Livox Hub
User Manual
©
2019 Livox Tech. All Rights Reserved.
11
Usage
Output Data
The output data of Livox Hub includes point cloud data, timestamps, and status codes.
Point Cloud Data
Livox Hub, as a processing unit to connect and integrate Livox LiDAR sensors, will not affect the point
cloud data output of the LiDAR sensors connected. Only the LiDAR sensors will affect the point cloud
data. Refer to the Output Data section in the corresponding Livox LiDAR sensor’s user manual for more
information.
Timestamp
Time synchronization is supported by IEEE 1588-2008 (PTPv2) and GPS.
IEEE 1588-2008 (PTPv2): IEEE 1588-2008 is the Precision Time Protocol (PTP) enabling precise
synchronization of clocks in measurement and control systems by Ethernet. Livox LiDAR sensors, as the
ordinary clock in the PTP, only supports UDP/IPV4 for PTP. Livox LiDAR sensors support the following
message events: Sync, Fllow_up, Delay_req, Delay_resp.
GPS: GPS is a way to precisely synchronize the point cloud sampling time using the sync pulse
generated. The time synchronization can be completed with a PPS signal and a NMEA $GPRMC record.
PPS is the precise pulse per second, and its rising edge is 1s. $GPRMC offers the UTC time of PPS. The
time sequence of PPS and $GPRMC is shown below. After time synchronization, each point cloud data
packet will include a timestamp indicating the sampling time of the point cloud. Please refer to the SDK
Communication Protocol for more information.
t0: 1000 ms
t1: 20 ms ≤ t1 ≤ 200 ms
t2: ~70 ms @ 9600 bps
t3: 0 ms ≤ t3 ≤ 430 ms
PPS
$GPRMC
t2
1
1
0
0
t0
t1
t3
Figure 5.1.1 GPS sync signal description
Working States & Working Modes
Working States
When Livox Hub is in use, it automatically monitors the working states of all the Livox LiDAR sensors
connected. Users can check the working state of Livox Hub and all the Livox LiDAR sensors connected
using Livox Viewer or the Livox SDK.
