ADAS Systems and Limitations

[Adnillien]

I see a lot of criticism of Lucid’s Dream Drive ADAS system. Some of which is well deserved, some if which also shows an incomplete understanding of how ADAS systems work. The biggest criticism seems to be reaction, or lack of reaction, to stopped cars. Lucid does seem worse than other systems, but almost every system includes a warning about stopped objects. Below is some background on fundamental ADAS components, their limitations and fusion of sensor data. I have NOT included ultrasonic and parking assist functions. I am also ignoring vision only systems (Tesla) because I have not spent any time researching that system. All sensors have advantages and limitations. Hence, multi-sensor systems are most common.

Below is a generic picture of different ADAS sensors. The number of radar, LiDAR and camera sensors can be different from different automakers. The overall view is common.

Due to limitations of posts on the forum, I will break this post into multiple sections. One on sensors and one on sensor fusion along with a summary.

 

[Adnillien]

Cameras
Camera systems are very inexpensive, have high resolution and with the right software can provide good target identification. Most importantly, highway lane marking along with sign recognition. Multiple cameras are easily placed around the car to form a 360 degree view of what is happening around the car.

The limitation of cameras is that they can be blinded by bright lights and see reflections as real images. In addition, images are obscured by rain, fog and snow. Distance information is limited by triangulation of multiple cameras and correct identification of the center of the target. Relative speed of a target has be calculated from multiple images over time.

Standard Radar (Old but still standard technology)
Most radar used for adaptive cruise control only is referred to as 3D radar. It senses distance, bearing and relative speed. It can see about 200 m and has an azimuth of 20 degrees with 4 degrees of resolution. Thinking of resolution another way, 150 m is about 4.5 seconds at 70mph. At 150 m, resolution is about 10 m or the width of 4.5 Lucids. It does not have any vertical information. It can only track a few hundred targets. Continental ARS4xx systems are representative of this type of radar.

4D Radar
4D radar adds vertical information and higher resolution to standard radar. Its field of view is 60 degrees in azimuth with 3 degrees of resolution. It has a vertical field of view of 15 degrees with 6 degrees of resolution. It can track around a thousand targets. The vertical information helps to distinguish between stationary objects that should be tracked (stopped cars) and fixed objects that should not be tracked. At a 150m, the resolution is 7.8 m or 3.5 Lucids wide. Continental ARS510 is an example.

4D Imaging Radar
4D imaging radar has range of 300 m with improved resolution of 1 degree in azimuth and 2 degrees vertically. It also allows tracking of more objects. At 150 m, one degree of resolution is 2.6 m or just a little wider than a typical car. Continental ARS540 is an example. Lucid’s forward radar is continental 5 series but I cannot tell if it is 4D or 4D imaging.

All Radars
Most cars have multiple radar sensors. Long range forward radar and shorter range corner radar to see cross traffic and form a full view around the car.
Radar has the advantage of seeing through most weather (rain, fog and snow). It provides relative speed information in a single pass. The primary disadvantage is low resolution. That is especially important with stopped cars where it sees multiple car widths as a single target. Radar can only track a limited number of targets and excludes stationary objects from tracking. Hence, a stopped car can easily be ignored and why most radar based systems warn about stopped traffic.

LiDAR
LiDAR has a range of 150 m, 120 degree field of view with a resolution of 0.05 degrees. It has a vertical field of view of 25 degrees. Most current LiDAR is based on time of flight meaning that it cannot detect relative speed in a single pass. Future LiDAR will migrate to Frequency Modulated Continuous Wave which will add target speed and lesson the potential for interference. The big advantage of LiDAR is resolution. At 150 m, it sees a target of 0.13m wide. Weather attenuates LiDAR but it is better at seeing through weather than optical cameras. Interference from other LiDAR systems may become a problem for time of flight systems.

The disadvantage of LiDAR is cost and placement. Lucid’s Robosense LiDAR unit costs around $1900. Radar is typically placed low on the front grille so that it can see cars ahead when coming over a hill. LiDAR is ideally placed as high as possible to see over objects in front of it. The different location is because LiDAR has a better vertical field of view than radar. Lucid’s placement looks great but may not be the best for functionality.

Here are Robosense specs. The source is edge emitting laser with Si Photo-multiplier receiver. 150 m range, 750,000 points per second. 120 degrees in azimuth with 0.05 degree resolution. 25 degree vertical field of view. 15 W power consumption.

 

[Adnillien]

Late Sensor Fusion
Traditional sensor fusion is called late fusion. In late fusion, each sensor has its on target detection and identification. The resulting information is combined at the end to complete perception. Late fusion was adopted because computing power can be distributed, individual sensor target detection requires less computing power than trying to do target recognition on all sensors data at once. The limitation is that final perception is based on filtered sensor data, reducing the information available for final perception. Think about the blurring of images across sensor resolution. Most legacy automakers are use this approach. Since late fusion has been around a long time, software is well developed and most systems are very good at perceiving objects. Below is a block diagram showing late fusion.

