# Recording the robots absolute base movement?

**URL:** <https://forum.hello-robot.com/t/recording-the-robots-absolute-base-movement/520>\
**Category:** Ask\
**Created:** [October 18, 2022, 4:42am UTC](https://forum.hello-robot.com/t/recording-the-robots-absolute-base-movement/520 "2022-10-18T04:42:07Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![thyatt](https://avatars.discourse-cdn.com/v4/letter/t/8491ac/32.png) [@thyatt](https://forum.hello-robot.com/u/thyatt)\
**Post date:** [October 18, 2022, 4:42am UTC](https://forum.hello-robot.com/t/recording-the-robots-absolute-base-movement/520/1 "2022-10-18T04:42:07Z")

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I am thinking about recording the absolute base movement of the robot (2 meters forward, 3 back, etc.) for a scientific experiment, but I want accuracy down to a centimeter or two. Is it possible to easily achieve this without resorting to external hardware? If so, has someone done so already? I have heard the base’s movements are not that precise, but is that just for control or for measuring as well?

Still quite a novice in this realm of engineering, and as I am already using the realsense camera externally, I would like to avoid attempting to range find with it as that may cause conflicts.

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**Author:** ![lamsey](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.hello-robot.com/lamsey/32/177_2.png) [@lamsey](https://forum.hello-robot.com/u/lamsey)\
**Post date:** [October 19, 2022, 3:39pm UTC](https://forum.hello-robot.com/t/recording-the-robots-absolute-base-movement/520/2 "2022-10-19T15:39:24Z")

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I haven’t formally measured the accuracy of the robot’s motion, but this may help. From my experience, wheel odometry alone drifts pretty significantly, especially on carpeted floors. Depending on your experiment, you may be able to get accurate enough localization using data from the LIDAR in the robot’s base. If you’re using ROS, check out [FUNMAP](https://github.com/hello-robot/stretch_ros/tree/master/stretch_funmap) or the [ROS Navigation Stack](http://wiki.ros.org/navigation). Recording the position tracked in those packages may fit your needs.