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Introduction
This is a description of how to decode AIVDM/AIVDO sentences. It collects and integrates information from publicly available sources and is intended to assist developers of open-source software for interpreting these messages.
AIVDM/AIVDO sentences are emitted by receivers for AIS, the marine Automatic Identification System. AIS transmitters are fitted to vessels, navigation markers, and certain types of shore station. They periodically squawk their position (and course, when applicable), using TDMA (Time Division Multiple Access) technology similar to the way cellphones do to avoid mutual interference. AIS receivers make this data available for navigation, anti-collision systems, and other uses.
The International Maritime Organization’s (IMO) International Convention for the Safety of Life at Sea (SOLAS) reqires operating AIS transmitters on all international cargo vessels of more than 300 tons displacement, all cargo vessels of more than 500 tons displacement, and all passenger vessels; see [SOLAS] for details. Individual maritime nations may have stricter and more detailed rules: for those obtaining in U.S. waters, see [US-REQUIREMENTS].
AIS receivers report ASCII data packets as a byte stream over serial or USB lines, using the NMEA 0183 or NMEA 2000 data formats. The RS422 variant of serial specified as a physical layer by NMEA 0183 is common in marine navigation systems; there may be a "pilot plug" [PILOTPLUG] which converts to USB. Alternatively, newer AIS receivers may report directly over RS232 or USB.
AIS packets have the introducer "!AIVDM" or "!AIVDO"; AIVDM packets are reports from other ships and AIVDO packets are reports from your own ship.
A lengthy description of AIS, focusing on the goals and history of the system, but not describing the data protocols in any detail, can be found at [AIS].
Standards
Multiple standards bear on the AIVDM/AIVDO format. This document exists because assembling them into a complete picture is technically difficult and was long impeded by legal barriers as well.
ITU Recommendation M.1371, "Technical Characteristics for a Universal Shipborne Automatic Identification System Using Time Division Multiple Access" [ITU1371], issued in 2001, first described the bit-level format of AIS radio messages. This standard was proprietary and expensive when issued. I did not have access to it or any of its followup revisions while assembling versions of this document up to 1.29.
ITU-R M.1371 was expanded and clarified by "IALA Technical Clarifications on Recommendation ITU-R M.1371-1" [IALA], which is freely available.
There have been three minor revisions of ITU-R M.1371 since it was originally issued. These add interpretations to packet bitfields that were previously marked "spare" and "regional reserved". ITU-R M.1371 revision 4 became available for free download, apparently at some point in early 2011, well after most of this document was assembled.
The ASCII format for AIVDM/AIVDO representations of AIS radio messages seems to have been set by IEC-PAS 61162-100, "Maritime navigation and radiocommunication equipment and systems" [IEC-PAS]. It is proprietary and I have not looked at it. Various public sources indicate that it has been "harmonized" with some version of NMEA 0183, which I also have not looked at because it too is proprietary and expensive, and surrounded by rapacious attack lawyers.
Information Sources
Together, the the IALA Technical Clarifications at [IALA] and the Coast Guard’s AIS pages at [NAVCEN] describe AIS message payloads type 1-24 almost completely. Certain specialized binary messages of types 6 and 8 defined by the International Maritime Organization are described in [IMO236] and [IMO289]. The detail information on payload formats in this document is mostly derived from these public sources.
Kurt Schwehr is a research scientist at the Center for Coastal and Ocean Mapping at the University of New Hamphire. Much of his research involves AIS. His work blog at [Schwehr] contains sample messages and descriptions of AIS operation in the wild that shed light on various obscure corners of the specification. He has explained the otherwise undocumented Repeat Indicator field and USCG extended AIVDM to me by email. He also communicated some critical information from [IEC-PAS], and supplied information about new messages and fields in ITU-1371-3.
Descriptions of messages 25 and 26 are based on AIS transceiver vendor documentation was originally forwarded to me by a source wishing to remain anonymous; I later checked them against ITU1371-4. Message type 27 was described in ITU1371-4 and added here after that became a freely available download.
Should you set out to write a decoder using this document, you are likely to find that one of your challenges is finding enough AIS packet data to make an effective regression test — especially if you live out of line of sight of any ship traffic and would get nothing from running an AIS receiver. Fortunately, various AIS sites offer live feeds over the Internet that aggregate AIS streams from all over the world. Some charge subscriptions; others offer time-delayed access for free and charge for a real-time feed. Still others are pool sites; you join by contributing your feed and receive all feeds.
AIS Hub ([AISHUB]) is a free, public AIS feed pool. It provides exchange of AIS data in raw NMEA format; all AISHub members share their own received AIS data and receive the merged feed from all other participating parties. It is open-source friendly, offering a Linux port in source of its software for collecting and forwarding AIS data. Peter Stoyanov and the other AIS Hub principals have generously donated a live feed to the GPSD project despite the fact that I live 60 miles inland and cannot send them anything interesting.
Some of what this document explains about the quirks of real-world encoders comes from examples provided by Kurt Schwehr. Other such information, especially for the less common sentences, comes from inspection of sentences forwarded to me from AIS Hub by various interested parties, and more recently from AIS Hub itself.
Improving This Document
To avoid copyright difficulties, I rely only on freely redistributable public documents and paraphrased reports from people who have seen the relevant proprietary standards. If you are such a person, please help by reporting the following to be included in future versions of this document:
For verification purposes, I need the raw sentences together with decoded dumps of their field values. Please note that sample sentences not accompanied by field dumps are not useful; I can get plenty of those.
Open-Source Implementations
The GPSD project ships an AIVDM/AIVDO sentence decoder as part of the daemon. This document was developed to be the specification for it, and it will decode all sentence type described herein.
The source-code repository of the GPSD project holds a conforming standalone Python decoder, ais.py, that is not included in shipped releases. It may be useful for developers working in that language.
[Schwehr] includes links to a collection of Python scripts for decoding and analyzing AIVDM sentences. Kurt Schwehr warns that this is research code rather than a production tool.
There is a GNU AIS project at SourceForge. It seems intended primarily to work directly with AIS radios.
The Maritec decoder looks to be pretty high-quality and can be exercised through a public web form. This is a useful resource for anyone qualifying an AIS decoder.
AIVDM/AIVDO Sentence Layer
AIVDM/AIVDO is a two-layer protocol. The outer layer is a variant of NMEA 0183, the ancient standard for data interchange in marine navigation systems; NMEA 0183 is described at [NMEA].
Here is a typical AIVDM data packet:
!AIVDM,1,1,,B,177KQJ5000G?tO`K>RA1wUbN0TKH,0*5C
And here is what the fields mean:
Field 1, !AIVDM, identifies this as an AIVDM packet.
Field 2 (1 in this example) is the count of fragments in the currently accumulating message. The payload size of each sentence is limited by NMEA 0183’s 82-character maximum, so it is sometimes required to split a payload over several fragment sentences.
Field 3 (1 in this example) is the fragment number of this sentence. It will be one-based. A sentence with a fragment count of 1 and a fragment number of 1 is complete in itself.
Field 4 (empty in this example) is a sequential message ID for multi-sentence messages.
Field 5 (B in this example) is a radio channel code. AIS uses the high side of the duplex from two VHF radio channels: AIS Channel A is 161.975Mhz (87B); AIS Channel B is 162.025Mhz (88B). In the wild, channel codes 1 and 2 may also be encountered; the standards do not prescribe an interpretation of these but it’s obvious enough..
Field 6 (177KQJ5000G?tO`K>RA1wUbN0TKH in this example) is the data payload. We’ll describe how to decode this in later sections.
Field 7 (0) is the number of fill bits requires to pad the data payload to a 6 bit boundary, ranging from 0 to 5. Equivalently, subtracting 5 from this tells how many least significant bits of the last 6-bit nibble in the data payload should be ignored. Note that this pad byte has a tricky interaction with the <[ITU-1371]> requirement for byte alignment in over-the-air AIS messages; see the detailed discussion of message lengths and alignment in a later section.
The *-separated suffix (*5C) is the NMEA 0183 data-integrity checksum for the sentence, preceded by "*". It is computed on the entire sentence including the AIVDM tag but excluding the leading "!".
For comparison, here is an example of a multifragment sentence with a nonempty message ID field:
!AIVDM,2,1,3,B,55P5TL01VIaAL@7WKO@mBplU@<PDhh000000001S;AJ::4A80?4i@E53,0*3E !AIVDM,2,2,3,B,1@0000000000000,2*55
Technically, NMEA0183 does not actually require that a !-led sentence be AIS. This format can be used for any encapsulated data. The syntax and semantics of fields 1-4 are fixed, and the fill-bit field and NEA checksum are required, but the payload fields may contain any encapsulated data.
It is, however, a safe bet that any such sentence containing an A or B channel code in field 5 is AIVDM/AIVDO.
Talker IDS
The AI prefix commonly found on these sentences is an NMEA talker ID for a mobile AIS station. Other possible values are as listed:
| !AB | NMEA 4.0 Base AIS station |
|---|---|
!AD |
MMEA 4.0 Dependent AIS Base Station |
!AI |
Mobile AIS station |
!AN |
NMEA 4.0 Aid to Navigation AIS station |
!AR |
NMEA 4.0 AIS Receiving Station |
!AS |
NMEA 4.0 Limited Base Station |
!AT |
NMEA 4.0 AIS Transmitting Station |
!AX |
NMEA 4.0 Repeater AIS station |
!BS |
Base AIS station (deprecated in NMEA 4.0) |
!SA |
NMEA 4.0 Physical Shore AIS Station |
AIVDM/AIVDO Payload Armoring
The data payload is an ASCII-encoded bit vector. Each character represents six bits of data. To recover the six bits, subtract 48 from the ASCII character value; if the result is greater than 40 subtract 8. According to [IEC-PAS], the valid ASCII characters for this encoding begin with "0" (64) and end with "w" (87); however, the intermediate range "X" (88) to "\_" (95) is not used.
| Char | ASCII | Decimal | Bits |
|---|---|---|---|
"0" |
48 |
0 |
000000 |
"1" |
49 |
1 |
000001 |
"2" |
50 |
2 |
000010 |
"3" |
51 |
3 |
000011 |
"4" |
52 |
4 |
000100 |
"5" |
53 |
5 |
000101 |
"6" |
54 |
6 |
000110 |
"7" |
55 |
7 |
000111 |
"8" |
56 |
8 |
001000 |
"9" |
57 |
9 |
001001 |
":" |
58 |
10 |
001010 |
";" |
59 |
11 |
001011 |
"<" |
60 |
12 |
001100 |
"=" |
61 |
13 |
001101 |
">" |
62 |
14 |
001110 |
"?" |
63 |
15 |
001111 |
"@" |
64 |
16 |
010000 |
"A" |
65 |
17 |
010001 |
"B" |
66 |
18 |
010010 |
"C" |
67 |
19 |
010011 |
"D" |
68 |
20 |
010100 |
"E" |
69 |
21 |
010101 |
"F" |
70 |
22 |
010110 |
"G" |
71 |
23 |
010111 |
"H" |
72 |
24 |
011000 |
"I" |
73 |
25 |
011001 |
"J" |
74 |
26 |
011010 |
"K" |
75 |
27 |
011011 |
"L" |
76 |
28 |
011100 |
"M" |
77 |
29 |
011101 |
"N" |
78 |
30 |
011110 |
"O" |
79 |
31 |
011111 |
"P" |
80 |
32 |
100000 |
"Q" |
81 |
33 |
100001 |
"R" |
82 |
34 |
100010 |
"S" |
83 |
35 |
100011 |
"T" |
84 |
36 |
100100 |
"U" |
85 |
37 |
100101 |
"V" |
86 |
38 |
100110 |
"W" |
87 |
39 |
100111 |
"`" |
96 |
40 |
101000 |
"a" |
97 |
41 |
101001 |
"b" |
98 |
42 |
101010 |
"c" |
99 |
43 |
101011 |
"d" |
100 |
44 |
101100 |
"e" |
101 |
45 |
101101 |
"f" |
102 |
46 |
101110 |
"g" |
103 |
47 |
101111 |
"h" |
104 |
48 |
110000 |
"i" |
105 |
49 |
110001 |
"j" |
106 |
50 |
110010 |
"k" |
107 |
51 |
110011 |
"l" |
108 |
52 |
110100 |
"m" |
109 |
53 |
110101 |
"n" |
110 |
54 |
110110 |
"o" |
111 |
55 |
110111 |
"p" |
112 |
56 |
111000 |
"q" |
113 |
57 |
111001 |
"r" |
114 |
58 |
111010 |
"s" |
115 |
59 |
111011 |
"t" |
116 |
60 |
111100 |
"u" |
117 |
61 |
111101 |
"v" |
118 |
62 |
111110 |
"w" |
119 |
63 |
111111 |
Concatenate all six-bit quantities found in the payload, MSB first. This is the binary payload of the sentence.
AIS Payload Data Types
Data in AIS message payloads (what you get after undoing the AIVDM/AIVDO armoring) is encoded as bitfields in the sentence. Bitfields may be interpreted in one of the following ways:
-
Signed or unsigned integer
-
Float (scaled from signed integer)
-
Flag or boolean
-
Index into a controlled vocabulary
-
Reserved bits
-
Spare bits
-
Strings
Numeric bitfields are interpreted as big-endian twos-complement integers; when signed, the sign bit is the highest.
Float fields have an associated divisor which should be applied to convert to the correct units. In one case, the ROT field in message types 1-3, the scaling operation involves a more laborate formula.
Flags are encoded as 1 for true/yes/on, 0 for false/no/off.
Indices into controlled vocabularies are numeric bitfields which must be interpreted using per-field string lists specified in the standards.
Spare fields generally seem to have been inserted in order to put certain field starts on 8-bit boundaries, and should be ignored. Decoders should not, however, assume that spare fields will be all zeroes.
Reserved fields should not be ignored, as they may be assigned for extension data in minor revisions of the AIS standard; it is noted in the message descriptions where this has already occurred. It is good practice for a decoder to make reserved fields available to client applications as uninterpreted bitfields.
Character-string fields within AIS messages are encoded in a special way, referred to as "six-bit" in the tables below. First, chop the string field into consecutive six-bit nibbles without padding (each span of three 8-bit bytes includes 4 of these). Each six-bit nibble maps to an ASCII character. Nibbles 0-31 map to the characters "@" ( ASCII 64) through "\_" (ASCII 95) respectively; nibbles 32-63 map to characters " " (ASCII 32) though "?" (ASCII 63). Lowercase ASCII letters, the backtick, right and left curly brackets, pipe bar, tilde and DEL cannot be encoded.
000000 |
0 |
"@" |
010000 |
16 |
"P" |
100000 |
32 |
" " |
110000 |
48 |
"0" |
000001 |
1 |
"A" |
010001 |
17 |
"Q" |
100001 |
33 |
"!" |
110001 |
49 |
"1" |
000010 |
2 |
"B" |
010010 |
18 |
"R" |
100010 |
34 |
""" |
110010 |
50 |
"2" |
000011 |
3 |
"C" |
010011 |
19 |
"S" |
100011 |
35 |
"\#" |
110011 |
51 |
"3" |
000100 |
4 |
"D" |
010100 |
20 |
"T" |
100100 |
36 |
"$" |
110100 |
52 |
"4" |
000101 |
5 |
"E" |
010101 |
21 |
"U" |
100101 |
37 |
"%" |
110101 |
53 |
"5" |
000110 |
6 |
"F" |
010110 |
22 |
"V" |
100110 |
38 |
"&" |
110110 |
54 |
"6" |
000111 |
7 |
"G" |
010111 |
23 |
"W" |
100111 |
39 |
"\'" |
110111 |
55 |
"7" |
001000 |
8 |
"H" |
011000 |
24 |
"X" |
101000 |
40 |
"(" |
111000 |
56 |
"8" |
001001 |
9 |
"I" |
011001 |
25 |
"Y" |
101001 |
41 |
")" |
111001 |
56 |
"9" |
001010 |
10 |
"J" |
011010 |
26 |
"Z" |
101010 |
42 |
"\*" |
111010 |
58 |
":" |
001011 |
11 |
"K" |
011011 |
27 |
"[" |
101011 |
43 |
"\+" |
111011 |
59 |
";" |
001100 |
12 |
"L" |
011100 |
28 |
"\" |
101100 |
44 |
"," |
111100 |
60 |
"<" |
001101 |
13 |
"M" |
011101 |
29 |
"]" |
101101 |
45 |
"-" |
111101 |
61 |
"=" |
001110 |
14 |
"N" |
011110 |
30 |
"\^" |
101110 |
46 |
"." |
111110 |
62 |
">" |
001111 |
15 |
"O" |
011111 |
31 |
"\_" |
101111 |
47 |
"/" |
111111 |
63 |
"?" |
According to the standard, trailing unused characters in six-bit fields will be represented by "@" (six-bit zero); however, real-world encoders are not careful about this and often have nonzero garbage after the "@". The terminating "@" should not be considered part of the text, and any non-"@" characters after it should be discarded. It is also common to space-fill short fields such as ship and station name, so a decoder should strip trailing spaces after stripping at-signs and the garbage after them.
