GPS malfunctioning or ???

Anyone get this error in their logs?  My Y6 would not hold position in Loiter/PosHold and it appears the hdop is increasingly exceeding 2.0. I took off in stab mode, switched to HoldPos to test, and the thing was wondering all over; I barely had control over it, had to switch to stab to prevent crash.

I don't remember seeing this before.

PwC9MSB.pngHere's a video of the Y6 just sitting in the front yard in MP flight data screen. Not a cloud in the sky.  What the?

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  • Ok, I'm feeling more confident something is really wrong with my copter and that it isn't pilot error.


    If interested, more here:

  • A couple things for all to consider.  I'm installing a NEO-7M GPS as a backup to the LEA-6H (3DR) GPS.  I've already conducted side by side tests of the two modules inside my home using 2 FTDI cables and running both on u-center software on the UBLOX website.  Aside from the fact that both GPS units operate a little different from one another, I did not observe any huge HDOP and VDOP differences.  Both resolved my position within a few feet of each other.  I also ran them overnight and outputted the results onto Goggle Earth to get a 3D perspective.  Neither one out performed the other as far as I could observe.  I did however not that the NEO-7M and u-center software allowed me to see in the sky all the satellites it held and the signal strengths.  The LEA-6H only showed me positional data but no mapping of satellites.


    So my next plan it to use beta 3.2 RC3+ to conduct flight tests on both units individually and combined with NEO-7M as my backup to LEA-6H GPS.  According to Randy and the devs, their software should use the GPS with the higher sat count.  Not sure if they also coded in HDOP values to help determine which is better to use.  More testing coming. 

  • Ok, I received the replacement GPS from 3DR. I don't think that is the problem after yesterday's experience, that being an out of control crash; the first. Fortunately it was low altitude.

    If you folks don't read the main Arducopter 3.x (Multicopter) thread, please check it out.

    I believe I unknowingly altered or reset the Taranis calibration and that is the root cause of the crash and what appears to have been the problem from the start. Please review and tell me if you agree or add additional comments.

    The motors were HOT. At first I thought there must be a motor/ESC issue.

    Dumb. Dumb. Dumb.

  • I sent log file and video to 3DR. They are replacing the GPS unit, although I can't see any logical reason for it to go bad after sitting for just 3 days. The only changes were rerouting wires during the vtx install. They questioned the flight mode error as evidence for poor gps signal. I've read others getting GPS reception inside their home, but out of the box I could never get one even standing in front my home's picture window so maybe it was weak from the start.

    3DR customer support has been very proactive since my purchase.

    • I am glad they are helping you out. I have had good experiences with them as well. Re GPS in the house I can usually pickup about 6 sats at my desk in my office where I work on it. This is about 10 feet from the closest window. 


    • I'm beginning to think the GPS has been weak from day one. I have a GPS receiver for another device that picks up satellites with ease when next to the window. My Y6 GPS has never locked inside. In fact, I've had some occasions in the field where it would lose the fix before flying, then correct itself and seemed to straighten out once in the air.  I'll just count my lucky there were no major glitches while flying missions.

      There was one mission where it looked to veer off course and corrected, but I attributed it to the waypoint. Looking back it was probably losing GPS intermittently many times but stayed good enough to complete the mission. 

      OT. I don't recall what is a good number for AccX and AccY. Anyone?

  • 100KM

    Interference sounds odd. These should all be digital signals and for EMF induced noise to induce a 0V or 3.3V/5V  to swap bits would be extremely unusual. A major reason communications moved from analogue to digital is that it is extremely rare for interference to flip a bit and cause this sort of error.

    I would suspect problems more related to GPS reception or power supply would be much more likely. I have also seen weird movements from my quad in loiter/pos hold modes when my compass orientation parameter was set incorrectly.

  • I talked to a friend, and since I moved the wiring around on top of the FC (Pixhawk), if the I2C wiring is wrapped around each other, the signals can leak and even just a few packet errors can cause the whole system to malfunction.

    Anyone else?

  • I should have been more thorough, but it was late:

    1) I added 1.3 ghz FPV 400mw

    2) 3DR telemetry radio was reinstalled (replacement one bad radio)

    3) rx/antenna had to be moved.

    4) Installed new GPS/Mag cable.

    The FPV tx has a notch filter. At first I blamed it on the vtx, so disconnected it, but that did not help. I moved the rx antenna away from the GPS, did not help.

    Also, Pixwhawk beeped the "no GPS lock" a few times, which started my suspicions something wasn't right. Basically I took a perfectly working Y6 that hovered steady, ran missions correctly, landed right etc. etc. and turned it into a mess. Back to the drawing board.

    There has never been shielding on the cables, but I will take that under advisement. Where's a good place to buy it?


  • If you have an android device try installing an app called K Index Monitor. Jerry Hardin put me into it.

    It's an app that, as I understand was developed by a multi rotor guy to monitor, in real time, the electromagnetic activity of the Sun and keep it constantly updated and visible on the top banner (don't know the technical name) of your android as a single digit number. That's all you see so don't look for a lot of intrusive interaction from the app.

    It's said that you shouldn't try to fly with a K Index above a 2 as the electromagnetic activity above that is too high and can interfere with your GPS. Read the comments on the app store for more precise info, but be aware there are a bunch of negative ones regarding the facts that: 1. The app notifies you every time it updated, and 2. That it runs on the background constantly.

    I find neither of these objectionable and am glad to know what the index number is. I'm also surprised at how much of the time it's at or above a 2!

    I noted that last evening (central time in the US) it was above a 4 where I was. My son, a UPS 747 pilot flying out of Anchorage all over the Far East and as far west as Germany, says that the company briefs them constantly on K Index, so I'm watching it carefully as I've already lost a Blade 350QX to an unexplained flyaway. Don't want that to happen to my X8!

    I love it so far.
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