Problem with Gmapping

Question

I'm trying to use gmapping to create a map of my lab. I'm using a NXT withLejos firmware, I checked that all the topic /tf, /odom and /scan are working well, but I get this error:

[ WARN] [1346231329.853649941]: MessageFilter [target=/odom ]: Dropped 100.00% of messages so far. Please turn the [ros.gmapping.message_notifier] rosconsole logger to DEBUG for more information.

The command I used to launch gmapping is:

rosrun gmapping slam_gmapping scan:=scan (/scan is the topic on which are published the message of type sensor_msgs::LaserScan)

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Originally posted by camilla on ROS Answers with karma: 255 on 2012-08-28

Post score: 0

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Original comments

Comment by dornhege on 2012-08-29:
Do this: Please turn the [ros.gmapping.message_notifier] rosconsole logger to DEBUG for more information.

Comment by camilla on 2012-08-29:
The problem was that I called my frame /world and not /odom, now that i adopted the ROS Naming Convenction the warning message doesn't appear anymore

Answer 1

If you are sure that the odom and the scan topic are published correctly and gmapping connects to them (verify with rosnode info gmapping), this probably happens because of bad time stamps.

gmapping requires to have correct time stamps in the odometry message and the laser scan as well as in the tf transforms between the robot's base frame and your laser. If you are using several machines, make sure that their clocks are synchronized.

For more information on what exactly is the problem, start up rxconsole and enable debug for ros.gmapping.message_notifier as the warning message states.

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Originally posted by Lorenz with karma: 22731 on 2012-08-29

This answer was ACCEPTED on the original site

Post score: 2

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Original comments

Comment by dornhege on 2012-08-29:
Maybe one remark: AFAIK gmapping does not use odometry from the odom topic, but uses the /odom frame from tf.

Comment by Lorenz on 2012-08-29:
True. It only uses tf.