Trailing string fields are often specified as "up to" a certain number of bits. Decoders should be prepared to handle any field length up to that number, including zero.
AIS Payload Interpretation
The following table describes message types that are international standards from [ITU1371] and its revisions. There are also local and regional extensions used on inland waterways such as the Danube and the Thames and in British and Irish coastal waters; pointers to some of these are included later in this document.
Note that many sources use 1-origin numbering for the bits. We’ll use 0-origin in this document.
The first 6 bits of the payload (0-5) are the message type. Message types are as follows:
01 |
Position Report Class A |
02 |
Position Report Class A (Assigned schedule) |
03 |
Position Report Class A (Response to interrogation) |
04 |
Base Station Report |
05 |
Static and Voyage Related Data |
06 |
Binary Addressed Message |
07 |
Binary Acknowledge |
08 |
Binary Broadcast Message |
09 |
Standard SAR Aircraft Position Report |
10 |
UTC and Date Inquiry |
11 |
UTC and Date Response |
12 |
Addressed Safety Related Message |
13 |
Safety Related Acknowledgement |
14 |
Safety Related Broadcast Message |
15 |
Interrogation |
16 |
Assignment Mode Command |
17 |
DGNSS Binary Broadcast Message |
18 |
Standard Class B CS Position Report |
19 |
Extended Class B Equipment Position Report |
20 |
Data Link Management |
21 |
Aid-to-Navigation Report |
22 |
Channel Management |
23 |
Group Assignment Command |
24 |
Static Data Report |
25 |
Single Slot Binary Message, |
26 |
Multiple Slot Binary Message With Communications State |
27 |
Position Report For Long-Range Applications |
In normal operation, an AIS transceiver will broadcast a position report (type 1, 2, or 3) every 2 to 10 seconds depending on the vessel’s speed while underway, and every 3 minutes while the vessel is at anchor and stationary. It will send a type 5 identification every 6 minutes. (More detail is at [IALA], part 2.3)
Class 6 is used for unencrypted structured extension messages systems conforming to the Inland AIS standard defined by [INLAND], and by local authorities such as the St. Lawrence Seaway and the U.S Coast Guard’s PAWSS. This document describes all of the Class 6 special message formats approved for use in [IMO236], [IMO289], and [INLAND].
Class 8 is in common use for private encrypted messages, such as location transmission in military exercises. It is also used for unencrypted structured extension messages by Inland AIS, and by local authorities such as the St. Lawrence Seaway and PAWSS. This document describes all of the Class 8 special message formats approved for use in [IMO236], [IMO289], and [INLAND].
Classes 12 and 14 are used for text messaging, nominally safety-related but also for traffic control and occasionally chatter.
In practice, message types other than 1, 3, 4, 5, 18, and 24 are unusual or rare; many AIS transmitters never emit them.
An MMSI is a Mobile Marine Service Identifier, a unique 9-digit ID for the ship’s radio(s). The first three digits convey information about the country in which the ID was issued [ITU-MID]. US vessels travelling solely in U.S. waters sometimes incorrectly omit the leading "3", the geography code for North and Centra America and Caribbean, emitting 8-digit MMSIs beginning with the U.S. country code of 669.
According to [MMSI], different formats of MMSI are used for different classes of transmitter. In the format descriptions below, a MID is a three-digit decimal literal ranging from 201 to 775 that identifies a country or other maritime jurisdiction. See [ITU-MID] for a list of MIDs.
| 8MIDXXXXX | Diver’s radio (not used in the U.S. in 2013) |
|---|---|
MIDXXXXXX |
Ship |
0MIDXXXXX |
Group of ships; the U.S. Coast Guard, for example, is 03699999 |
00MIDXXXX |
Coastal stations |
111MIDXXX |
SAR (Search and Rescue) aircraft |
99MIDXXXX |
Aids to Navigation |
98MIDXXXX |
Auxilary craft associated with a parent ship |
970MIDXXX |
AIS SART (Search and Rescue Transmitter) |
972XXXXXX |
MOB (Man Overboard) device |
974XXXXXX |
EPIRB (Emergency Position Indicating Radio Beacon) AIS |
Detailed descriptions of message types 1-24 follow. Message types 1-22 are derived from [IALA]. Message type 23 was decribed to me by Mike Greene based on [IEC-62287]. Message type 24 was described to me by [Schwehr], whose Python toolkit decodes it. Message types 25-26 are reported by [Schwehr], who observes they were added in Version 3 of [ITU1371]. Message type 27 is direct from [ITU1371] version 4.
The "Member" column in these tables is not derived from any of the ITU standards or amendments. I have invented it in order to be able to describe a lossless textual encoding of AIS sentences in JSON. These names are also chosen for suitability as structure/object member names in computer languages, so that application programming interfaces across different languages can have a common and readily intelligible set to use.
The "T" column declares the data type of the field, and may have any of the values in the following table. It is intended to be used for generating bitfield-extraction code directly from the message type descriptions.
| u | Unsigned integer |
|---|---|
U |
Unsigned integer with scale - renders as float, suffix is decimal places |
i |
Signed integer |
I |
Signed integer with scale - renders as float, suffix is decimal places |
b |
Boolean |
e |
Enumerated type (controlled vocabulary) |
x |
Spare or reserved bit |
t |
String (packed six-bit ASCII) |
d |
Data (uninterpreted binary) |
a |
Array boundary, numeric suffix is maximum array size. ^ before suffix means preceding fields is the length. Following fields are repeated to end of message |
The field breakdowns in this document have been checked against live decoded data rendered by known-good implementations for message types 1-15, 18-21, and 24. Described but unchecked are 16-17, 22-23, and 25-27. Also, the interpretation of IMO extension subtypes of messages 6 and 8 has yet to be tested.
Bit lengths and length ranges are given because decoders should check them against the message type. Messages with correct checksums but the wrong payload length for their type occur with about 0.3% frequency on AISHub; if you don’t reject these, your clients will see spurious zeros or garbage.
Types 1, 2 and 3: Position Report Class A
Type 1, 2 and 3 messages share a common reporting structure for navigational information; we’ll call it the Common Navigation Block (CNB). This is the information most likely to be of interest for decoding software. Total of 168 bits, occupying one AIVDM sentence.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 1-3 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
Message repeat count |
8-37 |
30 |
MMSI |
mmsi |
u |
9 decimal digits |
38-41 |
4 |
Navigation Status |
status |
e |
See "Navigation Status" |
42-49 |
8 |
Rate of Turn (ROT) |
turn |
I3 |
See below |
50-59 |
10 |
Speed Over Ground (SOG) |
speed |
U1 |
See below |
60-60 |
1 |
Position Accuracy |
accuracy |
b |
See below |
61-88 |
28 |
Longitude |
lon |
I4 |
Minutes/10000 (see below) |
89-115 |
27 |
Latitude |
lat |
I4 |
Minutes/10000 (see below) |
116-127 |
12 |
Course Over Ground (COG) |
course |
U1 |
Relative to true north, to 0.1 degree precision |
128-136 |
9 |
True Heading (HDG) |
heading |
u |
0 to 359 degrees, 511 = not available. |
137-142 |
6 |
Time Stamp |
second |
u |
Second of UTC timestamp |
143-144 |
2 |
Maneuver Indicator |
maneuver |
e |
See "Maneuver Indicator" |
145-147 |
3 |
Spare |
x |
Not used |
|
148-148 |
1 |
RAIM flag |
raim |
b |
See below |
149-167 |
19 |
Radio status |
radio |
u |
See below |
The Repeat Indicator is a directive to an AIS transceiver that this message should be rebroadcast. This was intended as a way of getting AIS messages around hills and other obstructions in coastal waters, but is little used as base station coverage is more effective. It is intended that the bit be incremented on each retransmission, to a maximum of three hops. A value of 3 indicates "Do not repeat".
0 |
Under way using engine |
1 |
At anchor |
2 |
Not under command |
3 |
Restricted manoeuverability |
4 |
Constrained by her draught |
5 |
Moored |
6 |
Aground |
7 |
Engaged in Fishing |
8 |
Under way sailing |
9 |
Reserved for future amendment of Navigational Status for HSC |
10 |
Reserved for future amendment of Navigational Status for WIG |
11 |
Reserved for future use |
12 |
Reserved for future use |
13 |
Reserved for future use |
14 |
AIS-SART is active |
15 |
Not defined (default) |
Note, the AIS-SART value was added after [IALA] and designates an AIS transmitter in an survival craft such as a lifeboat. See see [AIS-SART] for the field specification and [SART] for background.
Turn rate is encoded as follows:
-
0 = not turning
-
1…126 = turning right at up to 708 degrees per minute or higher
-
1…-126 = turning left at up to 708 degrees per minute or higher
-
127 = turning right at more than 5deg/30s (No TI available)
-
-127 = turning left at more than 5deg/30s (No TI available)
-
128 (80 hex) indicates no turn information available (default)
Values between 0 and 708 degrees/min coded by ROTAIS=4.733 * SQRT(ROTsensor) degrees/min where ROTsensor is the Rate of Turn as input by an external Rate of Turn Indicator. ROTAIS is rounded to the nearest integer value. Thus, to decode the field value, divide by 4.733 and then square it. Sign of the field value should be preserved when squaring it, otherwise the left/right indication will be lost.
Speed over ground is in 0.1-knot resolution from 0 to 102 knots. value 1023 indicates speed is not available, value 1022 indicates 102.2 knots or higher.
The position accuracy flag indicates the accuracy of the fix. A value of 1 indicates a DGPS-quality fix with an accuracy of < 10ms. 0, the default, indicates an unaugmented GNSS fix with accuracy > 10m.
Longitude is given in in 1/10000 min; divide by 600000.0 to obtain degrees. Values up to plus or minus 180 degrees, East = positive, West \= negative. A value of 181 degrees (0x6791AC0 hex) indicates that longitude is not available and is the default.
Latitude is given in in 1/10000 min; divide by 600000.0 to obtain degrees. Values up to plus or minus 90 degrees, North = positive, South = negative. A value of 91 degrees (0x3412140 hex) indicates latitude is not available and is the default.
Course over ground will be 3600 (0xE10) if that data is not available.
Seconds in UTC timestamp should be 0-59, except for these special values:
-
60 if time stamp is not available (default)
-
61 if positioning system is in manual input mode
-
62 if Electronic Position Fixing System operates in estimated (dead reckoning) mode,
-
63 if the positioning system is inoperative.
The Regional Reserved field is intended for use by local maritime authorities. It is not known to be in any actual use up to 2009.
The Maneuver Indicator (143-144) may have these values:
| 0 | Not available (default) |
|---|---|
1 |
No special maneuver |
2 |
Special maneuver (such as regional passing arrangement) |
Riverine and inland navigation systems conforming to [INLAND] designate this field "Blue Sign" with the following enumerated values:
| 0 | Not available (default) |
|---|---|
1 |
No |
2 |
Yes |
The interpretation of bits 143-147 has been a bit unstable. In [IALA]. and therefore in the original [ITU1371], they were described like this:
| Field | Len | Description |
|---|---|---|
143-145 |
3 |
Regional Reserved |
146-147 |
2 |
Spare |
The interpretation of 143-144 as a special maneuver field is new in revision 3 of [ITU1371].
The RAIM flag indicates whether Receiver Autonomous Integrity Monitoring is being used to check the performance of the EPFD. 0 = RAIM not in use(default), 1 = RAIM in use. See [RAIM] for a detailed description of this flag.
Bits 149-167 are diagnostic information for the radio system. Consult [IALA] for detailed description of the latter.
Type 4: Base Station Report
This message is to be used by fixed-location base stations to periodically report a position and time reference. Total of 168 bits, occupying one AIVDM sentence.
The standard uses "EPFD" to designate any Electronic Position Fixing Device.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 4 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
MMSI |
mmsi |
u |
9 decimal digits |
38-51 |
14 |
Year (UTC) |
year |
u |
UTC, 1-9999, 0 = N/A (default) |
52-55 |
4 |
Month (UTC) |
month |
u |
1-12; 0 = N/A (default) |
56-60 |
5 |
Day (UTC) |
day |
u |
1-31; 0 = N/A (default) |
61-65 |
5 |
Hour (UTC) |
hour |
u |
0-23; 24 = N/A (default) |
66-71 |
6 |
Minute (UTC) |
minute |
u |
0-59; 60 = N/A (default) |
72-77 |
6 |
Second (UTC) |
second |
u |
0-59; 60 = N/A (default) |
78-78 |
1 |
Fix quality |
accuracy |
b |
As in Common Navigation Block |
79-106 |
28 |
Longitude |
lon |
I4 |
As in Common Navigation Block |
107-133 |
27 |
Latitude |
lat |
I4 |
As in Common Navigation Block |
134-137 |
4 |
Type of EPFD |
epfd |
e |
See "EPFD Fix Types" |
138-147 |
10 |
Spare |
x |
Not used |
|
148-148 |
1 |
RAIM flag |
raim |
b |
As for common navigation block |
149-167 |
19 |
SOTDMA state |
radio |
u |
As in same bits for Type 1 |
| Code | Position Fix Type |
|---|---|
0 |
Undefined (default) |
1 |
GPS |
2 |
GLONASS |
3 |
Combined GPS/GLONASS |
4 |
Loran-C |
5 |
Chayka |
6 |
Integrated navigation system |
7 |
Surveyed |
8 |
Galileo |
Note: though values 9-15 are marked "not used" in [IALA], the EPFD type value 15 (all field bits 1) is not uncommon in the wild; it appears some receivers emit it as the Undefined value. Decoders should be prepared to accept this.
Type 5: Static and Voyage Related Data
Message has a total of 424 bits, occupying two AIVDM sentences.
In practice, the information in these fields (especially ETA and destination) is not reliable, as it has to be hand-updated by humans rather than gathered automatically from sensors.
Also note that it is fairly common in the wild for this message to have a wrong bit length (420 or 422). Robust decoders should ignore trailing garbage and deal gracefully with a slightly truncated destination field.
| Field | Len | Description | Member/Type | T | Encoding |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 5 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
Message repeat count |
8-37 |
30 |
MMSI |
mmsi |
u |
9 digits |
38-39 |
2 |
AIS Version |
ais_version |
u |
0=[ITU1371], 1-3 = future editions |
40-69 |
30 |
IMO Number |
imo |
u |
IMO ship ID number |
70-111 |
42 |
Call Sign |
callsign |
t |
7 six-bit characters |
112-231 |
120 |
Vessel Name |
shipname |
t |
20 six-bit characters |
232-239 |
8 |
Ship Type |
shiptype |
e |
See "Codes for Ship Type" |
240-248 |
9 |
Dimension to Bow |
to_bow |
u |
Meters |
249-257 |
9 |
Dimension to Stern |
to_stern |
u |
Meters |
258-263 |
6 |
Dimension to Port |
to_port |
u |
Meters |
264-269 |
6 |
Dimension to Starboard |
to_starboard |
u |
Meters |
270-273 |
4 |
Position Fix Type |
epfd |
e |
See "EPFD Fix Types" |
274-277 |
4 |
ETA month (UTC) |
month |
u |
1-12, 0=N/A (default) |
278-282 |
5 |
ETA day (UTC) |
day |
u |
1-31, 0=N/A (default) |
283-287 |
5 |
ETA hour (UTC) |
hour |
u |
0-23, 24=N/A (default) |
288-293 |
6 |
ETA minute (UTC) |
minute |
u |
0-59, 60=N/A (default) |
294-301 |
8 |
Draught |
draught |
U1 |
Meters/10 |
302-421 |
120 |
Destination |
destination |
t |
20 6-bit characters |
422-422 |
1 |
DTE |
dte |
b |
0=Data terminal ready, 1=Not ready (default). |
423-423 |
1 |
Spare |
x |
Not used |
[INLAND] specifies the following:
-
the IMO Number field should be zeroed for inland vessels.
