ArduCopter-3.2 beta testing

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)

Bill, you're right. So my solution is to shield the GPS antenna directly from "low elevation sats" and multipath signals. Remember my yoghurt pot trick.

Thomas, thank you for the ublox config, but..

As a every year discussion I don't agree with enabling the signal correction via SBAS. In my opinion that makes sense for 24/7 applications or those who need high absolute position accuracy. For our copters, who fly around 30min, it could lead to damage due to GPS glitches.

Imagine you have a 3D fix+max. satcount and take off, GPS position is a bit "off" (but doesn't matter for 30min bcs it keeps that offset the hole flight).
Flying around some minutes and suddenly EGNOS or WAAS data are received.(Sometimes 5min are not enough)
The GPS algorithm uses these values and calculates a new "correct" position(but 10m away).
AC navigation controller says puh, I have to correct my position...and copter flys away.

So I think we only need "relative position accuracy" where a bit off is accepted. I don't need to drop things on a 20cm target.

Randy told us, the ublox config is being sent to GPS on each boot. Is this still the case? Does this config overide the SBAS settings? Sorry I didn't have had time to investigate whats going on during boot.

Thanks

Replies

- - - - John > Bill Bonney June 27, 2014 at 10:04am
        
        Hi,
        
        HDOP says nothing about the accuracy in case of having reflections or Multi-Path reception.
        
        HDOP is only based on the position of the satellites received which determines how accurately you can in theory calculate the position if and only if the received signal is perfect. HDOP is not impacted by reflections, but the GPS accuracy definitely is.
        
        The effect is the following:
        
        - HDOP bad means that: the GPS position estimate is likely to be bad since the received satellites are in a non-optimal position.
        
        - HDOP good means that: the position estimate can be good based on the satellites received if the signal is not disturbed in the atmosphere and not reflected of buildings etc. HDOP will not indicate this at all.
        
        So a low HDOP indication while being in a very urban area or inside a building means nothing. Indeed typically the estimated position will be wandering all over the place.
    - Christian > Bill Bonney June 26, 2014 at 1:17am
      
      Bill, you're right. So my solution is to shield the GPS antenna directly from "low elevation sats" and multipath signals. Remember my yoghurt pot trick.
      
      Thomas, thank you for the ublox config, but..
      
      As a every year discussion I don't agree with enabling the signal correction via SBAS. In my opinion that makes sense for 24/7 applications or those who need high absolute position accuracy. For our copters, who fly around 30min, it could lead to damage due to GPS glitches.
      
      Imagine you have a 3D fix+max. satcount and take off, GPS position is a bit "off" (but doesn't matter for 30min bcs it keeps that offset the hole flight).
      
      Flying around some minutes and suddenly EGNOS or WAAS data are received.(Sometimes 5min are not enough)
      
      The GPS algorithm uses these values and calculates a new "correct" position(but 10m away).
      
      AC navigation controller says puh, I have to correct my position...and copter flys away.
      
      So I think we only need "relative position accuracy" where a bit off is accepted. I don't need to drop things on a 20cm target.
      
      Randy told us, the ublox config is being sent to GPS on each boot. Is this still the case? Does this config overide the SBAS settings? Sorry I didn't have had time to investigate whats going on during boot.
      
      Thanks
      - Admin
        
        Thomas J Coyle III > Christian June 26, 2014 at 1:55pm
        
        @Christian,
        
        I think that you can change the Mask parameter, which is 5 deg presently, instead of shielding the antenna from "low elevation satellites".
        
        Regards,
        
        TCIII ArduRover2 Developer
      - Developer
        
        Randy > Christian June 26, 2014 at 9:18am
        
        Christian,
        
        Yes, the config is being sent to the ublox on each boot. It doesn't send everything though and I had a look in the AP_GPS_UBLOX.cpp file to see what exactly it's sending but even for me that would take a bit of a review. It also tries to turn off messages that it doesn't recognise.
        
        Christian > Randy June 26, 2014 at 12:08pm
        
        Thanks Randy,
        
        with the help of that nice USB port I was able to connect and also booting up pixhawk at the same time. In Ucenter I recognized that the port was still set to SPI and also that the small lock was locked. I guess "you" didn't have a chance to change settings for the very first time. I set it to UART1 manually, unlocked the lock and safed settings. (Baudrate still at 9600)
        
        I disconnected every power source, reconnected, booted up pixhawk and tada your values had been sent. Now baudrate is at 38400 as expected. Also rate settings to 5hz.
        
        Could sb confirm this? pls make a backup of the settings so you could repeat that procedure.
      - gervais > Christian June 26, 2014 at 1:53am
        
        Seems to depend on location. If its not turned off, I did not experience any bad habit because of activated SBAS (EGNOS ..3 Channels)@ center of Germany . (Max M8Q with small active patch) I additionally disabled QZSS @ GNSS Config.
        
        @Emin: Peter showed a direct log comparision at drones-discuss between Max M8Q and LEA 6H as well between Max M8Q and NEO M8N, quite impressive.
- Emin Bu > Christian June 25, 2014 at 6:08pm
  
  so,will you use two gps?
  - Christian > Emin Bu June 26, 2014 at 12:31am
    
    Emin,
    
    yes I'll give it a try. It's a pitty that Missionplanner can't display both GPS data yet. I'm courios of what will happen.
- Raph > Christian June 25, 2014 at 11:52am
  
  that is awesome :). where did you grab the Ublox-Neo-M8N?
  
  edit: woops read up, i see it now http://www.csgshop.com/product.php?id_product=173
  - Distributor
    
    Felix Meissner > Raph June 25, 2014 at 12:55pm
    
    ordered one - I have to try it out :)

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