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Hi, We have a Velodyne Lidar (HDL-32E)(equipped with IMU) that I am trying to start with it. we have gathered UDP positioning packet(port 8308) which includes gyroscope, accelerometer and temperature measurements. I have a few questions:

1- Should all gyro measurements be negative? (mine are)

2- We get 6 accelerometer measurements (ACC1x, ACC1y, ACC2x, ACC2y, ACC3x, ACC3y). I expected to have 3 acceleration measures. How can I get these 6 to 3 x-y-z accelerations?

3- We get 3 temperature measures? why 3? do they differ?

I really appreciate your help.


Originally posted by MinaAttari on ROS Answers with karma: 21 on 2013-10-25

Post score: 2


Original comments

Comment by joq on 2013-10-25:
I have no access to that device and no experience with it. Maybe others can help.

Comment by joq on 2013-10-25:
Appendix B in the 32E manual does have some diagrams and hints: http://velodynelidar.com/lidar/products/manual/63-9113%20HDL-32E%20manual_Rev%20E_NOV2012.pdf .

Comment by Michiel on 2014-07-28:
I have the same question 2, how can I get the 3 x-y-z accelerations from these 6 measurements? You already figured it out?

Comment by Heikki on 2015-12-04:
In order to get the orientation and accelerations out of these 6 measurements, you should use some IMU algorithm. For example this: http://dx.doi.org/10.1155/2015/503814 and it has source code available here: https://github.com/hhyyti/dcm-imu

Comment by joq on 2015-12-04:
Note: there is now an experimental velodyne_gps_imu package in github. It's currently in the gps_imu branch, not yet merged into master. Anyone who tries it, please comment on pull request #53

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Figure B2 on Page 18 of the manual that @joq linked shows the orientation of the accelerometers and gyros.

The manual also notes "Note: Each gyro incorporates a 2-axis accelerometer which results in redundancy in some axial directions"

From all of that, it sounds like they're using three separate gyroscopes internally, each of which probably has its own temperature sensor for calibration.


Originally posted by ahendrix with karma: 47576 on 2014-07-28

This answer was ACCEPTED on the original site

Post score: 1

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