Non-Gps Navigation on a plane?

Hi to all! I have a small plane and i want to fly without gps just for educational reasons and to see what will do. I have search in the forum about that but i didn’t get enough info for a plane. My plane is already flying with orange cube+ and here3+ but now i have disconnected the gps.

  1. Is it possible eventually to fly in auto mode or is to risky?

  2. How can i setup the parameters file?
    I have already set:
    AHRS_GPS_USE = 0(DISABLED)
    AHRS_EKF_TYPE = 3(ENABLE EKF3)
    EK2_ENABLE = 0(DISABLED)
    EK3_ENABLE = 1(ENABLED)
    EK3_SRC1_POSXY = 0(NONE)
    EK3_SRC1_POSZ = 1(BARO)
    EK3_SRC1_VELXY = 0(NONE)
    EK3_SRC1_VELZ = 0(NONE)
    EK3_SRC1_YAW = 1(COMPASS)
    GPS_TYPE = 0 (NONE)

    I have already do accel calibration (3-axis)
    I have already do compass calibration
    I have used also a lua script that prints the home location and the origin location
    I am using on Mission Panner: “Set Home Here” and “Set EKF Origin Here” and i can see
    the coordinates from the lua script.

    Despite that i have an error “AHRS: not using configured AHRS type”
    Also i can not see the plane on the map.

Can you please explain what am i doing wrong or some documentation to read?
Thank’s in advance!

Just a small question, maybe you can answer it correct.
You are somewhere on the earth but don’t no where.
You are ordered to go home
How will you exactly do this?
If you don’t can answer this questions, how you think the FC will answer it.
For all auto modes you absolutely need a three dimensional position and orientation information. As long as you only have GPS and no other position source it will not work if you switch GPS off.

Thank you for your answer!
I thought that with the commnad “Set EKF Origin Here” says to the A.P. where it is on the earth(coordinates).
Βased on what you told me about the 3 dimensions, if the A.P. has the location it is in, it will be able to navigate in auto mode, right?

The FC always need his actual 3 dimensional position. So, not only the starting and the end point. In a ideal world it might work that you can go from A to B if you only know the initial direction and distance. But the FCs world isn’t ideal. There are much influence from outside which kicks the plane from the ideal path. The inbuilt IMU systems are not acurate enough to recalculate the position for more than some seconds.

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Thank you for your help!