3 ms·
"slightly accurate" is the correct description, though -- dead reckoning on a cell-phone-class IMU accumulates drift too quickly to keep objects anchored in spa
by addaon 3mo ago
"slightly accurate" is the correct description, though -- dead reckoning on a cell-phone-class IMU accumulates drift too quickly to keep objects anchored in space for more than seconds at a time. You need something (visual odometry, SLAM) that provides long-term stability, even if it has short-term noise or poor availability, to fuse in.
- gregsadetsky 3mo agoWhen this topic comes up, I'm always happy to share this incredible lecture from many many years ago about sensor fusion and dead reckoning and how you _cannot_ integrate acceleration twice: https://www.youtube.com/watch?v=C7JQ7Rpwn2k&t=1401s https://www.youtube.com/watch?v=C7JQ7Rpwn2k&t=1401s (the whole video is incredible, but this timestamp is the magical bit)
- pezezin 3mo ago12 years ago I had to write the firmware for an IMU. It took me some real effort to convince my bosses that double integration was, for all practical purposes, impossible. I wish I had known about this video back then... IMU are very useful to known your orientation though. Even an inaccurate IMU is useful to provide an initial estimate to feed vision-based algorithms.
- hahahaa 3mo agoSo you tend to need additional data or assumptions to constrain the double integral?
- pezezin 3mo agoYou don't double integrate, period. You essentially have three options: 1) An absolute positioning system like GPS. 2) A visual positioning system like fiducial markers or SLAM. 3) Something that can measure linear speed and then you integrate the speed only once. Easy to do on vehicles, but even the most accurate system will quickly drift.