SXBlue GPS Reference Manual
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The SXBlue GPS will reply with the following response:
$>
8.2.4 $JALT
This command turns altitude aiding on or off for the SXBlue GPS. When set to on,
altitude aiding uses a fixed altitude instead of using one satellite’s observations to
calculate the altitude. The advantage of this feature, when operating in an application
where a fixed altitude is acceptable, is that the extra satellite’s observations can be used
to betterment of the latitude, longitude, and time offset calculations, resulting in improved
accuracy and integrity. Marine markets, for example, may be well suited for use of this
feature.
This command has the following layout:
$JALT,c,v[,GEOID] <CR><LF>
Where feature status variable, ‘c’, and threshold variable, ‘v’, may be one of the
following:
c
Description
NEVER
This is the default mode of operation where
altitude aiding is not used.
SOMETIMES
Setting this feature to SOMETIMES allows
the receiver to use altitude aiding,
dependent upon the PDOP threshold,
specified by ‘v’
ALWAYS
Setting this feature to ALWAYS allow the
receiver to use altitude aiding regardless of
a variable. In this case, you may specify
the ellipsoidal altitude, ‘v’ that the receiver
should use. Optionally, if you specify the
‘,GEOID’ field, the receiver will use the
GEOID as its reference.
The SXBlue GPS will reply with the following response:
$>
8.2.5 $JLIMIT
This command is used to change the threshold of estimated horizontal performance for
which the DGPS position LED is illuminated. The default value for this parameter is a
conservative 10.0 meters. This command has the following format:
$JLIMIT,limit<CR><LF>
Where ‘Limit‘ is the new limit in meters.
The receiver will respond with the following message:
$>
