topic Re: Convert linear acceleration vector to earth frame of reference in MEMS sensors forum
https://community.bosch-sensortec.com/t5/MEMS-sensors-forum/Convert-linear-acceleration-vector-to-earth-frame-of-reference/m-p/27972#M7915
<P>Hi,</P><P>we're working on an exercise velocity tracking application. In order to precisely determine when an exercise has started and stopped (so we can minimize the integration drift of the accelerometer when calculating the velocity) we want to determine the direction that the acceleration is going towards, relative to a fixed coordinate system (for example <SPAN class="ILfuVd"><SPAN class="hgKElc">NED)</SPAN></SPAN>.</P><P>For this we tried the approach of using the rotation vector quaternion as outlined above, however we are unable to get a valid rotated acceleration vector out of the calculation.</P>Fri, 13 Aug 2021 10:38:36 GMTmaxlo2021-08-13T10:38:36ZConvert linear acceleration vector to earth frame of reference
https://community.bosch-sensortec.com/t5/MEMS-sensors-forum/Convert-linear-acceleration-vector-to-earth-frame-of-reference/m-p/27921#M7897
<P>Hi,</P><P>for the IoT Innovation Challenge we are using the Nicla Sense ME's integrated IMU to determine the acceleration in reference to a global basis.</P><P>For this we tried to use the SENSOR_ID_RV rotation Quaternion. However, using he quaternion data to rotate the acceleration vector (q*p*(q conj)) does not result in an accordingly rotated vector.</P><P>How can we use the rotation vector to rotate the data to the earth frame of reference?</P>Thu, 12 Aug 2021 21:19:14 GMThttps://community.bosch-sensortec.com/t5/MEMS-sensors-forum/Convert-linear-acceleration-vector-to-earth-frame-of-reference/m-p/27921#M7897maxlo2021-08-12T21:19:14ZRe: Convert linear acceleration vector to earth frame of reference
https://community.bosch-sensortec.com/t5/MEMS-sensors-forum/Convert-linear-acceleration-vector-to-earth-frame-of-reference/m-p/27926#M7901
<P>Hello maxlo,</P>
<P>Could we know some of your project information?</P>Fri, 13 Aug 2021 01:33:56 GMThttps://community.bosch-sensortec.com/t5/MEMS-sensors-forum/Convert-linear-acceleration-vector-to-earth-frame-of-reference/m-p/27926#M7901BSTRobin2021-08-13T01:33:56ZRe: Convert linear acceleration vector to earth frame of reference
https://community.bosch-sensortec.com/t5/MEMS-sensors-forum/Convert-linear-acceleration-vector-to-earth-frame-of-reference/m-p/27972#M7915
<P>Hi,</P><P>we're working on an exercise velocity tracking application. In order to precisely determine when an exercise has started and stopped (so we can minimize the integration drift of the accelerometer when calculating the velocity) we want to determine the direction that the acceleration is going towards, relative to a fixed coordinate system (for example <SPAN class="ILfuVd"><SPAN class="hgKElc">NED)</SPAN></SPAN>.</P><P>For this we tried the approach of using the rotation vector quaternion as outlined above, however we are unable to get a valid rotated acceleration vector out of the calculation.</P>Fri, 13 Aug 2021 10:38:36 GMThttps://community.bosch-sensortec.com/t5/MEMS-sensors-forum/Convert-linear-acceleration-vector-to-earth-frame-of-reference/m-p/27972#M7915maxlo2021-08-13T10:38:36ZRe: Convert linear acceleration vector to earth frame of reference
https://community.bosch-sensortec.com/t5/MEMS-sensors-forum/Convert-linear-acceleration-vector-to-earth-frame-of-reference/m-p/32552#M7953
<P>Update - we figured it out, the mistake was caused by not scaling the orientation quaternion data by 2^-14. Now it works like a charm!</P>Wed, 18 Aug 2021 15:24:28 GMThttps://community.bosch-sensortec.com/t5/MEMS-sensors-forum/Convert-linear-acceleration-vector-to-earth-frame-of-reference/m-p/32552#M7953maxlo2021-08-18T15:24:28Z