AIS Flashcards
What does AIS do?
Broadcast information about the transmitting ships identity, position, movement.
This may be received and displayed on radar, ECDIS.
Which vessels require AIS?
Solas over 300GT
How many reports is it capable of doing?
4500 reports per min
Updates every 2 seconds
SOTDMA?
Self organising time decision multiple access.
Ensures reliable ship to ship ooo ration at high broadcast rate.
Each AIS consists of what 3 things?
12.5w VHF TRANSMITTER
X2 VHF sotdma reciever.
X1 VHF DSC receiver
Name the two classes of AIS
Class A- meets IMO SOLAS 5
Class B- does NOT meet IMO requirements. (On non solas boats)
Class A, explain its voyage info given.
-updated every 6 mins
-draft
-destination, eta.
-hazardous cargo type
-any safety messages? Eg: NUC , armed personelle on board?
Class A- explain the static info given:
Updated every 6 mins
Ships name, IMO
MMSI number
Dimensions
Type of ship
Location of gps antenna.
Class A. While underway how many seconds does it take to broadcast data?
Every 2-10 seconds
Class A. How much time does it take to broadcast date while at anchor. And what info does it give you?
3 mins.
Position
Time stamp- UT
SOG,COG
Rate if turn
Nav status- at anchor. Underway using engines. NUC. Etc.
Class B - explain
Transmits reduced data
Every 6 mins static
30 mins dynamic
3 mins at anchor.
What info is not included in class b AIS.
IMO , draft, destination, ETA, ROT, nav status.
Advantages of AIS?
Give names to radar targets.
May indicate targets invisible to radar. (In the shadow) may clarify targets intentions
Improve target path prediction
Reduce VHF coms.
Limitations of AIS?
Bridge workload
Info overload
Inaccuracy due to GPS errors.
Which MGN is AIS?
MGN 324
