ATE and RPE errors

[L D]

Hello,

I have an estimated trajectory from GTSAM containing N poses and a ground truth trajectory containing Ngt poses. I want to caclulate the ATE (absolute trajectory error) and the RPE (relative trajectory error) and the corresponding RMSE (root mean square error) as defined in the link below:

https://www.ybliu.com/2020/07/visual-slam-evaluation-aterte.html

My issue is that in order to compute RMSE of the RPE, I need fixed time intervals between poses. In my case I have no timestamp but rather ground truth poses that are not uniformly spaced. Can I use, instead of Delta, a step S between the current and next pose although the poses are note equally spaced ?

Thank you for your help.