# GPDBT, GPHDT, GPGGA messages

If the appropriate output boxed is checked, CeruleanTracker emulates a “GPS” mounted on the ROV by outputting $GPDBT, $GPHDT, or $GPGGA messages with the ROV location and other data. $GPDBT and $GPHDT messages are never valid if a DVL is not present.

The $GPDBT numeric fields will be blank if a DVL-75 is not present or is present but not locked.

The $GPHDT fields will be blank if a DVL-75 is not attached.

The $GGA latitude and longitude fields will be blank if there is no lat/long calculated. The fix quality field of $GPGGA will be either ”0” (no fix) or “6” (dead reckoning fix). All other fields of the $GPGGA message are always dummy values.


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