Some questions about SD card logs

Hi all,

I'm analysing my flights logs a bit deeper and I have a bunch of questions:

  • GPS sampling: it seems to me, looking at the GPS time, that the sampling is not 10Hz but 5Hz. This is not a problem, just it is good to know
  • In the log.pde file, there are 7 fields for attitude, while in the logs there are 9 numbers! Where do they come from? The same kind of issue apply for other measures.
  • The units do not correspond to what indicated here. Is there an updated page for that?

Update: I managed to get 50Hz logs on everything. Here is a nice plot showing how motor control is working at very high frequency! I wonder if I have a vibration problem on the APM, those gyro readings are quite noisy...


Thank you!



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  • Hi again,

    I have maybe the answer to the 1st question: even if the update_gps is called at 50Hz, the log is written only when new data is available, and probably the mediatek gps is sending info at 5Hz to the APM.


    I have another question, more important:

    I want to log motors, together with attitude, at 50Hz. This will probably saturate the flash card but a minute flight should be enough for my purpose.

    Can I do this modification to the Arducopter.pde code?


    if (g.log_bitmask & MASK_LOG_ATTITUDE_FAST && motors.armed())


    if (g.log_bitmask & MASK_LOG_RAW && motors.armed())

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