How to map range bins to real distance?

Discussion in 'X4M03' started by wangyc, Apr 18, 2018.

  1. wangyc

    wangyc New Member

    Hello,
    I used Python script and X4m03 develop kit to collect radar baseband data and found that the received data matrix's size was 10000*188. The Frame Rate was set to 1000fps and it detected for 10 senconds. I realize that one frame inculdes 188 range bins, but how to map these bins to real distance?

    Thanks
     
  2. Aksel Johnsby

    Aksel Johnsby Moderator Staff Member

    Hi Wangyc,

    Each range bin is 5.14 cm long.
    188*5.14 = 966 cm

    Have a nice day!
     
    wangyc likes this.
  3. Charlie Shao

    Charlie Shao Moderator Staff Member

    The real distance can be calculated by:
    Given Fs=23.328GHz, the frame length is:
    LightSpeed = 299792458
    (1536-1)*LightSpeed/23.328e9/2
    Out[18]: 9.8632849586
    ~9.86 meters.
    1536 is the number of rf data sampling points.
     
    wangyc likes this.
  4. wangyc

    wangyc New Member

    Thanks a lot!
     
  5. wangyc

    wangyc New Member

    Thanks a lot!
     
  6. wangyc

    wangyc New Member

    Hello,
    I have another question, hope you don't mind. Does the x4m03 module has already adjust the signal power according to the reflection distance. For example, strength the signal which reflected back along a further path so that we don‘t have to consider electromagnetic wave fading?

    thanks
     
  7. wangyc

    wangyc New Member

    Hello,
    I have another question, hope you don't mind. Does the x4m03 module has already adjust the signal power according to the reflection distance. For example, strengthen the signal which reflected back along a further path so that we don‘t have to consider electromagnetic wave fading?

    thanks
     
  8. Charlie Shao

    Charlie Shao Moderator Staff Member

    The transmitting output power is fixed in order to follow UWB regulation, see this application note.
    There are two settings controlling the transmitting output power, the Pulse Repetition Frequency (PRF) and TX power level. See X4 datasheet for details and corresponding XEP functions: x4driver_set_tx_power and x4driver_set_prf_div. See the X4M05 datasheet (https://www.xethru.com/community/resources/x4m05-radar-sensor-datasheet.84/) for regulatory limitations on output power.
     
  9. wangyc

    wangyc New Member

    I‘m sorry i didn't say it clearly. I mean that when the module has already received the reflection signal(transmited at a fixed power), will it do something to adjust the signal's amplitude? Because the signal reflected from a further path will fade more, so it can enhance the received signal(from a further path) and let it be at the same level as the signal form closer reflection. Thanks for your patience.
     
  10. Charlie Shao

    Charlie Shao Moderator Staff Member

    Hi wangyc,
    No, it is not possible to enhance further path signal to the same level as closer reflection from chip side. The reflection signal of a further metal target might stronger than a wood closer target.
     
  11. wangyc

    wangyc New Member

    Thanks, now I get it.