  Data fusion algorithms that employ LiDAR measurements, such as Visual-LiDAR,
LiDAR-Inertial, or Multiple LiDAR Odometry and simultaneous localization and
mapping (SLAM) rely on precise timestamping schemes that grant synchronicity to
data from LiDAR and other sensors. Poor synchronization performance, due to
incorrect timestamping procedure, may negatively affect the algorithms' state
estimation results. To provide highly accurate and precise synchronization
between the sensors, we introduce an open-source hardware-software LiDAR to
other sensors time synchronization system that exploits a dedicated hardware
LiDAR time synchronization interface by providing emulated GNSS-clock to this
interface, no physical GNSS-receiver is needed. The emulator is based on a
general-purpose microcontroller and, due to concise hardware and software
architecture, can be easily modified or extended for synchronization of sets of
different sensors such as cameras, inertial measurement units (IMUs), wheel
encoders, other LiDARs, etc. In the paper, we provide an example of such a
system with synchronized LiDAR and IMU sensors. We conducted an evaluation of
the sensors synchronization accuracy and precision, and state 1 microsecond
performance. We compared our results with timestamping provided by ROS software
and by a LiDAR inner clocking scheme to underline clear advantages over these
two baseline methods.
