ros run mavros with permission denied.

edit

Hi, I am using mavros to read the signals of an AMP2.5 with a GPS connected, on ROS indigo and Ubuntu 14.04.

I install the package by executing

sudo apt-get install ros-indigo-mavros ros-indigo-mavros-extras

It seems that the package is installed correctly. Then I connect the AMP2.5 hardware, the serial number is ttyUSB0. I launch the package by

roslaunch mavros apm2.launch

It shows that 'FCU: DeviceError:serial:open: No such file or directory'.

... logging to /home/alex/.ros/log/a4cdafa8-81b3-11e5-b7f7-ac7ba1b27816/roslaunch-alex-Lenovo-IdeaPad-Y410P-4941.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://alex-Lenovo-IdeaPad-Y410P:54191/

SUMMARY
========

CLEAR PARAMETERS
 * /mavros/

PARAMETERS
 * /mavros/cmd/use_comp_id_system_control: False
 * /mavros/conn/heartbeat_rate: 1.0
 * /mavros/conn/system_time_rate: 0.0
 * /mavros/conn/timeout: 10.0
 * /mavros/conn/timesync_rate: 0.0
 * /mavros/fcu_url: /dev/ttyACM0:57600
 * /mavros/gcs_url: 
 * /mavros/global_position/frame_id: fcu
 * /mavros/global_position/rot_covariance: 99999.0
 * /mavros/global_position/tf/child_frame_id: fcu_utm
 * /mavros/global_position/tf/frame_id: local_origin
 * /mavros/global_position/tf/send: False
 * /mavros/image/frame_id: px4flow
 * /mavros/imu/angular_velocity_stdev: 0.000349065850399
 * /mavros/imu/frame_id: fcu
 * /mavros/imu/linear_acceleration_stdev: 0.0003
 * /mavros/imu/magnetic_stdev: 0.0
 * /mavros/imu/orientation_stdev: 1.0
 * /mavros/local_position/frame_id: fcu
 * /mavros/local_position/tf/child_frame_id: fcu
 * /mavros/local_position/tf/frame_id: local_origin
 * /mavros/local_position/tf/send: False
 * /mavros/mission/pull_after_gcs: True
 * /mavros/mocap/use_pose: True
 * /mavros/mocap/use_tf: False
 * /mavros/plugin_blacklist: ['actuator_contro...
 * /mavros/plugin_whitelist: []
 * /mavros/px4flow/frame_id: px4flow
 * /mavros/px4flow/ranger_fov: 0.0
 * /mavros/px4flow/ranger_max_range: 5.0
 * /mavros/px4flow/ranger_min_range: 0.3
 * /mavros/safety_area/p1/x: 1.0
 * /mavros/safety_area/p1/y: 1.0
 * /mavros/safety_area/p1/z: 1.0
 * /mavros/safety_area/p2/x: -1.0
 * /mavros/safety_area/p2/y: -1.0
 * /mavros/safety_area/p2/z: -1.0
 * /mavros/setpoint_accel/send_force: False
 * /mavros/setpoint_attitude/reverse_throttle: False
 * /mavros/setpoint_attitude/tf/child_frame_id: attitude
 * /mavros/setpoint_attitude/tf/frame_id: local_origin
 * /mavros/setpoint_attitude/tf/listen: False
 * /mavros/setpoint_attitude/tf/rate_limit: 10.0
 * /mavros/setpoint_position/tf/child_frame_id: setpoint
 * /mavros/setpoint_position/tf/frame_id: local_origin
 * /mavros/setpoint_position/tf/listen: False
 * /mavros/setpoint_position/tf/rate_limit: 50.0
 * /mavros/startup_px4_usb_quirk: False
 * /mavros/sys/disable_diag: False
 * /mavros/sys/min_voltage: 10.0
 * /mavros/target_component_id: 1
 * /mavros/target_system_id: 1
 * /mavros/tdr_radio/low_rssi: 40
 * /mavros/time/time_ref_source: fcu
 * /mavros/time/timesync_avg_alpha: 0.6
 * /mavros/vibration/frame_id: vibration
 * /mavros/vision_pose/tf/child_frame_id: vision
 * /mavros/vision_pose/tf/frame_id: local_origin
 * /mavros/vision_pose/tf/listen: False
 * /mavros/vision_pose/tf/rate_limit: 10.0
 * /mavros/vision_speed/listen_twist: False
 * /rosdistro: indigo
 * /rosversion: 1.11.13

NODES
  /
    mavros (mavros/mavros_node)

ROS_MASTER_URI=http://localhost:11311

core service [/rosout] found
process[mavros-1]: started with pid [4960]
[ INFO] [1446505874.563214852]: FCU URL: /dev/ttyACM0:57600
[ INFO] [1446505874.563451461]: serial0: device: /dev/ttyACM0 @ 57600 bps
[FATAL] [1446505874.563723048]: FCU: DeviceError:serial:open: No such file or directory
================================================================================REQUIRED process [mavros-1] has died!
process has finished cleanly
log file: /home/alex/.ros/log/a4cdafa8-81b3-11e5-b7f7-ac7ba1b27816/mavros-1*.log
Initiating shutdown!
================================================================================

Hence, I change the FCU to /dev/ttyUSB0:57600 and GCS to empty.

roslaunch mavros apm.launch fcu_url:=/dev/ttyUSB0:57600 gcs_url:=udp://@

And ... (more)