Hesai QT128C2X, User Manual

Page: 90 / 101

- 88 -
■ Absolute Time of Point Cloud Data Packets
Definition
· Every time the lidar passes a fixed time Δt or azimuth interval Δα (see Section 4.2 Web Control – Trigger Method), it sends a command that
triggers a round of firing.
· A round of firing can have either one or more returns (specified in Section 4.2 Web Control – Return Mode). The measurements of each
return are stored in one block (see Section 3.1.2 UDP Data – Body).
· The absolute time of a Point Cloud Data Packet is the time when the lidar sends the command that triggers a round of firing that will be
stored in the first block.
This absolute time is output to the Date & Time field and the Timestamp field in Point Cloud Data Packets.
Δt or Δα
···
Point Cloud
Data Packet
···
···
t0 t1
t2 tT t3
absolute time of
the Point Cloud
Data Packet
Block 1 Block 2 Block 3 Block 4 Block M-1 Block M
A round of firing
Last
Ch 1
Ch 2
...
Ch N
Strongest
Ch 1
Ch 2
...
Ch N
A round of firing
Last
Ch 1
Ch 2
...
Ch N
Strongest
Ch 1
Ch 2
...
Ch N
A round of firing
Last
Ch 1
Ch 2
...
Ch N
Strongest
Ch 1
Ch 2
...
Ch N
Return selected
according to Return
Mode, taking dual-
return (last and
strongest) as an
example
Trigger
firing