Warning #1: an issue has been found with Tower's Pause button which can cause the vehicle to fly to an old position if the vehicle has not sent a position update to Tower in some time.
Warning #2: Copter-3.3.2 fixes a bug found in Copter-3.3.1's desired climb rate initialisation which could lead to a sudden momentary drop when switching from Stabilize or Acro to AltHold, Loiter or PosHold.
Warning #3: Copter-3.3.2 fixes an issue found in Copter-3.3.1 which could lead to hard landings in RTL or AUTO if the WPNAV_SPEED_DN was set too high (i.e. >400 or 4m/s) and/or the WPNAV_ACCEL_Z was set too low (i.e. <100 or 1m/s/s).
Warning #4: a bug was found in Copter-3.3 which could cause a sudden crash if you abort a Take-off initiated from a ground station. Video description is here. The bug is fixed in Copter-3.3.1 so we recommend upgrading.
Note #1: AC3.3-rc8 corrected a long standing bug in the HDOP reporting. HDOP values will appear about 40% lower than previously but this does not actually mean the GPS position is better than before.
Note #2: if upgrading from AC3.2.1 the vehicle's accelerometer calibration needs to be done again.
Note #3: set SERIAL2_PROTOCOL to "3" and reboot the board to enable FrSky telemetry like in previous versions.
Note #4: the wiki will be updated over the next few weeks to explain how to use the new features
Copter-3.3.1 is available through the mission planner. The full list of changes vs AC3.2.1 can be see in the ReleaseNotes and below are the most recent changes since AC3.3.
Sadly this version (and all future versions) will not run on the APM2.x boards due to CPU speed, flash and RAM restrictions.
Changes from 3.3:
1) Bug fix to prevent potential crash if Follow-Me is used after an aborted takeoff
2) compiler upgraded to 4.9.3 (runs slightly faster than 4.7.2 which was used previously)
Changes from 3.3-rc11:
1) EKF recovers from pre-arm "Compass variance" failure if compasses are consistent
Changes from 3.3-rc10:
1) PreArm "Need 3D Fix" message replaced with detailed reason from EKF
Changes from 3.3-rc9
1) EKF improvements:
a) simpler optical flow takeoff check
2) Bug Fixes/Minor enhancements:
a) fix INS3_USE parameter eeprom location
b) fix SToRM32 serial protocol driver to work with recent versions
c) increase motor pwm->thrust conversion (aka MOT_THST_EXPO) to 0.65 (was 0.50)
d) Firmware version sent to GCS in AUTOPILOT_VERSION message
3) Safety:
a) pre-arm check of compass variance if arming in Loiter, PosHold, Guided
b) always check GPS before arming in Loiter (previously could be disabled if ARMING_CHECK=0)
c) sanity check locations received from GCS for follow-me, do-set-home, do-set-ROI
d) fix optical flow failsafe (was not always triggering LAND when optical flow failed)
e) failsafe RTL vs LAND decision based on hardcoded 5m from home check (previously used WPNAV_RADIUS parameter)
Thanks for your testing!
Replies
That's odd for sure since my 915Mhz telemetry radios are about the only thing that do NOT produce any noticeable noise lol.
I've seen an instance of the 3DR 900Mhz mavlink radio making a Pixhawk throw up lots of IMU errors, but the antenna was both horizontal same as the Pixhawk orientation, and fitted barely 20mm from the side of the case. That was nearly as bad for RF coupling as you could get and easily fixed by more suitable antenna placement.
Also had my FrSky D8R RX antenna drop my GPS sensitivity down enough to make HDOP sit above 3 all the time, again the remedy (once I knew it was the reason) was move the FrSky RX antennas away from the GPS receiver.
On my copters I now use a GPS riser mount at the back of the copter, and fit the FPV and Mavlink antennas out at the front. Even better would be out front and hanging below the chassis. I don't have GPS issues anymore.
Antenna separation is your friend when it comes to RF coupling and interference...
+1 for antennas separation. :-)
When "less weak than usual" Tx are used, care of antennas and positioning is quite important.
Mavlink 900 MHz by rfdesign 900 MHz modem gives up to 1 Watt output.
(software power setting is great!)
Video down link: 2.5W 1.3GHz Video Tx
Main batteries telemetry (2.4GHz): Cell by cell telemetry values
I believe in following each individual cell instead of total voltage. (But that is just me LOL)
And FRSky telemetry for electronics 5 Volts
Henri
Hi,
I by no means intend to respond instead of develpers who know best but I had same situation going on with telemetry screen showing 10-12 stas and low hdop but drone would not arm saying same 'need 3d fix'.
this problem combined with very slow progress rate from 5-6 sats to 10 sats was all related to a high level of EMI interference from the boscam transmitter 20cm away and FC BECs modules - so it took to put a solid copper plate under GPS unit for isolation and I look to do proper shielding now for GPS unit.
After this shielding it locks into 12-14 sats in less than a minute - M8N unit - and never plays this #D lock error message again if it shows me proper HDOP in the telemetry.
Roger,
Yes, you're right on the money. The EKF is doing additional checks beyond the GPS HDOP (I believe it checks the velocities coming out of the GPS agree with it's internal velocity estimates) and if those checks fail the pre-arm checks just display the GPS failure message. We could change the message to be more accurate...
this site keep dropping all input you type into it... it is annoying, after you typed a page or so of text.
in my case EMI noise was the reason of both compass and GPS errors. I think a lot of GPS units are extremely sensitive, also, BECs may have switched working mode if you dropped from 5.3V down to 3.3V and they may produce more noise now.
A while back a chap on RCG whom I will not name claimed that the X8R broadcasts out of band [they all do a little] and it was causing major issues with his GPS modules, his lapdog also claimed the same thing where as I tried and tried to reproduce the issue with 4 different RX's [2 X8R and 2 X4R-SB] and 6 different GPS units and I could not reproduce the issue. But it seems that some RX's do produce more noise than others and these new m8n's are uber sensitive to noise. I've not had any noise issues with any of them I have or have had but I DO see a lot of data drops with some of the cheaper ones, well actually ALL of them really if they are set to anything higher than a 2hz refresh. Doesn't seem to matte what baud as I have tested them from 9600 to 115200 and as soon as I go above 2Hz then they get a little spooky. I have one that goes so far as having mission planner report NO GPS then 3D lock then NO GPS over and over :(
Not saying it should affect the 6 or 7 series engines though. I'm just wondering if the devs changed something that gets uploaded to the GPS on boot.
I remember that LONG tread over at RCG the guy never could produce any facts as I recall. I've had zero problem with my X8R. The Taranis / X8R was the best thing I ever bought! Well.... after a pixhawk of course :]
To be fair he/they did present some fairly compelling evidence supporting their claims using some cheaper oscilloscopes but there was no data given other than what was on the screens really. I, at the time, wanted to corroborate their findings but I could not. And I am still flying everything with X series RX's and haven't had a major flyaway yet :)
I'm halfway finished converting all my equipment to X-series receivers. No issues.
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