
What is included in free GNSS corrections?
-IALA (2m)
-SBAS (4m)
-VHF/UHF/MF (Brazil, Canada).
What are the different versions of SBAS?
- US (WAAS).
- JPN (MSAS).
- EU (EGNOS).
What does dual frequency do?
Measures Are Ionospheric Delay.
What is the main use of DARPS?
Shuttle tanker take off.
What does DARPS stand for?
Differential Absolute & Relative Position Sensor
Where should a ultrasound transponder be placed in relation to the vessel
Upwind/Up current.
What Gain mode should be used when starting a new operation?
Low Gain.
What type of system is UTM?
Coordinate based system.
How many UTM zones are there?
60 Zones.
Why are false Eastings used?
Because surveyors don’t like negative numbers.
What percentage of Kalman filter is used to segregate readings?
67%.
What does HDOP stand for?
Horizontal Dilution of Precision.
What does HiPAP Stand for?
High Precision Acoustic Positioning system.
What does an LBL relay?
Range only.
What does USBL, SSBL & SBL relay?
Range and Bearing.
How long should the UPS battery back-up last after a mains supply failure?
30 minutes.
How many PRS’ are required for a class2/3 vessel?
3.
