Questions tagged [array-signal-processing]
Signal processing for data collected with an array of sensors.
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Need help in understanding temporal and spatial correlation of non homogeneous clutter data
I came across this paper entitled DiffWave for Sea Clutter Data Generation, and I need help understanding
I understand that here they are mainly showing how closely the generated data follows the ...
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Where do grating lobes occur for a ULA phased array?
To avoid grating lobes (spatial aliases), a uniform linear array (ULA) must space elements at most $d=\lambda/2$ apart (where $\lambda$ is the wavelength). But what if $d > \lambda/2$? Can we ...
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How to include internal clutter motion for generating nonhomogeneous clutter?
I want to incorporate internal clutter motion while simulating non-homogeneous clutter. According to the multiplicative model, received signal amplitude is the outcome of the product of two ...
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Why use Butterworth filter after MediaPipe smoothing (One-Euro) for pose landmarks?
I'm working on human pose estimation using MediaPipe (Pose or Face Mesh), which applies a LandmarkSmoothing filter (One-Euro style) to stabilize landmarks in real-time.
However, for offline post-...
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Does weights in Space-Time Adaptive Processing follow any distribution?
Does weights in Space-Time Adaptive Processing follow any distribution? If yes, does the distribution depend of the type of clutter, antenna pattern, grazing angles etc.
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How can wave-based machine vision (direct optical wave processing) improve spectral pattern recognition compared to traditional pixel-based methods?
I'm exploring the potential of wave-based machine vision, where machines directly process optical waveforms (e.g., spectral data of biological fluids) without converting them to pixel representations. ...
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Range-Doppler Maps for non-homogeneous clutter
As a continuation of my question signal-model-for-nonhomogeneous-clutter, I have tried to model nonhomogeneous clutter by taking random samples from K,Weibull, lognormal and gamma distribution and I ...
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Construction of Range Doppler Maps
I have come across various implementations of Range-Doppler Maps. If I correctly understand, once we receive the signal from the target we match filter it with the transmitted signal and then apply ...
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Signal Model for nonhomogeneous clutter
I came across a paper Robust STAP for nonhomogeneous clutter suppression
with a single snapshot that provides a signal model for clutter echo that is being observed from an airborne radar.
. In this ...
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Methods for calculating angle of arrival using signal strength
I'm trying to understand the methods and pitfalls for using a circular array of yagi antennas to calculate the angle of arrival of a radio signal. Or any tips on the proper jargon that can help me in ...
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MUSIC sensor limitations
Because MUSIC requires computing the correlation matrix $R_x \approx \hat{R}_x =\frac{1}{N} XX^H$ the MUSIC algorithm is limited to detecting up to N-1 signals for N total sensors. Are there methods ...
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Making the MIMO virtual array size appear in the FFT and Capon angle resolution
Trying to clarify MIMO angle resolution with equations and getting a bit confused. Using this paper's notations ($M$: number of RX, $N$: number of TX, $L$: number of snapshots), the RX signal matrix ...
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Multiplicative Array Processing
Has anyone tried multiplicative array processing (MAP) techniques? I read the paper Super-Resolution Direction-of-Arrival Estimation based on Multiplicative Array Processing. The results seem too good ...
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can a uniform linear array (ULA) be used to estimate both elevation and azimuth angles?
I wanted to clarify that,
If an ULA has certain crab angle with the velocity direction, then it can be used to estimate both elevation and azimuth angles of the target, is that right?
If that's ...
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Normalized spatial frequency for L-shaped array
I know that for an ULA array structure, the normalized spatial frequency (fs) is given by $f_s = \frac{d \cdot \cos(\text{az}) \cdot \cos(\text{el})}{\lambda}$.
But, in a L-shaped array structure ...
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Applying Digital Beamforming to FMCW radar signal prior to extracting the Respiratoy Rate yields unexpected results
I am currently working on a university project where my goal is to extract the respiratory waveform from FMCW radar recordings. I use Infineons DEMO BGT60TR13C to record my data. For achieving that ...
