Velodyne HDL-64E S3 User Manual

HDL-64E S3
High Definition LiDAR Sensor
Page 20
Velodyne LiDAR, Inc.
©
2019
63-HDL64ES3 REV K
Laser Firing Sequence and Timing
If the GPS timestamp feature is used, it can be useful to determine the exact firing time for each laser so
as to properly time-align with the other data sources.
The upper block and lower block collect distance points simultaneously, with each block issuing one laser
pulse at a time. That is, each upper block laser fires in sequence and in unison with a laser from the lower
block.
Lasers are numbered sequentially starting with 0 for the first lower block laser to 31 for the last lower
block laser; and 32 for the first upper block laser to 63 for the last upper block laser. For example, laser
32 fires simultaneously with laser 0, laser 33 fires with laser 1, and so on.
The sensor has an equal number of upper and lower block returns. Hence, when interpreting the delay
table, each sequential pair of data blocks represents the upper and lower block respectively. Each upper
and lower block data pair in the Ethernet packet has the same delay value.
Six firings of each block takes 139 µs and then the collected data is transmitted. It takes 100 µs to transmit
the entire 1248 byte Ethernet packet. This is equal to 12.48 Bytes/µs and 0.080128 µs/Byte. See Appendix
E for more information.
A timing table, shown in Appendix G, shows how much time elapses between the actual capturing of a
distance point and when that point is output from the device. By registering the event of the Ethernet data
capture, you can calculate back in time the exact time at which any particular distance point was captured.

Velodyne HDL-64E S3 Specifications

General

Brand	Velodyne
Model	HDL-64E S3
Category	Accessories
Language	English