Hallo Christian und willkommen im Forum,
as far as I remember the BAUD rate with which the HBs send is 4800. I don't know if that is sufficient to be used as an autopilot input data.
Concerning your GPS update rate on the 1197:
Which GPS receiver do you use and what software is on your unit?
If you have the AS-GR 16 receiver, change to a AS-GR50 or even better an AS-GRHA (if you still can find one).
The GPS update rate was enhanced with the last updates that came out.
Concerning the "faster" input source:
Are you planning to use a "tuned up" GPS mouse for that? I was also thinking to give this a try, but decided against it, because I'm not sure if that would be save for the unit.
Regards to Bavaria
Harry