Airmar LB150 - Manual (Page 8)

LB150 WeatherStation Technical Manual revision 0.013
Proprietary and Confidential
PRELIMINARY - DRAFT 5
NMEA 0183 TRANSMITTED SENTENCE
$GP
DTM
Summary
NMEA 0183 standard Datum Reference.
Syntax
$GPDTM,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>*hh<CR><LF>
Fields
<1> Three character alphabetical code for local datum:
W84 (WGS84)
W72 (WGS72)
S85 (SGS85)
P90 (PE90)
or IHO datum code from the International Hydrographic
Organization Publication S-60 Appendices B and C.
<2> One character subdivision datum code when available, as defined in
IHO Publication S-60 Appendices B and C.
<3> Latitude offset, to the nearest .0001 minute
<4> N if field <3> is North Latitude
S if field <3> is South Latitude
<5> Longitude offset, to the nearest .0001 minute
<6> E if field <5> is East Longitude
W if field <5> is West Longitude
<7> Signed altitude offset, to the nearest meter
<8> 3-character reference datum code:
W84 = WGS-84
Default State
Disabled. Transmitted once per second when enabled.
Notes
This sentence may be enabled or disabled via the $PAMTC,EN,DTM command.
Latitude and longitude offsets are positive numbers; the altitude offset may be
negative. Offsets change with position; position in the local datum is offset from
the position in the reference datum in the directions indicated:
P
local datum
= P
ref datum
+ offset