TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC
  1. TMC is currently READ ONLY.
    Click here for more info.

Hello, rear radar :-)

Discussion in 'Autopilot & Autonomous/FSD' started by lunitiks, Feb 18, 2018.

  1. BioSehnsucht

    BioSehnsucht Model 3 LR

    Joined:
    Apr 1, 2016
    Messages:
    1,787
    Location:
    DFW, TX
    Would it be feasible to design a phased array radar unit that was still relatively compact (2-4x the volume would probably still be manageable, in terms of hiding it behind a bumper), that could steer a narrower than usual beam from side to side (and perhaps top to bottom) and thus not only cover more area reliably but also with more precision versus a regular radar module?
     
  2. mongo

    mongo Well-Known Member

    Joined:
    May 3, 2017
    Messages:
    12,857
    Location:
    Michigan
    A phased array is basically a series of normal single emitters arranged and phased to alter the beam pattern. To make it steerable, you need additional elements in the axis of steering. So if you also wanted vertical aiming, you would need a few rows of elements vertically.

    Element size is tied to beam width is tied to frequency and antenna size. Higher frequency and larger size yield smaller beam patterns (for single elements and for arrays of elements).

    Assuming an electrically steered unit, if one used the entire bumper, it might be possible to achieve the max beam steering of +/- 60 degrees left/right (maybe more with a curved array). Element creation/ physical design (absorber? ) might get you a decent vertical roll off such that the beam is focused in a roughly level plane for object detection.
     
    • Love x 1
  3. Zarwin

    Zarwin Member

    Joined:
    May 12, 2014
    Messages:
    600
    Location:
    Hillsborough, NC
    #183 Zarwin, Feb 21, 2018
    Last edited: Feb 21, 2018
    As an update to my previous post about the location of the BT radios, I discovered one other thing interesting this morning when checking the car again. The BT naming has meaning. The last character designates the location.

    2018-02-20_9-24-35.jpg

    C - Center or Console
    D - Driver B-Pillar
    P - Passenger B-Pillar
    R - Rear (Bumper)

    EDIT: This will of course cause massive confusion with RHD cars :), should have used Port/Starboard

    For those new to the thread, this is in reference to my post earlier

    Also, this morning I noticed the dew on the B-pillars had a peculiar (not so peculiar) dry spot.
    2018-02-21_8-35-57.jpg
     
    • Informative x 14
    • Love x 2
    • Like x 1
  4. lunitiks

    lunitiks Cool James & Black Teacher

    Joined:
    Nov 19, 2016
    Messages:
    2,698
    Location:
    Prawn Island, VC
    hole.JPG
    hole2.JPG
    [​IMG]
    [​IMG]
    [​IMG]
     
    • Informative x 4
    • Helpful x 1
  5. MarcusMaximus

    MarcusMaximus Active Member

    Joined:
    Jan 2, 2017
    Messages:
    3,789
    Location:
    Los Gatos
    ...OR: They're actually going to bounce bluetooth signal off of cars as an alternate form of radar.
     
    • Like x 1
  6. lunitiks

    lunitiks Cool James & Black Teacher

    Joined:
    Nov 19, 2016
    Messages:
    2,698
    Location:
    Prawn Island, VC
    ...AND: Since it's tilted slightly upwards, they're going to bounce some of the bluetooth signals off of overhead signs, reflecting it in a downwards angle to cars behind the car behind you as an alternate form of humor
     
    • Funny x 1
  7. BigD0g

    BigD0g Active Member

    Joined:
    Jan 12, 2017
    Messages:
    2,019
    Location:
    Somewhere
    What happens if I approach from the front? I'm confused why they need a special rear BT setup if they don't need a front BT setup...
     
  8. Zarwin

    Zarwin Member

    Joined:
    May 12, 2014
    Messages:
    600
    Location:
    Hillsborough, NC
    Seems like a silly thought at first but who knows, lol. I just had the car out and parked in a packed parking lot. Walked away and at roughly 200 feet(60m) from the car, with no line of sight to the car (lots of other cars in the way) I still had one of the side radios and the back radio connected to my phone. I'll go out after work and see how far those things can connect to my phone. Not terribly scientific of course since it's just connecting to a phone, but I can also get the RSSI values at different distances for my phone which might be interesting.
     
  9. lunitiks

    lunitiks Cool James & Black Teacher

    Joined:
    Nov 19, 2016
    Messages:
    2,698
    Location:
    Prawn Island, VC
    Mods - what's up with keeping my original thread title? Please change it to "Hello, rear bluetooth-antenna". Or "Goodbye, rear radar" :) LOL!

    @Zarwin, I love your experimental nature. Please continue.

