User's Manual

95
A.5.13 HDG – Heading, Deviation and Variation
Heading (magnetic sensor reading), which if corrected for deviation will produce magnetic
heading, which if offset by variation will provide true heading.
$--HDG, x.x, x.x, a, x.x, a*hh<CR><LF>
Field No.
Format
Description
Remark
1
x.x
Magnetic sensor heading, degrees
2
x.x,a
Magnetic deviation, degrees E/W
3
x.x,a
Magnetic variation,degrees E/W
A.5.14 HDT – Heading True
Actual vessel heading in degrees true produced by any device or system producing true
heading.
$--HDT, x.x, T*hh<CR><LF>
Field No.
Format
Description
Remark
1
x.x, T
Heading, degrees true
A.5.15 LRF – AIS Long-Range Function
This sentence is used in both long-range interrogation requests and long-range interrogation replies.
The LRF-sentence is the second sentence of the long-range interrogation request pair, LRI and LRF
(see the LRI-sentence).
$--LRF,x,xxxxxxxxx,c—c,c—c,c—c*hh<CR><LF>
Field No.
Format
Description
Remark
1
x
Sequence number
2
xxxxxxxxx
MMSI of requestor
3
c—c
Name of requestor
4
c—c
Function request
5
c—c
Function reply status
A.5.16 LRI – AIS Long-Range Interrogation
The long-range interrogation of the AIS unit is accomplished through the use of two sentences. The
pair of interrogation sentence formatters, a LRI sentence followed by a LRF sentence, provides the
information needed by a universal AIS unit to determine if it should construct and provide the reply
sentences (LRF, LR1, LR2, and LR3).
$--LRI,x,a,xxxxxxxxx,xxxxxxxxx,llll.ll,a,yyyyy.yy,a,llll.ll,a,yyyyy.yy,a*hh<CR><LF>
Field No.
Format
Description
Remark
1
x
Sequence number
2
a
Control flag
3
xxxxxxxxx
MMSI of requestor
4
xxxxxxxxx
MMSI of destination
5
llll.ll,a
Latitude – N/S
6
yyyyy.yy,a
Longitude – E/W
7
llll.ll,a
Latitude – N/S