Where can I find the references paper for the pose estimation program in EKF2

[zhanqx1024]

Hello, I want to use vision for the external position estimation. I have set the Parameters EKF2_AID_MASK in QGroundControl, which of the bits in position 3 to enable vision position fusion, and the bits in position 4 to enable vision yaw fusion.

I get the pose estimation from my vision algorithm. Then I publish the position and orientation data via the publish node "/mavros/vision_pose/pose", I have flyed in a strong magnetic shielded environments, I can see the yaw from QGroundControl is not correct, so I put the drone static. But I find the yaw pointer from the QGroundControl have rotation, I subscribe the topic of "/mavros/imu/data", "/mavros/local_postion/pose", and "/aloam_high_frec"(which is my vision algorithm caculated pose node), I find the yaw data of "/mavros/local_position/pose" is almost the same to that from "mavros/imu/data", so I want to know what could be the cause of this problem. I read the "Firmware/src/module/ekf_main.cpp" and the "Firmware/src/lib/ecl/EKF/ekf.cpp", I can't find the implementation of the following functions: "predictCovriance()", "runYawEKFGSF()", "controlFusionModes()" and "runTerrainEstimator()". !

I also want to know the principle of ekf2 program realization, I have read the paper of "a linear kalman Filter for MARG Orientation Estimation Using the Algebric Quaternion Algorithm" and "the Estimation of IMU and MARG orientation using a gradient descent algorithm". I have understood the pose estimation of MARG sensor. But I want to know more about the fusion of the vision and the MARG sensor, so where can I find references for the pose estimation program in EKF2?

My email address is 1930739@tongji.edu.cn, I am very pleasure of your reply. Thank you very much!

[julianoes]

Have you seen this? https://github.com/PX4/ecl/tree/master/EKF/documentation

[bresch]

@zhanqx1024 You should be able to use your IDE or grep to find the definition of those function, if not, you can also search in GitHub: https://github.com/PX4/ecl/search?q=predictCovariance&unscoped_q=predictCovariance