You need the "Pro" or some other upgrade to enable GPS. From there I think it only uses serial ports. In another thread I wrote a n810 internal TO bluetooth program (it is in the source archive for minigpsd, but I may have removed it from the binary - n810asgps.sh). If you have GEPro under windows, I think it is HRT that has a "virtual serial port" that could take the data stream (22947 is the raw bidirectional port) to COMx under windows where I think GEPro would see it.

You can adjust the update rate using the Properties for the link (and the various fly-to speeds in the global settings). If you set it to 1/sec and get the height/angle right it should be less jerky.

I think it is by default set to slowly rise to the clouds and descend to the next point and that can take 4 seconds.