Erratic IMU in APM 2


I'm attempting to solve an issue with IMU readings from a new APM2 being used on a multirotor (hex).

  • Artificial horizon 'jumping', constantly changing orientation, rapid random steps-not smooth
  • Heading is 'jumping' in the same manor
  • Unconfirmed: but xBee seems to have bricked as well, was unable to connect via xBee after first reboot and a number of subsequent reboots, have been connecting USB since. 

I'm running APM firmware 2.5.3 Hexa and interacting through APM Planner 1.1.58.

The airframe is the 3DR Hexa set up per instructions with the power distribution board, sonar, and xBee.

Climate: outside, warm, and dry.

The platform had a couple test flights the day prior with no issues, now the artificial horizon is erratic, upon first connect/flight of the day.


I have not attempted a flight in this condition.

Things I've tried with no effect (more or less in order, restarting APM between logical steps):

  • Connecting through USB to eliminate battery and ECSs and xBee
  • Disconnecting xBee & sonar/disabled sonar
  • Changing location, outside/inside
  • Disconnecting radio gear & power PCB
  • Calibrating magnetometer
  • Leveling IMU (setting IMU offsets in 'setup' menu in Planner)
  • Reinstalling firmware

After all these attempts I gathered this info:

  • IMU data from Planner's terminal interface
    • These readings are erratic
  • Magnotometer data from Planner's terminal interface
    • These readings seem normal
  • Short log file through Planner
    • Platform sitting still inside producing erratic readings
I hope my description is concise enough to get this guy working again soon.
Thanks in advanced!


  • log file: 2012-03-28 11-13-00.tlog
  • text file of magnetometer  data: mag_data.txt
  • text file of imu data: gyro_readings.txt

2012-03-28 11-13-00.tlog



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  • I have an identical problem. Did you ever get this fixed?

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