A78 - possible GPS issues

[Chuck - Raymarine - Moderator]

silverbullet87,

Again, don't confuse COG with Heading ... these are different data items within your system. The COG data item will be populated with data from a GPS sensor and Heading data item will be populated with data from a magnetic north seeking compass or gyro compass. The S1000 requires GPS data from an external source. In the case of your vessel, it S1000 was likely getting GPS data from the a78 MFD via the SeaTalk to SeaTalkng converter.

[silverbullet87]

Hey Chuck - since the S1000 does not have a magnetic bearing sensor - should my a78 bearing mode be set to COG instead of magnetic bearing?

[Chuck - Raymarine - Moderator]

silverbullet87,

Q. since the S1000 does not have a magnetic bearing sensor - should my a78 bearing mode be set to COG instead of magnetic bearing?
A. Not necessarily and this is not the cause of the reported issue. As many boats have a fluid filled compass onboard, many user's will choose to have bearings reported in the magnetic rather than true reference frame to avoid having to mentally apply local variation to the COG or heading value reported by the system. In this way, the vessel's properly calibrated fluid filled compass, COG, and headng (if available) will all match.