I am trying to get high-quality attitude data to train some neural networks.
Most RKT report yaw (and sometimes pitch/roll) accuracies of around 0.1-0.2 degree with proper antenna separation. Taking into account that this will be fused in EKF with IMU/Mag sensors and also taking into account that attitude estimation in PX4 benefits from velocity updates - which are accurate in RTK - wouldn’t we reach much higher accuracy? 
@bresch This may interest you.