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How to construct covariance matrix on frequency domain
When we use time domain received signal to construct the interference and noise covariance matrix, sometimes the undesired clutter will also be included and affect the accuracy of the covariance ...
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Array signal processing: How to retrieve the snapshot information from Radar data cube
In DOA estimation we require a snapshot of data in time or frequency domain to perform the estimation. So how can we retrieve this information from the conventional radar data cube especially in the ...
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Conversion of Uniform Circular Array (UCA) into a virtual Uniform Linear Array (ULA). Is it practical?
Recently I came across a paper which converts an UCA into a virtual ULA, since ULA is easy to analyze and process mathematically. I have attached the paper here, A robust direction of arrival ...
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Signal model and doa estimation for Moving Targets
In this post What features can be used to estimate both azimuth and elevation angle using a deep learning model?, I have shared a signal model:
...
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What is the signal model for near field?
How will I model the signal and the array manifolds in case of near field scenario? Also, here only azimuth angle is shown, how will the near field signal model look like incase of both azimuth and ...
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Elevation beamforming
For a uniform planar array with MN elements, the steering vector can be given as
$$a(\theta,\phi)=\frac{1}{\sqrt{MN}}
\begin{pmatrix}
1\\
\vdots\\
e^{j\pi\sin\phi[(m-1)\cos\theta+(n-1)\sin\theta]}\\
\...
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Issues Receiving Signal with USRP B210 in MATLAB vs Simulink
I am new to signal processing and appreciate your understanding as I seek assistance.
I am trying to receive a signal generated by a signal generator using the USRP B210, and I am working with both ...
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Why is true time delay beamforming more expensive to implement?
From what I understand, PS beamforming applied a phase by multiplying the complex expontential ($e^{i\theta}$), while TTD applies a delay ($x(t-d)$)
It makes sense that multiplying a complex number to ...
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Understanding about correlation between random variables in context of Wireless Communication
I am trying to understand about correlation between random variables in context of wireless communication.
In research papers related to 6G, I came across the following statements:
Suppose there is a ...
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DOA beam pattern for circular array
Based on the tutorial for a linear array here, I've written the following code for a 6 microphone circular array. The array has a radius of 5cm. A beam pattern is generated but it doesn't look right ...
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Determining system clock frequency for a given sampling rate and number of channels
I am designing a multielectrode application on fpga. I am recording from multiple electrodes at a sampling rate of 2KHz. Lets say I want to create 60 channels for reading from 60 electrodes. My ...
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Complex Gaussian distribution in snapshot model
In Chapter 5 of the Optimum Array Processing by Harry van Trees [1], the formula of the complex Gaussian distribution appears very different from the formula that is used elsewhere in the same book ...
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How to find the pattern of a signal or main cycle of a signal?
I have a dataset where a certain pattern is repeatating in different time interval. The repetation of data pattern can come with slight change. I want first find the pattern (or cycle) and later by ...
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Calculation of a position from the angles of arrival
For locating a target by TDOA (Time Difference Of Arrival) with $3$ stations we have the Chan method which gives an exact solution of the position.
I keep the $3$ stations but instead of measuring the ...
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Elevation angle estimation from L-shaped antenna array
I have TI IWR6843ISK-ODS radar sensor and need point cloud data as output from it. The antenna arrangement is as follows:
I would like to know how to estimate elevation angle with this antenna ...
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error on angle of arrival
I have $2$ sensors allowing me to measure angles of arrival. These sensors are a distance $d$ ($d \simeq 10$ m) apart and the target to be located is at a distance $R$ with $d<<R$. In the ...
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Grating lobe in ULA exhibits a jump
The beam pattern of a uniform linear array is
$$B(\theta) = \frac{1}{N} \frac{\sin(\frac{N}{2} \frac{2\pi d}{\lambda} \cos(\theta))}{\sin(\frac{1}{2} \frac{2\pi d}{\lambda} \cos(\theta))}$$
where $N$ ...
