IALA

Wind Information Message

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.
Refer to Section 1.1 for description
Function Identifier 6 FI=1
 Reserved 2
 Message ID 6  Message Identifier = 2 (00 0010 in binary)
 Binary Data  Max 864  From 1 up to 6 wind information reports, each structured as defined in next table.
 Total Number of bits  Max 888  = 24 + N*144
 N Total Bits  (Slots Required)
 1 168 bits  (2 slots)
 2 312 bits  (2 slots)
 3 456 bits  (3 slots)
 4 600 bits  (4 slots)
 5 744 bits  (4 slots)
 6 888 bits  (5 slots)

Wind Information 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

 Reserved 4  Reserved for future use
 Total Number of bits 144

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

 

Wind Direction Quantization

 Direction Value    Description
0  N
23  NNE
45  NE
68  ENE
90  E
113  ESE
135  SE
158  SSE
180  S
203  SSW
225  SW
248  WSW
270  W
293  WNW
315  NW
338  NNW