Can someone help me with performing range fft on FMCW Radar ADC data?

10 次查看（过去 30 天）

Pratham 2024-2-13

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2081583-can-someone-help-me-with-performing-range-fft-on-fmcw-radar-adc-data

编辑： George 2025-8-7

I have a dataset of raw ADC data from an FMCW Radar which is in the form where for each radar frame, its raw data (*.mat) has 4 dimension:

samples (128), chirps (255), receivers (4), transmitters (2). I am unable to perform range FFT analysis on such data. Can someone help me with the same?

15 个评论
显示 13更早的评论隐藏 13更早的评论

Pratham 2024-2-20

编辑：Walter Roberson 2024-2-20

在 MATLAB Online 中打开

000003.mat

Hi @William Rose,

I am attatching below a sample .mat file for your reference. I am actually refering to the dataset on this github repo to perform range fft analysis. The code I have written so far is :

function [range_profiles] = perform_range_fft(adcData, fs, c)
if ~isequal(size(adcData), [128, 255, 4, 2])
    error('Data dimensions must be (samples, chirps, receivers, transmitters)');
end
% Create empty array for range profiles
range_profiles = zeros(size(adcData, 2), size(adcData, 3), size(adcData, 4));
% FFT parameters
N = size(adcData, 1); % Number of samples per chirp
% Loop through chirps, receivers, and transmitters
for chirp_index = 1:size(adcData, 2)
    for receiver_index = 1:size(adcData, 3)
        for transmitter_index = 1:size(adcData, 4)
            % Extract single-antenna data for this chirp and receiver-transmitter pair
            single_data = adcData(:, chirp_index, receiver_index, transmitter_index);
            % Apply windowing (optional, uncomment if desired)
            %window = hamming(N);
            %single_data = single_data .* window;
            % Perform FFT with zero-padding for improved resolution
            fft_output = fft(single_data, length(single_data) * 2, 1);
            % Shift result to center frequencies (optional)
            fft_output = fftshift(fft_output);
            % Calculate frequency axis (linearly mapped with zero-padding)
            f_axis = linspace(-fs/2, fs/2 - fs/N, N * 2);
            % Calculate range axis (convert frequency to range using speed of light)
            range_axis = c / (f_axis);
            % Take magnitude (absolute value) for range profile
            range_profile = abs(fft_output);
            % Store range profile
            range_profiles(chirp_index, receiver_index, transmitter_index) = range_profile;
        end
    end
end
end

I am getting an error message at the line "range_axis=c/f_axis" :

Error using /

Matrix dimensions must agree.

Error in perform_range_fft (line 34)

range_axis = c / (f_axis);

I am trying to find out the range fft for all the provided files in the dataset.

William Rose 2024-2-20

编辑：William Rose 2024-2-20

@Pratham

[Edit: fix spelling errors]

Now I see that you answered my question about zero-padding in your comments: you zero pad to improve the range resolution. I am not convinced that this gives a real improvement in range resolution. You have not added any additional data, so how can it improve real resolution? Some people zero-pad time-domain signals, to improve frequency resolution. It is true that this will give you a finer grid along the frequency axis, which makes it look like you have improved the frequency resolution. What really happens is that the prior spectral data gets interpolated, in a slightly complicated way, to a finer grid. Therefore the apparent improvement in frequency resolution is illusory. I syspect this is true for radar signal procressing also, but I could bre wrong.

I wrote script radarRanging.m, to call your function. I modified your function "perform_range_fft", to avoid an error, and gave it a new name (I added "_wr"), to distinguish it from your original posting. Script radarRanging.m plots the 8 complex traces for chirp 1 (four receivers, two transmitters). The script reads the data from the file you posted earlier, 000003.mat. The script makes the figure below. I am not sure what the results mean, but I was curious to know what the traces look like. The script and your modified function are attached.

William Rose 2025-8-6

@A,

I recommend that you post your question as a new question on Matlab Answers. Attach code and data files. Explain what part of the output from your code indicates that an error has occurred.

Meg Noah 2025-8-6

Maybe take a look at the feature extraction script here: https://github.com/shikuzen/FMCW_radar_features_matlab

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

George 2025-8-7

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2081583-can-someone-help-me-with-performing-range-fft-on-fmcw-radar-adc-data#answer_1568888

编辑：George 2025-8-7

The Radar Toolbox has a few examples that you can look at to help you process this radar data. Your processing will probably consist of a couple of steps, depending on your goals.

First, I am assuming that the radar uses time division multiplexing (switching off between transmit antennas to improve angular resolution) based on the structure of your data. So, you will probably want to re-arrange the data into a 128x255x8 virtual array. You can learn more about this in the examples linked at the end of my post.

If you are only interested in performing a range fft, the phased.RangeResponse object with processing mode set to "FFT" would be helpful:

https://www.mathworks.com/help/phased/ref/phased.rangeresponse-system-object.html

You can similarly use the phased.RangeDoppler response or phased.RangeAngle response to generate Doppler and angle responses along with the range response:

https://www.mathworks.com/help/phased/ref/phased.rangedopplerresponse-system-object.html

https://www.mathworks.com/help/phased/ref/phased.rangeangleresponse-system-object.html

For more comprehensive examples that demonstrate signal processing that seems very similar to what you are trying to acheive, check these out. One simulates a Texas Instruments radar board and performs signal processing. The other performs signal processing on real data collected with this board:

https://www.mathworks.com/help/radar/ug/create-a-digital-twin-of-a-TI-mmwave-radar.html

https://www.mathworks.com/help/radar/ug/iq-data-collection-detection-application-example.html