I have a setup where my robot is capturing images with an onboard camera, while its pose is being measured by an external motion capture system, whose software is running on a different PC. The two machines talk to each other over a WLAN. I need to have good synchronization of the timestamps in the camera's images and the poses from the mocap system. I plan on using the TF library to do the work of determining which pose message to pick (or messages to interpolate, perhaps?), but this assumes that the clocks on the computers are well synchronized. Thus far, I have one gateway computer on the WLAN with internet access that keeps its clock up to date with OpenNTP, and the two computers mentioned above using OpenNTP, with the gateway as their NTP source. I'm not sure of how to check how well this attempt at synchronization is working, though. How have others approached this problem? I have heard that Chrony is a possible solution and would be interested to hear of any experiences with it or any other method. Thanks, Pat