Kakute f4 mini ardupilot4.1.3 GPS problem

ArduCopter
1

good day,

I bought a brand new kakute F4 mini and flashed ardupilot 4.1.3 firmware， everything is ok except GPS. I use BN 880 GPS and connect to uart6， set baudrate to 38400, gps type to nema，also config gps via U center to this baudrate, the compass is good，but gps cannot be found. i changed the gps output to ublox，set gps type to ublox in mission planner， still no good. after i read some some post， I set the parameter GPS_DRV_OPTION=4, still no good. but when I changed GPS_AUTO_CONFIG=1, gps can be found. It seems only set GPS_AUTO_CONFIG=1, gps works.
Even set this，GPS is very difficult get 3D fix， it can float in the.map of mission planner for 5 minutes with no 3d fix， even never fix.

but when I connect BN880 to U center via FDTI， its 3d fix very quickly. so what the process and how ardupilot talk to gps， thats really get.me confused.

thanks for any suggestions.

2

Set your GPS to 115200 baud and set GPS_DRV_OPTIONS to 2.

38400 baud is too slow. If you do a search, you’ll find discussions about adding GPS_DRV_OPTIONS 2 and why it was necessary.

3

I set gps baudrate to 115200， and GPS_DRV_OPTION=2 or 4， it seems no difference. but if I set GPS_AUTO_CONFIG=0，
there is no gps in mission planner. I am still confused. why GPS_AUTO_CONFIG must be set as 1?