Global and local costmap are shifted in relation to the map mapped by gmapping

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Dear friends,

I have the following problem where I would love to get any hint that leads me to a solution. First of all here are my tech specs:

• ROS melodic with Stage 4.3 simulation
  • Ubuntu 5.4.0-65.73~18.04.1-generic 5.4.78
  • Environment variables ROS_ETC_DIR=/opt/ros/melodic/etc/ros ROS_ROOT=/opt/ros/melodic/share/ros

ROS_MASTER_URI=http://localhost:11311 ROS_VERSION=1 ROS_PYTHON_VERSION=2 ROS_PACKAGE_PATH=/home/emanuel/rccar_ws/src:/home/emanuel/testnav_ws/src:/home/emanuel/floribot_ws/src/base:/home/emanuel/floribot_ws/src/plc_connection:/opt/ros/melodic/share ROSLISP_PACKAGE_DIRECTORIES=/home/emanuel/rccar_ws/devel/share/common-lisp:/home/emanuel/testnav_ws/devel/share/common-lisp:/home/emanuel/floribot_ws/devel/share/common-lisp ROS_DISTRO=melodic

I am running a ROS Stage simulation with a differential drive robot equipped with a laser scanner and odometry. The robot is to pass through a corn field. It does not know the area at the beginning but is given an empty map that is dynamically builds up as the robot proceeds. The navigation stack is set up as described in http://wiki.ros.org/navigation/Tutori... with some modifications. I am using the following planners:

• global planner: A self written planner that simply returns the goal which yields to a straight line from the current position to the goal not depending on any costmap
  • local planner: DWAPlannerROS

Now to my question: When I am sending navigation goals to the robot it can follow and reach them eventually. But I have noticed that almost every time the global and local costmap are shifted and do not match the map mapped by gmapping. Thus, the costs in the costmaps which are indicating an obstacle (here: corn plant) do not sit directly at the mapped obstacles but are shifted as it can be seen in the picture. This leads to a very unstable navigation: Sometimes the robot can reach its given goals but sometimes not. What can I change to have the costmaps lay perfectly onto the mapped map?

Unfortunately I do not have enough points to include a picture - therefore I uploaded it to this page: https://ibb.co/yXGFzqj

I appreciate any hint that could help me fixing this. Kind regards, Eman

P.S. here are my costmap and planner config files

costmap_common_params.yaml

global_frame: map
robot_base_frame: base_link
obstacle_range: 5.0
raytrace_range: 10.0
footprint: [[0.275, 0.125], [-0.275, 0.125], [-0.275, -0.125], [0.275, -0.125]]

plugins:
    - {name: static_layer, type: "costmap_2d::StaticLayer"}
    - {name: obstacle_layer, type: "costmap_2d::ObstacleLayer"}
    - {name: inflation_layer, type: "costmap_2d::InflationLayer"}
publish_frequency: 1.0
static_layer:
    unknown_cost_value: -1
    lethal_cost_threshold: 250
    map_topic: map
    first_map_only: false
    subscribe_to_updates: false
    track_unknown_space: true
    use_maximum: false
    trinary_costmap: false
obstacle_layer:
    observation_sources: laser_scan_sensor
    laser_scan_sensor: {sensor_frame: base_laser_link, data_type: LaserScan, topic: base_scan, marking: true, clearing: true}
    track_unknown_space: true
    footprint_clearing_enabled: true
    combination_method: 0
#    origin_z: 0.0
#    z_resolution: 0.05
#    z_voxels: 10
#    unknown_threshold: 10
#    mark_threshold: 0
#    publish_voxel_map: false
inflation_layer:
    inflation_radius: 0.35 # = gap corn row / 2, so that robot runs in the very center of the row
    cost_scaling_factor: 15.0 # the higher, the quicker ...