Hdg Heading, Deviation And Variation; Hdm Heading, Magnetic - Simrad ES70 - REFERENCE MANUAL REV A Reference Manual

Simrad ES70
Format description
1 = talker identifier
– –
2 = telegram identifier.
GLL
3 = latitude north/south, position in degrees, minutes and hundredths.
llll.ll,a
Characters (North) or
N
= longitude east/west, position in degrees, minutes and hundredths.
4
yyyyy.yy,a
Characters (West) or
W
5 = coordinated universal time (UTC) of position.
hhmmss.ss
6 = status, characters
A
7 = mode indicator.
a

HDG Heading, deviation and variation

This telegram contains the heading from a magnetic sensor, which if corrected for
deviation will produce magnetic heading, which if offset by variation will provide true
heading.
Format
$--HDG,x.x,z.z,a,r.r,a*hh<CR><LF>
Heading conversions
• To obtain magnetic heading: Add easterly deviation (E) to magnetic sensor reading,
or subtract westerly deviation (W) from magnetic sensor reading.
• To obtain true heading: Add easterly variation (E) to magnetic heading, or subtract
westerly variation (W) from magnetic heading.
Format description
1 = talker identifier
– –
2 = telegram identifier
HDG
3 = magnetic sensor heading, degrees
x.x
4 = magnetic deviation, degrees east/west
z.z,a
5 = magnetic variation, degrees east/west
r.r,a

HDM Heading, magnetic

This telegram contains vessel heading in degrees magnetic. The telegram is no longer
recommended for use in new designs.
It is often replaced by the
Format
$--HDM,x.x,M*hh<CR><LF>
192
(South) identifies the bearing.
S
(East) identifies the bearing.
E
(data valid) or (data not valid) are used.
A V
telegram.
HDG
338106/A