The robot spawns fine but as soon as it takes off, it drifts a lot towards a direction I closely approximate to -x,-y (more towards -y). Also, after the takeoff, the robot should stay at a specific height, which it isn't staying at and is lifting upwards gradually.
I believe the problem is with the following:

(This is the logging of roslaunch cvg_sim_gazebo ardrone_testworld.launch)

Please correct it and comment on this issue so that others also get to know the new updates.

roslaunch cvg_sim_gazebo ardrone_testworld.launch
... logging to /home/dongxingshuai/.ros/log/1a9e1ff6-5c97-11eb-b184-3c58c2b57b29/roslaunch-lenovo-legion-y7000-2020h-18019.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

Deprecated: xacro tag 'property' w/o 'xacro:' xml namespace prefix (will be forbidden in Noetic)
when processing file: /home/dongxingshuai/uav/catkin_ws/src/tum_simulator_melodic/cvg_sim_gazebo/urdf/quadrotor_sensors.urdf.xacro
Use the following command to fix incorrect tag usage:
find . -iname "*.xacro" | xargs sed -i 's#<([/]?)(if|unless|include|arg|property|macro|insert_block)#<\1xacro:\2#g'

redefining global property: pi
when processing file: /home/dongxingshuai/uav/catkin_ws/src/tum_simulator_melodic/cvg_sim_gazebo/urdf/quadrotor_base.urdf.xacro
included from: /home/dongxingshuai/uav/catkin_ws/src/tum_simulator_melodic/cvg_sim_gazebo/urdf/quadrotor_sensors.urdf.xacro
started roslaunch server http://lenovo-legion-y7000-2020h:32889/

SUMMARY

PARAMETERS

• /gazebo/enable_ros_network: True
• /ground_truth_to_tf/frame_id: nav
• /ground_truth_to_tf/odometry_topic: ground_truth/state
• /robot_description: <?xml version="1....
• /robot_state_publisher/publish_frequency: 50.0
• /robot_state_publisher/tf_prefix:
• /rosdistro: melodic
• /rosversion: 1.14.10
• /use_sim_time: True

NODES
/
gazebo (gazebo_ros/gzserver)
gazebo_gui (gazebo_ros/gzclient)
ground_truth_to_tf (message_to_tf/message_to_tf)
robot_state_publisher (robot_state_publisher/robot_state_publisher)
spawn_robot (gazebo_ros/spawn_model)

auto-starting new master
process[master]: started with pid [18042]
ROS_MASTER_URI=http://localhost:11311

