Baseline YAW with 2 HERE4 problems

Hello, because i have big VTOL with big motors, i have many EM Electromagnetic interferences and make crazy magnetometer and compass i need to set baseline yaw.

we try many many times and read manuals, documents, forum but still not work
i have RTK FLOAT in one GPS and second 3dgps with always this error: **GPS[2] yaw not available
**
we have try reverse NODE ID or POSITION or BASE AND ROVER but still not work
after one week of try and many engineers

Arduplane 4.6.3
HERE last firmware 1.15.7