Since version 2.0.0:

GpsFix, NavSatFix, Odometry positions are generated from position information reported by a combination of the most recent OEM7 BESTPOS/BESTVEL and INSVPAS messages:

• BESTPOS: https://docs.novatel.com/OEM7/Content/Logs/BESTPOS.htm

• BESTVEL: https://docs.novatel.com/OEM7/Content/Logs/BESTVEL.htm

• INSPVAS: https://docs.novatel.com/OEM7/Content/SPAN_Logs/INSPVAS.htm

3D position quality is used to determine whether BESTPOS/BESTVEL or INSPVA are used. By default, INSPVAS is reported at a higher rate than BESTPOS/BESTVEL; so INSPVAS is used to generate GpsFix/NavSatFix.

It is possible to override this behavior by setting the '/novatel/oem7/receivers/main/position_source' parameter to:

• "BESTPOS": always use BESTPOS/BESTVEL as position source, regardless of availability of of more recent position.
• "INSPVAS": always use INPSVAS as position source, regardless of 3D quality.

When 'position_source' is not specified, the most recent message with the highest quality is used. This is the default configuration.

When using INS (INSPVAS) as position source, the driver accounts for undulation automatically. SPAN lever arm must be configured correctly by the user to obtain correct position/orientation.