Lidar Blocked whenever it rains - what does the Lidar do?

[Rogue]

An explanation for folks. This could maybe be resolved by software, but the hardware and physical aspects are the real issue.

Water is a pain for the electromagnetic spectrum. Each droplet has and will slightly affect the "sight" of the radar. Think of light bending through water (part of electromagnetic spectrum) as well as trying to grab something visually in a clear stream (mostly miss because of the offset). To the exact degree the lidar radiation is affected I do not know, but it uses the same electromagnetic spectrum.

Heavy rain would most likely continuously hit the radar wiping away any mist collection similar to rain on a windshield with smaller drops collecting into a big drop to consume more drops. A light rain would not do this, so you have a mist over the radar without any clear gaps to utilize through the droplets.

I hope this makes sense. A mist effectively blocks more surface area causing distortion at a close range vs. scattered drops with distortion pushed farther out allowing limited functionality (and dependent on rainfall heaviness).

Radars can overcome this with stronger radiation to a degree, but then you get into the issue of radiating people, plants, and animals at high doses... That's a huge no no. Plus, the efficiency of the car would decrease.

 

[don]

I am not up on auto technology - but what exactly does the Lidar do? I ask becuase I am wondering what features it impacts in the Lucid Air GT. Every time it rains I get a message on my dash while driving that says "Lidar Blocked - Try Cleaning Sensor". So what will not work on the car if it's blocked, becuase I am not going to stop my car every few miles and wipe the sensors off. And which sensors are the Lidar sensor? Is it just in front of the car or ? I am concerned that it will make the distance to the next car sensors not work - and frankly when it is raining I REALLY want my car to stop instead of slide into the car in front of me on wet pavement. I would think that you should be able to drive this car in the rain - but maybe not....I already hesitate to drive it due to the fragility of the tires, so this is just increasing concerns. Anyone know about Lidar?

My Touring was delivered Saturday and the same thing happened when it rained.

"Lidar Blocked - Try Cleaning Sensor"

 

[AirBo]

I am not up on auto technology - but what exactly does the Lidar do? I ask becuase I am wondering what features it impacts in the Lucid Air GT. Every time it rains I get a message on my dash while driving that says "Lidar Blocked - Try Cleaning Sensor". So what will not work on the car if it's blocked, becuase I am not going to stop my car every few miles and wipe the sensors off. And which sensors are the Lidar sensor? Is it just in front of the car or ? I am concerned that it will make the distance to the next car sensors not work - and frankly when it is raining I REALLY want my car to stop instead of slide into the car in front of me on wet pavement. I would think that you should be able to drive this car in the rain - but maybe not....I already hesitate to drive it due to the fragility of the tires, so this is just increasing concerns. Anyone know about Lidar?

I am glad you brought this up. I have a similar issue and it happens even when it is drizzling. I have informed the customer service but they replied it is not uncommon. I urge everyone to contact them and demand a fix since it is a software issue. We should not settle for any issue (the car is not cheap). When more people report an issue my experience is that the Lucid team ultimately resolves it (sometimes not to satisfaction but at least they try).

 

[AirBo]

An explanation for folks. This could maybe be resolved by software, but the hardware and physical aspects are the real issue.

Water is a pain for the electromagnetic spectrum. Each droplet has and will slightly affect the "sight" of the radar. Think of light bending through water (part of electromagnetic spectrum) as well as trying to grab something visually in a clear stream (mostly miss because of the offset). To the exact degree the lidar radiation is affected I do not know, but it uses the same electromagnetic spectrum.

Heavy rain would most likely continuously hit the radar wiping away any mist collection similar to rain on a windshield with smaller drops collecting into a big drop to consume more drops. A light rain would not do this, so you have a mist over the radar without any clear gaps to utilize through the droplets.

I hope this makes sense. A mist effectively blocks more surface area causing distortion at a close range vs. scattered drops with distortion pushed farther out allowing limited functionality (and dependent on rainfall heaviness).

Radars can overcome this with stronger radiation to a degree, but then you get into the issue of radiating people, plants, and animals at high doses... That's a huge no no. Plus, the efficiency of the car would decrease.

Why was the radar not installed inside in this case? This is an engineering issue!

 

[Rogue]

Why was the radar not installed inside in this case? This is an engineering issue!

What? Lidar is installed. I did call it radar, but that is an issue primarily of semantics, not functionality and operation.

No, this is not a software issue so much as it is a physics issue. Software is not a magic bullet. Thus, there was this whole explanation you quoted with something tangible most people have experienced: "optical illusions of water" aka distortion of the electromagnetic radiation aka lidar's eyes.

While folks have joked about tiny wiper blades, that would be a clever resolution.

 

[BNL]

You should NOT get this message just because it rains... I drive in the rain all the time, and it doesn't happen for me.

I get this same warning most rainy days. Not all.

 

[Tâm]

No, this is not a software issue so much as it is a physics issue. Software is not a magic bullet. Thus, there was this whole explanation you quoted with something tangible most people have experienced: "optical illusions of water" aka distortion of the electromagnetic radiation aka lidar's eyes.

