Cannot find node robot_pose_ekf ?
I installed robot_pose_ekf according to http://wiki.ros.org/robot_pose_ekf , but when I run the launch file, thisi is the errer I receive
SUMMARY
========
PARAMETERS
* /robot_pose_ekf/base_footprint_frame: base_footprint
* /robot_pose_ekf/freq: 30.0
* /robot_pose_ekf/imu_used: True
* /robot_pose_ekf/odom_used: True
* /robot_pose_ekf/output_frame: odom_combined
* /robot_pose_ekf/sensor_timeout: 1.0
* /robot_pose_ekf/vo_used: True
* /rosdistro: indigo
* /rosversion: 1.11.21
NODES
/
robot_pose_ekf (robot_pose_ekf/robot_pose_ekf)
auto-starting new master
process[master]: started with pid [64634]
ROS_MASTER_URI=http://localhost:11311
setting /run_id to 7023c802-54c3-11e7-8be4-14feb5de14ae
process[rosout-1]: started with pid [64647]
started core service [/rosout]
ERROR: cannot launch node of type [robot_pose_ekf/robot_pose_ekf]: can't locate node [robot_pose_ekf] in package [robot_pose_ekf]
How do I debug thsi error?