IRIS looses altitude during Loiter

This happens a lot with my IRIS, especially on windy days!

Just upgraded today to the latest beta FW, calibrated compass and acc, result the same.

Remote mid point etc are also good.

I looked at the logs myself, saw the EKF errors, not sure related but can an expert please take a look at my logs and tell me why IRIS is not able to hold altitude during loiter?

BTW, I use a 4S battery.

Thanks in advance.

2014-10-26 14-25-33.log

2014-10-26 14-25-33.log.gpx

2014-10-26 14-25-33.kmz

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  • Can you please enable logging for vibrations and do a test flight again. You barometer-based altitude and GPS based altitude differ a bit at times (See below). This is usually caused by vibrations.


    When did you purchase your IRIS? Did you buy it directly from 3DR or from a 3rd party?

    Did you do the Pixhawk adjustment ( 

    • Auto tune seems to help with the issue, I have the parts but haven't done the relocation of the pixhawk yet.

      Thanks for looking at my logs.

    • I had similar issues with an Iris. If your GPS/Compass is touching (or very close) your Pixhawk it can cause these issues. After you enable the IMU logging and send another flash log file we will be able to tell. Excessive vibration on the Z axis can cause many random strange behaviors.


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