IALA

Advice of waypoints (AWP) and/or route plan of VTS

ntroduction/Additional information:

This IFM should be used by a VTS to advise its waypoints and/or its route plan. If the VTS uses this IFM 18 within an addressed binary message, then the waypoints and/or the route plan will be available to the addressed recipient, one ship, only. If the VTS uses this IFM 18 within a broadcast binary message, then the information will be available to all other ships in the VTS’s vicinity.

When transmitting, the VTS should include up to 12 advised waypoints and/or a route specified by a textual description, if available. If waypoints are transmitted, then a recommended turning radius may be transmitted for each waypoint.

Details:

 

Number of bits Description
AWP 4 Number of advised waypoints (1-12);  0 = no waypoint = default; 12-15 = not used
WP i.Lon 28 Longitude of advised waypoint i in 1/10 000 min (±180°, East = positive, West = negative). Field required if and as often as  1 ≤ i ≤ AWP, i = 1, 2, 3, …, 12; field not required if AWP = 0
WP i.Lat 27 Latitude of advised waypoint i in 1/10 000 min (±90°, North = positive, South = negative). Field required if and as often as 1 ≤ i ≤ AWP, i = 1, 2, 3, …, 12; field not required if AWP = 0
Advised turning radius i 12 Advised turning radius at advised waypoint i in metres; 0 = not available = default; 1-4 095 m. Field required if and as often as 1 ≤ i ≤ AWP, i = 1, 2, 3, …, 12; field not required if AWP = 0
Advised route specified by textual description 120 Description of the advised route in textual form, e.g. —west channel“; maximum 20 characters using 6-bit ASCII; @@@@@@@@@@@@@@@@@@@@ = not available (field must not be omitted)
Spare AWP Bits Spare. Not used. Should be set to zero
0, 8 4
1, 9 1
2, 10 6
3, 11 3
4, 12 0
5 5
6 2
7 7
Number of bits 128-928 The number of bits of the IFM 17 may be calculated as follows: 124 + (AWP × 67) + spare

 

 Number of next waypoints   transmitted 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
 Number of slots used for this   message 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5