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Understanding Implementation of ULA Array Response and Beamforming Techniques in MATLAB
I am currently working on a MATLAB project where I aim to replicate the functionality of certain Phased Array System Toolbox functions (phased.ULA() and ...
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What wavelength do we use when calculating the array manifold vector when transmitting LFM waveforms?
We know that the array manifold vector, also called the steering vector, for an M element array is given by:
$$ \mathbf{a}(\theta, \phi) = [e^{-j \omega \tau_{1}(\theta, \phi)}, e^{-j \omega \tau_{2}(\...
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Expanding cross correlation DOA estimation to n microphones
I need to detect the Direction of Arrival of a speech signal using an 8 microphone array as part of a project I've been working on. Currently, I have a working solution in the 2 microphone case:
$$G(\...
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Scipy.signal.find_peaks in c/c++
Hi guys I am trying to find a peak in waveform 1-d array data until I can find peaks in Python using scipy.signal find_peaks reference for that https://docs.scipy.org/doc/scipy/reference/generated/...
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How to use MUltiple SIgnal Classification (MUSIC) algorithm to detect the wavenumber of a received signal at array of sensors?
I am working on analyzing data obtained from Fiber Optic - Distributed Acoustic Sensor (DAS) to estimate the properties of acoustic waves that impinge FO cable, such as velocity of acoustic waves. FO-...
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Can one use MUSIC algorithm to estimate DOA for a circular microphone array with a small radius?
I am trying to locate the sound source using MUSIC algorithm in a circular microphone array. The array that I am using is "ReSpeaker Mic Array - Far-field w/7 PDM Microphones", and the ...
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How to modulate a signal to a certain frequency in time domain
I have a root-raised cosine pulse signal of bandwidth $500$ MHz.
If the signal is modulated at the frequency $6$ GHz, the result should apparently look like this :
If I understand well, to modulate ...
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Time of arrival
The definition for the time of arrival is:
$TOA=\frac{d}{c}+t_e$ where $c$ the wave speed, $d$ the range between the transmitter and the receiver and $t_e$ the transmission time of the signal to the ...
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What is the difference between array gain and diversity gain?
In a multi-antenna system, we often mention diversity gain in fading channels. I am doing simulations with multiple antenna settings at the receiver considering TDLC channel, for example, 1rx, 2rx, ...
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Plotting beam pattern of uniform linear array
I am trying to reproduce Fig. 2.17 from the book 'Optimum Array Processing' by Van Trees.
The figure is a polar plot of the beam pattern $B_{\theta}(\theta)$ given by
$$B_{\theta}(\theta) = \frac{1}{...
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Noise leakage problem with least square estimation in the frequency-distance domain
I have data $d$ recorded from an antenna of sensors. These data are composed of a Gaussian noise $n$ and a signal $s$ which I try to estimate. This signal propagates on the antenna with frequency ...
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Phase Difference Calculation in Frequency Domain
I am currently working on an application in which I have a Linear acoustic array, the audio of which is analyzed using FFT. Now I also want to perform phase difference calculation and have also learnt ...
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How to extract human voice from cluttered signal?
I have a signal which has human speech, background voice and noise as it can be seen in below figure.
I have calculated its power spectral density (PSD) using many different methods which can be seen ...
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Effect of down-sampling to PSD from auto-correlation?
I have a problem to evaluate the PSD from auto-correlation.
As you know, PSD is the Fourier Transform of the auto-correlation.
But I observe the spur at PSD when I calculate the auto-correlation with ...
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Is the beamforming result described by this matlab code useful?
A narrow-band beamformer for $0$ degree in the frequency domain is created for $8$ sensors and compared with a usual delay and sum beamformer. The question can also be expressed as : can we have ...
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FFT channelising for DF
I have a 25 MHz IBW real time signal analyser throwing out 25 MHz wide complex data at 50 MHz sampling frequency.
I want the frequency resolution to be 12.5 kHz (width of a vhf channel) so need 2000 (...
