File: sensor_msgs/TimeReference.msg
# Measurement from an external time source not actively synchronized with the system clock.
Header header # stamp is system time for which measurement was valid
# frame_id is not used
time time_ref # corresponding time from this external source
string source # (optional) name of time source
Expanded Definition
Header header
uint32 seq
time stamp
string frame_id
time time_ref
string source