[aatschouten]

I have a PMB 648 GPS module which works fine for GGA,GSV,GSA and RMC messages. But I dont know how to  activate output of VTG and GLL messages. Could you please inform me which commands I have to send to the module ?

Thank you in advance for your reply.

[TheOtherCliff]

I don't know of anyone who has tried to use one of those.  What you ask would probably be a manufacturer documentation thing.

About using NMEA GPS protocol...  The one time I tried a long time ago, there was an AttitudeState oscillation with it sitting still on the ground and I didn't even try to fly it.  There may be an issue with data delay / synchronization issues, or it may be that NMEA does not have real velocity data.

I recommend that NMEA GPS not be considered an issue that a beginner should tackle.  My 2 cents.