Localiztion in Nav2d is very poor on Turtlebot 2 with default configuration

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I did not find the localizer node seperately in the launch file of nav2d. there are nodes for mapper "<node name="Mapper" pkg="nav2d_karto" type="mapper">", GetMap, Explore, SetGoal & operator but not for localization. I am new to ROS so I would appreciate if you could give me details. Thank you,

The mapper node implements SLAM (Simultaneous Localization and Mapping), so it builds a map and localizes the robot within the map, so you only need the nodes from the tutorial3 launch file (minus the simulator) and your robot driver, nothing else.

i cross checked the launch files and tutorial 2 & tutorial 3 of nav 2d. i am following tutorial 3, which does not have the selflocalization node. i suspect the shift in map while mapping is caused by SLAM itself. Is my understanding correct? is there a way to fine tune it to have a good map?

So there is really no particle filter running on your system now? Then it might help to do a "rosrun tf view_frames" on your robot and check if any transformations are missing or double-published. Have you checked whether the odometry gives resonable results?

The tf tree looks good, with one single connected tree. map(/mapper)->offset(mapper)->odom_fused(robot_pose_ekf)->base_footprint(robot_state_publisher) etc. The topic /odom is subsribed by robot_pose_ekf & mobile_base_nodelet_manager. /robot_pose_ekf.odom_combined is not subscribed by any one.

Would you please tell me how i could verify the odom output? Thanks a lot for taking time & helping me out.

i doubt that there is particle filter is still running, maybe from SLAMs itself, because there are parametes in the mapper.yaml with regard to localization & changing the values of min_particles & max_particles changes the map quality as mentioned in the first post.

The mapper uses a particle filter in a multi-robot setup, that's why these parameters exist. They should have no influence at all in your setup. (Make sure that robot_id is set to 1)