AttributeError: 'NoneType' object has no attribute 'x'

[HuaYuXiao]

[ERROR] [1716884704.309348, 0.000000]: bad callback: <bound method Communication.cmd_vel_flu_callback of <__main__.Communication object at 0x7fa747b0b460>>
Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/rospy/topics.py", line 750, in _invoke_callback
    cb(msg)
  File "/home/hyx020222/Prometheus/Modules/EasonDrone_Control/script/multirotor_communication.py", line 118, in cmd_vel_flu_callback
    self.hover_state_transition(msg.linear.x,
  File "/home/hyx020222/Prometheus/Modules/EasonDrone_Control/script/multirotor_communication.py", line 176, in hover_state_transition
    self.hover()
  File "/home/hyx020222/Prometheus/Modules/EasonDrone_Control/script/multirotor_communication.py", line 226, in hover
    self.target_motion = self.construct_target(x=self.current_position.x,
AttributeError: 'NoneType' object has no attribute 'x'