# Revision history [back]

### Failed to compute odometry pose

Hi, i'm trying to use nav2d package to make autonomous exploration with a turtlebot3 burger. When i roslaunch my robot, before starting mapping and exploration, rviz says that no map is received and trying to debug with rqt_console i've found this warnings/errors:

Failed to compute odometry pose, skipping scan (Lookup would require extrapolation into the past. Requested time 1455208818.863310001 but the earliest data is at time 1531473492.888660568, when looking up transform from frame [base_scan] to frame [offset])

and:

Costmap2DROS transform timeout. Current time: 1531473499.6759, global_pose stamp: 1455208815.6299, tolerance: 0.3000

I haven't found a solution through other questions on this forum, i have a problem with sync time i suppose, but even if i tried to change something( clicking on reset like is said here link text or setting true on sim_time), nothing changed and i don't understand how to solve this problem. On this question link text was suggested to use this command

\$ sudo ntpdate ntp.ubuntu.com

but it says that no suitable server for synchronization is found.

Thanks for help!!