IWR6843AOPEVM: The "Range Profile" of "Vital Sign Reader Demo"

Hsincheng Li

Part Number: IWR6843AOPEVM

I would like to ask about the "Vital Signs" example in the "mmwave industrial toolbox 4.12.1". In the "Vital Signs Reader Demo" (mmwave_industrial_toolbox_4_12_1\labs\Vital_Signs\68xx_vital_signs\gui\gui_exe\VitalSignsRadar_Demo.exe), there are four waveform charts, namely: "Breathing Waveform," "Heart Waveform," "Chest Displacement," and "Range Profile."

Regarding the waveform chart of "Range Profile," its Y-axis title is "Magnitude (a.u.)." May I know what formula is used to calculate this value?

After examining the code of "Vital Signs Reader Demo" (mmwave_industrial_toolbox_4_12_1\labs\Vital_Signs\68xx_vital_signs\gui\gui_source\mainwindow.cpp), I found that the RCS value under the code seems to be determined by the maximum value of the Range Profile.

Does this mean that the Y-axis of the "Range Profile" waveform chart represents the RCS value?

I want to use the "value of RCS" or "value of Range Profile" to further determine or predict the subject's current behavior (turning left or turning right), rather than relying solely on the "Motion Detection Flag" to judge whether the subject is currently moving.

Is the above method feasible?

Have a good day.

over 2 years ago

0 Angie Mitchell over 2 years ago

TI__Genius 10730 points

Hello,

I will be getting back to you with a response on this in the next 48 hours.

Thank you,

Angie

0 Angie Mitchell over 2 years ago in reply to Angie Mitchell

TI__Genius 10730 points

Hello,

The range profile values are the sum of the log2 magnitudes of the raw inputs from the data received from the radar antennas. The output of this will change as the person moves closer to or away from the sensor.

Thanks,

Angie

0 Hsincheng Li over 2 years ago in reply to Angie Mitchell

Prodigy 30 points

Does "the raw inputs from the data received from the radar antennas" refer to the energy levels of each range bin?

Can you provide me with the formula for the raw inputs?

Thank you :D

0 Angie Mitchell over 2 years ago in reply to Hsincheng Li

TI__Genius 10730 points

Hi Hsincheng,

Yes, this refers to the energy level of each range bin.

Please see this thread for more info on the format: https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1166296/iwr6443-q-format-of-range-profile-and-noise-profile/4389967?tisearch=e2e-sitesearch&keymatch=range%252525252525252520profile#4389967

Thank you,

Angie

0 Hsincheng Li over 2 years ago in reply to Angie Mitchell

Prodigy 30 points

So the meaning is that Range Profile is a value generated for signal strength and RCS data.
It is related to the values of signal strength and RCS data, but cannot derive the exact values of signal strength and RCS data.
So, MAX_RCS in the DEMO is also not an exact RCS value.

Is my understanding correct?

Thank you for your reply.:D
Have a good day.

0 Angie Mitchell over 2 years ago in reply to Hsincheng Li

TI__Genius 10730 points

Hi Hsincheng,

Yes, it is related to signal strength and RCS but cannot be derived from that. The max_rcs in the demo is an estimate of the actual RCS value.

Thanks,

Angie

0 Hsincheng Li over 2 years ago in reply to Angie Mitchell

Prodigy 30 points

May I confirm if Range FFT refers to the process of performing Fourier transform on the reflection signals on each Range Bin in a radar signal, in order to obtain corresponding frequency spectrum information and further acquire detection, identification and positioning of radar targets?

And does Range Profile mean the result obtained during the Range FFT process, i.e. the spectrum values on each Range Bin?

Can Range Profile reflect the distribution of target objects on the Range Bin?

Here is the last question.

Thank you for your reply, have a good day.:D

+1 Angie Mitchell over 2 years ago in reply to Hsincheng Li

TI__Genius 10730 points

Hi Hsincheng,

The range profile is the product of the range FFT showing the spectrum values for each range bin. It gives you an idea of the positioning of the radar targets in the space. It returns one value per range bin so it does give an idea in space where the target is, but not where inside the range bin itself the target is.

More information that might be helpful can be found here, this explains the difference between the range profile discussed in the OOB/SDK documentation and the vitals specific range profile : https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1109847/iwr6843aopevm-similarity-between-logmag-range-profile-in-out-of-box-and-range-profile-in-vital-sign-demo

Thanks,

Angie

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IWR6843AOPEVM: The "Range Profile" of "Vital Sign Reader Demo"