BGT60TR13C Segmentation maximum detectable range

[Siyu]

Hello,

I am using the BGT60TR13C radar board to perform segmentation task using raspberry pi and I would like to adjust the maximum detectable range of the radar. I've read from the documentation that the Segmentation APP is based on the presence detection APP, but I am confused about how should I implement it.

I have tried to run the "./app_segmentation --config=<filename>" to add in my own config file and change the max_range_m here:

but it gives me an error:

Does the app_segmentation only works with the fmcw_single_shape? because it could run using the fmcw_single_shape config file, but the responsiveness is quite bad, in a sense that it takes a long time for it to detect a human standing infront of the radar board, and when moving across segments.

Can someone tell me what I'm doing wrong here? Thank you in advance.

Best Regards,

Siyu

[AdeelJ · Accepted solution]

Hi @Siyu ,

Firstly, I would recommend to update to the RDK 3.3. Configuration json can be obtained using app_segmentation.exe -r <recording_filename>. The configuration contains the "fmcw_single_shape" configuration.

This can be modified with some constraints.

About the app_segmentation and the error you are seeing, The application in it's current shape has a stringent requirement on the Radar Data Cube. [ samples x chirps x antennas ] = [ 128 x 16 x 2 ]
For changing a parameter like max_range you would need to manipulate the chirp frequencies in a way that the Data Cube dimensions remain constant.

The following bandwidth (Hz) should result in a range of 5 meters
1918650000
This can be realized with the following settings
"start_frequency_Hz": 59500000000,
"end_frequency_Hz": 61418650000,

Best regards,

[Siyu]

Hello, thank you for the reply.

I have tried maximizing the bandwidth and it managed to limit the max range to 3m. However, I was wondering if the samples per chirp and the chirps per frame could be modified in any ways to achieve a even shorter max range like 1 meter? 

Thank you.

Best Regards,

Siyu

[AdeelJ]

Hi @Siyu , In theory you can limit the maximum range by reducing the the "samples per chirp".
But in the "app_segmentation" this is fixed to 128. If you configure the Radar above or below this number, an error will be thrown.

You can look at the Python Example "range-angle-map.py" in "apps/py" where you will be more flexible to modify the configuration. You can use this as a starting point for your custom application. This application returns an object location probability in terms of range and angle. This information can also be formatted as "segments".

With your maximized bandwidth, if you configure "samples per chirp" to 64, the maximum range will be further reduced to half of the max range you have achieved now.

Best regards,

[AdeelJ]

Revisiting the initial calculation: 
A Bandwidth of 3837300000Hz would give you a range of 2.5 meters (with the app_segmentation configured 128 samples per chirp)
This would be further halved when you use 64 as samples per chirp.
the reduction of samples per chirp is not possible in app_segmentation in it's current form. The application "range-angle-map.py" may offer you the possibility of using this configuration.

Thanks,

Adeel

[Yashraj_P]

Hi @Siyu ,

We will be locking this thread  due to inactivity. If you have further queries, please create a new thread.

Thanks and regards,
Yashraj