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別添4
St. Lawrence Seaway AIS Data Messaging
Formats and Specifications
Harmonized with U.S. Coast Guard PAWSS
AIS Messages
Revision 4.0A
May 9, 2002
Developed for the:
Saint Lawrence Seaway Development Corporation
Saint Lawrence Seaway Management Corporation
By:
U.S. Department of Transportation
John A. Volpe Transportation systems center
55 Broadway
Cambridge, MA 02142 別添4
Revision History
| Document Version |
Description |
| 1.0 (all versions) |
Internal draft, Not publicly released |
| 2.0 (all versions) |
Internal draft, Not publicly released |
| 3.0 (all versions) |
Initial draft release, Seaway specific messages |
| 4.0 (April 25, 2002) |
Revised all messages to harmonize with USCG PAWSS AIS messages |
| 4.0A (May 9, 2002) |
Corrections:
Page 6, changed text to read "If there is more than six station readings,・・・
Section 7, Page 15, Main table - corrected bit count on table
Section 7.2, Page 16, Example - corrected Function ID in example
Section 8.1 , Page 18, Example - Corrected Function ID in Example
Section 9, Page 19, put the two reserved bits between App ID and Function ID
Section 12, Page 21 , Hydro message - corrected spare bit count from 14 to 16
Section 12. Page 23, Revised Vessel Procession Order Message 2 |
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1 Introduction
1.1 Message Structure
All Saint Lawrence Seaway AIS messages defined in
this specification (except for the safety related text messages in Section 10)
are transmitted as either Broadcast or Addressed Binary messages. The message
data formats defined in the following sections make up the "binary data" parameter
of ITU-R M.1371 messages 6 and 8. A description of the proposed AIS sentence formats
used to interface to the AIS transponder presentation port is found in Annex B
of IEC 61993-2 or IEC PAS 6112-100.
Messages transmitted within the border of the United
States shall have a Designated Area Code (DAC) of 366. A DAC of 316 shall be used
for transmissions that originate within the border of Canada.
Except for the safety related messages, as discussed
in Section 10, the Function Identifier (FI) for all transmitted Seaway messages
shall be:
| Function Message Type |
Function Identifier (FI) |
| Metrological and Hydrological |
1 |
| Vessel/Lock Scheduling |
2 |
| Seaway Specific Messages |
32 |
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Individual message types shall be identified by the
Message ID field following the Application Identifier.
1.2 Broadcast Intervals
Each individual Seaway message has an assigned update
interval established by the Seaway Traffic Management System (TMS). However, the
AIS network may elect to retransmit any messages, system resources permitting,
at more frequent intervals.
1.3 Location Fields
All binary messages include a location field (latitude
and longitude in WGS-84 datum). The position designates the general or specific
area for which the message data is applicable. For example, weather information
messages specify the location of the actual weather sensor used as the data source.
The position field for some message types may define an arbitrary point in the
vicinity of the applicable area. For example, a lockage order message will include
a latitude and longitude near the lock, but not necessary at center of the lock
chamber.
The location fields are intended to provide a reference
point for the data in the messages so that the information may be represented
geographically with appropriate symbology. How this data is represented on electronic
chart display systems is left to the discretion of the developers (at least until
an agreed upon standard is developed for "marine information object" display).
2 Common Message Fields
The following message fields are commonly found in
more than one Seaway messages.
2.1 Application Identifier
| Parameter |
Number of bits |
Description |
| Designated Area Code |
10 |
The Designated Area Code will be 366 for the United States
or 316 for Canada depending on the location of transmitter. Refer to Section 1.1
for description |
| Function Identifier |
6 |
Function Identifier, See Section 1.1 |
| Total number of bits |
16 |
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2.2 UTC Time
| Parameter |
Number of bits |
Description |
| Month |
4 |
Month of year (01 - 12 Month); 0 = not available; 13-15 not
used |
| Day |
5 |
Day of month (01 - 31 Days); 0 = not available |
| Hours |
5 |
UTC Hours (0-23), 24 = not available, 25-31 not used |
| Minutes |
6 |
UTC Minutes (0-59), 60 = not available, 61-63 not used |
| Total number of bits |
20 |
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All time-referenced information, including month,
day and time of sensor reading observations, will be expressed in Coordinated
Universal Time (UTC).
Example: May 29, 12:34AM
| Month |
Day |
Hour |
Minute |
| 0 |
1 |
0 |
1 |
1 |
1 |
1 |
0 |
1 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
0 |
1 |
0 |
| 5 |
29 |
00 |
34 |
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