Early Sensor Fusion
A newer sensor fusion strategy is referred to early fusion. In early fusion, all of the sensor information is combined before target identification. The advantage is that all sensor information, rather than filtered targets, is available for the perception algorithm. The disadvantage is that it requires a very high power central processor for the fusion. This is the approach used by Lucid and most of the Chinese EV makers. Since it is a newer strategy, the perception algorithms are not as well developed. It is also why I have hope that the Lucid system will continue to improve. A block diagram of early fusion is shown below.

Summary
All sensors have strengths and limitations. Cameras for resolution and target identification. Radar for seeing through weather. LiDAR for best angular resolution. Fusion from multiple sensors overcomes individual sensor limitations and takes advantage of each sensors advantages. Don’t count on any radar based system to recognize stopped cars. Even if some systems are better at it then others, this weakness is inherent with the radar technology. LiDAR should help to overcome this weakness. Early fusion, used by Lucid, has potential for better perception but needs a lot more development.

 

[MoniputerLM]

The ACC in my wife's Mercedes SL, AMG EQS and in my Lincoln, Navigator will slow down and stop if the traffic in front has stopped. My Lucid will not. As far as I am concerned the Lucid is broken.

 

[Adnillien]

The ACC in my wife's Mercedes SL, AMG EQS and in my Lincoln, Navigator will slow down and stop if the traffic in front has stopped. My Lucid will not. As far as I am concerned the Lucid is broken.

You have said this before and I have said before that you should heed the warnings in the manual before you trust your life to something.

 

[MoniputerLM]

You have said this before and I have said before that you should heed the warnings in the manual before you trust your life to something.

Lucid did not do a good job of implementing ACC, end of story.

 

[Adnillien]

Lucid did not do a good job of implementing ACC, end of story.

Not really since Lucid provides OTA updates.

 

[Alex]

Lucid did not do a good job of implementing ACC, end of story.

It’s also possible that Lucid didn’t implement the ACC system, because the implementation is provided by Nvidia. Maybe they are waiting for Nvidia to update their drivers.

 

[Hoosier Owner]

A few days ago I was backing my Lucid Air Dream Edition out of a parking spot in a garage. I was paying attention, but to my dismay my vehicle hit a long truck that was sticking out on the other side without stopping automatically, but worse there was no audible warning that I was getting close to the other vehicle. Lucid customer service basically told me the system does not always work properly. I'm in shock. A $179,000 car that does not have this software/hardware perfected yet! I have a 2018 Mercedes S560 that gets this right 100% of the time. Twice backing out of a parking spot it abruptly slammed on the brakes as it determined a car was coming, thereby avoiding the collision.

I also have a 2021 Honda CR-V Touring that does better than the Lucid at collision warnings and avoidance.

So now when I drive the Lucid, I basically treat it like a 1990 Honda without any cameras or safety equipment. I do not trust that my Lucid would stop if I approach a car ahead of me too fast; maybe it would work sometime, but other times the software latency might be an issue that causes me to smash into the car ahead of me. Amazing that software with the Lucid is so very poor all around. No wonder no one wants to buy their cars.

 

[hydbob]

A few days ago I was backing my Lucid Air Dream Edition out of a parking spot in a garage. I was paying attention, but to my dismay my vehicle hit a long truck that was sticking out on the other side without stopping automatically, but worse there was no audible warning that I was getting close to the other vehicle. Lucid customer service basically told me the system does not always work properly. I'm in shock. A $179,000 car that does not have this software/hardware perfected yet! I have a 2018 Mercedes S560 that gets this right 100% of the time. Twice backing out of a parking spot it abruptly slammed on the brakes as it determined a car was coming, thereby avoiding the collision.

I also have a 2021 Honda CR-V Touring that does better than the Lucid at collision warnings and avoidance.

So now when I drive the Lucid, I basically treat it like a 1990 Honda without any cameras or safety equipment. I do not trust that my Lucid would stop if I approach a car ahead of me too fast; maybe it would work sometime, but other times the software latency might be an issue that causes me to smash into the car ahead of me. Amazing that software with the Lucid is so very poor all around. No wonder no one wants to buy their cars.

Just so I understand this crappy situation correctly, you were reversing and hit a stationary object because there was no audible warning? Was the reverse camera not function or the 360 view not working?

 

[Hoosier Owner]

Yes, I hit a stationary object (truck that had it's back end sticking far out of its parking spot; no excuse as still my fault for hitting him). Reverse camera and 360 view were both functioning. But the audible warning I expect was not working. And I thought the car would stop itself before hitting an object while backing out, but that tech is apparently not yet available on the Lucid Air.

