Can the GPGGA positions be output with more decimal places?

The GPGGA latitude and longitude fields output data to 4 decimal places.  If you need higher precision than this, you can use the GPGGALONG log which goes to 7 decimal places.  The altitude also has a higher precision (3 decimal places rather than 2) in the GPGGALONG log. 

For more information, see Position Precision of NMEA Logs under the definition of the GPGLL log in the OEMV firmware reference:  http://www.novatel.com/assets/Documents/Manuals/om-20000094.pdf