-
ATIS code should be used for inland vessels
-
ship dimensions should be set to the maximum rectangle size of the convoy
-
draught information should be rounded up to nearest decimeter
-
For the destination, UN/LOCODE and ERI terminal codes should be used
Ship dimensions will be 0 if not available. For the dimensions to bow and stern, the special value 511 indicates 511 meters or greater; for the dimensions to port and starboard, the special value 63 indicates 63 meters or greater.
| Code | Ship & Cargo Classification |
|---|---|
0 |
Not available (default) |
1-19 |
Reserved for future use |
20 |
Wing in ground (WIG), all ships of this type |
21 |
Wing in ground (WIG), Hazardous category A |
22 |
Wing in ground (WIG), Hazardous category B |
23 |
Wing in ground (WIG), Hazardous category C |
24 |
Wing in ground (WIG), Hazardous category D |
25 |
Wing in ground (WIG), Reserved for future use |
26 |
Wing in ground (WIG), Reserved for future use |
27 |
Wing in ground (WIG), Reserved for future use |
28 |
Wing in ground (WIG), Reserved for future use |
29 |
Wing in ground (WIG), Reserved for future use |
30 |
Fishing |
31 |
Towing |
32 |
Towing: length exceeds 200m or breadth exceeds 25m |
33 |
Dredging or underwater ops |
34 |
Diving ops |
35 |
Military ops |
36 |
Sailing |
37 |
Pleasure Craft |
38 |
Reserved |
39 |
Reserved |
40 |
High speed craft (HSC), all ships of this type |
41 |
High speed craft (HSC), Hazardous category A |
42 |
High speed craft (HSC), Hazardous category B |
43 |
High speed craft (HSC), Hazardous category C |
44 |
High speed craft (HSC), Hazardous category D |
45 |
High speed craft (HSC), Reserved for future use |
46 |
High speed craft (HSC), Reserved for future use |
47 |
High speed craft (HSC), Reserved for future use |
48 |
High speed craft (HSC), Reserved for future use |
49 |
High speed craft (HSC), No additional information |
50 |
Pilot Vessel |
51 |
Search and Rescue vessel |
52 |
Tug |
53 |
Port Tender |
54 |
Anti-pollution equipment |
55 |
Law Enforcement |
56 |
Spare - Local Vessel |
57 |
Spare - Local Vessel |
58 |
Medical Transport |
59 |
Noncombatant ship according to RR Resolution No. 18 |
60 |
Passenger, all ships of this type |
61 |
Passenger, Hazardous category A |
62 |
Passenger, Hazardous category B |
63 |
Passenger, Hazardous category C |
64 |
Passenger, Hazardous category D |
65 |
Passenger, Reserved for future use |
66 |
Passenger, Reserved for future use |
67 |
Passenger, Reserved for future use |
68 |
Passenger, Reserved for future use |
69 |
Passenger, No additional information |
70 |
Cargo, all ships of this type |
71 |
Cargo, Hazardous category A |
72 |
Cargo, Hazardous category B |
73 |
Cargo, Hazardous category C |
74 |
Cargo, Hazardous category D |
75 |
Cargo, Reserved for future use |
76 |
Cargo, Reserved for future use |
77 |
Cargo, Reserved for future use |
78 |
Cargo, Reserved for future use |
79 |
Cargo, No additional information |
80 |
Tanker, all ships of this type |
81 |
Tanker, Hazardous category A |
82 |
Tanker, Hazardous category B |
83 |
Tanker, Hazardous category C |
84 |
Tanker, Hazardous category D |
85 |
Tanker, Reserved for future use |
86 |
Tanker, Reserved for future use |
87 |
Tanker, Reserved for future use |
88 |
Tanker, Reserved for future use |
89 |
Tanker, No additional information |
90 |
Other Type, all ships of this type |
91 |
Other Type, Hazardous category A |
92 |
Other Type, Hazardous category B |
93 |
Other Type, Hazardous category C |
94 |
Other Type, Hazardous category D |
95 |
Other Type, Reserved for future use |
96 |
Other Type, Reserved for future use |
97 |
Other Type, Reserved for future use |
98 |
Other Type, Reserved for future use |
99 |
Other Type, no additional information |
Note that garbage values greater than 99 are supposed to be unused, but are not uncommon in the wild; AIS transmitters seem prone to put junk in this field when it’s not explicitly set. Decoders should treat these like value 0 rather than throwing an exception until and unless the controlled vocabulary is extended to include the unknown values.
Type 6: Binary Addressed Message
Message type 6 is an addressed point-to-point message with unspecified binary payload. The St. Lawrence Seaway AIS system, the USG PAWSS system, and the Port Authority of London use this payload for local extension messages. [IMO236] and [IMO289] describe payload use as international extension messages. This type is variable in length up to a maximum of 1008 bits (up to 5 AIVDM sentence payloads).
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70 |
1 |
Retransmit flag |
retransmit |
b |
0 = no retransmit (default) 1 = retransmitted |
71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
Designated Area Code |
dac |
u |
Unsigned integer |
82-87 |
6 |
Functional ID |
fid |
u |
Unsigned integer |
88 |
920 |
Data |
data |
d |
Binary data May be shorter than 920 bits. |
Interpretation of the binary payload is controlled by:
-
The Designated Area Code, which is a jurisdiction code: 366 for the United States. It uses the same encoding as the area designator in MMMSIs; see [ITU-MID]. 1 designates international (ITU) messages.
-
The FID, which is the Functional ID for a message subtype. In some sources this is abbreviated FI.
The following is a non-exhaustive list of standardized DAC-FID pairs in use for type 6.
DAC |
FID |
Source |
Status |
Description |
1 |
12 |
Deprecated |
Dangerous cargo indication |
|
1 |
14 |
Deprecated |
Tidal window |
|
1 |
16 |
Deprecated/In Use |
Num persons on board |
|
1 |
16 |
Standard |
Num persons on board |
|
1 |
18 |
Standard |
Clearance time to enter port |
|
1 |
20 |
Standard |
Berthing data (addressed) |
|
1 |
23 |
In use |
Area notice (addressed) |
|
1 |
25 |
Standard |
Dangerous Cargo indication |
|
1 |
28 |
Standard |
Route info addressed |
|
1 |
30 |
Standard |
Text description addressed |
|
1 |
32 |
Standard |
Tidal Window |
|
200 |
21 |
Standard |
ETA at lock/bridge/terminal |
|
200 |
22 |
Standard |
RTA at lock/bridge/terminal |
|
200 |
55 |
Standard |
Number of persons on board |
|
235 |
10 |
In use |
AtoN monitoring data (UK) |
|
250 |
10 |
In use |
AtoN monitoring data (ROI) |
DAC/FID pairs are assigned separately per message type.
Note that the apparent presence of one of these DAC/FID pairs dooes not guarantee that the message is structured. Decoders should perform range validation on the structured fields and interpret the message as unstructured if any check fails. (As of Aug 2014 no such collisions have been in the wild; but see the parallel note for Type 8.)
A list of binary layouts for selected subtypes of message 6 follows.
IMO236 Dangerous Cargo Indication
This message should be used as a response to a request for Dangerous Cargo Indication from a competent authority. The message content is used to identify the port where the documents for the dangerous goods cargo can be found, e. g. last and next port of call, and to allow the requesting authority to form a danger estimate.
A message 6 subtype. DAC = 001 FID = 12. Fixed length: 360 bits. This is the [IMO236] version, now deprecated; there is a later [IMO289] version.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
u |
0 = no retransmit (default), 1 = retransmitted |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 001 |
82-87 |
6 |
FID |
fid |
u |
FID = 12 |
88-117 |
30 |
Last Port Of Call |
lastport |
t |
5 6-bit characters, UN locode |
118-121 |
4 |
ETA month (UTC) |
lmonth |
u |
1-12, 0=N/A (default) |
122-126 |
5 |
ETA day (UTC) |
lday |
u |
1-31, 0=N/A (default) |
127-131 |
5 |
ETA hour (UTC) |
lhour |
u |
0-23, 24=N/A (default) |
132-137 |
6 |
ETA minute (UTC) |
lminute |
u |
0-59, 60=N/A (default) |
138-167 |
30 |
Next Port Of Call |
nextport |
t |
5 6-bit characters, UN locode |
168-171 |
4 |
ETA month (UTC) |
nmonth |
u |
1-12, 0=N/A (default) |
172-176 |
5 |
ETA day (UTC) |
nday |
u |
1-31, 0=N/A (default) |
177-181 |
5 |
ETA hour (UTC) |
nhour |
u |
0-23, 24=N/A (default) |
182-187 |
6 |
ETA minute (UTC) |
nminute |
u |
0-59, 60=N/A (default) |
188-307 |
120 |
Main Dangerous Good |
dangerous |
t |
20 6-bit characters |
308-331 |
24 |
IMD Category |
imdcat |
t |
4 6-bit characters |
332-344 |
13 |
UN Number |
unid |
u |
1-3363 UN Number |
345-354 |
10 |
Amount of Cargo |
amount |
u |
Unsigned integer |
355-356 |
2 |
Unit of Quantity |
unit |
e |
See "Cargo Unit Codes" |
357-359 |
3 |
Spare |
x |
Not used |
| Code | Unit |
|---|---|
0 |
Not available (default) |
1 |
kg |
2 |
metric tons |
3 |
metric kilotons |
IMO236 Tidal Window
This message should be used by shore stations to inform vessels about tidal windows which allow a vessel the safe passage of a fairway. The message includes 1-3 predictions of current speed and current direction. Acknowledgment is required.
A message 6 subtype. DAC = 001 FID = 14. Variable length: 190-376 bits This is the [IMO236] version; there is an [IMO289] version with different widths for the latitude, longitude, and current-speed fields (also the order of lat/lon is swapped).
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
See Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
b |
0 = no retransmit (default), 1 = retransmitted |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 001 |
82-87 |
6 |
FID |
fid |
u |
FID = 14 |
88-91 |
4 |
Month |
month |
u |
1-12; 0 = N/A (default) |
92-96 |
5 |
Day |
day |
u |
1-31; 0 = N/A (default) |
97 |
tidals |
a3 |
Tidal information array |
||
0-26 |
27 |
Latitude |
lat |
I4 |
Unit = minutes * 0.0001, 91000 = N/A (default), N positive, S negative. |
27-54 |
28 |
Longitude |
lon |
I4 |
Unit = minutes * 0.0001, 181000 = N/A (default), E positive, W negative. |
55-59 |
5 |
From UTC Hour |
from_hour |
u |
0-23, 24 = N/A (default) |
60-65 |
6 |
From UTC Minute |
from_min |
u |
0-59, 60 = N/A (default) |
66-70 |
5 |
To UTC Hour |
to_hour |
u |
0-23, 24 = N/A (default) |
71-76 |
6 |
To UTC Minute |
to_min |
u |
0-59, 60 = N/A (default) |
77-85 |
9 |
Current Dir. Predicted |
cdir |
u |
0-359 deg, 360-N/A (default) |
86-92 |
7 |
Current Speed Predicted |
cspeed |
U1 |
0-126, units of 0.1 knots, 127 = N/A (default). |
The group of fields from longitude on may repeat twice more to convey up to three points of tidal information.
IMO236 Number of persons on board
This message should be used by a ship to report the number of persons on board, e.g. on request by a competent authority. Acknowledgement required.
A message 6 subtype. DAC = 001 FID = 16.
[IMO236] describes a fixed-length, 72-bit message with this layout:
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-49 |
10 |
DAC |
dac |
u |
DAC = 001 |
50-55 |
6 |
FID |
fid |
u |
FID = 16 |
55-68 |
14 |
# persons on board |
persons |
u |
Unsigned integer 0 = N/A (default) 8191 = >= 8191 persons. |
69-71 |
3 |
Spare |
x |
Not used |
OPEN-QUESTION: Note that though this is a message 6 subtype and described in [IMO236] with the attribute "addressed", there is no destination address. A strikeout in [IMO236] suggests that this was originally a subtype of 8. It would be good defensive implementation for a decoder to accept either. Bit length may be used to distinguish them.
[IMO289] describes a fixed-length, 136-bit message with this layout:
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
b |
0 = no retransmit (default), 1 = retransmitted. |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 001 |
82-87 |
6 |
FID |
fid |
u |
FID = 16 |
88-100 |
13 |
# persons on board |
persons |
u |
Unsigned integer, 0 = N/A (default), 8191 = >= 8191 persons. |
101-135 |
35 |
Spare |
x |
Not used |
IMO289 Clearance Time To Enter Port
This message provides specific ships with information on the port to call and time to enter. It should be transmitted by an authority competent to grant use of the port.
A message 6 subtype. DAC = 001 FID = 18. Fixed length: 360 bits.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
b |
0 = no retransmit (default), 1 = retransmitted. |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 001 |
82-87 |
6 |
FID |
fid |
u |
FID = 18 |
88-97 |
10 |
Message Linkage ID |
linkage |
u |
Unsigned integer |
98-101 |
4 |
Month (UTC) |
month |
u |
1-12; 0 = N/A (default) |
102-106 |
5 |
Day (UTC) |
day |
u |
1-31; 0 = N/A (default) |
107-111 |
5 |
Hour (UTC) |
hour |
u |
0-23; 24 = N/A (default) |
112-117 |
6 |
Minute (UTC) |
minute |
u |
0-59; 60 = N/A (default) |
118-237 |
120 |
Name of Port & Berth |
portname |
t |
20 6-bit characters |
238-267 |
30 |
Destination |
destination |
t |
5 6-bit characters |
268-292 |
25 |
Longitude |
lon |
I3 |
Unit = minutes * 0.001, 181000 = N/A (default). |
293-316 |
24 |
Latitude |
lat |
I3 |
Unit = minutes * 0.001, 91000 = N/A (default). |
317-359 |
43 |
Spare |
x |
Not used |
IMO 289 Berthing Data (addressed)
This message provides information on the ship’s berth. If sent from a ship it is a berthing request; if it is transmitted by a competent authority it is a berthing assignment.
A message 6 subtype. DAC = 001 FID = 20. Fixed Length: 360 bits.
The 2-bit fields after "availabilty" describe services which may be available at the berth. They are valid only if this master availability bit is on.
| Field | Len | Description | Member/Type | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
b |
0 = no retransmit (default) 1 = retransmitted |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
AC = 001 |
82-87 |
6 |
FID |
fid |
u |
ID = 20 |
88-97 |
10 |
Message Linkage ID |
linkage |
u |
Unsigned integer |
98-106 |
9 |
Berth length |
berth_length |
u |
In 1m steps, 1-510m, 511 = >= 511m 0 = N/A (default). |
107-114 |
8 |
Berth Water Depth |
berth_depth |
U1 |
0.1-25.4m in 0.1 steps 255 = >= 25.5m 0 = N/A (default) |
115-117 |
3 |
Mooring Position |
position |
e |
See "Mooring Position" |
118-121 |
4 |
Month (UTC) |
month |
u |
1-12; 0 = N/A (default) |
122-126 |
5 |
Day (UTC) |
day |
u |
1-31; 0 = N/A (default) |
127-131 |
5 |
Hour (UTC) |
hour |
u |
0-23; 24 = N/A (default) |
132-137 |
6 |
Minute (UTC) |
minute |
u |
0-59; 60 = N/A (default) |
138-138 |
1 |
Services Availability |
availability |
b |
0 = services unknown (default) 1 = services known |
139-140 |
2 |
Agent |
agent |
e |
See "Service Status" |
141-142 |
2 |
Bunker/fuel |
fuel |
e |
See "Service Status" |
143-144 |
2 |
Chandler |
chandler |
e |
See "Service Status" |
145-146 |
2 |
Stevedore |
stevedore |
e |
See "Service Status" |
147-148 |
2 |
Electrical |
electrical |
e |
See "Service Status" |
149-150 |
2 |
Potable water |
water |
e |
See "Service Status" |
151-152 |
2 |
Customs house |
customs |
e |
See "Service Status" |
153-154 |
2 |
Cartage |
cartage |
e |
See "Service Status" |
155-156 |
2 |
Crane(s) |
crane |
e |
See "Service Status" |
157-158 |
2 |
Lift(s) |
lift |
e |
See "Service Status" |
159-160 |
2 |
Medical facilities |
medical |
e |
See "Service Status" |
161-162 |
2 |
Navigation repair |
navrepair |
e |
See "Service Status" |
163-164 |
2 |
Provisions |
provisions |
e |
See "Service Status" |
165-166 |
2 |
Ship repair |
shiprepair |
e |
See "Service Status" |
167-168 |
2 |
Surveyor |
surveyor |
e |
See "Service Status" |
169-170 |
2 |
Steam |
steam |
e |
See "Service Status" |
171-172 |
2 |
Tugs |
tugs |
e |
See "Service Status" |
173-174 |
2 |
Waste disposal (solid) |
solidwaste |
e |
See "Service Status" |
175-176 |
2 |
Waste disposal (liquid) |
liquidwaste |
e |
See "Service Status" |
177-178 |
2 |
Waste disposal (hazardous) |
hazardouswaste |
e |
See "Service Status" |
179-180 |
2 |
Reserved ballast exchange |
ballast |
e |
See "Service Status" |
181-182 |
2 |
Additional services |
additional |
e |
See "Service Status" |
183-184 |
2 |
Regional reserved 1 |
regional1 |
e |
See "Service Status" |
185-186 |
2 |
Regional reserved 2 |
regional2 |
e |
See "Service Status" |
187-188 |
2 |
Reserved for future |
future1 |
e |
See "Service Status" |
189-190 |
2 |
Reserved for future |
future2 |
e |
See "Service Status" |
191-310 |
120 |
Name of Berth |
berth_name |
t |
20 6-bit characters |
311-335 |
25 |
Longitude |
berth_lon |
I3 |
Minutes * 0.001, 181000 = N/A (default) |
336-359 |
24 |
Latitude |
berth_lat |
I3 |
Minutes * 0.001, 91000 = N/A (default) |
The UTC timestamp refers to the time requested or granted for berthing.
