Warning #1: PX4/Pixhawk users upgrading from AC3.1.5 (or earlier) may need to re-do their compass and accelerometer calibration because AC3.2 also uses the backup compass and accels. Pre-arm checks have been added to ensure this has been done.
Warning #2: on the APM2.x the logs must be downloaded using MAVlink instead of the terminal.
AC3.2-rc14 is now available for BetaTesters through the mission planner’s Beta Firmwares link. The full release notes can be found in ReleaseNotes.txt and changes from -rc13 can be seen below.
Feel free to raise issues found during testing on this discussion or in the new support section in the APM Forum.
It’s a big release with “the onion” restructure and a bunch of new features (including these 57 closed items) so we need to re-test almost everything including all flight modes, all mission commands and all the new features. Marco and I will be maintaining (and adding to) this testing list. Issues reported will first be checked by Jonathan, Marco and I and then confirmed bugs/issues will be put on the github issues list (and then hopefully fixed).
Thanks especially to the beta testers who put their copters at risk testing each release. Enjoy!
Changes from 3.2-rc13
1) Safety Features:
a) fail to arm if second gyro calibration fails (can be disabled with ARMING_CHECK)
2) Bug fixes:
a) DCM-check to require one continuous second of bad heading before triggering LAND
b) I2C bug that could lead to Pixhawk freezing up if I2C bus is noisy
c) reset DCM and EKF gyro bias estimates after gyro calibration (DCM heading could drift after takeoff due to sudden change in gyro values)
d) use primary GPS for LED status (instead of always using first GPS)
Replies
A lot of good advice here already, I would add that it's unlikely to be a software issue but rather interference from something on the vehicle. It could even be interference from the flight controller itself although I haven't noticed the Pixhawk ever causing GPS interference myself.
The way I track down causes of interference is I load up AC onto a board somewhere where I know I can get good GPS reception (my house is mostly wood so I can do it indoors at my desk). Next connect with MP and display the HDOP value in the Flight Data screen's Quick tab at the bottom. I then let the hdop settle and connect/disconnect things and look for an impact on the hdop value. In general hot-swapping things is not a good idea but I make an exception during this kind of testing.
Next you can determine if the interference is "radiated" (through the air) or "transmitted" (along the communication wires) by repeating the tests but attaching the devices to a second flight controller.
Note that some devices only create interference when they're being used. So for example I found the early prototypes of the LIDAR-Lite range finder disrupted the GPS signal but it only happened when we were actively requesting data from the sensor.
Randy, I too had issues with occasional fly-aways with Pixhawk (and EKF On) that never happened before with AMP 2.6, but I think I may be on to the root cause now. I thought it was GPS at first, but it seems maybe not now...
With the APM 2.6 I never saw need to use the Compass-Motor Current calibration available in Mission Planner, because I never had a compass related issue on this frame (that I saw anyway), and the couple of times I tried to use anyway it I couldn't work out how to do it properly. So I ignored it after that...
I finally did it again on the Pixhawk at Leonard's advice and was very surprised to find an interference level reading of 93% !
Now with Leonard's help also, I ran multiple Compass-Motor Current calibrations with things like battery wires twisted, iron shielding added and batteries removed and extended away from the frame etc, and finally found issue with the magnetic field from the Hobbyking Quadcopter Power Distribution Board I have used. Moving the GPS/Mag unit away from it dropped the reading dramatically, so the board needs to be replaced with something better.
I've now built a new distribution board from double sided FR4 that should be better at neutralising it's magnetic fields, and am going to retest this weekend.
I wonder if Ravi has checked the Compass-Motor Current interference level on Pixhawk ?
Martin
A follow up to my post about the compass-Mot interference levels, and my home made distribution board.
I made a new board the same size as the HK board but with + & - only on one side. It reduced the interference figure in the Mission Planner test from the original 93% down to 51%.
A worthwhile change, but doing more than that would require new cables on the ESC's as the length was only just long enough with no twists in it.
Martin
PS. I have photos if anyone is interested.
%51 with an external compass? Although it is down from 93%, it is still way too much. I think 30% is the borderline and anything over it requires modification in physical setup.
I had been using APM 2.5 with internal mag. till recently and was having very high interference. After switching to external mag. (which sits about 20cm above the power distribution board), it went down to 14% level.
Yes, all advice says that is still too much (51% interference).
I've 'fixed' it by retiring that frame now...
One thing I can't figure out is how is it that The Iris or the Phantom have the gps in such close proximity to the electrons yet it is fairly well established that for us home made quads the gps and compass needs to be on a mast? I moved mine closer to the frame and lost the quad soon there after. I don't know if it's related but I'm guessing it is.
It's not the gps that causes the problem, it is the magnetometer that has to be distanced from stray magnetic fields.
On the Phantom it lives down on one of the legs ?
On the phantom the GPS is indeed very close to the FC and other electronics, but it is shielded with metallic foil.
I wish I knew what they used. I bought some copper foil but it seemed to have no effect.
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