While folks have joked about tiny wiper blades, that would be a clever resolution.

I don't see why physical issues can't be solved with software. Star Link says its signal can't penetrate below the water, so don't blame it for the Titan submersible problem. However, with no issues, technology has evolved to carry voice, data, and video signals from other submersibles on the ocean floor to the mothership. The Titan submersible used a flawed communication system, not because the technology was unavailable.

As mentioned in post #8, rain is no longer a problem for Lidar in Waymo in natural (not artificial) heavy rain.

Another company with artificial rain produced by a water truck:

 

[joec]

An explanation for folks. This could maybe be resolved by software, but the hardware and physical aspects are the real issue.

Water is a pain for the electromagnetic spectrum. Each droplet has and will slightly affect the "sight" of the radar. Think of light bending through water (part of electromagnetic spectrum) as well as trying to grab something visually in a clear stream (mostly miss because of the offset). To the exact degree the lidar radiation is affected I do not know, but it uses the same electromagnetic spectrum.

Heavy rain would most likely continuously hit the radar wiping away any mist collection similar to rain on a windshield with smaller drops collecting into a big drop to consume more drops. A light rain would not do this, so you have a mist over the radar without any clear gaps to utilize through the droplets.

I hope this makes sense. A mist effectively blocks more surface area causing distortion at a close range vs. scattered drops with distortion pushed farther out allowing limited functionality (and dependent on rainfall heaviness).

Radars can overcome this with stronger radiation to a degree, but then you get into the issue of radiating people, plants, and animals at high doses... That's a huge no no. Plus, the efficiency of the car would decrease.

This makes sense, given the one time I got this warning it was raining lightly. I've driven many, many times in hard rain and got nothing.

I agree this is a hardware problem. But it could be mitigated in software by making the warning a little less dire-looking. As far as I can tell, LiDAR isn't doing much in the car right now, anyway. Especially if you aren't using HA at the time. So maybe put up a little light in the warnings bar on the bottom of the cockpit center panel to let you know it's not working optimally and be done with it? I certainly don't think it needs to take up an entire side of the screen.

 

[Rogue]

I don't see why physical issues can't be solved with software. Star Link says its signal can't penetrate below the water, so don't blame it for the Titan submersible problem. However, with no issues, technology has evolved to carry voice, data, and video signals from other submersibles on the ocean floor to the mothership.

As mentioned in post #8, rain is no longer a problem for Lidar in Waymo.

There are a couple issues with this comparison.

1) The "rain" was extremely light. If we ignore the quantity issue, then there is the matter of coverage. They did a few meters worth, not 1000+ meters of coverage.
2) The lidar was not subjected/exposed to rain on the surface. As discussed in this thread, the issue derives from a misted over surface vs. seeing through the rain with a clean surface.
3) The outputs of their lidar vs. Lucid's lidar are unknown.
4) This was clearly advertisement brushing over the first two points. If this was a real dive into their capabilities, I would expect an explanation of how they bypass the very clear noise from the poorly executed rain simulation blocking what was behind it in the eyes of the lidar.

Traversing from one medium to another is not trivial for the reasons explained in my earlier post. If you are isolated to a single medium, then sure you could work with that. However, the type of the signal is almost certainly not the same (frequency, power output, regulations on both, etc.).

Again, software is not a magic bullet. The physics of signal processing and data from signal processing are only as good as what a lidar/radar can detect/see. If the lidar cannot see to begin with, then the software has nothing to work off of.

 

[Tâm]

Again, software is not a magic bullet....

I don't deny that, in theory, LIDAR should not work in the rain.

However, in reality, Waymo has been running around in the rain in real life (not testing, not artificial rain) for Youtubers:

 

[Tâm]

...The physics...

Five years ago, Torc Self-Driving in heavy rain (doesn't look like it in the picture but it is).

4 years ago compilation in the rain:

Pony in bad weather, including heavy rain:

 

[Rogue]

Five years ago, Torc Self-Driving in heavy rain (doesn't look like it in the picture but it is).

I went to Waymo's website onto the technology page for this video:

Look closely at the timestamps of 1:32-1:45. The part labeled as Lidar spins. Why does it spin? My guess would be to counter the very issue we are facing: water collection on the surface of the lidar. That would be a hardware solution, not a software solution.

Once more to denote discrepancies and subtleties of argument:
1) We do not know the total contribution of the Lidar and other sensors in the decision process for the autonomous driving. Maybe they have videos, but the ones you and I both have provided do not delve into this information.
2) Other sources of input are being used vs. just lidar. This is a similar approach to Lucid.
3) The packaging mechanisms are both larger and constructed in a way as to minimize the effects of weather. Cameras and sensors appear to be tucked into open cubbies. Where applicable, sensors spin and move as part of the data collection process and removal of possible water collection.

All this to say that Lucid has included a variety of sensors to offset and future proof system redundancies. The team is most likely focused/spread out on other software aspects, and these features are complex in nature. Improvements will come as the underlying software systems evolve to compensate for the lidar's inoperability at times.