The longitude and latitude refer to the center of the berth.
| Code | Position |
|---|---|
0 |
Not available (default) |
1 |
Port-side to |
2 |
Starboard-side to |
3 |
Mediterranean (end-on) mooring |
4 |
Mooring buoy |
5 |
Anchorage |
6-7 |
Reserved for future use |
| Code | Meaning |
|---|---|
0 |
Not available or requested (default) |
1 |
Service available |
2 |
No data or unknown |
3 |
Not to be used |
IMO289 Area Notice (addressed)
This should be used to convey time- and location-dependent information about hazards to navigation. For information-lifetime restrictions and usage guidance, refer to [ITU1371].
A message 6 subtype. DAC = 001 FID = 23. 230 to 1013 bits. There is a related Message 8 subtype for broadcast use.
The message consists of a fixed-length header of 143 bits, followed by 1 to 10 sub-area indications which are fixed-length records 87 bits long. Here is the message header format:
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
b |
0 = no retransmit (default), 1 = retransmitted. |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 001 |
82-87 |
6 |
FID |
fid |
u |
FID = 23 |
88-97 |
10 |
Message Linkage ID |
linkage |
u |
Unsigned integer |
98-104 |
7 |
Notice Description |
notice |
e |
See "Area Notice Description" |
105-108 |
4 |
Month (UTC) |
month |
u |
1-12; 0 = N/A (default) |
109-113 |
5 |
Day (UTC) |
day |
u |
1-31; 0 = N/A (default) |
114-118 |
5 |
Hour (UTC) |
hour |
u |
0-23; 24 = N/A (default) |
119-124 |
6 |
Minute (UTC) |
minute |
u |
0-59; 60 = N/A (default) |
125-142 |
18 |
Duration |
duration |
In minutes, 262143 = N/A (default), 0 = cancel this notice. |
143 |
subarea |
a10 |
Subarea array |
0-2 |
||
2 |
shape |
u |
Subarea shape |
3-86 |
The Message Linkage field is, as usual, for linking to a textual explanatory message sent with the same linkage ID. The standard says that in this context it has the semantics of being an identifier of or reference to an area.
Notice description types are as follows:
| 0 | Caution Area: Marine mammals habitat |
|---|---|
1 |
Caution Area: Marine mammals in area - reduce speed |
2 |
Caution Area: Marine mammals in area - stay clear |
3 |
Caution Area: Marine mammals in area - report sightings |
4 |
Caution Area: Protected habitat - reduce speed |
5 |
Caution Area: Protected habitat - stay clear |
6 |
Caution Area: Protected habitat - no fishing or anchoring |
7 |
Caution Area: Derelicts (drifting objects) |
8 |
Caution Area: Traffic congestion |
9 |
Caution Area: Marine event |
10 |
Caution Area: Divers down |
11 |
Caution Area: Swim area |
12 |
Caution Area: Dredge operations |
13 |
Caution Area: Survey operations |
14 |
Caution Area: Underwater operation |
15 |
Caution Area: Seaplane operations |
16 |
Caution Area: Fishery – nets in water |
17 |
Caution Area: Cluster of fishing vessels |
18 |
Caution Area: Fairway closed |
19 |
Caution Area: Harbour closed |
20 |
Caution Area: Risk (define in associated text field) |
21 |
Caution Area: Underwater vehicle operation |
22 |
(reserved for future use) |
23 |
Environmental Caution Area: Storm front (line squall) |
24 |
Environmental Caution Area: Hazardous sea ice |
25 |
Environmental Caution Area: Storm warning (storm cell or line of storms) |
26 |
Environmental Caution Area: High wind |
27 |
Environmental Caution Area: High waves |
28 |
Environmental Caution Area: Restricted visibility (fog, rain, etc.) |
29 |
Environmental Caution Area: Strong currents |
30 |
Environmental Caution Area: Heavy icing |
31 |
(reserved for future use) |
32 |
Restricted Area: Fishing prohibited |
33 |
Restricted Area: No anchoring. |
34 |
Restricted Area: Entry approval required prior to transit |
35 |
Restricted Area: Entry prohibited |
36 |
Restricted Area: Active military OPAREA |
37 |
Restricted Area: Firing – danger area. |
38 |
Restricted Area: Drifting Mines |
39 |
(reserved for future use) |
40 |
Anchorage Area: Anchorage open |
41 |
Anchorage Area: Anchorage closed |
42 |
Anchorage Area: Anchorage prohibited |
43 |
Anchorage Area: Deep draft anchorage |
44 |
Anchorage Area: Shallow draft anchorage |
45 |
Anchorage Area: Vessel transfer operations |
46 |
(reserved for future use) |
47 |
(reserved for future use) |
48 |
(reserved for future use) |
49 |
(reserved for future use) |
50 |
(reserved for future use) |
51 |
(reserved for future use) |
52 |
(reserved for future use) |
53 |
(reserved for future use) |
54 |
(reserved for future use) |
55 |
(reserved for future use) |
56 |
Security Alert - Level 1 |
57 |
Security Alert - Level 2 |
57 |
Security Alert - Level 3 |
59 |
(reserved for future use) |
60 |
(reserved for future use) |
61 |
(reserved for future use) |
62 |
(reserved for future use) |
63 |
(reserved for future use) |
64 |
Distress Area: Vessel disabled and adrift |
65 |
Distress Area: Vessel sinking |
66 |
Distress Area: Vessel abandoning ship |
67 |
Distress Area: Vessel requests medical assistance |
68 |
Distress Area: Vessel flooding |
69 |
Distress Area: Vessel fire/explosion |
70 |
Distress Area: Vessel grounding |
71 |
Distress Area: Vessel collision |
72 |
Distress Area: Vessel listing/capsizing |
73 |
Distress Area: Vessel under assault |
74 |
Distress Area: Person overboard |
75 |
Distress Area: SAR area |
76 |
Distress Area: Pollution response area |
77 |
(reserved for future use) |
78 |
(reserved for future use) |
79 |
(reserved for future use) |
80 |
Instruction: Contact VTS at this point/juncture |
81 |
Instruction: Contact Port Administration at this point/juncture |
82 |
Instruction: Do not proceed beyond this point/juncture |
83 |
Instruction: Await instructions prior to proceeding beyond this point/juncture |
84 |
Proceed to this location – await instructions |
85 |
Clearance granted – proceed to berth |
86 |
(reserved for future use) |
87 |
(reserved for future use) |
88 |
Information: Pilot boarding position |
89 |
Information: Icebreaker waiting area |
90 |
Information: Places of refuge |
91 |
Information: Position of icebreakers |
92 |
Information: Location of response units |
93 |
VTS active target |
94 |
Rogue or suspicious vessel |
95 |
Vessel requesting non-distress assistance |
96 |
Chart Feature: Sunken vessel |
97 |
Chart Feature: Submerged object |
98 |
Chart Feature:Semi-submerged object |
99 |
Chart Feature: Shoal area |
100 |
Chart Feature: Shoal area due north |
101 |
Chart Feature: Shoal area due east |
102 |
Chart Feature: Shoal area due south |
103 |
Chart Feature: Shoal area due west |
104 |
Chart Feature: Channel obstruction |
105 |
Chart Feature: Reduced vertical clearance |
106 |
Chart Feature: Bridge closed |
107 |
Chart Feature: Bridge partially open |
108 |
Chart Feature: Bridge fully open |
109 |
(reserved for future use) |
110 |
(reserved for future use) |
111 |
(reserved for future use) |
112 |
Report from ship: Icing info |
113 |
(reserved for future use) |
114 |
Report from ship: Miscellaneous information – define in associated text field |
115 |
(reserved for future use) |
116 |
(reserved for future use) |
117 |
(reserved for future use) |
118 |
(reserved for future use) |
119 |
(reserved for future use) |
120 |
Route: Recommended route |
121 |
Route: Alternative route |
122 |
Route: Recommended route through ice |
123 |
(reserved for future use) |
124 |
(reserved for future use) |
125 |
Other – Define in associated text field |
126 |
Cancellation – cancel area as identified by Message Linkage ID |
127 |
Undefined (default) |
Subarea types are as follows:
| 0 | Circle or point |
|---|---|
1 |
Rectangle |
2 |
Sector |
3 |
Polyline |
4 |
Polygon |
5 |
Associated text |
6-7 |
Reserved |
Subarea payload layouts are as follows:
| Field | Len | Description | Member/Type | T | Units |
|---|---|---|---|---|---|
0-2 |
3 |
Shape of area |
shape |
e |
Constant: 0 |
3-4 |
2 |
Scale factor |
scale |
u |
Exponent for area dimensions 1 = meters (default) |
5-29 |
25 |
Longitude |
lon |
I3 |
Longitude of center point, Unit = minutes * 0.001, 181000 = N/A (default). |
30-53 |
24 |
Latitude |
lat |
I3 |
Latitude of center point, Unit = minutes * 0.001, 91000 = N/A (default). |
54-56 |
3 |
Precision |
precision |
u |
Decimal places of precision (defaults to 4) |
57-68 |
12 |
Radius |
radius |
u |
Radius of area 0 = point (default), else 1-4095 * 10^scale m |
69-86 |
18 |
Spare |
x |
Not used |
| Field | Len | Description | Member/Type | T | Units |
|---|---|---|---|---|---|
0-2 |
3 |
Shape of area |
shape |
e |
Constant: 1 |
3-4 |
2 |
Scale factor |
scale |
u |
Exponent for area dimensions 1 = meters (default) |
5-29 |
25 |
Longitude |
lon |
I3 |
Longitude of SW corner Unit = minutes * 0.001, 181000 = N/A (default). |
30-53 |
24 |
Latitude |
lat |
I3 |
Latitude of SW corner Unit = minutes * 0.001, 91000 = N/A (default). |
54-56 |
3 |
Precision |
precision |
u |
Decimal places of precision (defaults to 4) |
57-64 |
8 |
E dimension |
east |
u |
Box dimension east 0 = N/S line (default), else 1-255 * 10^scale m |
65-72 |
8 |
N dimension |
north |
u |
Box dimension north 0 = E/W line (default), else 1-255 * 10^scale m |
73-81 |
9 |
Orientation |
orientation |
u |
Degrees clockwise from true N, 0 = no rotation (default), else 1-359, 360-511 reserved. |
82-86 |
5 |
Spare |
x |
Not used |
| Field | Len | Description | Member/Type | T | Units |
|---|---|---|---|---|---|
0-2 |
3 |
Shape of area |
shape |
e |
Constant: 2 |
3-4 |
2 |
Scale factor |
scale |
u |
Exponent for area dimensions 1 = meters (default) |
5-29 |
25 |
Longitude |
lon |
I3 |
Longitude of center point, Unit = minutes * 0.001, 181000 = N/A (default). |
30-53 |
24 |
Latitude |
lat |
I3 |
Latitude of center point, Unit = minutes * 0.001, 91000 = N/A (default). |
54-56 |
3 |
Precision |
precision |
u |
Decimal places of precision (defaults to 4) |
57-68 |
12 |
Radius |
radius |
u |
Radius of area 0 = point (default), else 1-4095 * 10^scale m |
69-77 |
9 |
Left boundary |
left |
u |
Degrees clockwise from true N, 0 = no rotation (default), else 1-359, 360-511 reserved. |
78-86 |
9 |
Right boundary |
right |
u |
Degrees clockwise from true N, 0 = no rotation (default), else 1-359, 360-511 reserved. |
| Field | Len | Description | Member/Type | T | Units |
|---|---|---|---|---|---|
0-2 |
3 |
Shape of area |
shape |
e |
Constant: 3 |
3-4 |
2 |
Scale factor |
scale |
u |
Exponent for area dimensions 1 = meters (default) |
5 |
waypoints |
a4 |
Waypoints array |
||
0-9 |
10 |
Bearing |
bearing |
u |
True bearing in half-degree steps from previous waypoint; 720 = N/A (default). |
10-19 |
10 |
Distance |
distance |
u |
Distance from prev. waypoint, 0 = no point (default), else 1-1023 * 10^scale m |
The last two fields are repeated 4 times; the final 2 bits of 87 are unused. A polyline must be preceded by either (a) a circle, in which case the first bearing is from the center, or (b) a polyline, in which case the first beariing is from the implied last point.
| Field | Len | Description | Member/Type | T | Units |
|---|---|---|---|---|---|
0-2 |
3 |
Shape of area |
shape |
e |
Constant: 4 |
3-4 |
2 |
Scale factor |
scale |
u |
Exponent for area dimensions 1 = meters (default) |
5 |
vertices |
a4 |
Vertices array |
||
0-9 |
10 |
Bearing |
bearing |
u |
True bearing in half-degree steps from previous vertex; 720 = N/A (default). |
10-19 |
10 |
Distance |
distance |
u |
Distance from prev. vertex, |
The last two fields are repeated 4 times; the final 2 bits of 87 are unused. A polygon must be preceded by a circle; the first bearing is from the circle center, which is treated as the zero vertex. There is an implied boundary from the last polygon vertex to the zero vertex.
| Field | Len | Description | Member/Type | T | Units |
|---|---|---|---|---|---|
0-2 |
3 |
Shape of area |
shape |
e |
Constant: 5 |
3-86 |
84 |
Text |
text |
t |
14 chars of packed 6-bit. |
IMO289 Dangerous Cargo Indication
See the IMO236 variant for the meaning of this message.
A message 6 subtype. DAC = 001 FID = 25. Variable length: 117-576 bits. This is the [IMO289] version; there is an earlier [IMO236] version with a different layout, deprecated in [IMO289].
| Field | Len | Description | Membe | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
b |
0 = no retransmit (default) 1 = retransmitted |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 001 |
82-87 |
6 |
FID |
fid |
u |
FID = 25 |
88-89 |
2 |
Unit of Quantity |
unit |
e |
See "Cargo Unit Codes" |
90-99 |
10 |
Amount of Cargo |
amount |
u |
Unsigned integer 0 = N/A (default) 0 = N/A (default) |
100 |
cargos |
a28 |
Cargo types array |
||
0-3 |
4 |
Cargo code |
code |
e |
See "Cargo Codes" |
4-16 |
13 |
Cargo subtype |
subtype |
u |
Unsigned integer 0 = N/A (default) |
The last two fields may repeat to describe up to 28 subcargos. The count of repetitions must be computed from the message payload length.
For cargo unit codes, see the description of the IMO236 variant of this message.
| Code | Code under which cargo is carried |
|---|---|
0 |
Not available (default) |
1 |
IMDG Code (in packed form) |
2 |
IGC code |
3 |
BC Code (from 1.1.2011 IMSBC) |
4 |
MARPOL Annex I List of oils (Appendix 1) |
5 |
MARPOL Annex II IBC Code |
6 |
Regional use |
7-15 |
Reserved for future use |
The subtype field may be interpreted as an IMDG class or division code (if the cargotype is 1 = IMDG code) or as a UN number (if the cargotype is 2 = IGC code) or as a pair of BC class and IMDG class (if the cargotype is 3 = BC code) or as a MARPOL Annex I code (if the cargotype is 4 = MARPOL Annex I) or as a MARPOL Annex II code (if the cargotype is 5 = MARPOL Annex II).
| 0 | N/A (default) |
|---|---|
1 |
asphalt solutions |
2 |
oils |
3 |
distillates |
4 |
gas oil |
5 |
gasoline blending stocks |
6 |
gasoline |
7 |
jet fuels |
8 |
naphtha |
9-15 |
reserved for future use |
| 0 | N/A (default) |
|---|---|
1 |
Category X |
2 |
Category Y |
3 |
Category Z |
4 |
Other substances |
5-7 |
reserved for future use |
IMO289 Route Information (addressed)
The content of this message is a time and a list of waypoints describing a course. It has a broadcast equivalent that is a message 8 subtype.
A message 6 subtype. DAC = 001 FID = 28. Variable length: 204-1029 bits.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
b |
0 = no retransmission (default), 1 = retransmitted. |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 001 |
82-87 |
6 |
FID |
fid |
u |
FID = 28 |
88-97 |
10 |
Message Linkage ID |
linkage |
u |
Unsigned integer |
98-100 |
3 |
Sender Class |
sender |
u |
0 = ship (default), 1 = authority, 27 = reserved for future use |
101-105 |
5 |
Route Type |
rtype |
e |
See "Route Type Codes" |
106-109 |
4 |
Start month (UTC) |
month |
u |
1-12, 0=N/A (default) |
110-114 |
5 |
Start day (UTC) |
day |
u |
1-31, 0=N/A (default) |
115-119 |
5 |
Start hour (UTC) |
hour |
u |
0-23, 24=N/A (default) |
120-125 |
6 |
Start minute (UTC) |
minute |
u |
0-59, 60=N/A (default) |
126-143 |
18 |
Duration |
duration |
u |
Minutes from start time, 0 = cancel route, 262,143 = N/A (default), |
144-148 |
5 |
waycount |
u |
Waypoint count (1-16), Values 17-31 are not used. |
|
149 |
waypoints |
a^16 |
Waypoint array |
||
0-27 |
28 |
Longitude |
lon |
I4 |
Minutes * 0.0001, 181000 = N/A (default), E positive, W negative. |
28-54 |
27 |
Latitude |
lat |
I4 |
Minutes * 0.0001, 91000 = N/A (default), N positive, S negative. |
The final pair of fields in the table above is a waypoint. The message may end with 1 to 16 waypoints.
| 0 | Undefined (default) |
|---|---|
1 |
Mandatory |
2 |
Recommended |
3 |
Alternative |
4 |
Recommended route through ice |
5 |
Ship route plan |
6-30 |
Reserved for future usage |
31 |
Cancel route identified by message linkage |
IMO289 Text description (addressed)
This message may be used to attach a text description to another message with a Message Linkage ID matching this one. It is intended that the combination of MMSI and Message Linkage ID should be unique.
