ROS Answers: Open Source Q&A Forum - RSS feedhttps://answers.ros.org/questions/Open source question and answer forum written in Python and DjangoenROS Answers is licensed under Creative Commons Attribution 3.0Mon, 09 Jan 2012 00:45:51 -0600How do you obtain covariance from manufacturer datasheet?https://answers.ros.org/question/12413/how-do-you-obtain-covariance-from-manufacturer-datasheet/I am looking through the imu driver code ([microstrain_3dmgx2_imu](http://www.ros.org/wiki/microstrain_3dmgx2_imu)) to understand how I can write a driver for my own IMU.
I notice the parameters for orientation/angular velocity/linear acceleration stdev were derived from the manufacturer datasheet ("The default value, derived from the manufacturer datasheet, is very conservative.")
What I would like to know is, how is this derivation done? For example, if the "Accelerometer nonlinearity" is 0.2%, and "Accelerometer bias stability" 0.010 g, how do I get the variance?Tue, 20 Dec 2011 13:15:06 -0600https://answers.ros.org/question/12413/how-do-you-obtain-covariance-from-manufacturer-datasheet/Comment by mjcarroll for <p>I am looking through the imu driver code (<a href="http://www.ros.org/wiki/microstrain_3dmgx2_imu">microstrain_3dmgx2_imu</a>) to understand how I can write a driver for my own IMU.</p>
<p>I notice the parameters for orientation/angular velocity/linear acceleration stdev were derived from the manufacturer datasheet ("The default value, derived from the manufacturer datasheet, is very conservative.")</p>
<p>What I would like to know is, how is this derivation done? For example, if the "Accelerometer nonlinearity" is 0.2%, and "Accelerometer bias stability" 0.010 g, how do I get the variance?</p>
https://answers.ros.org/question/12413/how-do-you-obtain-covariance-from-manufacturer-datasheet/?comment=20255#post-id-20255Related: http://answers.ros.org/question/413/how-do-i-compute-the-covariance-matrix-for-anMon, 09 Jan 2012 00:45:51 -0600https://answers.ros.org/question/12413/how-do-you-obtain-covariance-from-manufacturer-datasheet/?comment=20255#post-id-20255Answer by weiin for <p>I am looking through the imu driver code (<a href="http://www.ros.org/wiki/microstrain_3dmgx2_imu">microstrain_3dmgx2_imu</a>) to understand how I can write a driver for my own IMU.</p>
<p>I notice the parameters for orientation/angular velocity/linear acceleration stdev were derived from the manufacturer datasheet ("The default value, derived from the manufacturer datasheet, is very conservative.")</p>
<p>What I would like to know is, how is this derivation done? For example, if the "Accelerometer nonlinearity" is 0.2%, and "Accelerometer bias stability" 0.010 g, how do I get the variance?</p>
https://answers.ros.org/question/12413/how-do-you-obtain-covariance-from-manufacturer-datasheet/?answer=18534#post-id-18534Turns out that the "Accelerometer bias stability" is the standard deviation. So variance is just the square of it -- in this case (0.010 g)^2
note: g is the gravitational accel 9.81ms^-2Sun, 08 Jan 2012 15:39:34 -0600https://answers.ros.org/question/12413/how-do-you-obtain-covariance-from-manufacturer-datasheet/?answer=18534#post-id-18534