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Why did Tesla decide not to use radar any more? What wavelengths do other cars' radars operate at? How big are the apertures?

by twic 5y ago

sschueller 5y ago
I can only think of three reasons: incompetence, arrogance or cost. I tend to think it's mostly arrogance in believing the self driving "problem" can be purely done with cameras and software. Cost as well as availability of parts became an issue this year as well.
- Pyramus 5y ago
  My bet is on cost. It's the stated reason not to use lidar and it only makes sense to apply to radar (not knowing the cost of a radar sensor compared to camera - please share if you do). Elon may not be a great engineer but he is a genius businessman in many aspects so that would also make sense.
  - phpnode 5y ago
    I'm sure aesthetics play a large role too, lidar is not only costly, it's bulky and ugly. To a layman the sole reliance on cameras seems like one of Tesla's biggest mistakes.
    - enriquto 5y ago
      > lidar is not only costly, it's bulky and ugly. This is quite subjective. My opinion is not very representative, but I for one find teslas horrifically bulky and ugly (and most other cars, in fact). They all look like gigantic broken eggshells. On the other hand, a lidar rig looks very cool.
  - baybal2 5y ago
    Imaging radars are way more expensive than cameras, but the type useful in the most basic collision avoidance costs just few dollars. There is no reason to not to have them in a car priced $100k, even just as a failsafe backup to the videocamera. In the future though, mass produced single chip radars have all the chances to beat every other sensing method on cost.
- Retric 5y ago
  Radar has serious issues detecting stationary objects. Which is why early automatic cruse control systems had minimum speeds, they simply don’t work in stop and go traffic. Lidar on the other hand has no problem with stationary objects, but cars can’t depend on it in all weather conditions. Which means full self driving cars need to be able to operate based on vision like we do. I would expect all level 5 systems to use Lidar especially if costs continue to drop, but it’s not as clear cut as you might think.
  - baybal2 5y ago
    Not every radar out there is a Doppler radar. But you are right on the point of there being no silver bullet sensing technology. All of them have their own very glaring weaknesses. Radars are superior for simple collision avoidance for them being able to directly sense the velocity, but they are obviously useless for lane keeping. Lidars are super unreliable from both internal factors, and the environment. Basically, a splat of dirt, and a collision. Cameras are subject to all uncertainties of a CV system, and smog, smoke, and weather as well.
  - masklinn 5y ago
    The advantage of computer integration is that self-driving vehicle can use all three technologies to make the best use of everything and compensate for any technology's failures. Unless they remove them and rely on only one type of sensor, which is exactly what Tesla has done. It's like complaining that each sense has issues, then removing all but one. Multimodal integration is literally how we use our senses normally.
    - Retric 5y ago
      I am not convinced any self driving system is going to be dependent on RADAR in 20 years. Tesla was using RADAR and stopped because it just don’t really solve any specific problems well. RADAR is great for collision detection and early breaking systems because drivers don’t depend on them. If they fail in an early breaking system noting worse happens. But self driving systems can’t accept failures like that. These systems would need to stop if their camera/Lidar system failed so what’s it actually useful for?
- dham 5y ago
  Radar has too many issues detecting stopped objects. A parked car vs a manhole cover. Both Tesla and Comma.ai think solving self driving is purely a software problem and can be solved with just vision. For instance, humans, the only known driving implementation currently, drive with only vision. This videos goes over sensors briefly. https://www.youtube.com/watch?v=h6zYS7WSyw8 https://www.youtube.com/watch?v=h6zYS7WSyw8
- 542354234235 5y ago
  The main reason is cost. LIDAR has issues and limitations, but so does every imaging system. A LIDAR/camera system is far superior than a camera only system, and LIDAR does far more thing better than cameras, than cameras do better than LIDAR (judging distance, reduced computing effort, detecting reflective surfaces and surfaces with 2D images on them).[0] But LIDAR was running $70k per vehicle, which is just not feasible. But thanks to technological development and economies of scale, the price of LIDAR (and the size) has drop precipitously, and now can run below $1,000. [1][2] Now in the long run, for true driverless cars, LIDAR will be rendered obsolete by sufficiently accurate AI interpretations of camera feeds. But in the medium term, I think they are key to filling in huge weaknesses camera only systems have, and freeing up computing power currently being used by trying to judge “depth perception” using cameras, to be freed up to better deal with other things cameras are actually good at like color/text recognition for reading traffic signs, facial recognition for determining if a pedestrian sees you, differentiating between hard and soft objects, etc. [0] https://www.automotiveworld.com/articles/lidars-for-self-driving-vehicles-a-technological-arms-race/ https://www.automotiveworld.com/articles/lidars-for-self-dri... [1] https://asia.nikkei.com/Business/Automobiles/Cheaper-lidar-sensors-brighten-the-future-of-autonomous-cars https://asia.nikkei.com/Business/Automobiles/Cheaper-lidar-s... [2] https://news.itu.int/the-price-of-lidar-is-falling/ https://news.itu.int/the-price-of-lidar-is-falling/
DeBraid 5y ago
IIRC, in this[1] video Andrej Karpathy mentions radar was mostly redundant, and in addition was occasionally harmful (sending conflicting signals vs. video), so they got rid of it to reduce cost and complexity. [1]: https://youtu.be/g6bOwQdCJrc https://youtu.be/g6bOwQdCJrc
- londons_explore 5y ago
  In that video Karpathy says a lot of things which are the corporate line, but don't really match up with math and statistics...
snarf21 5y ago
Yeah, nothing makes sense except cost. Even for these kind of level 2 system, they should be forced to have camera + lidar + radar. There is no reason to not use as many data sources as possible. If it is to expensive, work on that. Batteries used to be more expensive too but they focused on that. Spend some of your stock on lidar/radar acquisitions.
baybal2 5y ago
Apertures are very small, and predominant majority of radars are not imaging. Yet, that's the very point. These very primitive radars are more than enough for a car to avoid an obvious collision threat.
DoingIsLearning 5y ago
> Why did Tesla decide not to use radar any more? System redundancy in safety-critical systems exists for a reason. Either their engineering team refused to see this or they were unable to make Product/Management/Regulatory people see it. AEB is quite finicky and needs quite a fair bit of calibration and mechanical alignment, still like the article says can suffer from false positives. But although LIDAR is still prohibitively expensive it is possible to design ADAS that can integrate stereo camera, RADAR and long range sonar, that would at least give you three sources of data for some margin. > What wavelengths do other cars' radars operate at? The spectrum used for AEB in most transceivers is 76 GHz to 81 GHz (so between about 3.9 and 3.7 mm) some older implementations also worked at 24GHz i think.

