IALA

Water Level Message

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 = 3 (00 0011 in binary)
 Binary Data  Max 864  From 1 up to 4 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)

 

 

 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)
 Water Level Type 1 0 or 1; 0 = Relative to reference datum , 1 = Water Depth ,
Note: Always 0 for Saint Lawrence Seaway
Water Level 16 Water level in centimeters -327.67 to +327.67 meters,
-32767 = -327.67 m or less, +32767 = +327.67 m or greater
-32768 = not available
Reference Datum 2 Defines datum used
0 = MLLW
1 = IGLD-85
2,3 = reserved for future use
Note: Always 1 for Saint Lawrence Seaway
 Reserved 14  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

 

 

Water Level Report