So after reading too many posts on here, I got curious and started hunting down patents both on the Lidatek LE-10 (which I have, and have never used) which I believe has a flaw in the description, and on lidar units themselves. In particular I was always rather curious how a lidar gun is able to so accurately measure distance. When you send a pulse out and it comes back, light is traveling effectively 150 million meters per second, so that means to get 1 cm accuracy you'd need roughly a 1.5GHz counter, and to get mm accuracy you'd need more like a 15GHz counter. While this is doable, its not really in the realm of reasonable for relatively cheap mid-90s commercial technology.
While reading through LTI's patents, I was actually quite impressed (something I rarely am when reading patents since most of them appear to be total garbage). Besides explaining at least roughly how they deal with the above issue they explicitly or implicitly mentioned that they have the following capabilities:
1) Ability to randomize when they send out a pulse for the purpose of fooling laser jammers that want to try to memorize their pattern. (This was explicitly mentioned as being intended to counter laser jammers).
2) Ability to measure and alter the exact length of the pulse they send out
3) The ability to dynamically adjust the "window" in which they observe the receiving pulse. In otherwords, if a jammer sends out a pulse and its not received while the window is open, the pulse is completely rejected -- and they explicitly state they do adjust the window after each pulse received.
Here's the deal... Let's say you have a vehicle moving at 100 meters per second (a little over 200 mph), and you are sending out 100 pulses per second, that means that the vehicle can move up to 1 meter between pulses, which means the time of flight should change no more than 6.666 ns from the last pulse. So if the lidar unit sends out a pulse, and sees a reflection after say 10 microseconds, it knows the next time it sends it out it should be 10 us +/- 7 ns. If the next time it sends it out, it sees the time of flight was 9.999 us, then it can be reasonably sure the third pulse will have a time of flight of 9.998, but you could even open up that window to be 9.997 to 9.999. Afterall, even a Lamborghini is going to have a hard time doing 30 to 60 in .01 seconds.
If they chose to use windows like that, in order for your jammer to have any effect whatsoever on lidar gun you'd have to have your response timed to within a few nanoseconds. And remember, the lidar unit can randomize when it sends out the pulse. So say instead of every 10 ms, it was every 10 ms +/- 100 microseconds. You'd have to guess ahead of time when its going to send out the pulse to get your timing right, within a 15 nanosecond window of 200000 nanoseconds. Not real likely.
But then there's the fact that the gun has the ability to measure and alter its pulse width. So the gun sends out a random pulse width, and is looking for a pulsewidth of the exact same length. Again, if it randomizes the pulse width on each firing, you would have to have foreknowledge of the pulse width. Not real likely either. It can simply reject a pulse that is of a different length than it fired.
Even if the lidar unit didn't filter out the false pulses with its windowing technique, it still has the capability to observe multiple return pulses. If it looks at the data in totality over multiple pulses, and its seeing one return that is saying the target is at an almost constant distance but changing slowly and predictably, and a bunch of others that are erratic, it shouldn't be too hard to pick out the correct return.
So the only way I see a lidar jammer as working is if the unit, 1) doesn't effectively use windowing (relatively easy), 2) doesn't randomize the pulse stream (easy), and 3) doesn't do good signal processing (relatively difficult, although getting easier with every passing year), or if the lidar jammer were some how able to send out false returns before it actually received the first one (nearly impossible unless its constantly operating, which as far as I know, none do).