Mounting Page
23
Document id: 7000 108-011 A2
Choosing values for A, B, C and D
The R4-AIS Shipborne Class A Transponder System stores one
”external reference point” for the external (D)GNSS’ antenna
positions and one ”internal reference point” for the internal AIS
GPS, which is used as fallback for position reporting.
The locations of these reference points have to be set using values
A, B, C and D, see definition in Figure 5.
Ship’s dimensions, i.e. overall length and width of the ship, are
given automatically by the values A, B, C, and D. Note that ship’s
dimensions (A+B and C+D) must be identical when entering
external and internal reference points.
Reference
point
A
B
D
C
Distance
(m)
A
0 - 511
B
0 - 511
C
0 - 63;
63 = 63 m or greater
D
0 - 63;
63 = 63 m or greater
The dimension A should be in the direction of
the transmitted heading information (bow).
Reference point of reported position not
available, but dimensions of ship are available:
A = C = 0 and B
≠
0 and D
≠
0.
Neither reference point of reported position
nor dimensions of ship available:
A = B = C = D = 0 (=default)
Figure 5 Reference point
Note: If the GNSS antenna is installed in the portside corner of a
rectangular bow, one of the values A or C should be set to 1.