Why did Tesla decide not to use radar any more? What wavelengths do other cars' radars operate at? How big are the apertures?

by twic 5y ago

Why did Tesla decide not to use radar any more? What wavelengths do other cars' radars operate at? How big are the apertures?

sschueller 5y ago

I can only think of three reasons: incompetence, arrogance or cost. I tend to think it's mostly arrogance in believing the self driving "problem" can be purely done with cameras and software. Cost as well as availability of parts became an issue this year as well.

Pyramus 5y ago
My bet is on cost. It's the stated reason not to use lidar and it only makes sense to apply to radar (not knowing the cost of a radar sensor compared to camera - please share if you do). Elon may not be a great engineer but he is a genius businessman in many aspects so that would also make sense.
- phpnode 5y ago
  I'm sure aesthetics play a large role too, lidar is not only costly, it's bulky and ugly. To a layman the sole reliance on cameras seems like one of Tesla's biggest mistakes.
  - enriquto 5y ago
    > lidar is not only costly, it's bulky and ugly. This is quite subjective. My opinion is not very representative, but I for one find teslas horrifically bulky and ugly (and most other cars, in fact). They all look like gigantic broken eggshells. On the other hand, a lidar rig looks very cool.
- baybal2 5y ago
  Imaging radars are way more expensive than cameras, but the type useful in the most basic collision avoidance costs just few dollars. There is no reason to not to have them in a car priced $100k, even just as a failsafe backup to the videocamera. In the future though, mass produced single chip radars have all the chances to beat every other sensing method on cost.
Retric 5y ago
Radar has serious issues detecting stationary objects. Which is why early automatic cruse control systems had minimum speeds, they simply don’t work in stop and go traffic. Lidar on the other hand has no problem with stationary objects, but cars can’t depend on it in all weather conditions. Which means full self driving cars need to be able to operate based on vision like we do. I would expect all level 5 systems to use Lidar especially if costs continue to drop, but it’s not as clear cut as you might think.
- baybal2 5y ago
  Not every radar out there is a Doppler radar. But you are right on the point of there being no silver bullet sensing technology. All of them have their own very glaring weaknesses. Radars are superior for simple collision avoidance for them being able to directly sense the velocity, but they are obviously useless for lane keeping. Lidars are super unreliable from both internal factors, and the environment. Basically, a splat of dirt, and a collision. Cameras are subject to all uncertainties of a CV system, and smog, smoke, and weather as well.
- masklinn 5y ago
  The advantage of computer integration is that self-driving vehicle can use all three technologies to make the best use of everything and compensate for any technology's failures. Unless they remove them and rely on only one type of sensor, which is exactly what Tesla has done. It's like complaining that each sense has issues, then removing all but one. Multimodal integration is literally how we use our senses normally.
  - Retric 5y ago
    I am not convinced any self driving system is going to be dependent on RADAR in 20 years. Tesla was using RADAR and stopped because it just don’t really solve any specific problems well. RADAR is great for collision detection and early breaking systems because drivers don’t depend on them. If they fail in an early breaking system noting worse happens. But self driving systems can’t accept failures like that. These systems would need to stop if their camera/Lidar system failed so what’s it actually useful for?
dham 5y ago
