The KITTI dataset provides its IMU raw outputs in its raw data fold. There are two kinds of coordinate systems, one of which can be expressed as xyz and the other as flu. For example, the accelerations are shown as ax, ay, az and af, al, au. They two seem to be the body coordinate system. However, I compare the two related of them (such as ax and af) and they are not equal.
How can I understand them well?
Just a general hint: It is always a difference if you describe your accelerations and turn rates in the sensor coordinate system or the body frame of the vehicle. They both can have the same orientation (in this case: forward, left, up), but since there are some effects like euler-, and coriolis-forces occuring in the transformation, the values not the same.
I'm not familiar with this dataset, but I assume that ax,ay,az is in body-frame, and af, al, au is in IMU-sensorframe.
Benjamin Tennstedt
Thank you! I am not familiar with the Q&A of Research Gate and I can only tell you to know my reply.
Yes. In fact, when I use the SINS or IMU mounted in a body, the body-frame and IMU-sensor frame you remind are different and they have a installation error. Unfortunately, the KITTI dataset does not provide the calibration matrix of it. I am not sure of the meannings of them.
There seems to be a paper describing this dataset, including a sketch of the experimental setup and leverarms.
https://www.mrt.kit.edu/z/publ/download/2013/GeigerAl2013IJRR.pdf
Apparently they also describe the two (xyz) and (flu) systems ;)
Cheers,
Benjamin
Benjamin Tennstedt
Thank you very much! I see the paper and the descriptions of xyz and flu-frames.
Thank you! Best Regards！
Yuxuan Cao & Benjamin Tennstedt Thanks for a helpful discussion. By any chance are you able to see actual any calibration matrix (IMU to Vehicle frame ) ? I also wonder, how to interpret xyz and flu coordinate values.
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