Discussions

INAVerr- Is it the GPS or FC or neither?

Posted by DG on February 22, 2015 at 4:34pm

Should I expect a crash at some point?

Nervously I took the Spy 750 Y6 up for the first time in over 3 weeks (had a warm spell of 25F today).

In stab it flies great, then switching to poshold it seemed fine, but did the twitchy thing again for a few seconds here and there, then seemed to smooth out (subjective). I brought it down and hovered nearby where it stayed rock steady for a minute or so and landed.

So, what does it mean when INAVerr goes to 255 and stays there? From what I understand it is the FC not receiving data from the GPS properly. Apparently this copter has done it from day one since transplanting the PIxhawk and running on AC3.2 and 3.2.1, with the 3DR GPS and the current CSGShop Neo-M8N. These errors did not exist on the Y6B with 3.1.5 and the 3DR GPS.

Any help is appreciated.

bxCuDK8.png

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –
Follow

Replies

                  • AKcopter > AKcopter March 8, 2015 at 4:17am

                    My log is very large almost 27 MB.....there is a 7MB limit here ...how do I post my logs??

                  • DG > AKcopter March 7, 2015 at 12:00pm

                    AKcopter,

                       If you post your log, I'd like to run it through Excel.

            • Jim Dowdle > Hans Bouwmeester February 28, 2015 at 2:43pm

              Very gppd!

              I just check for M8N firmware update.  There is none yet available.

              Do you know of a way to set Arducopter to interface the GPS at a higher baud rate?

              How about update rate?

              I just checked for GPS parameters.  There is a GPS_type1 and 2.  Apparently you can have 2 GPS's.  That might be interesting.  My type is set to 1 : auto.  Type 2 is Ublox.

              I wonder what would happen if you set type to ublox.

              • DG > Jim Dowdle February 28, 2015 at 5:17pm

                According to the following reference, Pixhawk recognizes the Neo-M8N and automatically sets the parameters. All the user needs to is reset the GPS to default first using U-Center.

                   http://www.rcgroups.com/forums/showthread.php?t=2353323

                NOTE: When connected to either APM 2.xx or Pixhawk, the firmware recognizes the ublox GPS
                and sends instruction to set the baudrate to 38,400, rate to 5Hz, turn off NMEA protocol, turn on UBX protocol, as well as other settings suited for use with APM and Pixhawk meaning that the "Default parameters" are irrelevant
                as they are overridden by the APM or Pixhawk firmware.

            • DG > Hans Bouwmeester February 28, 2015 at 2:28pm

              Here's the raw data in Excel for INVerr

              PHBmGNK.pngI'm puzzled because the flight ended at 49xxxx and I don't recall leaving the power on after landing.

              Here is the data as seen in MP. It's missing the time values, but I wanted to get this posted while I remember.......going to try another quick flight before it gets dark.

              C8o6FHY.png

              • DG > DG February 28, 2015 at 3:45pm

                The first graph above should read "GPS"

                t5e3T0I.png

                • DG > DG February 28, 2015 at 4:38pm

                  I flew for ~6 minutes. The logging was changed to 'Almost All'.

                  I also changed the ins_mpu6k_filter from 0 (default) to 20.  Default I believe is 42hz. I don't have issues with vibration, but have read that 20 can smooth out issues with "twitching" and such. It did seem to fly very well, but that's neither here no there for this topic.

                  I digress.

                  No logging was performed before arming. INAVerr was 255 straight across.

                  The GPS values, which I assume (nobody has said, just guessing) is the raw data used to capture the INAVerr. I'm not getting why in this case under PM it shows 255 throughout the flight, yet under GPS it varies. Having not studied the code to find how INAVerr is calculated, I'm probably totally off base.  I don't care to learn the code, it reminds me of work too much :) (is there a detailed summary of how to analyze logs?)  I just wanna fly and have confidence it will come back and in one piece.

                  aeWRDuJ.pngThe raw data from 'GPS'. So what do these data represent?

                  3cmT2oO.pngNsat and Hdop

                  mOtCRby.pngVibration:

                  4g7xZXw.png

                  And the kmz. No gaps? Huh?

                  jxSwQPN.jpg

    • DG > Hans Bouwmeester February 27, 2015 at 9:11pm

      Wow! I'm not alone. I'd have to look at the logs again, but it climbs to 255+ quite fast. The twitching may not be related, and not knowing what INAVerr really is about makes it worse. I think there is an issue in GPS modes because the copter flies fine in stab mode without simple/super simple mode.

      CSGShop did not even attempt to explain what may be the problem, only place the blame on PIxhawk. I linked to DIY, but apparently they are not interested in helping.

      I still have not uploaded the data and load into Excel, but the gaps are plainly visible. If you create a kmz file for Google Earth, look at the pattern of data gaps while in poshold.

      I'm not ready to toss the CSGShop yet; will put the 3DR GPS back on and test, but I thought it was happening with it on as well; not positive to be honest. In any case, based on what I've observed and Randy's caution that it may be a real problem, my confidence level is about 5% right now to go back up. This copter has not been crashed yet, and I'd like to keep it that way especially due to mechanical failure.

      In about a month I'll have another copter put together with a new FC/GPS to see how it goes, but it won't be a GPS from CSGShop this time. 

      • Hans Bouwmeester > DG February 28, 2015 at 11:05am

        Hi DG,

        I too see "missing" datapoints in the KMZ file. See attached picture. They do not seem to be at the regular intervals you see them though, which could explain why your INAVErr seems to climb to 255 (the max) faster than mine (?).

        Hans.3702688197?profile=original

  • Jim Dowdle February 23, 2015 at 4:47am

    Is your satellite count good?  I had one copter where the satcount would go to 0 for half a sec or so.  The copter would fly away.  I got rid of that gps to cure the problem, and have started using Neo M8N.  Now I get 16-20 sats and constant reception.

    If your connections are good, not routed near interference, twisted.....and I would guess it is not likely the wires, I would suspect GPS reception.  There are definately not-so-good units out there.

    They may be other ways to check this, which I dont know right off.  There is a quality term for the gps.  I have not used it.  I simply lost sats.

This reply was deleted.

Activity