ACR Electronics AIS-B - REV C, Руководство по поддержке продукта

Страница: 24 / 32

24
Y1-03-0222 Rev. C
NOTE 2 The sequential message identifier provides a message identification number from 0 to 9 that is
sequentially assigned and is incremented for each new multi-sentence message. The count resets to 0
after 9 is used. For a message requiring multiple sentences, each sentence of the message contains
the same sequential message identification number. It is used to identify the sentences containing
portions of the same message. This allows for the possibility that other sentences might be interleaved
with the message sentences that, taken collectively, contain a single message. This shall be a null field
for messages that fit into one sentence.
NOTE 3
The AIS channel is indicated as either “A” or “B”. This channel indication is relative to the operating
conditions of the AIS unit when the packet is received. This shall be a null field when the channel
identification is not provided. The VHF channel numbers for channels “A” and “B” are obtained by using
a “query” (See IEC 61162-1, clause 5.3.2) of the AIS unit for an ACA sentence.
NOTE 4 This field supports a maximum of 62 valid characters for messages transferred using multiple
sentences, and 63 valid characters for messages using a single sentence.
NOTE 5 This cannot be a null field. (
See “x4” in IEC 61162-1, clause 5.3.3).
VDM message types
For example, the information contained in the s - - s portion of the VDM = Encapsulated ITU-R M.1371 radio
message. Note that messages 5 and 19 may be sent as multi part messages using the x1, x2 and x3
parameters for message sequence control.
VDL Message number VDM Message description
AIS Target Display Information
1, 2, 3, 9,18, 21 position report
4 base station report
5* voyage related data
19* Class B
– extended data
Safety message handling
12 addressed safety related
14 broadcast safety related
External Application
handling
6 binary addressed
8 binary broadcast
System control
7 binary acknowledge (INFO)
10 UTC and data inquiry (INFO)
11 UTC and data response (INFO)
13 safety related ack (INFO)
15 interrogation (INFO)
16 assignment mode command (INFO)
17 DGNSS corrections (INFO)
20 data link management (INFO)
22 channel management (INFO)
*Note that messages 5 and 19 may be sent as multi part messages.