Optical flow and GPS simultaneously

Hello,

    Does anyone know how to make sure that both GPS and optical flow are working simultaneously, with special care to optical flow? I have searched deeply about it on "all" ardupilot guides and I don´t know to make it work. I tried the following and it fails:
  • EK2_ENABLE = 1
  • EKF_ENABLE = 0
  • EK2_IMU_MASK = 3
  • EK2_FLOW_GATE = 1000 (maximum, so it works even with bad signal)
  • EK2_POS_GATE = 100 (minimum)