Water Level Message

Registrant: 
Saint Lawrence Seaway Development Corporation
Message number: 
6
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.
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