IMU 1/2/3 X/Y/Z position

Hi all,

I want to set the IMU 1/2/3 X/Y/Z position in relation to the COG as possible now in AC 3.5.
To determine the postion I need to know which is IMU1 and IMU2. According to:

for the Pixracer it is:
IMU 1: ICM20608
IMU 2: MPU9250

Is this correct?

TIA and best regards,

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I don’t think you should worry about setting different values for each IMU. Setting them all the same, based on the distance from the center of the flight controller to the vehicle’s IMU is going to be more than accurate enough I think.

By the way, I’ve created a wiki page today to explain how to set the various sensor offsets. Hope this helps.

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Randy, thanks for your feedback and for the update!
I just had a look at a Dropix and the IMUs are about 1.6cm apart, on the Pixracer it should be around 8mm.

You write that:

In most vehicles which have all their sensors (IMU, GPS, optical flow, etc) within 15cm of each other, it is unlikely that providing the offsets will provide a noticeable performance improvement

But, since it compensates the position estimate setting the offsets should help for RTK applications even if the sensors are within 15cm of each other. For sure this only makes sense if hotshoe trigger feedback is used and if the camera sensor position is compensated as well:

Looking forward to testing it!
Thanks again!

Yes, that is correct.

Francisco, Thanks a lot!

Thanks for looking and trying this out. I’m happy to adjust the “within 15cm” comment. I just don’t want people thinking they need to spend a bunch of time setting this up when for most people, it’s unlikely to make a noticeable difference.

@rmackay9 Maybe change the 15cm comment to a note saying most people don’t need to set it as improvement would be negligible? I think those parameters will only really be important for people already looking for improvements and they would disregard any note.

This function parameter setting is still very meaningful, in the relatively large helicopter, you can get on the installation of a more comfortable electromagnetic environment at the same time, but also to ensure that the GPS receiver position and the main IMU position relative overlap!

Thanks ArdPilot to join this feature!

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I am confuse about the meters and centimeters.
In the imu parameters field( INS_POS1_X, INS_POS1_Y, INS_POS1_Z IMU’s position from the vehicle’s center-of-gravity ) when i change to 20cm the position of the imu should i write(200) or 20?.

sorry it seams a dumb question but i dont get it.


the units is meters, so if you want change 20 cm just write 0,20