setting /run_id to 1a9e1ff6-5c97-11eb-b184-3c58c2b57b29
process[rosout-1]: started with pid [18056]
started core service [/rosout]
process[gazebo-2]: started with pid [18059]
process[gazebo_gui-3]: started with pid [18061]
process[spawn_robot-4]: started with pid [18069]
process[robot_state_publisher-5]: started with pid [18074]
process[ground_truth_to_tf-6]: started with pid [18079]
[ WARN] [1611308966.651703347]: The root link base_link has an inertia specified in the URDF, but KDL does not support a root link with an inertia. As a workaround, you can add an extra dummy link to your URDF.
[ INFO] [1611308976.096499913]: Finished loading Gazebo ROS API Plugin.
[ INFO] [1611308976.097042844]: Finished loading Gazebo ROS API Plugin.
[ INFO] [1611308976.097532237]: waitForService: Service [/gazebo_gui/set_physics_properties] has not been advertised, waiting...
[ INFO] [1611308976.098146706]: waitForService: Service [/gazebo/set_physics_properties] has not been advertised, waiting...
[ INFO] [1611308980.642690491]: waitForService: Service [/gazebo/set_physics_properties] is now available.
[ INFO] [1611308980.658945020]: Physics dynamic reconfigure ready.
[INFO] [1611308985.417830, 0.000000]: Loading model XML from ros parameter robot_description
[INFO] [1611308985.422096, 0.000000]: Waiting for service /gazebo/spawn_urdf_model
[INFO] [1611308985.423517, 0.000000]: Calling service /gazebo/spawn_urdf_model
Warning [parser_urdf.cc:1115] multiple inconsistent exists due to fixed joint reduction overwriting previous value [true] with [false].
Warning [parser_urdf.cc:1115] multiple inconsistent exists due to fixed joint reduction overwriting previous value [false] with [true].
[ INFO] [1611308986.760460499, 663.134000000]: Camera Plugin: Using the 'robotNamespace' param: '/'
[ INFO] [1611308986.767189849, 663.134000000]: Camera Plugin: Using the 'robotNamespace' param: '/'
[INFO] [1611308986.775840, 663.134000]: Spawn status: SpawnModel: Successfully spawned entity
Error [Element.cc:702] Missing element description for [offset]
Error [Element.cc:702] Missing element description for [drift]
Error [Element.cc:702] Missing element description for [driftFrequency]
[ERROR] [1611308986.896472769, 663.134000000]: CALLED FROM GAZEBO_ROS_IMU.CPP,CHANGED BY SURAJ MAY CAUSE ERRORS
Error [Element.cc:702] Missing element description for [accelOffset]
Error [Element.cc:702] Missing element description for [accelDriftFrequency]
Error [Element.cc:702] Missing element description for [rateOffset]
Error [Element.cc:702] Missing element description for [rateDriftFrequency]
Error [Element.cc:702] Missing element description for [headingOffset]
Error [Element.cc:702] Missing element description for [headingDriftFrequency]
[ERROR] [1611308986.905809857, 663.134000000]: CALLED FROM GAZEBO_ROS_BARO.CPP,CHANGED BY SURAJ MAY CAUSE ERRORS
Error [Element.cc:702] Missing element description for [driftFrequency]
[ERROR] [1611308986.907413251, 663.134000000]: CALLED FROM GAZEBO_ROS_MAGNETIC.CPP,CHANGED BY SURAJ MAY CAUSE ERRORS
Error [Element.cc:702] Missing element description for [driftFrequency]
[ERROR] [1611308986.908828058, 663.134000000]: CALLED FROM GAZEBO_ROS_GPS.CPP,CHANGED BY SURAJ MAY CAUSE ERRORS
Error [Element.cc:702] Missing element description for [offset]
Error [Element.cc:702] Missing element description for [driftFrequency]
Error [Element.cc:702] Missing element description for [velocityOffset]
Error [Element.cc:702] Missing element description for [velocityDriftFrequency]
[ INFO] [1611308986.983614755, 663.134000000]: Camera Plugin (ns = /) <tf_prefix_>, set to ""
[ INFO] [1611308986.984212773, 663.134000000]: Camera Plugin (ns = /) <tf_prefix_>, set to ""
[spawn_robot-4] process has finished cleanly
log file: /home/dongxingshuai/.ros/log/1a9e1ff6-5c97-11eb-b184-3c58c2b57b29/spawn_robot-4*.log
[ERROR] [1611308990.922357526, 663.134000000]: CALLED FROM QUADROTOR_SIMPLE_CONTROLLER.CPP,CHANGED BY SURAJ MAY CAUSE ERRORS
[ INFO] [1611308990.930075730, 663.134000000]: Using imu information on topic ardrone/imu as source of orientation and angular velocity.
[ INFO] [1611308990.931448187, 663.134000000]: Using state information on topic ground_truth/state as source of state information.
[ERROR] [1611308990.972335495, 663.134000000]: CALLED FROM QUADROTOR_STATE_CONTROLLER.CPP,CHANGED BY SURAJ MAY CAUSE ERRORS
[ INFO] [1611308990.979000759, 663.134000000]: Using imu information on topic ardrone/imu as source of orientation and angular velocity.
[ INFO] [1611308990.980382519, 663.134000000]: Using sonar information on topic sonar_height as source of altitude.
[ INFO] [1611308990.981295953, 663.134000000]: Using state information on topic ground_truth/state as source of state information.

Hi, I compiled this package in my computer. However, when I run "roslaunch cvg_sim_gazebo ardrone_testworld.launch", there are some error messages in the terminal. Is anybody can give me any suggestion on this matter? Thank you.