The VLS-128 has 4× the data density and 2× the range of the HDL-64 it replaces.
Murray Slovick, Contributing Editor
In engineering you are cautioned against making sweeping generalizations and you try not to engage in hyperbole. Nevertheless, Velodyne has come out with a new LiDAR unit, designated VLS-128, and unashamedly boasts that it is the highest-performing LiDAR sensor on the market in terms of all the metrics that count: field of view, range, resolution, and ability to deal with a complex environment.
Designed for autonomous vehicles and the ADAS market, the Velodyne VLS-128, with 128 laser beams, replaces the company’s HDL-64 LiDAR unit.
By way of review LiDAR—the acronym stands for light detection and ranging—can be thought of as light-based radar. In operation, a sensor sends out short pulses of invisible laser light, and a detector times how long it takes (TOF, Time of Flight) to see the reflection. Since we know exactly how fast light travels in air, TOF then determines exactly how far away the target is. By firing off millions of beams of light per second, the measurements from a LiDAR sensor also enable a visualization of the world in 3D.
Can Velodyne back up its claims? Well, the company did not issue test reports but compared to the model it replaces VLS-128 represents quite a jump in performance.
For example, high resolution is the key to simultaneously judging the speed of other vehicles, determining pedestrian locations, and calculating safety margins. In terms of object detection and collision avoidance, high-resolution LiDAR is essential when traveling at speeds higher than 30 miles per hour; the faster a vehicle goes, the more data is needed for safety evaluation.
Velodyne claims the VLS-128 has four times the resolution of the HDL-64, which, according to its datasheet has 0.08 deg. angular resolution (the minimum angular separation at which two equal targets can be separated when at the same range) along with double the range of the HDL-64. Since the range of the HDL-64 is 120m, that would put the VLS-128 at 240m.
The new Velodyne sensor has 128 scanning channels (compared to 64 channels in the HDL-64) and four times the data density of its predecessor (which generated 2.2 million points per second), enhancing its ability for object detection and collision avoidance. At the same time the 128 is 70% smaller than the HDL-64.
Solid-state LiDAR is LiDAR on a microchip and in this case VLS-128 is built with 905nm technology using a mass-produced CMOS semiconductor process. It is manufactured at Velodyne’s factory in San Jose; earlier this year the company said it would produce over a million units a year at the new plant. Velodyne says the factory has a proprietary fully automatic laser alignment and manufacturing system. Future models will also be produced as part of Velodyne’s Tier-1 Automotive Program.