The navigation stack needs sensor information.
For the simulated ROSbot2 in Gazebo, Are the messages: sensor_msgs/LaserScan or sensor_msgs/PointCloud published from Gazebo? I need to undersatnd this
The data from lidar is published from Gazebo. It is published on topic /scan as a sensor_msgs/LaserScan msg.
Hope it is the info you wanted.
Best Regards, Nicolas.