A message 6 subtype. DAC = 001 FID = 30. Variable length: 104-1028 bits.
Intended to be used to associate a text annotation with another message via the Message Linkage ID field.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
u |
0 = no retransmit (default), 1 = retransmitted |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 001 |
82-87 |
6 |
FID |
fid |
u |
FID = 30 |
88-97 |
10 |
Message Linkage ID |
linkage |
u |
Unsigned integer |
98-? |
6-930 |
Description |
description |
t |
String |
There is an equivalent subtype of message 8 that is a broadcast description.
Tidal Window (IMO289)
See the [IMO239] version of this message for intended meaning.
A message 6 subtype. DAC = 001 FID = 32. Variable length: 186-362 bits. This is the [IMO289] version; there is an [IMO289] version with different bit widths for the latitude and longitude fields.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
b |
0 = no retransmit (default), 1 = retransmitted |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 001 |
82-87 |
6 |
FID |
fid |
u |
FID = 32 |
88-91 |
4 |
Month |
month |
u |
1-12; 0 = N/A (default) |
92-96 |
5 |
Day |
day |
u |
1-31; 0 = N/A (default) |
97 |
tidals |
a3 |
Tidal information array |
||
0-24 |
25 |
Longitude |
lon |
I3 |
Unit = minutes * 0.001, 181000 = N/A (default), E positive, W negative. |
25-48 |
24 |
Latitude |
lat |
I3 |
Unit = minutes * 0.001. 91000 = N/A (default), N positive, S negative. |
49-53 |
5 |
From UTC Hour |
from_hour |
u |
0-23, 24 = N/A (default) |
54-59 |
6 |
From UTC Minute |
from_min |
u |
0-59, 60 = N/A (default) |
60-64 |
5 |
To UTC Hour |
to_hour |
u |
0-23, 24 = N/A (default) |
65-70 |
6 |
To UTC Minute |
to_min |
u |
0-59, 60 = N/A (default) |
71-79 |
9 |
Current Dir. Predicted |
cdir |
u |
0-359 true bearing, 360 = N/A (default). |
80-87 |
8 |
Current Speed Predicted |
cspeed |
U1 |
0-250, units of 0.1 knots, 251 = speed >= 25.1 knots, 255 = N/A (default). |
The group of fields from longitude on may repeat twice more to convey up to three points of tidal information.
ETA at lock/bridge/terminal (Inland AIS)
A message 6 subtype. DAC = 200 FID = 21. Fixed length, 248 bits.
Should be used by inland vessels only, to send an ETA report to a lock, bridge or terminal in order to apply for a time slot in resource planning.
An acknowledgement by Inland AIS message 22 should be received within 15 minutes. Otherwise, the Inland AIS message 21 should be repeated once.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70 |
1 |
Retransmit flag |
retransmit |
u |
0 = no retransmit (default), 1 = retransmitted |
71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 200 |
82-87 |
6 |
FID |
fid |
u |
FID = 21 |
88-99 |
12 |
UN Country Code |
country |
t |
2 six-bit characters |
100-117 |
18 |
UN/LOCODE |
locode |
t |
3 six-bit characters |
118-147 |
30 |
Fairway section |
section |
t |
5 six-bit characters |
148-177 |
30 |
Terminal code |
terminal |
t |
5 six-bit characters |
178-207 |
30 |
Fairway hectometre |
hectometre |
t |
5 six-bit characters |
208-211 |
4 |
ETA month |
month |
u |
1-12, 0=N/A (default) |
212-216 |
5 |
ETA day |
day |
u |
1-31, 0=N/A (default) |
217-221 |
5 |
ETA hour |
hour |
u |
0-23, 24=N/A (default) |
222-227 |
6 |
ETA minute |
minute |
u |
0-59, 60=N/A (default) |
228-230 |
3 |
Assisting Tugs |
tugs |
u |
0-6, 7 = unknown (default) |
231-242 |
12 |
Air Draught |
airdraught |
u |
0-4000 * 0.01m, 0 = Unknown (default) |
243-247 |
5 |
Spare |
x |
Not used |
[INLAND] says of the Destunation MMSI field "a virtual MMSI number should be used for each country, each national AIS network should route messages addressed to other countries using this virtual MMSI number".
OPEN-QUESTION: [INLAND] does not specify whether ETA time is UTC or local.
RTA at lock/bridge/terminal (Inland AIS)
A message 6 subtype. DAC = 200 FID = 22. Fixed length, 232 bits.
This message should be sent by base stations only, to assign a RTA at a lock, bridge or terminal to a certain vessel in response to the preceding ETA request.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
u |
0 = no retransmit (default), 1 = retransmitted |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 200 |
82-87 |
6 |
FID |
fid |
u |
FID = 21 |
88-99 |
12 |
UN Country Code |
country |
t |
2 six-bit characters |
100-117 |
18 |
UN/LOCODE |
locode |
t |
3 six-bit characters |
118-147 |
30 |
Fairway section |
section |
t |
5 six-bit characters |
148-177 |
30 |
Terminal code |
terminal |
t |
5 six-bit characters |
178-207 |
30 |
Fairway hectometre |
hectometre |
t |
5 six-bit characters |
208-211 |
4 |
RTA month |
month |
u |
1-12, 0=N/A (default) |
212-216 |
5 |
RTA day |
day |
u |
1-31, 0=N/A (default) |
217-221 |
5 |
RTA hour |
hour |
u |
0-23, 24=N/A (default) |
222-227 |
6 |
RTA minute |
minute |
u |
0-59, 60=N/A (default) |
228-229 |
2 |
Status |
status |
e |
See "Status Codes" below |
230-231 |
2 |
Spare |
x |
Not used |
OPEN-QUESTION: [INLAND] does not specify whether ETA time is UTC or local.
OPEN-QUESTION: No default is specified for the Status field.
| 0 | Operational |
|---|---|
1 |
Limited operation |
2 |
Out of order |
3 |
N/A |
Number of persons on board (Inland AIS)
This message should be sent by inland vessels only, to inform about the number of persons (passengers, crew, shipboard personnel) on board.
A message 6 subtype. DAC = 200 FID = 55. Fixed length, 168 bits.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
u |
0 = no retransmit (default), 1 = retransmitted |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 200 |
82-87 |
6 |
FID |
fid |
u |
FID = 55 |
88-95 |
8 |
# crew on board |
crew |
u |
Unsigned integer 0-254, 255 = Unknown (default) |
96-108 |
13 |
# passengers on board |
passengers |
u |
Unsigned integer 0-8190, 8191 = Unknown (default) |
109-116 |
8 |
# personnel on board |
personnel |
u |
Unsigned integer 0-254, 255 = Unknown (default) |
117-167 |
51 |
Spare |
x |
Not used |
AtoN monitoring data (GLA)
This message provides AtoN (Aid to navigation) monitoring data for the General Lighthouse Authorities (GLA), which consists of Trinity House (England & Wales), Northern Lighthouse Board (Scotland) and the Commissioners of Irish Lights (Ireland). It is described in [IALA-A126].
A message 6 subtype. DAC = 235 or 250 FID = 10. Fixed length: 136 bits.
DAC and FI are user configurable, DAC=235/FI=10 is used in UK, DAC=250/FI=10 in the Republic Of Ireland.
The interval between the transmission of these messages will be synchronized with message 21, although not necessarily at the same reporting rate. If Message 21 is not used at a particular site, then the reporting interval should be selected to minimize the power requirement of the transponder, whilst still providing enough data to enable meaningful diagnostic analysis.
OPEN-QUESTION: [INLAND] lists a broadcast (type 8) variant of this message, but without indicating how the Destination MMSI field is to be set or interpreted. Robust implementations should accept and process this variant.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Sequence Number |
seqno |
u |
Unsigned integer 0-3 |
40-69 |
30 |
Destination MMSI |
dest_mmsi |
u |
9 decimal digits |
70-70 |
1 |
Retransmit flag |
retransmit |
u |
0 = no retransmit (default), 1 = retransmitted |
71-71 |
1 |
Spare |
x |
Not used |
|
72-81 |
10 |
DAC |
dac |
u |
DAC = 235 or 250 |
82-87 |
6 |
FID |
fid |
u |
FID = 10 |
88-97 |
10 |
Analogue |
ana_int |
u |
0.05-36V, 0.05V step Supply voltage to AIS Unit 0 = Not Used |
98-107 |
10 |
Analogue (ext. #1) |
ana_ext1 |
u |
0.05-36V, 0.05V step 0 = Not Used |
108-117 |
10 |
Analogue (ext. #2) |
ana_ext2 |
u |
0.05-36V, 0.05V step 0 = Not Used |
118-119 |
2 |
RACON status |
racon |
u |
00 = no RACON installed 01 = RACON not monitored 10 = RACON operational 11 = RACON ERROR |
120-121 |
2 |
Light status |
light |
u |
00 = no light or no monitoring 01 = Light ON 10 = Light OFF 11 = Light ERROR |
122 |
1 |
Health |
health |
b |
0 = Good Health, 1 = Alarm |
123-130 |
8 |
Status (external) |
stat_ext |
u |
7 Digital Input 0=Off, 1=On : : 0 Digital Input 0=Off, 1=On |
131-131 |
1 |
Position status |
off_pos |
b |
0=On position, 1=Off position |
132-135 |
4 |
Spare |
x |
Not used |
Type 7: Binary Acknowledge
Message type 7 is a receipt acknowledgement to the senders of a previous messages of type 6. Total length varies between 72 and 168 bits by 32-bit increments, depending on the number of destination MMSIs included.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 7 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-69 |
30 |
MMSI number 1 |
mmsi1 |
u |
9 decimal digits |
70-71 |
2 |
Sequence for MMSI 1 |
mmsiseq1 |
u |
Not used |
72-101 |
30 |
MMSI number 2 |
mmsi2 |
u |
9 decimal digits |
102-103 |
2 |
Sequence for MMSI 2 |
mmsiseq2 |
u |
Not used |
104-133 |
30 |
MMSI number 3 |
mmsi3 |
u |
9 decimal digits |
134-135 |
2 |
Sequence for MMSI 3 |
mmsiseq3 |
u |
Not used |
136-165 |
30 |
MMSI number 4 |
mmsi4 |
u |
9 decimal digits |
166-167 |
2 |
Sequence for MMSI 4 |
mmsiseq4 |
u |
Not used |
Use of the MMSI sequence fields was introduced in ITU-1371-5 to indicate the sequence number of the Type 6 to which this responds. In earlier versions these were spare fields.
Type 8: Binary Broadcast Message
Message type 8 is a broadcast message with unspecified binary payload. The St. Lawrence Seaway AIS system, the USG PAWSS system, and the Port Authority of London use this payload for local extension messages. [IMO236] and [IMO289] describe payload use as international extension messages. This type is variable in length up to a maximum of 1008 bits (up to 5 AIVDM sentence payloads).
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 8 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-49 |
10 |
Designated Area Code |
dac |
u |
Unsigned integer |
50-55 |
6 |
Functional ID |
fid |
u |
Unsigned integer |
56 |
952 |
Data |
data |
d |
Binary data, May be shorter than 952 bits. |
Interpretation of the binary payload is controlled by DAC/FID as in message type 6. The following is a non-exhaustive list of standardized DAC-FID pairs in use for type 8:
| DAC | FID | Sub | Source | Status | Description |
|---|---|---|---|---|---|
1 |
11 |
Deprecated/In Use |
Meteorological/Hydrological Data |
||
1 |
13 |
Deprecated |
Fairway closed |
||
1 |
15 |
Deprecated |
Extended ship and voyage |
||
1 |
17 |
In use |
VTS-Generated/Synthetic targets |
||
1 |
19 |
Standard |
Marine traffic signals |
||
1 |
21 |
Standard |
Weather observation from ship |
||
1 |
22 |
In use |
Area notice (broadcast) |
||
1 |
24 |
Standard |
Extended ship and voyage |
||
1 |
26 |
Standard |
Environmental |
||
1 |
27 |
Standard |
Route info broadcast |
||
1 |
29 |
Standard |
Text description broadcast |
||
1 |
31 |
In use |
Meteorological and Hydrological |
||
200 |
10 |
Standard |
Ship static and voyage related data |
||
200 |
23 |
Standard |
EMMA warning report |
||
200 |
24 |
Standard |
Water levels |
||
200 |
40 |
Standard |
Signal status |
||
316/366 |
1 |
2 |
In use |
Wind |
|
316/366 |
1 |
1 |
In use |
Weather station |
|
316/366 |
1 |
3 |
In use |
Water level |
|
316/366 |
1 |
6 |
In use |
Water flow |
|
316/366 |
2 |
1 |
In use |
Lockage Order |
|
316/366 |
2 |
2 |
In use |
Estimated Lock Times |
|
316/366 |
32 |
1 |
In use |
Seaway Version Message |
|
366 |
1 |
4 |
In use |
PAWS Hydro / Current |
|
366 |
1 |
6 |
In use |
PAWS Hydro / Salinity Temp |
|
366 |
1 |
3 |
In use |
PAWS Vessel Procession Order |
DAC/FID pairs are assigned separately per message type. For St. Lawrence Seaway messages, the DAC may be 316 (Canada) or 366 (U.S.) depending on the transmitter location.
Note that the apparent presence of one of these DAC/FID pairs dooes not guarantee that the message is structured. Decoders should perform range validation on the structured fields and interpret the message as unstructured if any check fails. Actual false matches with DAC/FID = 200/10 have been observed in the wild.
DAC/FID pairs 1/23, 1/28, and 1/30 have addressed versions descrubed under type 6.
FID types 11-15 are being phased out and are not to be used after 1 Jan 2013. The deprecated IMO236 1/11 has a different binary layout from the IMO289 1/31. FID type 17 is in use; there is a proposed update for it in [IMO289].
Breakdowns of Message 8 subtypes from [IMO289] follow.
