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M500 Altitude Issues

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  • K Offline
    K Offline
    KeeganBarrett
    Contributor
    wrote on last edited by
    #1

    Several of our m500 vehicles are experiencing issues with their altitude. Many times on the ground they will report altitudes of over 2,500 feet AGL or below -500 feet AGL. The vehicle is unable to launch while experiencing these huge variances in altitude. It sometimes will sort itself out, sometimes it requires a few power cycles. What could be causing these altitude readouts to be so far from truth? (attached is a screenshot from our gcs software showing the altitude) m500_alt_issue.jpg

    In addition to these altitude issues, 3 out of 5 of the m500 vehicles we have flight tested are experiencing mid air altitude issues. They will constantly ascend and descend for no apparent reason. Let me know if there is a fix or explanation for this. Thanks.

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    • Chad SweetC Offline
      Chad SweetC Offline
      Chad Sweet
      ModalAI Team
      wrote on last edited by
      #2

      Can you disable VIO and test again?

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      • Z Offline
        Z Offline
        zkern5254
        Contributor
        wrote on last edited by
        #3

        Chiming in because since I'm on OPs' team. Do you mean completely disable it through voxl-vision-px4? It was disable from the FCU side in terms of the EKF aid mask was not using the VIO inputs (EKF2_AID_MASK = 1.) Will the VIO messages continue to affect the vehicles state estimation even if the EKF should not be reading in those measurements?

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        • Chad SweetC Offline
          Chad SweetC Offline
          Chad Sweet
          ModalAI Team
          wrote on last edited by
          #4

          No, if you have disabled in EKF then it seems like the FC should ignore.

          Then, this error doesn't seem right. Have you logged the barometer and PX4 EKF data? We've not heard of anyone having this issue before.

          Also, are you using the ModalAI firmware?

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          • Chad SweetC Chad Sweet

            No, if you have disabled in EKF then it seems like the FC should ignore.

            Then, this error doesn't seem right. Have you logged the barometer and PX4 EKF data? We've not heard of anyone having this issue before.

            Also, are you using the ModalAI firmware?

            Z Offline
            Z Offline
            zkern5254
            Contributor
            wrote on last edited by
            #5

            @Chad-Sweet We are using the ModalAI firmware. We can get you some logs for you to look into.

            We have seen this issue so far on 5 of the m500 platforms that we've received in the last 3 months with varying levels of consistency (sometime altitude is correct right away, sometimes it takes some time, sometimes it figures itself out on takeoff.) We will be testing 20 more m500 vehicles in the coming week and I will let you know if they have the same issues.

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            • Chad SweetC Offline
              Chad SweetC Offline
              Chad Sweet
              ModalAI Team
              wrote on last edited by
              #6

              Is it preventing you from arming? There was some thoughts px4 should correct the altitude on takeoff

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              • Chad SweetC Chad Sweet

                Is it preventing you from arming? There was some thoughts px4 should correct the altitude on takeoff

                T Offline
                T Offline
                T-Sandman
                wrote on last edited by
                #7

                @Chad-Sweet The bad altitude reading will sometimes prevent us from arming - but it also effects the M500s in the air. During a loiter at a specified hold point, one of the M500s was bobbing up/down about ±50ft - another instance resulted in an M500 experiencing CFIT because it thought it was at an altitude higher than what it was

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