    Anyone: Why would Tesla bother to install such a "chunk" in the rear bumper? Model X for instance, has tiny bluetooth antennas everywhere, also in the rear bumper, center. What's with the form factor? What are they building in there?
     
    • Like x 1
    • Funny x 1
  10. mongo

    mongo Well-Known Member

    Joined:
    May 3, 2017
    Messages:
    12,857
    Location:
    Michigan
    If you want it changed, the most effective way is to report your first post and put the request in the comment.
     
    • Like x 1
  11. mongo

    mongo Well-Known Member

    Joined:
    May 3, 2017
    Messages:
    12,857
    Location:
    Michigan
    I think it is also the near field RDIF/card reader, hence the large size for the antenna. Why also on the rear sensor? Guessing commonality.
     
  12. lunitiks

    lunitiks Cool James & Black Teacher

    Joined:
    Nov 19, 2016
    Messages:
    2,698
    Location:
    Prawn Island, VC
    What do you mean @mongo? I see no such box on the B-pillars...?
     
  13. mongo

    mongo Well-Known Member

    Joined:
    May 3, 2017
    Messages:
    12,857
    Location:
    Michigan
    Am I inventing a parallel universe again:oops:? I assumed that since the Bluetooth node were at the same locations as the RFID readers, they were the same module.
     
  14. lunitiks

    lunitiks Cool James & Black Teacher

    Joined:
    Nov 19, 2016
    Messages:
    2,698
    Location:
    Prawn Island, VC
    Clearly they're not the same form factor at least. Look at the pillar images upthread, compare it to the black box on page 7.
     
    • Helpful x 1
  15. Zarwin

    Zarwin Member

    Joined:
    May 12, 2014
    Messages:
    600
    Location:
    Hillsborough, NC
    #195 Zarwin, Feb 21, 2018
    Last edited: Feb 21, 2018
    That would make sense, but RFID it isn't enabled anywhere except the driver side B-pillar according to the manual. I just checked to make sure this was accurate and it is. Tried it on the passenger B-pillar and of course had to try it on the rear bumper as well. Doesn't do anything unless it's on the driver side B-pillar. Still makes sense that it is combined in the same module though.

    EDIT: And this would make sense for the center console as well since RFID to enable drive is in the same place as the console BT it seems
     
    • Helpful x 1
  16. mongo

    mongo Well-Known Member

    Joined:
    May 3, 2017
    Messages:
    12,857
    Location:
    Michigan
    Yeah, I'm off, the rear module does not have any secondary communication function. The B pillar version is dual role BLE + RFID. The chunky size may be to ensure the spacing requirement from the antenna?
     
  17. Joerg

    Joerg Member

    Joined:
    May 3, 2016
    Messages:
    26
    Location:
    Germany
    For RHD it makes sense to include the RF(/BT) on the right side and only to make it active thru software later for those markets. On the back it might be handy to unlock if you approach from behind and first want to open trunk?
     
  18. mongo

    mongo Well-Known Member

    Joined:
    May 3, 2017
    Messages:
    12,857
    Location:
    Michigan
    I had the same trunk thought, but there is no button that I know of for it. Oh! Unless it uses the backup camera, and you wave your hand or some such...
     
    • Like x 2
  19. BioSehnsucht

    BioSehnsucht Model 3 LR

    Joined:
    Apr 1, 2016
    Messages:
    1,787
    Location:
    DFW, TX
    Well, some googling later and apparently some R&D has been done way back in 2014 but I can't find much concrete info about it or any progress updates on commercializing.

    Researchers unlock potential of phased-array radar for automotive deployment

    With Phased-Array Radar Technologies, UC San Diego Electrical Engineers Aim to Make Car Travel Safer

    A 77–81-GHz 16-Element Phased-Array Receiver With - Beam Scanning for Advanced Automotive Radars - IEEE Journals & Magazine

    I wish you didn't have to pay for access to IEEE, might be something interesting in there.

    100 degree field of view (I'm guessing this means +-50 degrees from straight ahead) and up to 100m distance.

    From the picture of the chip, it looks pretty small, but it's not clear if that's just the RF processing (phase shifting, etc) or the antennas too (seems too small to include the antennas). Though since it's being developed for automotive applications, surely it can't be too big ...

    From Radar for Pedestrian Safety image doesn't seem like the overall package is much larger than typical radars, but I'm just guessing from the size of the screw holes.
     
    • Informative x 3
  20. run-the-joules

    run-the-joules Active Member

    Joined:
    Aug 13, 2017
    Messages:
    3,528
    Location:
    SF Bay
    There's a button on the trunk.
     
    • Helpful x 3

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


    SUPPORT TMC