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Example for sensor_msgs/Imu covariance matrix

asked 2019-05-21 11:12:24 -0500

beluga gravatar image

Hello, I am having hard time understanding how to use the covariance matrices.

I checked some websites and I think I understand what covariance matrices are, and how I can implement them into a sensor_msgs/Imu format message if I know them.

I have an imu and I am publishing a sensor_msgs/Imu format message with the help of this link:

I am putting -1 for the first element of all 3 covariance matrices(orientation, lin.acc.,ang.vel.). So it looks like I am publishing the message without any issues.

I wanted to ask if there is a way to calculate these covariances if my imu not giving any details about them. Or if there is a better way than just writing -1 for the first element of the matrices?

The imu/gps I have is publishing velocity uncertainty, position uncertainty, but it requires gps for that. Right now I wanted to try without the gps info and even if I have the gps connected I dont think those uncertainties are related to covariances, right?

Thank you!

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What do you mean that IMU is publishing uncertainty? Is it a ROS node publishing that message? What type of message is?

ricber gravatar image ricber  ( 2019-06-06 03:03:13 -0500 )edit

So I have this imu/gps --> VN200 by Vectornav. It prints out velocity uncertainty and position uncertainty each as a single value, float. In order to use it the GPS is needed to be connected. This is the uncertainty of GPS, right? I should not be using it in the covariance matrix.

beluga gravatar image beluga  ( 2019-06-13 08:36:39 -0500 )edit

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answered 2019-06-06 03:02:37 -0500

ricber gravatar image

updated 2019-06-06 03:03:05 -0500

The question about IMU covariances has already been asked here.

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Asked: 2019-05-21 11:12:24 -0500

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Last updated: Jun 06 '19