Drift in z using Livox MID-360
LotfiZ opened this issue · 7 comments
Hello dear,
First, what an amazing work that pushes the LIO state of art further !
I started to play a little bit with the package using a LIVOX mid-360 on a grounded robot and i observed that in x-y the estimation is quite good, however there is a significant drift in Z, as you can see in the following picture :
What do you think about this behaviour ? i can also provide the bag file if its necessary !
EDIT : To prevent that, is it possible to add a constraint regarding the flatness of the world ?
Thank you !
same here! i've observed this with other LIO/LO algorithms also, fastlio, pointlio, voxelmapping, fasterlio.
Same here!
Hey fellow mid-360 users. Might this be due to the fact that the imu values are normalized in the topic, and has to be multiplied by gravity constant in order to be useful. I have yet to find a documented value which livox use internally, and we all have to guess. Which gravity values are you using? Do you see the same error when increasing/lowering the constant?
Hi @schablonmassig, do you mean increasing/decreasing the 9.8 value in the ig_node ? And yes, i observed the same drift in all the SOTA LIO algorithms even without using IMU.
@LotfiZ tried that, didn't work
i thought since imu gyr values are normalized, we would need to multiply the gravity factor to make it right, but that is not the case.
maybe try this
enable_acc_correct: true
tried fiddling with the gravity values, it drifts.
enable_acc_correct denormalizes the acceleration values by multiplying with 9.80665. But that also doesn't help.