Meteorological and Hydrological Data (IMO236)
A message 8 subtype. DAC = 001 FID = 11. Fixed length, 352 bits. This is in use and described in [IMO236], but has been deprecated by [289] in favor of a message with the same title but FID = 31 and a different binary layout. [IMO236] specifies a maximum interval between broadcast of this message of 12 minutes.
| Field | Len | Description | Member | u | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 8 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-49 |
10 |
DAC |
dac |
u |
DAC = 001 |
50-55 |
6 |
FID |
fid |
u |
FID = 11 |
56-79 |
24 |
Latitude |
lat |
I3 |
Unit = minutes * 0.001, 0x7FFFFF = N/A (default), E positive, W negative. |
80-104 |
25 |
Longitude |
lon |
I3 |
Unit = minutes * 0.001, 0xFFFFFF = N/A (default), N positive, S negative. |
105-109 |
5 |
Day (UTC) |
day |
u |
1-31, 31=N/A (default) |
110-114 |
5 |
Hour (UTC) |
hour |
u |
0-23, 31=N/A (default) |
115-120 |
6 |
Minute (UTC) |
minute |
u |
0-59, 63=N/A (default) |
121-127 |
7 |
Average Wind Speed |
wspeed |
u |
10-min avg wind speed, knots, 127 = N/A (default). |
128-134 |
7 |
Gust Speed |
wgust |
u |
10-min max wind speed, knots, 127 = N/A (default). |
135-143 |
9 |
Wind Direction |
wdir |
u |
0-359, degrees fom true north 511 = N/A (default) |
144-152 |
9 |
Wind Gust Direction |
wgustdir |
u |
0-359, degrees fom true north 511 = N/A (default) |
153-163 |
11 |
Air Temperature |
temperature |
u |
Dry bulb temp: 0.1 deg C -60.0 to +60.0, 2047 = N/A (default), |
164-170 |
7 |
Relative Humidity |
humidity |
u |
0-100%, units of 1%, 127 = N/A (default). |
171-180 |
10 |
Dew Point |
dewpoint |
u |
-20.0 to +50.0: 0.1 deg C, 1023 = N/A (default), |
181-189 |
9 |
Air Pressure |
pressure |
u |
800-1200hPa: units 1hPa, 511 = N/A (default). |
190-191 |
2 |
Pressure Tendency |
pressuretend |
e |
0 = steady, 1 = decreasing, 2 = increasing, 3 - N/A (default). |
192-199 |
8 |
Horiz. Visibility |
visibility |
U1 |
0-25.0, units of 0.1nm 255 = N/A (default) |
200-208 |
9 |
Water Level |
waterlevel |
I1 |
-10.0 to +30.0 in 0.1m, 511 = N/A (default). |
209-210 |
2 |
Water Level Trend |
leveltrend |
e |
0 = steady, 1 = decreasing, 2 = increasing, 3 - N/A (default). |
211-218 |
8 |
Surface Current Speed |
cspeed |
U1 |
0.0-25.0 knots: units 0.1 knot |
219-227 |
9 |
Surface Current Direction |
cdir |
u |
0-359: deg from true north, 511 = N/A (default) |
228-235 |
8 |
Current Speed #2 |
cspeed2 |
U1 |
0.0-25.0 in units of 0.1 knot, 255 = N/A (default). |
236-244 |
9 |
Current Direction #2 |
cdir2 |
u |
0-359: deg. fom true north, 511 = N/A (default) |
245-249 |
5 |
Measurement Depth #2 |
cdepth2 |
U1 |
0-30m down: units 0.1m, 31 = N/A (default). |
250-257 |
8 |
Current Speed #3 |
cspeed3 |
U1 |
0.0-25.0: units of 0.1 knot, 255 = N/A (default). |
258-266 |
9 |
Current Direction #3 |
cdir3 |
u |
0-359: degrees fom true north, 511 = N/A (default). |
267-271 |
5 |
Measurement Depth #3 |
cdepth3 |
U1 |
0-30m down: units 0.1m, 31 = N/A (default). |
272-279 |
8 |
Wave height |
waveheight |
U1 |
0-25m: units of 0.1m, 255 = N/A (default). |
280-285 |
6 |
Wave period |
waveperiod |
u |
Seconds 0-60: 63 = N/A (default). |
286-294 |
9 |
Wave direction |
wavedir |
u |
0-359: deg. fom true north, 511 = N/A (default). |
295-302 |
8 |
Swell height |
swellheight |
U1 |
0-25m: units of 0.1m 255 = N/A (default). |
303-308 |
6 |
Swell period |
swellperiod |
u |
Seconds 0-60: 63 = N/A (default). |
309-317 |
9 |
Swell direction |
swelldir |
u |
0-359: deg. fom true north, 511 = N/A (default). |
318-321 |
4 |
Sea state |
seastate |
e |
See "Beaufort Scale" |
322-331 |
10 |
Water Temperature |
watertemp |
U1 |
-10.0 to 50.0: units 0.1 C, 1023 = N/A (default). |
332-334 |
3 |
Precipitation |
preciptype |
e |
See "Precipitation Types" |
335-343 |
9 |
Salinity |
salinity |
U1 |
0.0-50.0%: units 0.1%, 511 = N/A (default) |
344-345 |
2 |
Ice |
ice |
e |
0 = No 1 = Yes 2 = (reserved for future use) 3 = not available = default |
346-351 |
6 |
Spare |
x |
Not used |
[IMO236] says "If there is no data available, default value to be transmitted is the highest available binary value for that particular data field.", the above table reflects that. The day, hour and minute have to be considered not available when all three are set to their individual "N/A" value. For the latitude and the longitude, the highest positive value is used, as the highest available binary value for a signed integer is -1, which would forbid the -0.001/-0.001 position. The replacement FID=31 message has different default values that remove any ambiguities.
[IMO236] gives the length of this message as 352, but lists only 336 payload bits.
Water level is deviation from local chart datum and includes tide.
The waveheight field is labeled as "Significant" in [IMO236], for whatever that means.
The seastate field has a note in [IMO236] reading "(manual input?)"?
WMO 306 Code table 4.201 specifies the following precipitatiuon type values:
| Code | Precipitation Type |
|---|---|
0 |
Reserved |
1 |
Rain |
2 |
Thunderstorm |
3 |
Freezing rain |
4 |
Mixed/ice |
5 |
Snow |
6 |
Reserved |
7 |
N/A (default) |
| Scale | Description | Sea Conditions |
|---|---|---|
0 |
Calm |
Flat. |
1 |
Light air |
Ripples without crests. |
2 |
Light breeze |
Small wavelets. |
Crests of glassy appearance, not breaking. |
||
3 |
Gentle breeze |
Large wavelets. |
Crests begin to break; scattered whitecaps. |
||
4 |
Moderate breeze |
Small waves. |
5 |
Fresh breeze |
Moderate (1.2 m) longer waves. Some foam and spray. |
6 |
Strong breeze |
Large waves with foam crests and some spray. |
7 |
High wind |
Sea heaps up and foam begins to streak. |
8 |
Gale |
Moderately high waves with breaking crests |
forming spindrift. Streaks of foam. |
||
9 |
Strong gale |
High waves (6-7 m) with dense foam. |
Wave crests start to roll over. Considerable spray. |
||
10 |
Storm |
Very high waves. The sea surface is white and there |
is considerable tumbling. Visibility is reduced. |
||
11 |
Violent storm |
Exceptionally high waves. |
12 |
Hurricane force |
Huge waves. Air filled with foam and spray. Sea |
completely white with driving spray. Visibility |
||
greatly reduced. |
||
13 |
N/A (default) |
|
14-15 |
Reserved |
Fairway Closed
This message should be broadcast from shore stations to inform ships, in particular to give guidance to large vessels about temporary closed fairways or sections in ports.
A message 8 subtype. DAC = 001 FID = 13. Fixed length, 472 bits. Described in [IMO236] but deprecated by [IMO289].
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 8 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-49 |
10 |
DAC |
dac |
u |
DAC = 001 |
50-55 |
6 |
FID |
fid |
u |
FID = 13 |
56-175 |
120 |
Reason For Closing |
reason |
t |
20 6-bit characcters |
176-295 |
120 |
Location Of Closing From |
closefrom |
t |
20 6-bit characcters |
296-415 |
120 |
Location of Closing To |
closeto |
t |
20 6-bit characcters |
416-425 |
10 |
Radius extension |
radius |
u |
0-1000, 10001 = N/A (default) |
426-427 |
2 |
Unit of extension |
extunit |
u |
0=m, 1=km, 2=nm, 3=cables |
428-432 |
5 |
From day (UTC) |
fday |
u |
1-31, 0=N/A (default) |
433-436 |
4 |
From month (UTC) |
fmonth |
u |
1-12, 0=N/A (default) |
437-441 |
5 |
From hour (UTC) |
fhour |
u |
0-23, 24=N/A (default) |
442-447 |
6 |
From minute (UTC) |
fminute |
u |
0-59, 60=N/A (default) |
448-452 |
5 |
To day (UTC) |
tday |
u |
1-31, 0=N/A (default) |
453-456 |
4 |
To month (UTC) |
tmonth |
u |
1-12, 0=N/A (default) |
457-461 |
5 |
To hour (UTC) |
thour |
u |
0-23, 24=N/A (default) |
462-467 |
6 |
To minute (UTC) |
tminute |
u |
0-59, 60=N/A (default) |
468-471 |
4 |
Spare |
x |
Not used |
No default is specified for the radius field in the standard.
IMO236 Extended Ship Static and Voyage Related Data
This message should be used by a ship to report the height over keel.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 8 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-49 |
10 |
DAC |
dac |
u |
DAC = 001 |
50-55 |
6 |
FID |
fid |
u |
FID = 15 |
55-66 |
11 |
Air Draught |
airdraught |
u |
Height in meters, 0 = N/A (default), 2047 = >= 2047 m, |
67-71 |
5 |
Spare |
x |
Not used |
VTS-Generated/Synthetic targets
A message 8 subtype. DAC = 001 FID = 17. Variable length: 176-536 bits. This message is laid out identically in [IMO236] and [IMO289]. In [IMO236] it is titled "Pseudo-AIS Targets".
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 8 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-49 |
10 |
DAC |
dac |
u |
DAC = 001 |
50-55 |
6 |
FID |
fid |
u |
FID = 17 |
56 |
targets |
a4 |
Synthetic targets array |
||
0-1 |
2 |
Identifier type |
idtype |
e |
0 = id is the MMSI number, 1 = id is the IMO number, 2 = id is the call sign, 3 = Other (default). |
2-43 |
42 |
Target identifier |
id |
u |
Target ID data. |
44-47 |
4 |
Spare |
x |
Not used |
|
48-71 |
24 |
Latitude |
lat |
I3 |
Minutes * 0.001, 91000 = N/A (default), N positive, S negative. |
72-96 |
25 |
Longitude |
lon |
I3 |
Minutes * 0.001, 181000 = N/A (default), E positive, W negative. |
97-105 |
9 |
Course Over Ground |
course |
u |
0-359 deg from true north, 360 = N/A (default). |
106-111 |
6 |
Time Stamp |
second |
u |
Second of UTC timestamp. |
112-121 |
10 |
Speed Over Ground |
speed |
u |
0-254 in knots, 255 = N/A. |
The interpretation of the target identifier field depends on the ppreceding type key. For 0 and 1 it is a big-endian unsigned binary integer (as shown above). For type 2 and 3 it is 6-bit ASCII text. An unknown target is expressed by type 3 and the string "@@@@@@@".
OPEN-QUESTION: [IMO289] says: "When MMSI or IMO number is used, the least significant bit should equal bit zero of the Target Identifier." It is unclear how "bit zero" is to be interpreted, but it is not possible to reconcile interpreting it as the leading bit of the field with AIS big-endian encoding. Settling this awaits live testing.
The trailing eight fields may be repeated up to 3 times (for a total of 1 to 4 field groups) to represent up to 4 targets.
IMO289 Marine Traffic Signal
This message provides information on a signal station and status of the control signal at the entrance of a harbour or channel where the shipping direction controlled so that the traffic flow be kept in order.
A message 8 subtype described in [IMO289]. DAC = 001 FID = 19. Fixed length: 360 bits.
| Field | Len | Description | Member | u | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 8 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-49 |
10 |
DAC |
dac |
u |
DAC = 001 |
50-55 |
6 |
FID |
fid |
u |
FID = 19 |
56-65 |
10 |
Message Linkage ID |
linkage |
u |
Unsigned integer |
66-185 |
120 |
Name of Signal Station |
station |
t |
20 6-bit chars |
186-210 |
25 |
Longitude |
lon |
I3 |
Unit = minutes * 0.001 181000 = N/A (default) E positive, W negative. |
211-234 |
24 |
Latitude |
lat |
I3 |
Unit = minutes * 0.001 91000 = N/A (default) N positive, S negative. |
235-236 |
2 |
Status of Signal |
status |
u |
0=N/A (default 1 = In regular service 2 = Irregular service 3 = Reserved for future use |
237-241 |
5 |
Signal In Service |
signal |
e |
See "Marine Traffic Signals" |
242-246 |
5 |
UTC hour |
hour |
u |
0-23, 24=N/A (default) |
247-252 |
6 |
UTC minute |
minute |
u |
0-59, 60=N/A (default) |
253-257 |
5 |
Expected Next Signal |
nextsignal |
e |
See "Marine Traffic Signals" |
258-359 |
102 |
Spare |
x |
Not used |
| Code | Position Fix Type |
|---|---|
0 |
N/A (default) |
1 |
IALA port traffic signal 1: Serious emergency – all vessels to stop |
or divert according to instructions. |
|
2 |
IALA port traffic signal 2: Vessels shall not proceed. |
3 |
IALA port traffic signal 3: Vessels may proceed. One way traffic. |
4 |
IALA port traffic signal 4: Vessels may proceed. Two way traffic. |
5 |
IALA port traffic signal 5: A vessel may proceed only when it has |
received specific orders to do so. |
|
6 |
IALA port traffic signal 2a: Vessels shall not proceed, except that |
vessels which navigate outside the main channel need not comply with |
|
the main message. |
|
7 |
IALA port traffic signal 5a: A vessel may proceed only when it has |
received specific orders to do so; except that vessels which navigate |
|
outside the main channel need not comply with the main message. |
|
8 |
Japan Traffic Signal - I = "in-bound" only acceptable. |
9 |
Japan Traffic Signal - O = "out-bound" only acceptable. |
10 |
Japan Traffic Signal - F = both "in- and out-bound" acceptable. |
11 |
Japan Traffic Signal - XI = Code will shift to "I" in due time. |
12 |
Japan Traffic Signal - XO = Code will shift to "O" in due time. |
13 |
Japan Traffic Signal - X = Vessels shall not proceed, except a vessel |
which receives the direction from the competent authority. |
|
14-31 |
Reserved |
IMO289 Weather observation report from ship
There are two variants of this message. They are distinguished by bit 56, the WMO bit. Field layouts after that bit vary depending on it.
A message 8 subtype described in [IMO289]. DAC = 001 FID = 21. Fixed length: 360 bits.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 8 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-49 |
10 |
DAC |
dac |
u |
DAC = 001 |
50-55 |
6 |
FID |
fid |
u |
FID = 21 |
56-56 |
1 |
Variant |
wmo |
b |
Constant: 0 in this variant |
57-176 |
120 |
Location |
location |
t |
20 6-bit characters |
177-201 |
25 |
Longitude |
lon |
I3 |
Unit = minutes * 0.001, 181000 = N/A (default), E positive, W negative. |
202-225 |
24 |
Latitude |
lat |
I3 |
Unit = minutes * 0.001, 91000 = N/A (default), N positive, S negative. |
226-230 |
5 |
UTC Day |
day |
u |
1-31, 0=N/A (default) |
231-235 |
5 |
UTC hour |
hour |
u |
0-23, 24=N/A (default) |
236-241 |
6 |
UTC minute |
minute |
u |
0-59, 60=N/A (default) |
242-245 |
4 |
Present Weather |
weather |
u |
wmocode: 0-15 |
246-246 |
1 |
Visibility Limit |
vislimit |
b |
See below |
247-253 |
7 |
Horiz. Visibility |
visibility |
U1 |
0.0-12.6nm, units = nm*0.1, 127 = N/A (default). |
254-260 |
7 |
Relative Humidity |
humidity |
u |
0-100%: units of 1%, 127 = N/A (default). |
261-267 |
7 |
Average Wind Speed |
wspeed |
u |
10-min avg wind speed knots, 127 = N/A (default). |
268-276 |
9 |
Wind Direction |
wdir |
u |
0-359, deg. fom true north, 360 = N/A (default). |
277-285 |
9 |
Air Pressure |
pressure |
u |
800-1200hPa: units 1hPa, 402 = pressure >= 1201 hPa, 403 - N/A (default), else add 400 to value, |
286-289 |
4 |
Pressure Tendency |
pressuretend |
u |
WMO FM13 code |
290-300 |
11 |
Air Temperature |
airtemp |
I1 |
Dry bulb temp: units 0.1C, -60.0 to +60.0, -1024 = N/A (default). |
301-310 |
10 |
Water Temperature |
watertemp |
I1 |
-10.0 to 50.0 in 0.1 C, 601 = N/A (default), else -10C after scaling. |
311-316 |
6 |
Wave period |
waveperiod |
u |
Seconds: 0-60, 63 = N/A (default). |
317-324 |
8 |
Wave height |
waveheight |
U1 |
0-25m in units of 0.1m, 255 = N/A (default). |
325-333 |
9 |
Wave direction |
wavedir |
u |
0-359: deg. fom true north, 360 = N/A (default). |
334-341 |
8 |
Swell height |
swellheight |
U1 |
0-25m: units 0.1m, 255 = N/A (default) |
342-350 |
9 |
Swell direction |
swelldir |
u |
0-359: deg, fom true north, 360 = N/A (default). |
351-356 |
6 |
Swell period |
swellperiod |
u |
Seconds: 0-60, 63 = N/A (default). |
357-359 |
3 |
Spare |
x |
Not used |
The vislimit bit, when on, indicates that the maximum range of the visibility equipment was reached and the visibility reading shall be regarded as > x.x NM.
