Weather Station Message

Permitted as from:

09/03/2002

Registrant:

Saint Lawrence Seaway Development Corporation

Physical link:

AIS

Message number (0=VDES-VDE):

DAC or VPFI:

316

FI / Message ID:

Sub:

Technical point of contact:

U.S. Department of Transportation
John A. Volpe
Transportation Systems Center
55 Broadway
Cambridge, MA 02142

State:

in force

Number of slots (max):

Last modified:

29/01/2021 - 23:18

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.

Used by:

Saint Lawrence Seaway Development Corporation

Area link:

St. Lawrence River sector [1]

Welland Canal sector [2]

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