ROS Navigation. Global Costmap clears obstacles behind robot.

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Hello!

So I am starting out in ROS 2D navigation (with RTABMap), and I have managed to create a database, saving it, and then have the turtlebot navigate on it (following the RTABMap navigation demo). I am using an Astra camera (following the 3dsensor.launch with the Astra SDK), and using the depthimage_to_laserscan to produce a scan topic.

Now, when I add a new obstacle in front of the camera, the global costmap updates and shows the area as an obstacle, wherever I place them, this is working fine. The problem is, that when I rotate the robot and it can no longer see the obstacle, the global costmap immediately updates and clears the obstacle from the map.

I have tried reading the navigation stack documentation, and I thought that raytracing only clears obstacles if the laserscanner sees that there's an unblocked view on where the obstacle used to be. It seems that it is just clearing any obstacle that is no longer in the laser scanner field of view.

I also tried going through the forum, but all the questions I could find were referring to actually clearing the obstacle (while my problem is that they are clearing when they shouldn't). Seems that the problem for most people is that the obstacles do not clear.

The problem I am having is:

1. The global costmap clears any obstacle that it cannot see, even if the obstacle is outside of the field of view of the laser scanner.

Could someone provide me with some pointers to fix this? I tried changing the costmap_params (common, global), but the obstacles keep clearing.

This is my costmap_common_params.yaml

max_obstacle_height: 0.60  # assume something like an arm is mounted on top of the robot

# Obstacle Cost Shaping (http://wiki.ros.org/costmap_2d/hydro/inflation)
robot_radius: 0.20  # distance a circular robot should be clear of the obstacle (kobuki: 0.18)
# footprint: [[x0, y0], [x1, y1], ... [xn, yn]]  # if the robot is not circular

map_type: voxel

obstacle_layer:
  enabled:              true
  max_obstacle_height:  0.6
  origin_z:             0.0
  z_resolution:         0.2
  z_voxels:             2
  unknown_threshold:    15
  mark_threshold:       0
  combination_method:   1
  track_unknown_space:  true    #true needed for disabling global path planning through unknown space
  obstacle_range: 2.5
  raytrace_range: 3.0
  origin_z: 0.0
  z_resolution: 0.2
  z_voxels: 2
  publish_voxel_map: false
  observation_sources: bump
  bump:
    data_type: PointCloud2
    topic: mobile_base/sensors/bumper_pointcloud
    marking: true
    clearing: false
    min_obstacle_height: 0.0
    max_obstacle_height: 0.15
  # for debugging only, let's you see the entire voxel grid

#cost_scaling_factor and inflation_radius were now moved to the inflation_layer ns
inflation_layer:
  enabled:              true
  cost_scaling_factor:  5.0  # exponential rate at which the obstacle cost drops off (default: 10)
  inflation_radius:     0.5  # max. distance from an obstacle at which costs are incurred for planning paths.

static_layer:
  enabled:              true

Thank you!

EDIT1: So one of the problems was that I had not added the obstacle layer definition in the global_costmap_params.yaml. I changed it to this and it is now partly working:

global_costmap:
   global_frame: /map
   robot_base_frame: /base_footprint
   update_frequency: 1.0
   publish_frequency: 0.5 ...