The standard ([IMO289]) does not list the WMO FM13 codes. The following table applies:
| Code | Precipitation Type |
|---|---|
0 |
Clear (no clouds at any level) |
1 |
Cloudy |
2 |
Rain |
3 |
Fog |
4 |
Snow |
5 |
Typhoon/hurricane |
6 |
Monsoon |
7 |
Thunderstorm |
8 |
N/A (default) |
9-15 |
Reserved for future use |
| 0-5 | 6 | Message Type | type | u | Constant: 8 |
|---|---|---|---|---|---|
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-49 |
10 |
DAC |
dac |
u |
DAC = 001 |
50-55 |
6 |
FID |
fid |
u |
FID = 21 |
56-56 |
1 |
Variant |
wmo |
u |
Constant: 1 in this variant |
57-72 |
16 |
Longitude |
lon |
I3 |
Unsigned: minutes * 0.01, E positive, W negative, Lon = (value / 100) – 180, 65536 = N/A (default). |
73-87 |
15 |
Latitude |
lat |
I3 |
Unsigned: minutes * 0.01, N positive, S negative, Lat = (value / 100) – 90, 32767 = N/A (default). |
88-91 |
4 |
UTC Month |
month |
u |
1-12, 15=N/A (default) |
92-97 |
6 |
UTC Day |
day |
u |
1-31, 63=N/A (default) |
98-102 |
5 |
UTC hour |
hour |
u |
0-23, 31=N/A (default) |
103-105 |
3 |
UTC minute |
minute |
u |
0-50, 7=N/A (default), Minute = (value * 10). |
106-112 |
7 |
Course Over Ground |
course |
u |
0-359, unit = 1 degree, average over last 10 minutes. |
113-117 |
5 |
Speed Over Ground |
speed |
U1 |
0-14.5m/s: SOG = (value * 0.5) for 0-29, 30 = 15 m/s and more, average over last 10 minutes. 31 = N/A (default) |
118-124 |
7 |
Heading of the ship |
heading |
u |
5-360: units of 5 degrees, HDT = (value * 5) for 1-72, average over last 10 minutes. 127 = N/A (default) |
125-135 |
11 |
Pressure at sea level |
pressure |
U1 |
90-1100 hPa: P = (value/10)+900 for 0-2000 |
136-145 |
10 |
Pressure Change |
pdelta |
U1 |
-50-+50hPa: units of 0.1hPa, d = (value/10)-50 for 0-100, averaged over last 3 hours. 1023 = N/A (default) |
146-149 |
4 |
Pressure Tendency |
ptend |
u |
WMO BUFR table 010063: Averaged over last 3 hours, 0-8, 15 = N/A. |
150-156 |
7 |
True Wind Direction |
twinddir |
u |
005-360: deg: average over last 10 minutes, dir = (value*5), value 1-72, 0 = calm, 127 = N/A (default). |
157-164 |
8 |
True Wind Speed |
twindspeed |
u |
0-127 m/s: average over last 10 mins, speed = value * 0.5, 255 = N/A (default). |
165-171 |
7 |
Relative Wind Direction |
rwinddir |
u |
005-360 deg: average over last 10 mins, dir = (value*5) for 1-72, 0 = calm, 127 = N/A (default). |
172-179 |
8 |
Relative Wind Speed |
rwindspeed |
U1 |
0-127 m/s: average over last 10 mins, speed = val*0.5 for 0-254, 255 = N/A (default). |
180-187 |
8 |
Maximum Gust Speed |
mgustspeed |
U1 |
0-127 m/s: speed = val*0.5 for 0-254, 255 = N/A (default), |
188-194 |
7 |
Maximum Gust Direction |
mgustdir |
u |
05-360 deg: dir = (value*5) for 1-72, 0 = calm, 127 = N/A (default). |
195-204 |
10 |
Air Temperature |
airtemp |
U1 |
Dry bulb temp: units 0.1C, 223-323K (c.-50C - +50C). T = (val/10)+223 for 0-1000, 1023 = N/A (default). |
205-211 |
7 |
Relative Humidity |
humidity |
u |
0-100%: units of 1%, 127 = N/A (default). |
212-220 |
9 |
Sea Surface Temperature |
surftemp |
U1 |
268-318K (c.-5C - +45C): T = (val/10)+268 for 0-500, 511 = N/A (default). |
221-226 |
6 |
Horiz. Visibility |
visibility |
U2 |
0-50000m, Vis = (val**2)*13.073 for 0-62, 63 = N/A (default). |
227-235 |
9 |
Present Weather |
weather |
u |
BUFR table 020003: Codes 0-510, 511 = N/A (default). |
236-240 |
5 |
Past Weather 1 |
pweather1 |
u |
BUFR table 020005: Codes 0-30, 31 = N/A (default). |
241-245 |
5 |
Past Weather 2 |
pweather2 |
u |
BUFR table 020004: Codes 0-30, 31 = N/A (default). |
246-249 |
4 |
Total Cloud Cover |
totalcloud |
u |
0-100%: Cover = val * 10% for 0-10, 15 = N/A (default.) |
250-253 |
4 |
Cloud amount (low) |
lowclouda |
u |
0-14: BUFR table 020011: 15 = N/A (default). |
254-259 |
6 |
Cloud type (low) |
lowcloudt |
u |
0-62: BUFR table 020012: 63 = N/A (default). |
260-265 |
6 |
Cloud type (middle) |
midcloudt |
u |
0-62: BUFR table 020012: 63 = N/A (default). |
266-271 |
6 |
Cloud type (high) |
highcloudt |
u |
0-62: BUFR table 020012: 63 = N/A (default). |
272-278 |
7 |
Height of cloud base |
cloudbase |
U2 |
0-2500m: h = (value*2).0.16 for 0-125, 126 = more than 2500m, 127 = N/A (default). |
279-283 |
5 |
Period of Wind Waves |
wwperiod |
u |
0-30s: 31 = N/A (default). |
284-289 |
6 |
Height of Wind Waves |
wwheight |
u |
Height in meters: 0-30, h = (value * 0.5) for 0-60, 63 = N/A (default). |
290-295 |
6 |
First Swell Direction |
swelldir1 |
u |
10-360 deg: dir = (value*10) for 1-36, 0 = calm, 63 = N/A (default). |
296-300 |
5 |
First Swell Period |
swperiod1 |
u |
Period in seconds: 0-30, 31 = N/A (default). |
301-306 |
6 |
First Swell Height |
swheight1 |
U1 |
Height in meters: 0-30, h = (value * 0.5) for 0-60, 63 = N/A (default). |
307-312 |
6 |
Second Swell Direction |
swelldir2 |
u |
10-360 deg: dir = (value*10) for 1-36, 0 = calm, 63 = N/A (default). |
313-317 |
5 |
Second Swell Period |
swperiod2 |
u |
Period in seconds: 0-30, 31 = N/A (default). |
318-323 |
6 |
Second Swell Height |
swheight2 |
U1 |
Height in meters: 0-30, h = (value * 0.5) for 0-60, 63 = N/A (default). |
324-330 |
7 |
Ice deposit (thickness) |
icedeposit |
u |
Thickness: 0-126cm, 127 = N/A (default). |
331-333 |
3 |
Rate of Ice Accretion |
icerate |
u |
0-6: BUFR table 020032: 7 = N/A (default). |
334-336 |
3 |
Cause of Ice Accretion |
icecause |
u |
0-6: BUFR table 020033: 7 = N/A (default). |
337-341 |
5 |
Sea Ice Concentration |
seaice |
u |
0-30: BUFR table 020034: 31 = N/A (default). |
342-345 |
4 |
Amount and Type of Ice |
icetype |
u |
0-14: BUFR table 020035: 15 = N/A (default). |
346-350 |
5 |
Ice Situation |
icestate |
u |
0-30: BUFR table 020036: 31 = N/A (default). |
351-355 |
5 |
Ice Development |
icedevel |
u |
0-30: BUFR table 020037: 31 = N/A (default). |
356-359 |
4 |
Bearing of Ice Edge |
icebearing |
u |
Bearing: 45-360 deg, dir = (value*45) for 1-8, 15 = N/A (default). |
The "minute" entry actually only identifies the end of a 10-minute interval.
In [IMO289], the Latitude formula is given as "Lat = (value / 100) – 9000". This is incorrect; the decrement needs to be 90 for the range to be -90..+90.
Swell directions are arrival directions.
IMO289 Area Notice (broadcast)
This should be used to broadcast time- and location-dependent information about hazards to navigation. For information-lifetime restrictions and usage guidance, refer to [ITU1371].
A message 8 subtype. DAC = 001 FID = 22. 196 to 981 bits. There is a related Message 6 subtype for addressed use.
The message consists of a fixed-length header of 111 bits, followed by 1 to 10 sub-area indications which are fixed-length records 87 bits long. Here is the message header format:
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-49 |
10 |
DAC |
dac |
u |
DAC = 001 |
50-55 |
6 |
FID |
fid |
u |
FID = 22 |
56-65 |
10 |
Message Linkage ID |
linkage |
u |
Unsigned integer |
66-72 |
7 |
Notice Description |
notice |
u |
See table below |
73-76 |
4 |
Month (UTC) |
month |
u |
1-12; 0 = N/A (default) |
77-81 |
5 |
Day (UTC) |
day |
u |
1-31; 0 = N/A (default) |
82-86 |
5 |
Hour (UTC) |
hour |
u |
0-23; 24 = N/A (default) |
87-92 |
6 |
Minute (UTC) |
minute |
u |
0-59; 60 = N/A (default) |
93-110 |
18 |
Duration |
duration |
In minutes, 262143 = N/A (default), 0 = cancel this notice. |
143 |
subarea |
a10 |
Subarea array |
0-2 |
||
2 |
shape |
u |
Subarea shape |
3-86 |
The sub-area indications are as described under the addressed form, message type 6 with DAC = 1 and FID = 23.
IMO289 Extended Ship Static and Voyage Related Data
This message should be used by a ship to report the height over keel.
A message 8 subtype. DAC = 001 FID = 24 in [IMO289]. Fixed length, 360 bits. Replaces a deprecated trial message from [IMO236].
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 8 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in CNB |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-49 |
10 |
DAC |
dac |
u |
DAC = 001 |
50-55 |
6 |
FID |
fid |
u |
FID = 24 |
56-65 |
10 |
Message Linkage ID |
linkage |
u |
Unsigned integer |
66-78 |
13 |
Air Draught |
airdraught |
u |
Unsigned int, in 0.1m 1-81.9 m. 0 = N/A (default) 81.91 = >= 81.91 m |
79-108 |
30 |
Last Port Of Call |
lastport |
t |
5 6-bit chars, UN locode |
109-138 |
30 |
Next Port Of Call |
nextport |
t |
5 6-bit chars, UN locode |
139-168 |
30 |
Second Port Of Call |
secondport |
t |
5 6-bit chars, UN locode |
169-170 |
2 |
AIS Class A |
ais_state |
e |
See "SOLAS Status" |
171-172 |
2 |
Automatic Tracking Aid |
ata_state |
e |
See "SOLAS Status" |
173-174 |
2 |
BNWAS |
bnwas_state |
e |
See "SOLAS Status" |
175-176 |
2 |
ECDIS Back-up |
ecdisb_state |
e |
See "SOLAS Status" |
177-178 |
2 |
Paper Nautical Chart |
chart_state |
e |
See "SOLAS Status" |
179-180 |
2 |
Echo sounder |
sounder_state |
e |
See "SOLAS Status" |
181-182 |
2 |
Electronic plotting aid |
epaid_state |
e |
See "SOLAS Status" |
183-184 |
2 |
Emergency steering gear |
steer_state |
e |
See "SOLAS Status" |
185-186 |
2 |
GNSS |
gnss_state |
e |
See "SOLAS Status" |
187-188 |
2 |
Gyro compass |
gyro_state |
e |
See "SOLAS Status" |
189-190 |
2 |
LRIT |
lrit_state |
e |
See "SOLAS Status" |
191-192 |
2 |
Magnetic compass |
magcomp_state |
e |
See "SOLAS Status" |
193-194 |
2 |
NAVTEX |
navtex_state |
e |
See "SOLAS Status" |
195-196 |
2 |
Radar (ARPA) |
arpa_state |
e |
See "SOLAS Status" |
197-198 |
2 |
Radar (S-band) |
sband_state |
e |
See "SOLAS Status" |
199-200 |
2 |
Radar (X-band) |
xband_state |
e |
See "SOLAS Status" |
201-202 |
2 |
Radio HF |
hfradio_state |
e |
See "SOLAS Status" |
203-204 |
2 |
Radio INMARSAT |
inmarsat_state |
e |
See "SOLAS Status" |
205-206 |
2 |
Radio MF |
mfradio_state |
e |
See "SOLAS Status" |
207-208 |
2 |
Radio VHF |
vhfradio_state |
e |
See "SOLAS Status" |
209-210 |
2 |
Speed Log over ground |
grndlog_state |
e |
See "SOLAS Status" |
211-212 |
2 |
Speed Log through water |
waterlog_state |
e |
See "SOLAS Status" |
213-214 |
2 |
THD |
thd_state |
e |
See "SOLAS Status" |
215-216 |
2 |
Track control system |
tcs_state |
e |
See "SOLAS Status" |
217-218 |
2 |
VDR/S-VDR |
vdr_state |
e |
See "SOLAS Status" |
219-220 |
2 |
Reserved |
x |
Not used |
|
221-224 |
4 |
Ice Class |
iceclass |
e |
See "Ice Class" |
225-242 |
18 |
Shaft Horsepower |
horsepower |
u |
Total ship HP: 1hp units, 262,142 = >= 262,142hp, 262,143 = N/A (default). |
243-254 |
12 |
VHF Working Channel |
vhfchan |
u |
Channel number, 0 = N/A (default). |
255-296 |
42 |
Lloyd’s Ship Type |
lshiptype |
t |
7 six-bit characters |
297-314 |
18 |
Gross Tonnage |
tonnage |
u |
0-262,141, 262,142 = >= 262,142hp, 262,143 = N/A (default). |
315-316 |
2 |
Laden or Ballast |
lading |
e |
0 = N/A (default), 1 = Laden, 2 = Ballast, 3 = Not in use. |
317-318 |
2 |
Heavy Fuel Oil Bunkered |
heavyoil |
e |
0 = N/A (default), 1 = No, 2 = Yes, 3 = Not in use. |
319-320 |
2 |
Light Fuel Oil Bunkered |
lightoil |
e |
0 = N/A (default), 1 = No, 2 = Yes, 3 = Not in use. |
321-322 |
2 |
Diesel Oil Bunkered |
dieseloil |
e |
0 = N/A (default), 1 = No, 2 = Yes, 3 = Not in use. |
323-336 |
14 |
Total Bunker Oil |
totaloil |
u |
0-16381 in tonnes, 16382 = >= 16382 tonnes, 16382 = N/A (default). |
337-349 |
13 |
Number of persons |
persons |
u |
0 = N/A (default), 1-8190, 8191 = >= 8191. |
350-359 |
10 |
Spare |
x |
Not used |
The special value of 81.91 for air draught is probably a drafting error in [IMO289], as the scaled field does not have the precision required to represent it. The actual special value is unknown.
The 2-bit _state fields describe the operational state of various sorts of SOLAS-required navigational equipment. GNSS systems may include GPS, Loran-C, or GLONASS. BNWAS is the Bridge Navigational Watch Alarm System. THD is a Transmitting Heading Device. Paper Nautical Chart state is officially "ECDIS/Paper Nautical Chart" state in [IMO289]. Status codes should be interpreted according to the following table:
| Code | Meaning |
|---|---|
0 |
Not available or requested (default) |
1 |
Equipment operational |
2 |
Equipment not operational |
3 |
No data (equipment may or may not be on board/or its status is unknown) |
| Code | Meaning |
|---|---|
0 |
Not classified |
1 |
IACS PC 1 |
2 |
IACS PC 2 |
3 |
IACS PC 3 |
4 |
IACS PC 4 |
5 |
IACS PC 5 |
6 |
IACS PC 6 / FSICR IA Super / RS Arc5 |
7 |
IACS PC 7 / FSICR IA / RS Arc4 |
8 |
FSICR IB / RS Ice3 |
9 |
FSICR IC / RS Ice2 |
10 |
RS Ice1 |
11-14 |
Reserved for future use |
15 |
Not available = default |
ACS = International Association of Classification Societies
PC = Polar Class. For further details, see IACS Req. 2007 Requirements concerning POLAR CLASS and MSC/Circ.1056 and MEPC/Circ.399 on Guidelines for ships operating in Arctic ice-covered waters.
FSICR = Finnish-Swedish Ice Class Rules. For further details, see Finnish Maritime Administration’s Bulletin No.10/10.12.2008 Ice class regulations 2008 (Finnish-Swedish ice class rules). Note: Authorized classification society equivalents for the Finnish-Swedish Ice Class Rules should also be recognized, as issued in the Finnish Maritime Administration’s Bulletin No.4/2.4.2007 (as amended). Both bulletins can be found at www.fma.fi.
RS = Russian Maritime Register of Shipping. For further details see Rules for the classification and construction of seagoing ships, Edition 2008.
VHF channel number is encoded according to Recommendation ITU-R M.1084.
The lshiptype field uses Lloyd’s Register STATCODE 5 encoding.