 

[hydbob]

Yes, I hit a stationary object (truck that had it's back end sticking far out of its parking spot; no excuse as still my fault for hitting him). Reverse camera and 360 view were both functioning. But the audible warning I expect was not working. And I thought the car would stop itself before hitting an object while backing out, but that tech is apparently not yet available on the Lucid Air.

Was it one of those lifted pickups? I remember some other member did the exact same thing because the location of the sensors was lower than where the truck bed was located so it did not detect the object and hence no warning. Sorry this happened to you!

 

[Hoosier Owner]

It might have been lifted. It was for sure an extended bed truck, very long, and not pulled into its spot. It had a rubber-type bumper and so no damage to the truck. On my Lucid it made scuff marks on the right side (middle part from top to bottom), but no dent.

 

[borski]

Yes, I hit a stationary object (truck that had it's back end sticking far out of its parking spot; no excuse as still my fault for hitting him). Reverse camera and 360 view were both functioning. But the audible warning I expect was not working. And I thought the car would stop itself before hitting an object while backing out, but that tech is apparently not yet available on the Lucid Air.

It does try to stop, but it isn’t perfect; no driver assistance is. It always behooves you to watch the cameras and look in the mirrors / over your shoulder.

 

[AirDoll]

A few days ago I was backing my Lucid Air Dream Edition out of a parking spot in a garage. I was paying attention, but to my dismay my vehicle hit a long truck that was sticking out on the other side without stopping automatically, but worse there was no audible warning that I was getting close to the other vehicle. Lucid customer service basically told me the system does not always work properly. I'm in shock. A $179,000 car that does not have this software/hardware perfected yet! I have a 2018 Mercedes S560 that gets this right 100% of the time. Twice backing out of a parking spot it abruptly slammed on the brakes as it determined a car was coming, thereby avoiding the collision.

I also have a 2021 Honda CR-V Touring that does better than the Lucid at collision warnings and avoidance.

So now when I drive the Lucid, I basically treat it like a 1990 Honda without any cameras or safety equipment. I do not trust that my Lucid would stop if I approach a car ahead of me too fast; maybe it would work sometime, but other times the software latency might be an issue that causes me to smash into the car ahead of me. Amazing that software with the Lucid is so very poor all around. No wonder no one wants to buy their cars.

I wasn’t aware my car would essentially drive itself. All of this time I’ve been doing all the work myself and don’t need to? In all seriousness you are still the operator of the car, and if the cameras were working and you saw the object, why didn’t you hit the brake yourself? It’s also my understanding that the automatic braking is used at higher speeds. I don’t think you can blame Lucid for this, sorry.

 

[Bunnylebowski]

That’s unfortunate your car got damaged (I scraped the side of my house recently, the car was alarming but it was my own stupid fault, I didn’t expect it to
auto brake), but saying “no wonder why no one wants to buy their cars” because the car isn’t 100% effective in preventing 100% of collisions is absurd. Your own description of the accident implies this wasn’t a normal type object placement anyway. The Lucid has saved me from 2 parking lot collisions and one T-bone where my view was blocked of a car coming from my left. Yeah what a piece of crap, they should go bankrupt over the fact that it’s not perfect.

 

[Bunnylebowski]

I also must add I had a 2019 Mercedes with the same tech your 2018 one had, and it was not perfect, there were a couple occasions in parking lots where I luckily was able to intervene rapidly because the car did not recognize the impending impact.

 

[Ampere]

Why do so many people expect technology to save them? Although my Lucid Air Touring includes all the helpful aids to prevent me from damaging my car or someone else's vehicle, I still operate it like my 2007 Camry. When parking or in tight situations I roll slowly, repeatedly look in all directions and then use the Lucid's screens to double-check my blind spots. The bleeps and beeps are more of an annoyance than an aid. The Air is a wonderful car with impressive technology, but ultimately I, the driver, am totally responsible for its operation. Similarly, driving the Air gives me great pleasure. I'm not sure I want autonomous driving. It's nice to have warnings and emergency systems to help me avoid accidents, but I like being the driver. Cruise control and lane keeping make life behind the wheel easier, but one of my hands always rests on the steering wheel and my foot remains ready to hit the brake or accelerator in an emergency.

 

[Hoosier Owner]

I wasn’t aware my car would essentially drive itself. All of this time I’ve been doing all the work myself and don’t need to? In all seriousness you are still the operator of the car, and if the cameras were working and you saw the object, why didn’t you hit the brake yourself? It’s also my understanding that the automatic braking is used at higher speeds. I don’t think you can blame Lucid for this, sorry.

I admitted it was my mistake in this thread. I was using the backup camera but I fucked up by not watching closely enough. In any case, my Mercedes does and has stopped. I hope Lucid improves this technology to get up to where the Mercedes is with theirs.

 

[Sparky2]

Well, with last weeks update , I am grateful that I no longer have to fight with the "center lane keeping system" when I put on my turn signal to change lanes, it had been a huge aggravation . Now the car nologer fights me when I try to change lanes.!!