Once the cost goes down, multiple LIDAR units can be mounted behind the windshield. Cars designed for automatic driving should reserve the top inch or so of the windshield for sensors, with the optical sensor suite mounted at the front edge of the roof and covered with padding matched to the headliner. (Yes, auto glass today is often infrared-opaque to reduce heat input, but the IR-opaque layer could be omitted for the top inch.) Putting cameras behind the rear view mirror is already done, but more space may be needed.
The rotating Velodyne thing Google uses is an interim research tool. In production, expect to see better design.
With enough LIDAR units, full-circle coverage can be achieved. This is already being done with cameras. The rear and side units need less power and range than the front-facing units, so they can have a smaller collecting aperture, making them easier to place. For the front-facing units, the emitter can be spread out, allowing higher power. The rules on eye safety are concerned with the maximum power coming through a 1/4" hole (human eye pupil). If the laser emitters are spread out over the width of the windshield, the maximum power per unit area is reduced.
The CMU/Cadillac demo a few years ago managed to conceal all the sensors. It can be done. It just costs too much until one of the three companies claiming to be building low-cost automotive LIDARs Real Soon Now manages to deliver.
> ...costs too much until one of the three companies claiming to be building low-cost automotive LIDARs Real Soon Now manages to deliver.
All I see is future promises. Tesla wants to do this now, that too at mass market costs, independent of whether those promises materialize or not.
It also depends on how much you trust their R&D team. If they thought this was a week sensor suite and something else was just around the corner, they won't risk fitting their cars with inferior technology which would be obsolete in a couple of years, making all the collected data worthless. Yes I am aware they did this to existing cars lacking the full autonomy hardware, but I find that OK, since, for them, they never promised full autonomy to begin with.
No, Tesla doesn't want to do automatic driving now. They want to hype it now. The software isn't ready yet. In their announcement, they say that the new hardware will, right now, support fewer automatic driving features than the current hardware.
Low-cost LIDAR is a problem that can be solved with money and a customer ready to buy a lot of units. So far, no car company has said "we'll take a million units a year at $100 if they meet these specs." It's lack of demand, not lack of technology. It's a risk for the LIDAR maker. There are automotive radars available better than those currently on cars, but they don't have a volume buyer yet.
You provided no evidence for the hype claim but even then you are contradicting yourself:
Statement A: Tesla is just hyping autonomous driving since no technology can deliver fully autonomous driving right now.
Statement ~A: Low-cost LIDAR is available to any high-volume customer, of which Tesla is one, given Model 3 demand. And LIDAR can deliver fully autonomous driving.
The point simply being, I have a hard time believing that even with good-looking, cheap LIDAR being a possibility, as you claim, Tesla chose to go with an inferior sensor suite, for no apparent reason.
What they're doing now is a minor retrofit to their existing crashes-into-big-solid-objects "autopilot".
The Model 3 is at least two years away. By then, the technology should be better.
Volvo already has a concealed LIDAR in their self driving car.[1] Volvo will put 100 self-driving cars in the hands of ordinary drivers in Sweden in 2017. This is self-driving by the pros. Makes Tesla look amateurish.[2]
And Volvo is way ahead on marketing self-driving.[3]
