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IWR6843ISK: Short range and resolution

Oliver Konert
Prodigy 20 points
Part Number: IWR6843ISK
Other Parts Discussed in Thread: IWR6843, DCA1000EVM

Hi,

I currently startet to use your IWR6843 evaluation module.
Having testet some prebuilt labs (such as OOB and Heart beat measurement) I am now about to tune the board for my application.
Therefore I'd need a reasonable smaller viewing area than in the OOB and a better resolution. Is the resoultion shown in the Demo visualizer the real limitation of data or only the limitation given by the visualizer?
I'm wondering what could be the best approach to achieve a smaller viewing area (especially range) and a better resolution and how to get there on the best/fastest way.

Moreover I've heared it's possible to get raw data without the DCA1000EVM.
Could you give me a short guide how to get these raw data without the additional board?

Thanks and regards,
Oliver

  • 0
    TI__Expert 7510 points

    Hello,

    Can you be specific about what you mean about resolution. There are three types of resolution with FMCW radar 1. range 2. Doppler 3. Angle (Azimuth/Elevation).

    All of these resolutions combined with the CFAR algorithm will determine what points are detected in the GUI visualizer. To get more information about the theoretical concepts behind FMCW radar then I would highly suggest watching the following video series:

    mmWave Training Series
    https://training.ti.com/mmwave-training-series

    The only way to get raw ADC data from the device is by utilizing the DCA1000EVM.

    Best regards,

    Connor Desmond

  • 0 in reply to Connor Desmond
    Prodigy 20 points

    For us the cirtical resolution is the range/depth resolution. This ist what we need to improve.

    After watching the video series where should I start then to make some changes? Which programm/code should I use to optimise the board for my appliacation?

    I've been told that it should be possible to get raw data form a serial port located on the EVM as well... is that wrong?

  • 0 in reply to Oliver Konert
    TI__Expert 7510 points

    Hello,

    The video series that I described detailed what parameters effect range resolution as shown below:

    So this means that the only parameter that you can change is "B" or the swept bandwidth for the chirp. For our device this limited to 4GHz. According to the equation (9) this roughly translates to a maximum range resolution of 4cm. You will not be able to resolve detected objects whose relative radial distance from the radar are less than 4c

    UART does not have the transmission rate to support data from the ADC. Thus we provide an LVDS interface to the DCA1000 which takes ADC data over Ethernet to a host PC. Ethernet has the transmission rate to support the data coming from the ADC.

    Best regards,

    Connor Desmond

  • 0 in reply to Connor Desmond
    Prodigy 20 points

    Hello,

    thanks for your help.

    Regarding the resolution:
    Looking at the life science lab you are able to track very small motions of the human body which are way down below the resolution of 4cm. How do you get the required data/information for this?

    So besides the DCA1000 there is no other option to get the raw wave intensity or wave phase data or anything similar like that?

    Best regards,
    Oliver

  • +1 in reply to Oliver Konert
    TI__Expert 7510 points

    Hello,

    To be clear range resolution is the separation of two objects in a scene such that if the separation is lowered, then the radar will not be able to resolve two objects, it will just appear as one object. Range resolution does mean that the minimum range that you can see an object is 4cm. With regards to small motions of the human body the keyword in that is motion. When an object changes its radial position this causes a change in phase of the IF signal.

    This "delta d" can be in the mm range which enough to detect human breath rate for example. As mentioned previously this concept is as well as the image provided from above are from the training series, so I would suggest watching those until you have a firm grasp of the concepts.

    Natively, if you want to get data from the device you have two options.

    1. Get processed data through UART (or some other communication protocol). This information is detected objects, range profile, range-azimuth heatmap etc.

    2. Use DCA1000 to get raw ADC data from the device over LVDS and then use Ethernet to get that data to the PC. Note that is a capture, not a stream. For example you specify how many frames of ADC data that you want and that is collected on the PC in a data file which then can be processed by MATLAB or any other program. If you want ADC data from the device you must use DCA1000 EVM.

    Best regards,

    Connor Desmond