Waymo has/had the backing and brain power of one of the largest tech giants, if not the largest, Google. Appearances were certainly not a consideration given the tacking of equipment to the outside of the cars. Operation is limited to a handful of cities and pre-selected passengers.

The future is bright no matter how you look at it for greater safety features and autonomous driving (for those who want it).

 

[Alex]

Look closely at the timestamps of 1:32-1:45. The part labeled as Lidar spins. Why does it spin? My guess would be to counter the very issue we are facing: water collection on the surface of the lidar. That would be a hardware solution, not a software solution.

The LIDAR spinning is for scanning the surroundings. The LIDAR imaging uses a set if Vertical transmitters and sensors and needs to spin in order to cover 360º field of view. The removal of rain is just a byproduct. The LIDAR sensor in the Lucid is a fixed kind which is solid state, roughly using the same principals as the iPhone face recognition hardware.

 

[Tâm]

1) We do not know the total contribution of the Lidar and other sensors in the decision process for the autonomous driving. Maybe they have videos, but the ones you and I both have provided do not delve into this information.

People often think that if LIDAR is added that means there's no need for Radar and Sonars...

Tesla does not believe in sensor fusion but the rest of the industry does. LIDAR still needs clues from other sensors to decipher the rain algorithm as well.

2) Other sources of input are being used vs. just lidar. This is a similar approach to Lucid.

Yes. Sensor fusion is important and even more in the rain.

3) The packaging mechanisms are both larger and constructed in a way as to minimize the effects of weather. Cameras and sensors appear to be tucked into open cubbies. Where applicable, sensors spin and move as part of the data collection process and removal of possible water collection.

Yes. All that means is LIDAR can work in the rain as long as the hardware/software setups are appropriate.

Waymo has/had the backing and brain power of one of the largest tech giants, if not the largest, Google. Appearances were certainly not a consideration given the tacking of equipment to the outside of the cars. Operation is limited to a handful of cities and pre-selected passengers.

No doubt. It's just like when Boeing Starliner couldn't reach the International Space Station on its first try to orbit the earth, not because there's no technology to do it. There is but it's a matter of using the technology correctly to get to the ISS (it is blamed on the clock error).

Same with LIDAR, it's possible to use LIDAR in the rain because others can.

 

[borski]

Why was the radar not installed inside in this case? This is an engineering issue!

Radar is installed behind the bumper but does not need line of sight. LiDAR, due to the fact that it uses lasers, which are light, requires clear sight, and thus cannot be installed behind the bumper (though it is behind a translucent cover).

 

[Julesncate]

I am about a year late to this discussion...but I get this message EVERYTIME it rains. And that's concerning since bad weather is when you would want your sensors to work for you. Has there been any solution to this issue?

 

[Tâm]

I am about a year late to this discussion...but I get this message EVERYTIME it rains. And that's concerning since bad weather is when you would want your sensors to work for you. Has there been any solution to this issue?

Most ADAS are designed for easy, boring scenarios such as good weather, straight roads... If they are curvy roads, make sure they are not too curvy.

Humans are supposed to take over in more challenging scenarios.

Current active consumer Mercedes Lidar is being used in Europe for L3 and soon in the US but notice that its L3 is disabled if the system detects enough wetness, so no rain for you!

If you want the machine to work hard for you in challenging scenarios (rain), those are L4 and L5 but no one sells those to consumers yet. You can ride an L4 Waymo but you can't buy it.

 

[Julesncate]

Most ADAS are designed for easy, boring scenarios such as good weather, straight roads... If they are curvy roads, make sure they are not too curvy.

Humans are supposed to take over in more challenging scenarios.

Current active consumer Mercedes Lidar is being used in Europe for L3 and soon in the US but notice that its L3 is disabled if the system detects enough wetness, so no rain for you!

If you want the machine to work hard for you in challenging scenarios (rain), those are L4 and L5 but no one sells those to consumers yet. You can ride an L4 Waymo but you can't buy it.

thanks Tam...then why is it in the car? and why did we pay big bucks to have it? it's like the great sound systerm we can't really get the full benefit from (especially when sirius xm doesn't work) and the rapid charging when there are virtually no (few) (other than Tesla) super chargers that can charge our GT's that fast.

 

[hydbob]

thanks Tam...then why is it in the car? and why did we pay big bucks to have it? it's like the great sound systerm we can't really get the full benefit from (especially when sirius xm doesn't work) and the rapid charging when there are virtually no (few) (other than Tesla) super chargers that can charge our GT's that fast.

The sound system you can definitely get full benefit from, not through Sirius though.

 

[Tâm]

thanks Tam...then why is it in the car? and why did we pay big bucks to have it? it's like the great sound systerm we can't really get the full benefit from (especially when sirius xm doesn't work) and the rapid charging when there are virtually no (few) (other than Tesla) super chargers that can charge our GT's that fast.

Because if Waymo can do it, hopefully we will be able to do a cheapo version of Waymo.

Waymo has much more robust hardware and firmware. We have a much more rudimentary version of Waymo.

Once Lucid is more mature, we can expect it will be able to do as described on the advertisement: