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Check frame conversions (NED->ENU ROS) #49
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I did the same, inverting the Y & Z axis for orientation and acceleration. Don't forget to switch X and Y for the magnetometer and invert Z. |
Why magnetometer use different conversion? |
Normal NED <> ENU conversion is swap X and Y and invert Z. What is the invert Y & Z conversion for? |
Is it front not X? Or it is for body? I do rotation on X 180° => Y & Z inverts. |
Acceleration and angular rates are related to the body frame itself so 180 degrees rotates it according to the body frame that is needed for ROS. Using ROS's standard X is forward, Y is left and Z is up. Using the absolute frame ENU, East is X and forward, North is Y and left and Up is Z and Up. So going from NED to ENU, those changes need to be made to follow the ROS standard. I have not tested the magnetometer since I use my APM unit in an area with magnetic interference but I will do so soon. |
I can test, but don't know how to visualize it and where it should point (North?). |
Hard to visualize. The maximum values for XYZ should be at ENU, so when X is pointing East it should be the largest value and West the smallest. For North and South, it should be zero. I can test later today. |
Change conversion to swap X & Y, invert Z.
3DR GPS module arrow pointing to East, and x ~= 101000.0 when pointing to West. |
I believe it is correct as well, I tested with my 3DR GPS/compass. |
I need to know, what quaternion conventions are we using on the IMU data topics? |
Invert Y & Z, then convert (tf:Quaternion.setRPY). |
Released 0.6. This theme still opened for hotfix (if any). |
I was checking this... If I point the Pixhawk horizontally (flat), I get +9.8 on Z Is that correct??????? In ENU, will X be pointing forward and Y be pointing right? |
Y must point to left. Try imu rviz plugin to check. In my case vector pointing up in all poses (see my screenshots in #33). |
New question: how to convert quaternion? |
What quaternion to euler angles? https://www.dropbox.com/s/my1fvqr81rtfpoe/quaternion-rotations-tested_g.xls On Thu, Jul 24, 2014 at 10:03 PM, Vladimir Ermakov <notifications@github.com
Regards, M: +61 (0) 413 902 541 |
No, convert frame ENU→NED. |
I believe it is: |
@mhkabir and @ggregory8 I call your attention also to this. |
I have a doubt regarding the conventions, which I need to clarify to add to my thesis: |
Initially it confuse me too, but later I found that the x-forward refers to a body-fixed frames. |
Yes. At least i use that convention in code. |
@mhkabir Look at the diagram of the last TSC21's post for body-frame. |
Thanks. Got it already :)
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@vooon |
The mag is absolute and the others are relative. |
* master: (52 commits) travis: update coverity scan plugin: sts_time: Code cleanup and codestyle fix. plugin: command: Quirk for older FCU's (component_id) plugin: rc_io: #185 Use synchronized timestamp. plugin: gps: #185 use synchronized timestamp uas: Fix ros timestamp calculation. plugin: add synchronisation to most plugins (fixed) readme: Add notes about coordinate frame conversions #49 travis: add gitter notification Added Gitter badge mocap_pose_estimate: Switched from pose to poseStamped. 0.9.4 Prepare correction release 0.9.4 plugin: sys_time: enable EMA 0.9.3 Prepare minor release 0.9.3 #182 Initiliser fix plugin: visualisation - Fixes CI build plugin: visualisation plugin: visualization minor patch ...
Hi, everyone |
It is not a global ENU -> NED modified, but a body one, see discussion on mavlink/mavros#49
Current implementation use this definitions av8n.com of NED and ENU. Conversion is just invert Y & Z axis (all right-handed).
But according to CoordinateFramConventions it is left-handed?
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