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Level 4
Level 4

Hello,

I understand that the angle estimation of radar is computed by doing FFT on the result of Doppler FFT(2D FFT),

it is called "Angle FFT(3D FFT)". Please see page3-4 of the following document.

https://par.nsf.gov/servlets/purl/10074169

However, it seems that the element of Angle FFT isn't included on "range-angle-map.py".

If my guess is correct, ...

please let me know why the Angle FFT is not used on "range-angle-map.py".

Best regards, Shoko

1 Solution

Moderator
Moderator

Hi @shoko_s ,

Apologies for the delay in response !

Although the current RDK does not use the Angle FFT, DBF is quite capable and would allow precise and simultaneous processing of different angles and frequencies, only limited by the computational effort, but theoretically with arbitrary precision.

Hope this helps !

Best Regards,

Deepa

11 Replies

Moderator
Moderator

Hi @shoko_s ,

Please note that since it's not an infineon documentation, the terms could very well be different. From our understanding, the paper states the same procedure of Angle Computation as mentioned in our algorithm. We happen to take the Range FFT first which is a 2D FFT and then the Doppler FFT is performed on the Range FFT which is again a 2D FFT for computing the Angle. This same procedure is evident in the code that the Angle of Arrival is estimated from the Range-doppler computation. The '3D FFT/ Angle FFT' that the paper talks about, from our interpretation, is same as the 'Doppler FFT', just a different term in place.

Hope this helps !

Best regards,

Deepa

Level 4
Level 4

Hello Deepa,

Thank you for your response. I understand that 3D FFT/ Angle FFT of public term is same as your "Doppler FFT".

I can't find the code for 3D FFT/Angle FFT, because the element of fft isn't included in the part of #compute range-angle map of "range-angle-map.py". Also, it does not contain the arrival angle formula.

It seems that the DBF is used for it, instead.

Could you please tell me which line in range-angle-map.py indicates 3D FFT/Angle FFT?

Best ragards, Shoko

Moderator
Moderator

Hi @shoko_s ,

The following line where parameters are passed to DopplerAlgo, is actually linking to the Doppler.py file which contains the Doppler FFT algorithm.

The Range-Doppler map is given as the input of the DBF algorithm. The output of the DBF is a Range-Beam map, a three-dimensional object which gives the magnitude for all combinations of range and beam number. The range and angle of the target is obtained from the Range-Beam map through a simple peak search.

Best regards,

Deepa

Level 4
Level 4

Hello Deepa,

Thank you for reply & information.

Regarding the line of the above image, I think the answer should be 2D FFT/Doppler FFT, not 3D FFT/Angle FFT.

Because  the comment statement of the line is # Create objects for "Range-Doppler".

Does this program do third-FFT for 3D FFT/Angle FFT?

Which line in range-angle-map.py indicates the following formura to calculate the arrival angle?

Thank you, Shoko

Moderator
Moderator

Hi @shoko_s,

Yes, the above lines are for computing 2D FFT/Doppler FFT. As mentioned, The Range-Doppler map is given as the input of the DBF algorithm which facilitates the computation of angle. Therefore, our algorithm doesn't use the formula or the 3D FFT/Angle FFT for computation of Angle of Arrival. Please note that beamforming differs from other analytic algorithms for Angle of Arrival detection, as it can be compared to applying a windowing function in 3D space.

The modules on the python code used for estimating range and angle is as shown below and the same has been elaborated on the Application Note : AN652_Digital_Beamforming_using_the_BGT60TR13C_Radar_Sensor_V1.3.pdf.

Also, if you happen to be looking specifically for the implementation of formula for Angle of Arrival with reference to the change in phase, then there is a module in RDK titled 'Angle Monopulse' which happens to use the same concept for angle calculation but please note that this has not been implemented in the python code and you'd have to implement it on your side.

Hope this helps !

Best regards,

Deepa

Level 4
Level 4

Hello Deepa,

Thank you for your response. I understand "range-angle-map.py" uses DBF algorithm instead of 3D FFT/Angle FFT.

Could it detect and display the angle ot the multi targets using DBF algorithm?

(If it uses Angle FFT, I think it can be achieved... )

Thank you, Shoko

Level 4
Level 4

Hello,

Thanks, Shoko

Moderator
Moderator

Hi @shoko_s ,

Apologies for the delay in response !

Although the current RDK does not use the Angle FFT, DBF is quite capable and would allow precise and simultaneous processing of different angles and frequencies, only limited by the computational effort, but theoretically with arbitrary precision.

Hope this helps !

Best Regards,

Deepa

Level 4
Level 4

Hello Deepa,

Let me confirm one thing. Does not the current RDK "range-angle-map.py" support the simultaneous processing of different angles and frequencies?

Because "range-angle-map.py" application does not display multi targets.

Thank you, Shoko

Moderator
Moderator

Hi @shoko_s ,

Confirming your statement, the range-angle-map.py does detect multiple targets at various ranges and angles depending on the strength of the targets. You'll be able to visualize the same in the application.

Best regards,

Deepa