Range-Azimuth-chrips

[Acciwu]

Hi! I would like to do only two FFTs on your ADC data to get range-azimuth-chrips. I used the OpenRadar SDK, first do the FFT on the range, then on the azimuth, can I get range-azimuth-chrips? Are other radar parameters required? look forward to your reply!

[Acciwu]

[Acciwu]

Is it okay to perform distance FFT first and then directly perform azimuth FFT? Can you help me, thank you very much!

import numpy as np import matplotlib.pyplot as plt

c=3.0e8;
B=768e6; # FM bandwidth K=30e12; # chirp rate T=B/K; # FM period Tc=160e-6; # Chirp total cycle fs=10e6; # sampling rate f0=77e9; # Initial frequency Lambda = c / f0; # Radar signal wavelength d=Lambda / 2 # Antenna array spacing n_samples=256; # Number of sampling points/pulse N=256; # FFT points in range direction n_chirps=64; # Number of pulses per frame M=64; # Doppler FFT points n_RX=8; # Number of RX antenna channels

Q = 180 # angle FFT points

Q = 256; # angle FFT points xx = 1; # Frame xx

data_radar = adc_data

range FFT

range_win = choose_windows('Hamming', n_samples) # add Hamming Windowing doppler_win = choose_windows('Hamming', n_chirps) range_profile = np.zeros((256, 64, 8)) for k in range(n_RX): for m in range(n_chirps): temp = data_radar[:,m,k] * range_win # Hamming Windowing temp_fft=np.fft.fft(temp, N, 0) # Do N-point FFT for each chirp range_profile[:,m,k] = temp_fft print(range_profile.shape)

azimuth FFT

angle_profile = np.zeros((256, 64, 256)) for n in range(N): # range for m in range(M): # chirps temp= range_profile [n,m,:] temp_fft=np.fft.fftshift(np.fft.fft(temp, Q)) angle_profile[n,m,:] = temp_fft print(angle_profile.shape)

in 0 chrip

plt.imshow(abs(angleprofile[:,0,:])) 

[ZhangAoCanada]

Hi, thanks for the question.

To answer your question: Yes, you can directly perform DOA after RangeFFT.

To explain why: the way of data formation is as follow. Each radar frame contains 1 single chirp per receiver. That means, you can collect 8 chirps from 2 transmitters * 4 receivers. The Doppler axis is to accumulate several (64 in my configurations) consecutive radar frames and then perform FFT on that axis. If you are using my ADC data (256, 64, 8), you can perform RangeFFT on 256 and AzimuthFFT on 8. Then sum up the 64 and normalize them. That will do.

One thing to NOTE: do remember to do FFTshift after FFT, if you want to get readable results.

Thanks,

[braundeniz]

So am i right, that i cant use the RAW ADC data from your dataset directly?

Do i have to perform the FFT's, proposed from @Acciwu first?

Because i loaded the RAW Data downloaded from your Drive and they have the shape [256,256,64], which should be the shape for the RAD Tensor am i right?

So in my understanding the Data from the OneDrive is already in RAD Format?

Thanks in advance

[Gabo181]

Hey @braundeniz , did you get any results to bring your data cube into (256, 256, 64)

[huiwenXie]

@Acciwu Hello, I have some questions to ask you. I found that the data size is 256648, do you know that the data is " 1 frame with 64 chirp“ or "64 frame and each frame has 1chirp"? Additionlly, if the data is " 1 frame with 64 chirp“, do you know the time inteval between each chirp? If the data is " 64 frame and each frame has 1chirp“, do you know the time inteval between each frame? Thanks a lot! If you are willing to answer my quesiton, I will be very happy.