Radar has too many issues detecting stopped objects. A parked car vs a manhole cover. Both Tesla and Comma.ai think solving self driving is purely a software problem and can be solved with just vision. For instance, humans, the only known driving implementation currently, drive with only vision. This videos goes over sensors briefly. https://www.youtube.com/watch?v=h6zYS7WSyw8 https://www.youtube.com/watch?v=h6zYS7WSyw8
542354234235 5y ago
The main reason is cost. LIDAR has issues and limitations, but so does every imaging system. A LIDAR/camera system is far superior than a camera only system, and LIDAR does far more thing better than cameras, than cameras do better than LIDAR (judging distance, reduced computing effort, detecting reflective surfaces and surfaces with 2D images on them).[0] But LIDAR was running $70k per vehicle, which is just not feasible. But thanks to technological development and economies of scale, the price of LIDAR (and the size) has drop precipitously, and now can run below $1,000. [1][2] Now in the long run, for true driverless cars, LIDAR will be rendered obsolete by sufficiently accurate AI interpretations of camera feeds. But in the medium term, I think they are key to filling in huge weaknesses camera only systems have, and freeing up computing power currently being used by trying to judge “depth perception” using cameras, to be freed up to better deal with other things cameras are actually good at like color/text recognition for reading traffic signs, facial recognition for determining if a pedestrian sees you, differentiating between hard and soft objects, etc. [0] https://www.automotiveworld.com/articles/lidars-for-self-driving-vehicles-a-technological-arms-race/ https://www.automotiveworld.com/articles/lidars-for-self-dri... [1] https://asia.nikkei.com/Business/Automobiles/Cheaper-lidar-sensors-brighten-the-future-of-autonomous-cars https://asia.nikkei.com/Business/Automobiles/Cheaper-lidar-s... [2] https://news.itu.int/the-price-of-lidar-is-falling/ https://news.itu.int/the-price-of-lidar-is-falling/

DeBraid 5y ago

IIRC, in this[1] video Andrej Karpathy mentions radar was mostly redundant, and in addition was occasionally harmful (sending conflicting signals vs. video), so they got rid of it to reduce cost and complexity. [1]: https://youtu.be/g6bOwQdCJrc https://youtu.be/g6bOwQdCJrc

londons_explore 5y ago
In that video Karpathy says a lot of things which are the corporate line, but don't really match up with math and statistics...

snarf21 5y ago

Yeah, nothing makes sense except cost. Even for these kind of level 2 system, they should be forced to have camera + lidar + radar. There is no reason to not use as many data sources as possible. If it is to expensive, work on that. Batteries used to be more expensive too but they focused on that. Spend some of your stock on lidar/radar acquisitions.

baybal2 5y ago

Apertures are very small, and predominant majority of radars are not imaging. Yet, that's the very point. These very primitive radars are more than enough for a car to avoid an obvious collision threat.

DoingIsLearning 5y ago

> Why did Tesla decide not to use radar any more? System redundancy in safety-critical systems exists for a reason. Either their engineering team refused to see this or they were unable to make Product/Management/Regulatory people see it. AEB is quite finicky and needs quite a fair bit of calibration and mechanical alignment, still like the article says can suffer from false positives. But although LIDAR is still prohibitively expensive it is possible to design ADAS that can integrate stereo camera, RADAR and long range sonar, that would at least give you three sources of data for some margin. > What wavelengths do other cars' radars operate at? The spectrum used for AEB in most transceivers is 76 GHz to 81 GHz (so between about 3.9 and 3.7 mm) some older implementations also worked at 24GHz i think.