Why base_pose_ground_truth isn't publishing the real position in stageros?

Question

Hi,

I'm using the stage simulator to make an multi robot experiment. I need a global and perfect position to make it, so the topic base_pose_ground_truth would be perfect for it.

But the problem is that base_pose_ground_truth is not showing the position of the robot as appears in the screen of stage simulator. It's strange because the odometry seems ok, and description page of Stage stack says that base_pose_ground_truth will always publish perfect position.

In most of cases, the x published position is the real y position, and the y published position is the negative of real x position.

I've tested with some .world files of stage stack and navigation_stage package and I got the same problem.

There is an image of an simulation with stageros and the information published in /base_pose_ground_truth (left) and /odom (right). The initial position of the robot was [0 0 0 0].

image description http://dl.dropbox.com/u/24232831/stage.jpg

What should I do to make base_pose_ground_truth show the real position?

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Originally posted by lucascoelho on ROS Answers with karma: 497 on 2012-02-26

Post score: 4

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Original comments

Comment by Procópio on 2012-08-17:
same problem here.

Answer 1

Hello guys,

I modified the stageros code in order to fix this problem. The code can be accesed here. Not all problems were solved, I think that /base_link still wrong. But at least /base_pose_ground_truth topic is working fine. The stageros code is very clear and pretty easy to modify.

Another way to solve this problem is using an localization system, like amcl. But note that amcl has a significant computational cost and it publishes geometry_msgs/PoseWithCovarianceStamped messages, not nav_msgs/Odometry.

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Originally posted by lucascoelho with karma: 497 on 2012-09-18

This answer was ACCEPTED on the original site

Post score: 1

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Original comments

Comment by Lorenz on 2012-09-18:
If you made a useful patch to the code, please open a ticket containing a patch file in the stage's bug tracker so that other people also profit from your contribution.