Finally.  I was pushing for this back in 2003, but the volume wasn&#x27;t there.<p>There are quite good eye-safe flash LIDAR units.[1] Advanced Scientific Concepts in Santa Barbara makes some.[1]  A pulsed laser sends out a flash, and the receiver has a 128x128 pixel chip with time of flight counters for each pixel.  Range in hundreds of meters, in sunlight. No moving parts except a fan.  Cost is about $100K, because they are hand-made using custom ICs produced in tiny volumes.  Space-X uses one on the Dragon spacecraft to dock with the space station.<p>Back in 2003, when we were preparing for the DARPA Grand Challenge, I went down to Santa Monica to see the thing. But the demo was of components on an optical bench, aimed out a garage door into a parking lot.  The technology wasn&#x27;t ready to use yet, but it was clearly the right idea, something that would become cheap in volume.  They were working more on making the device more sensitive than on making it cheaper, because they were getting DoD funding.  Some of their units even have a photomultiplier tube stage, like an image intensifier.  The photoelectric effect is at the atomic level, and so fast you can use it in front of a time of flight device.<p>So we ended up using the SICK LMS scanner, like everybody else.<p>There&#x27;s a tradeoff between field of view and range with flash LIDAR, because there&#x27;s a limited amount of illumination power. A single one of these devices won&#x27;t give a full circle of scan, like the Velodyne rotating devices.<p>There&#x27;s a cheaper, but less precise, approach, used in the Kinect 360. That&#x27;s the ZCam technology.  See p. 13 of this paper [2] for how it works.  It&#x27;s a phase-shift type LIDAR; the outgoing beam is modulated with an RF signal, and the phase shift of the RF carrier is measured on return. That&#x27;s also all solid state, but not as good at rejecting interfering illumination.  It doesn&#x27;t have digital counters for each pixel; the timing system is analog.  So they don&#x27;t need counters running at tens of GHz behind every pixel.<p>Once someone is ready to order &gt; 100,000 flash LIDARs, they&#x27;ll get cheap. The technology is not inherently that expensive.<p>The main reason for having a LIDAR is not to see obstacles. It&#x27;s to profile the terrain ahead.  You can detect potholes and drop-offs.  Since we were driving off-road for the DARPA Grand Challenge, that was absolutely essential.  Automatic driving systems for on-road use can sleaze by without doing that.  Most of the time.  Until they encounter a big pothole, or are misled by road markings into a ditch.  That&#x27;s why Google has that LIDAR up on top.<p>[1] <a href="http:&#x2F;&#x2F;www.advancedscientificconcepts.com&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.advancedscientificconcepts.com&#x2F;</a> 
[2] <a href="http:&#x2F;&#x2F;tesi.cab.unipd.it&#x2F;47172&#x2F;1&#x2F;Tesi_1057035.pdf" rel="nofollow">http:&#x2F;&#x2F;tesi.cab.unipd.it&#x2F;47172&#x2F;1&#x2F;Tesi_1057035.pdf</a>