The usage of autoware_pose_covariance_modifier

[LuZhishan]

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Why does the autoware_pose_comvariant node only use GNSS to correct the covariance of NDT in PoseSource:: GNSS_NDT mode, instead of simultaneously correcting the pose of NDT?
When the covariance of GNSS is small, it is reasonable to directly use the pose of GNSS. But when the gnss_pose_stddev_xy is between threshold_gnss_stddev_xy_bound_upper_ and threshold_gnss_stddev_xy_bound_lower_, only the GNSS covariance is used without using the GNSS pose. Is the GNSS location unreliable here？

[LuZhishan]

Could you help me with this problem @xmfcx @meliketanrikulu @cyn-liu

[LuZhishan]

Thanks for your reply, I understand now

[LuZhishan]

@xmfcx
I still have a question. I read the EKF node and found that the EKF node only receives GNSS data for initialization pose. After that it only uses NDT pose information, then the GNSS pose is not used.

[xmfcx]

@LuZhishan

If you don't use autoware_pose_covariance_modifier node, you are right.

But if you use it, this node controls what is sent to the EKF node. See the diagram below:

[meliketanrikulu]

Did you activate use_autoware_pose_covariance_modifier parameter. When you set this parameter true autoware_pose_covariance_modifier will be activate. This package is not working, GNSS poses used only for pose initialization and it uses NDT poses for EKF , in default autoware.

You can find here to difference between default autoware and pose_covariance_modifier activated.

[LuZhishan]

@xmfcx @meliketanrikulu Thanks for your help. It works now

[meliketanrikulu]

Hello @LuZhishan Thanks for testing and sharing your feedback.

1. )The covariance values ​​of NDT and GNSS poses are important for EKF in the next step. Covariance values ​​actually indicate how much we trust that pose. Since GNSS also gives us the error of the pose, we trust the covariance values ​​it gives. However, we set the NDT covariances ourselves. Instead of setting fixed NDT covariances, we change the NDT covariance values ​​​​in this stage so that we can benefit from GNSS at the maximum level. I don't understand what you mean by correcting the NDT pose. Could you explain in more detail?

2.) It uses GNSS/INS and NDT poses together. when the gnss_pose_stddev_xy is between threshold_gnss_stddev_xy_bound_upper_ and threshold_gnss_stddev_xy_bound_lower_ .