Weather Station Message
Registrant:
Saint Lawrence Seaway Development Corporation
DAC:
366
FI:
1
State:
in force
Used by:
Saint Lawrence Seaway Development Corporation
Number of slots (max):
5
Reporting Rate:
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.
Permitted as from:
09/03/2002
Technical point of contact:
U.S. Department of Transportation
John A. Volpe
Transportation Systems Center
55 Broadway
Cambridge, MA 02142
Details:
| 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. |
|
| Function Identifier | 6 | FI=1 | |
| Reserved | 2 | ||
| Message ID | 6 | Message Identifier = 1 (00 0001 in binary) | |
| Binary Data | Max 768 | Message contains 1 to 4 weather station reports, each structured defined in next table. | |
| Total Number of bits | Max 792 | = 24 + N*192 | |
| N Total Bits | (Slots Required) | ||
| 1 216 bits | (2 slots) | ||
| 2 408 bits | (3 slots) | ||
| 3 600 bits | (4 slots) | ||
| 4 792 bits | (5 slots) | ||
Weather Station Report
| Parameter | Number of bits | Description |
| Timetag | 20 | Month, Day and Time of measurement, See UTC Time |
| Station ID | 42 | Seven 6-bit ASCII character ID |
| Longitude | 25 | Longitude in 1/1000 minute (±180 degrees, East = positive, West = negative. 181 degrees = not available) |
| Latitude | 24 | Latitude in 1/1000 minute (±90 degrees, North = positive, South = negative. 91 degrees = not available) |
| Wind Speed | 10 | Average Wind Speed in 1/10th Knot (0-102,2 knots, 1022 = 102,2 kts or greater, 1023 = not available) |
| Wind Gust | 10 | Wind Gust in 1/10th Knot (0-102,2 knots, 1022 = 102,2 kts or greater, 1023 = not available) |
| Wind Direction | 9 | Quantized to 16 compass points (Seaway only);Direction, 0-359 degrees, 511 = not available. For Saint Lawrence Seaway, refer to table below for descriptions of quantized values.
See Wind Direction Quantization |
| Atmospheric Pressure |
14 | Expressed in 1/10
th millibars. (16383 = not available) |
| Air Temp | 10 | Temperature in 1/10th of a degree Celsius (signed) (-511 to 511 valid range, -511 = -51.1°C or less, 511 = 51.1°C or greater, -512 = not available) |
| Dew Point | 10 | Temperature in 1/10th of a degree Celsius (signed) (-511 to 511 valid range, -511 = -51.1°C or less, 511 = 51.1°C or greater, -512 = not available) |
| Visibility | 8 | Visibility in 1/10 kilometers. (0-254, 254 = 25.4km or greater, 255 = not available) |
| Water Temp | 10 | Temperature in 1/10th of a degree Celsius (signed) (-511 to 511 valid range, -511 = -51.1°C or less, 511 = 51.1°C or greater, -512 = not available) |
| Total Number of bits | 192 |