IMO289 Environmental
A message 8 subtype. DAC = 001 FID = 26. Variable length: 168-1008 bits.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-5 |
6 |
Message Type |
type |
u |
Constant: 6 |
6-7 |
2 |
Repeat Indicator |
repeat |
u |
As in Common Navigation Block |
8-37 |
30 |
Source MMSI |
mmsi |
u |
9 decimal digits |
38-39 |
2 |
Spare |
x |
Not used |
|
40-49 |
10 |
DAC |
dac |
u |
DAC = 001 |
50-55 |
6 |
FID |
fid |
u |
FID = 26 |
56 |
reports |
a5 |
Sensor records array |
||
0-3 |
4 |
Sensor Report Type |
sensor |
u |
See table below |
4-8 |
5 |
Day (UTC) |
day |
u |
1-31; 0 = N/A (default) |
9-13 |
5 |
Hour (UTC) |
hour |
u |
0-23; 24 = N/A (default) |
14-19 |
6 |
Minute (UTC) |
minute |
u |
0-59; 60 = N/A (default) |
20-26 |
7 |
Site ID |
site |
u |
Binary ID of sensor site |
27-111 |
85 |
Sensor payload |
payload |
d |
Sensor payload data |
The fixed header is followed by 1-5 sensor records, each 112 bits long. The Sensor Report Type is interpreted as follows, and controls the interpretation of the sensor payload data.
| 0 | Site location |
|---|---|
1 |
Station ID |
2 |
Wind |
3 |
Water level |
4 |
Current flow (2D) |
5 |
Current flow (3D) |
6 |
Horizontal current flow |
7 |
Sea state |
8 |
Salinity |
9 |
Weather |
10 |
Air gap/Air draft |
11 |
(reserved for future use) |
Here are the payload types for each variant:
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-27 |
28 |
Longitude |
lon |
I4 |
As in Common Navigation Block |
28-54 |
27 |
Latitude |
lat |
I4 |
As in Common Navigation Block |
55-65 |
11 |
Altitude |
alt |
u |
Sensor altitude above MSL, 0-200 in units of 0.1m, 2001 = 200.1 m or higher, 2002 = N/A (default), 2003-2046 reserved. |
66-69 |
4 |
Sensor owner |
owner |
e |
See "Sensor Owner Codes" |
70-72 |
3 |
Data timeout |
timeout |
e |
See "Data Timeout Codes" |
73-84 |
12 |
Spare |
x |
Not used |
| 0 | Unknown (default) |
|---|---|
1 |
Hydrographic office |
2 |
Inland waterway authority |
3 |
Coastal directorate |
4 |
Meteorological service |
5 |
Port Authority |
6 |
Coast guard |
7-13 |
(reserved for future use) |
14 |
(reserved for regional use) |
| 0 | No time period (default) |
|---|---|
1 |
10 minutes |
2 |
1 hour |
3 |
6 hours |
4 |
12 hours |
5 |
24 hours |
6-7 |
(reserved for future use) |
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0 |
84 |
Name |
name |
t |
14 chars of six-bit ASCII. |
84 |
1 |
Spare |
x |
Not used |
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-6 |
7 |
Average Wind Speed |
wspeed |
u |
10-min avg wind speed, 0-120 in 1-knot units, 121 = 121 knots or greater, 122 = N/A (default), 123-126 = reserved. |
7-13 |
7 |
Wind Gust |
wgust |
u |
10-min max wind speed, 0-120 in 1-knot units, 121 = 121 knots or greater, 122 = N/A (default), 123-126 = reserved. |
14-22 |
9 |
Wind Direction |
wdir |
u |
0-359, degrees fom true north >=360 = N/A (default) |
23-31 |
9 |
Wind Gust Direction |
wgustdir |
u |
0-359, degrees fom true north >=360 = N/A (default) |
32-34 |
3 |
Sensor Description |
sensortype |
e |
See "Sensor Types" |
35-41 |
7 |
Forecast Wind Speed |
fwspeed |
u |
Predicted average wind speed, 0-120 in 1-knot units, 121 = 121 knots or greater, 122 = N/A (default), 123-126 = reserved. |
42-48 |
7 |
Forecast Wind Gust |
fwgust |
u |
Predicted max wind speed, 0-120 in 1-knot units, 121 = 121 knots or greater, 122 = N/A (default), 123-126 = reserved. |
49-57 |
9 |
Forecast Wind Direction |
fwdir |
u |
0-359, degrees fom true north >=360 = N/A (default) |
58-62 |
5 |
Day (UTC) |
day |
u |
1-31; 0 = N/A (default) |
63-67 |
5 |
Hour (UTC) |
hour |
u |
0-23; 24 = N/A (default) |
68-73 |
6 |
Minute (UTC) |
minute |
u |
0-59; 60 = N/A (default) |
74-81 |
8 |
Duration |
duration |
u |
Forecast duration in minutes, 255 = N/A (default), 0 = cancel forecast. |
82-84 |
3 |
Spare |
x |
Not used |
The timestamp group is intended as a valid time of forecast.
| 0 | No data (default) |
|---|---|
1 |
Raw real time |
2 |
Real time with quality control |
3 |
Predicted (based on historical statistics) |
4 |
Forecast (predicted, refined with real-time information) |
5 |
Nowcast (a continuous forecast) |
6 |
(reserved for future use) |
7 |
Sensor not available |
| 0-0 | 1 | Water Level Type | absolute | b | False if relative to reference datum. |
|---|---|---|---|---|---|
1-16 |
16 |
Water Level |
level |
i |
In 0.001 meter steps, -327.67 to 327.67, -32767 = -327.67m or less, 32767 = 327.67m or more, -32768 = N/A (default). |
17-18 |
2 |
Water Level Trend |
leveltrend |
u |
0 = increasing, 1 = decreasing, 2 = steady, 3 = N/A (default). |
19-23 |
5 |
Vertical Reference Datum |
datum |
u |
See table below |
24-26 |
3 |
Sensor Description |
sensortype |
e |
See "Sensor Types" |
27-27 |
1 |
Forecast Water Level Type |
absolute |
b |
False if relative to reference datum. |
28-43 |
16 |
Forecast Water Level |
level |
i |
In 0.001 meter steps, -327.67 to 327.67, -32767 = -327.67m or less, 32767 = 327.67m or more, -32768 = N/A (default). |
44-48 |
5 |
Day (UTC) |
day |
u |
1-31; 0 = N/A (default) |
49-53 |
5 |
Hour (UTC) |
hour |
u |
0-23; 24 = N/A (default) |
54-59 |
6 |
Minute (UTC) |
minute |
u |
0-59; 60 = N/A (default) |
60-67 |
8 |
Duration |
duration |
u |
Forecast duration in minutes, 255 = N/A (default), 0 = cancel forecast. |
68-84 |
17 |
Spare |
x |
Not used |
IMO289 says water level is in 0.1m steps, but this is incompatible with the two digits of precision in the range.
The timestamp group is intended as a valid time of forecast.
| 0 | Mean Lower Low Water (MLLW) |
|---|---|
1 |
International Great Lakes Datum (IGLD-85) |
2 |
Local river datum |
3 |
Station Datum (STND) |
4 |
Mean Higher High Water (MHHW) |
5 |
Mean High Water (MHW) |
6 |
Mean Sea Level (MSL) |
7 |
Mean Low Water (MLW) |
8 |
National Geodetic Vertical Datum (NGVD-29) |
9 |
North American Vertical Datum (NAVD-88) |
10 |
World Geodetic System (WGS-84) |
11 |
Lowest Astronomical Tide (LAT) |
12 |
pool |
13 |
gauge |
14 |
Unknown/not available (default) |
15-30 |
Reserved for future use |
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-7 |
8 |
Current Speed #1 |
cspeed1 |
U1 |
0.0-24.5 knots: units 0.1 knots, 246 = speed >= 24.6 knots, 247 = N/A (default), 248-255 (reserved). |
8-16 |
9 |
Current Direction #1 |
cdir1 |
u |
0-359: deg from true north, >=360 = N/A (default). |
17-25 |
9 |
Measurement Depth #1 |
cdepth1 |
u |
0-360m down: units 1m, 361 = 361m or greater, 362 = N/A (default), 363-511 (reserved). |
26-33 |
8 |
Current Speed #2 |
cspeed2 |
U1 |
0.0-24.5 knots, units 0.1 knots, 246 = speed >= 24.6 knots, 247 = N/A (default), 248-255 (reserved). |
34-42 |
9 |
Current Direction #2 |
cdir2 |
u |
0-359: deg. fom true north, >=360 = N/A (default) |
43-51 |
9 |
Measurement Depth #2 |
cdepth2 |
u |
0-360m down: units 1m, 361 = 361m or greater, 362 = N/A (default), 363-511 (reserved). |
52-59 |
8 |
Current Speed #3 |
cspeed3 |
U1 |
0.0-24.5 knots: units 0.1 knots, 246 = speed >= 24.6 knots, 247 = N/A (default), 248-255 (reserved). |
60-68 |
9 |
Current Direction #3 |
cdir3 |
u |
0-359: degrees fom true north, >=360 = N/A (default). |
69-77 |
9 |
Measurement Depth #3 |
cdepth3 |
u |
0-360m down: units 1m, 361 = 361m or greater, 362 = N/A (default), 363-511 (reserved). |
78-80 |
3 |
Sensor Description |
sensortype |
e |
See "Sensor Types" |
81-84 |
4 |
Spare |
x |
Not used |
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-7 |
8 |
Current Vector component North (u) #1 |
cnorth1 |
U1 |
0.0-24.5 knots: units 0.1 knots, 246 = speed >= 24.6 knots, 247 = N/A (default), 248-255 (reserved). |
8-15 |
8 |
Current Vector component East (v) #1 |
ceast1 |
U1 |
0.0-24.5 knots: units 0.1 knots, 246 = speed >= 24.6 knots, 247 = N/A (default), 248-255 (reserved). |
16-23 |
8 |
Current Vector component Up (z) #1 |
cup1 |
U1 |
0.0-24.5 knots: units 0.1 knots, 246 = speed >= 24.6 knots, 247 = N/A (default), 248-255 (reserved). |
24-32 |
9 |
Measurement Depth #1 |
cdepth1 |
u |
0-360m down: units 1m, 361 = 361m or greater, 362 = N/A (default), 363-511 (reserved). |
33-40 |
8 |
Current Vector component North (u) #2 |
cnorth2 |
U1 |
0.0-24.5 knots: units 0.1 knots, 246 = speed >= 24.6 knots, 247 = N/A (default), 248-255 (reserved). |
41-48 |
8 |
Current Vector component East (v) #2 |
ceast2 |
U1 |
0.0-24.5 knots: units 0.1 knots, 246 = speed >= 24.6 knots, 247 = N/A (default), 248-255 (reserved). |
49-56 |
8 |
Current Vector component Up (z) #2 |
cup2 |
U1 |
0.0-24.5 knots: units 0.1 knots, 246 = speed >= 24.6 knots, 247 = N/A (default), 248-255 (reserved). |
57-65 |
9 |
Measurement Depth #2 |
cdepth2 |
u |
0-360m down: units 1m, 361 = 361m or greater, 362 = N/A (default), 363-511 (reserved). |
66-68 |
3 |
Sensor Description |
sensortype |
e |
See "Sensor Types" |
69-84 |
16 |
Spare |
x |
Not used |
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-8 |
9 |
Current Bearing #1 |
bearing1 |
u |
0-359: deg from true north, >=360 = N/A (default). |
9-15 |
7 |
Current Distance #1 |
distance1 |
u |
0-120m: 121 = 121m or greater, 122 = N/A (default), 123-127 (reserved). |
16-23 |
8 |
Current Speed #1 |
speed1 |
U1 |
0.0-24.5 knots: units 0.1 knots, 246 = speed >= 24.6 knots, 247 = N/A (default), 248-255 (reserved). |
24-32 |
9 |
Current Direction #1 |
direction1 |
u |
0-359: deg from true north, >=360 = N/A (default). |
33-41 |
9 |
Measurement Depth #1 |
depth1 |
u |
0-360m down: units 1m, 361 = 361m or greater, 362 = N/A (default), 363-511 (reserved). |
42-50 |
9 |
Current Bearing #2 |
bearing1 |
u |
0-359: deg from true north, >=360 = N/A (default). |
51-57 |
7 |
Current Distance #2 |
distance1 |
u |
0-120m: 121 = 121m or greater, 122 = N/A (default), 123-127 (reserved). |
58-65 |
8 |
Current Speed #2 |
speed1 |
U1 |
0.0-24.5 knots: units 0.1 knots, 246 = speed >= 24.6 knots, 247 = N/A (default), 248-255 (reserved). |
66-74 |
9 |
Current Direction #2 |
direction1 |
u |
0-359: deg from true north, >=360 = N/A (default). |
75-83 |
9 |
Measurement Depth #2 |
depth1 |
u |
0-360m down: units 1m, 361 = 361m or greater, 362 = N/A (default), 363-511 (reserved). |
84-84 |
1 |
Spare |
x |
Not used |
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-7 |
8 |
Swell Height |
swheight |
U1 |
Units 0.1m: 0.0-24.5m, 246 = height >= 24,6m, 247 = N/A (default), 248-255 reserved, else h = (value * 0.5). |
8-13 |
6 |
Swell Period |
swperiod |
u |
Period in seconds: 0-60, 61 = N/A (default), 62-63 (reserved). |
14-22 |
9 |
Swell Direction |
swelldir |
u |
0-359 deg: 0-359 true bearing, 360 = N/A (default), 361-511 reserved, |
23-26 |
4 |
Sea State |
seastate |
u |
Beaufort scale: 0-12 >= 13 = N/A (default) |
27-29 |
3 |
Swell Sensor Description |
swelltype |
e |
See "Sensor Types" |
30-39 |
10 |
Water Temperature |
watertemp |
U1 |
-10.0 to 50.0: units 0.1 C, >=601 = N/A (default). 602-1023 reserved, else -10.0m after scaling. |
40-46 |
7 |
Water Temperature Depth |
distance1 |
U1 |
0.0-12.0m: 0.1m units, 121 = 12.1m or greater, 122 = N/A (default), 123-126 (reserved). |
47-49 |
3 |
Depth Sensor Description |
depthtype |
e |
See "Sensor Types" |
50-57 |
8 |
Wave Height |
waveheight |
U1 |
Height 0.0-24.5m: units 0.1m, 246 = height >= 24.6m, 247 N/A (default), 248-255 reserved. |
58-63 |
6 |
Wave Period |
waveperiod |
u |
0-60: units of seconds, 61 = N/A (default), 62-63 reserved. |
64-72 |
9 |
Wave Direction |
wavedir |
u |
0-359: true bearing, 360 = N/A (default), 361-511 reserved. |
73-75 |
3 |
Wave Sensor Description |
wavetype |
e |
See "Sensor Types" |
76-84 |
9 |
Salinity |
salinity |
U1 |
0.0-50.0%: units of 0.1% 501 = salinity >= 50.1% 502 = data N/A (default) 503 - sensor N/A, 504-511 reserved. |
The standard does not fix the meaning of a water temperature depth of 127.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-9 |
10 |
Water Temperature |
watertemp |
U1 |
-10.0 to 50.0: units 0.1 C, >=601 = N/A (default). 602-1023 reserved, else -10.0m after scaling. |
10-19 |
10 |
Conductivity |
conductivity |
U1 |
In Siemens/m, 0.0-7.0, 0.1 S/m steps, 701 = not less than 7.01, 702 = data N/A, 703 = sensor N/A (default), 704-1023 (reserved). |
20-35 |
16 |
Water Pressure |
pressure |
U1 |
Water pressure: 0.0-6000.0, 0.1 decibar steps, 60001 = pressure >= 6000.1, 60002 = data N/A, 60003 = sensor N/A (default), 60004-65536 reserved. |
36-44 |
9 |
Salinity |
salinity |
U1 |
0.0-50.0%: units of 0.1% 501 = salinity >= 50.1% 502 = data N/A (default) 503 - sensor N/A, 504-511 reserved. |
45-46 |
2 |
Salinity Type |
salinitytype |
e |
0 = measured, 1 = calculated using PSS-78, 2 = calclated using other method, 3 = reserved. |
47-49 |
3 |
Sensor Description |
sensortype |
e |
See "Sensor Types" |
50-84 |
35 |
Spare |
x |
Not used |
No default is specified for salinity type.
| Field | Len | Description | Member | T | Units |
|---|---|---|---|---|---|
0-10 |
11 |
Air Temperature |
temperature |
i |
Dry bulb temp: 0.1 deg C -60.0 to +60.0, -1024 = data N/A (default), 601-1023 reserved. |
11-13 |
3 |
Temp. Sensor Type |
sensortype |
e |
See "Sensor Types" |
14-15 |
2 |
Precipitation Type |
preciptype |
e |
0 = rain, 1 = rain and snow, 2 = rain and snow, 3 = other. |
16-23 |
8 |
Horiz. Visibility |
visibility |
U1 |
Units of 0.1 nautical miles, 0.0-24.0, 241 = visibility >= 24.1nm, 242 = data N/A, 243 = sensor N/A (default), 244-255 reserved. |
24-33 |
10 |
Dew Point |
dewpoint |
i |
-20.0 to +50.0: 0.1 deg C, 501 = N/A (default), 502-511 rsserved, -511—201 rsserved. |
34-36 |
3 |
Dewpoint Sensor Type |
dewtype |
e |
See "Sensor Types". |
37-45 |
9 |
Air Pressure |
pressure |
u |
0 = pressure ⇐ 800hpA, 1-401 = 800-1200hPa, 402 = pressure >= 1201 hPa, 403 - data N/A (default), 404-511 reserved. |
46-47 |
2 |
Pressure Tendency |
pressuretend |
e |
0 = steady, 1 = decreasing, 2 = increasing, 3 - N/A (default). |
48-50 |
3 |
Pressure Sensor Type |
pressuretype |
e |
See "Sensor Types" |
51-59 |
9 |
Salinity |