SL-C510-AIS
Compact 5-9NM Solar Marine Lantern
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Using the FATDMA (Fixed Access TDMA) access scheme the actual slot for each transmission made
by the transceiver is specified. There are 2250 slots per minute (or frame) on each AIS channel. The
scheduled slots must be reserved for the transceiver by an AIS base station operating in the same
area using AIS message #20. Further information on FATDMA reservations and slot allocation schemes
can be found in IALA A-124, Appendix 14.
The parameters required for an FATDMA schedule are as follows:
•
Channel 1 Start UTC
This is the hour and minute for transmission on Channel 1. This specifies the AIS frame (minute
within a day in which the start slot for Channel 1 resides.
•
Channel 1 Start Slot
This is the slot number for the first transmission on Channel 1. The slot number can range from -1
(transmission disabled on this channel) to 2249. Note that each message #21 transmission occupies
two slots and associated base station slot reservations must therefore reserve two slots.
•
Channel 1 Interval
This is the interval in slots between transmissions on Channel 1. The interval can range from 0 to
3240000 slots, which equates to an interval of one day. Typically, the interval is set to 13500 slots (6
minutes) on each channel which results in an overall interval of 3 minutes.
• Channel 2 Start UTC
This is the hour and minute for transmission on Channel 2. This specifies the AIS frame (minute)
within a day in which the start slot for Channel 2 resides. Typically the Channel 2 start time is offset
by 3 minutes from the start time used for Channel 1. With a 6 minute reporting interval on each
channel this results in a transmission every 3 minutes on alternating channels.
• Channel 2 Start Slot
This is the slot number for the first transmission on Channel 2. The slot number can range from -1
(transmission disabled on this channel) to 2249. Note that each message #21 transmission occupies
two slots and associated base station slot reservations must therefore reserve two slots.
• Channel 2 Interval
This is the interval in slots between transmissions on Channel 2. The interval can range from 0 to
3240000 slots, which equates to an interval of one day. Typically the interval is set to 13500 slots (6
minutes) on each channel which results in an overall interval of 3 minutes.
FATDMA Schedule Configuration