Specifications

AIRMAR
®
PB100 WeatherStation Technical Manual revision 1.007
29
2.2.1. Precedence of Data
In a given installation, certain data items might be available from more than one source.
In this circumstance, the following precedence rules apply. The calculation of true wind,
in particular, depends on these precedence rules.
SOG/COG:
$--VTG supersedes $--RMC, which supersedes the WeatherStation's internal GPS. Note
that to be valid, SOG and COG must both be available from the same source.
Magnetic Variation:
$--HDG supersedes $--VTG, which supersedes $--RMC, which supersedes the
WeatherStation internal calculation. The internal calculation determines magnetic
variation using the present position and the date: these data provided from an external
GPS will supersede the data from the internal GPS.
Heading and Deviation:
$--HDG supersedes the internal compass. (Note: if heading is supplied in a received
$--VHW sentence, it is ignored.)