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asked 2014-06-16 06:10:06 -0500

updated 2014-06-18 06:06:12 -0500

I'm using hector GPS in my robot. I followed the instructions to introduce it in the EKF (robot_pose_ekf). However, the estimated pose is much worse taking the gps into account than that obtained ignoring it.

I think that the problem comes from de gps I am using because when I move the robot around it accumulates an error which never disappears. My GPS is Hector gps

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answered 2014-06-16 10:12:27 -0500

Tom Moore gravatar image

Integration of GPS with robot_pose_ekf proved to be difficult for me when I tried it as well. Someone may have a good answer for you, but if it proves too difficult, I recently released the robot_localization package, which contains both an EKF localization node and a UTM transform node. The former can be used in place of robot_pose_ekf, and the latter allows for integration of GPS data. The tutorials page contains a tutorial that details how to integrate a GPS sensor.

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I have taken a look to it and I thinks it is great. I received an error which I couldn't identify

arenillas gravatar image arenillas  ( 2014-06-18 04:18:27 -0500 )edit

[ERROR] [1403082870.757635304, 20.409000000]: Odometry pose transform error: Lookup would require extrapolation into the future. Requested time 20.409000000 but the latest data is at time 20.402000000, when looking up transform from frame [base_footprint] to frame [base_link]

arenillas gravatar image arenillas  ( 2014-06-18 04:18:30 -0500 )edit

Does that error happen repeatedly, or does it happen just once or twice and then stop? Which node is reporting the error?

Tom Moore gravatar image Tom Moore  ( 2014-06-18 14:39:26 -0500 )edit

Sorry about the delay, but I was working in another project these days. The ekf_localization_node generates the error continously.

arenillas gravatar image arenillas  ( 2014-06-27 08:58:25 -0500 )edit

Are all the messages originating on the same machine? At what rate is your base_link->base_footprint transform being broadcast? Feel free to send me an e-mail (see my GitHub page). I may have to have a look at your bag file and then we can update this question when we figure out the issue.

Tom Moore gravatar image Tom Moore  ( 2014-06-28 07:37:34 -0500 )edit

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Asked: 2014-06-16 06:10:06 -0500

Seen: 910 times

Last updated: Jun 18 '14