Account menu

Satellite Ship Weather Small

Introduction/Additional information: 

The Satellite Ship Weather Small message is intended to be used to transmit weather observations over ship that will be received by Satellite AIS receivers. The difference between this message and the DAC 1 FI 21 Ship Weather report is that this message has been reduced in size to provide increased probability of detection via satellite. Similar to the rationale for the AIS message 27, this message is less than a single slot.

All directions are relative to True North, all positions are WGS-84 Datum.

For this message, the data is assumed to be from transmitting MMSI, and is a ship station. The sensor owner is the source of the data, as indicated by the MMSI. The data is assumed to be raw real time data with a validity interval of 6 hours.

Permitted as from: 
01/10/2019
Registrant: 
USACE
Physical link: 
AIS
Message number (0=VDES-VDE): 
8
DAC or VPFI: 
367
FI / Message ID: 
24
Version: 
0
Technical point of contact: 

Dr. Gregory Johnson

State: 
draft
State link: 
Weather observation report from ship
Number of slots (max): 
1
Last modified: 
02/03/2021 - 13:57
Reporting Rate: 

For the current testing a reporting interval of 3 min has been used.

Used by: 
USACE
MARAD
NOAA
Details: 

Parameter

# of bits

Description

Standard Message Header

Message ID

6

Identifier for Message 8; always 8.

Repeat Indicator

2

Used by the repeater to indicate how many times a message has been repeated. (See ITU-R M.1371-3, Annex 2, § 4.6.1).

0 – 3; 0 = default; 3 = do not repeat any more. Set to 0 (default).

Source MMSI

30

MMSI number of source station. This varies according to the transmitter ID.

Spare

2

Not to be used. Set to zero.

Binary Data

Designated Area Code

10

Designated area code (DAC). (See Rec. ITU-R M.1371-3 § 2.1, Annex 5). Set to 367 (US).

Function Identifier

6

Function identifier. Set to 24.

 

Version

3

Sequential number used to indicate the message version in steps of 1.

0 = test message = default; 1 – 7 = message version.

Set to 0.

UTC hour

5

UTC hour of the time of the data.

0 – 23; 24 = UTC hour not available = default;
25 - 31 (reserved for future use).

UTC minute

6

UTC minute of the time of the data.

0 – 59; 60 = UTC minute not available = default;
61 - 63 (reserved for future use).

Longitude

25

Longitude of the center in 1/1,000 minute (±180°) in WGS-84 datum.
East = positive, West = negative (as per 2’s complement);

181° = not available = default.

Latitude

24

Latitude of the center in 1/1,000 minute (±90°) in WGS-84 datum.
North = positive, South = negative (as per 2’s complement);

91° = not available = default.

Air Pressure

9

Air pressure, defined as pressure reduced to sea level, in 1 hPa increments.

0 = pressure <800 hPa; 1 - 401 = 800 – 1200 hPa;
402 = pressure of 1201 hPa or greater;
403  = data unavailable = default;
404-510 = reserved; 511 = not to be used.

Spare

0

Set to zero.

Total bits

128

1 slot message
How portrayed: 

Display on an ECS the same as other weather information; however this message is intended for the transmission of data from ship to shore (via satellite) and then input to the GTS

Attachment: 
PDF icon ssw_small_fi24_release_0-18jan19.pdf