Questions tagged [radar]

Anything related to RADAR (RAdio Detection And Ranging) systems and radar signal processing.

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66 views

Range-Doppler Matrix Cells

I am working on developing an understanding on range-gates and the size of each cell. I haven't had much luck in finding information in how the matrix in the image below is generated, so I have some ...
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23 views

Which is the proper input for the MUSIC algorithm, in the context of Angle of Arrival determination?

I am trying to code a MUSIC algorithm in Python, to process FMCW radar signal and get the angle of arrival (AoA) of targets. I have computed the range, velocity and AoA via 3D FFT, and I am now ...
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22 views

Range-Azimuth Heat map (FFT)

I have a question regarding performing a 2D complex FFT on a 2D array of frequency information in one dimension and azimuthal change in degrees in the other dimension. That is, I ran a test with an ...
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20 views

What input is most appropriate for CFAR processing in FMCW radars and why?

I am estimating range, velocity, angle of arrival from a FMCW radar. To detect potential target candidates points in this 3D domain, I am using a OS-CFAR after the doppler-range to detect the ...
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61 views

Does the Radar CFAR thresholds depends on the type of radar?

I am new to radars and I am trying to understand their functioning. I have understood that after the so-called pre-processing of the baseband signals we get from the radar the so-called 4D radar cube ...
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89 views

How can radars find the elevation angle of a target?

I know that radars can find the azimuth of a target in the angle at which they receive the peak of a reflected signal, but, how can they find the elevation of a target? I know that modern phased array ...
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50 views

3dFFT to compute angle of arrival in FCMW radars

I hope I am not asking any already-answered question. I have a simulated doppler-range map of a 1Tx - 4Tx (azimuthally displaced) FMCW radar and I am doing something wrong to calculate the angle of ...
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1answer
57 views

Alias free-range extent and range resolution formula proof

I've consulted many books about radar working principle. The well known formula of the resolution and alias free range extent (unambiguous range) appear referred to FMCW radar,ie $$ \delta R = c/(2B) $...
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61 views

Consideration about the choice of the radar operating bandwidth

I'm writing an essay about imaging radar. I was wondering the possible consequences that the bandwidth at which the radar operates could have on the measurements, and therefore on the image. One ...
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1answer
102 views

Motion detection with FMCW radar

I am studying the work of a microwave rangefinder and faced such a problem, but before that, a preface: I have a microwave module that operates at 24GHz. I use a 1kHz triangle waveform as the ...
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29 views

Radar beamforming receiver combining vector estimation

I don't have much experience with radar signals. I know in the cellular system, the channel directional vector can be estimated using pilot symbols based on MMSE, EW-MMSE, and LS. Then, we can use the ...
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48 views

How to reduce phase noise in radar?

Instability of oscillator can introduce phase noise to the signal received by radar [1]. Are there commonly used digital signal processing methods can reduce the phase noise? [1] Aubry, Augusto, et al....
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35 views

Faster way to Implement a CFAR (window average) Threshold

I implemented a version of a CFAR average in MATLAB but it's 'slow' and I need to speed it up. I included the pseudo code and logic below. I used a nested for loop to calculate the moving average but ...
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1answer
110 views

Radar MIMO Virtual Antenna Array Formation

Referring to the figure attached above, is the ordering of the virtual antenna arrays (shown on the right) to measure azimuth and elevation angles of arrival correct? In my understanding, the ordering ...
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1answer
35 views

How do I confirm that range cell migration correction was done correctly? Is there a way to check this graphically without looking at the signal data?

I am implementing the Range Doppler Algorithm for a Synthetic Aperture Radar project and I am at the step where I must perform Range Cell Migration Correction. This step involves creating a sinc ...
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52 views

FMCW radar transmitter signal splitter

An FMCW radar generates a chirp signal in the transmitter. The chirp is transmitted through a splitter device to both the TX antenna and the mixer in the receive path. Some object generates a ...
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1answer
34 views

Cut-off frequency for Low-pass filters in Arctangent Demodulation

According to literature, the arctan-demodulation method commonly used in Radio-frequency radar systems is the one shown below: Is there a rule of thumb regarding the cut-off frequency of these Low-...
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71 views

Create a Range Doppler Map using "Arbitrary" phase coded Waveforms

This is my first questions I am asking to this community! I want to understand how to create a Range-Doppler Map (RDM) for a phase/frequency coded radar return using an arbitrary waveform generator (...
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1answer
118 views

Aliasing in Doppler Radar

my book about RADAR says that: If a Continuous wave radar sends a sine wave at frequency $f_T$ to a moving object (at speed V), a frequency $f_R$ is received. Their difference is called Doppler ...
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69 views

Requirement on sampling rate for Doppler shift estimation

What is the requirement of sampling rate on channel impulse response (CIR) for Doppler shift estimation? Suppose that there is a bi-static radar system with perfect synchronization, the receiver ...
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3answers
137 views

Is there processing gain for FMCW using heterodyne-style receiver as opposed to matched filter?

Beat signal of a single target will be a sinusoid in the idealized world, so theoretically the signal processing gain of an FMCW pulse correlated with Tx waveform in this way should be analogous to ...
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1answer
21 views

How does one go about choosing a Radar Cross Section for a human when modelling a Pulse micro-Doppler microwave radar?

So as part of a personal project I'm in the process of simulating and making a fall detector using a 2.7GHz microwave sensor with a range of 8m. I've been using MATLAB's example code to simulate each ...
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38 views

Friendly target identification in radar

How do radar systems identify friendly targets to avoid AA locks during combat scenarios? Do friendly planes broadcast a known signal or is something else going on?
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78 views

Beginner Educational Resources

New member here. Recently got hired into a mid level EE position. Have a BSEE but performed more radar performance analysis at a higher system level previously. In my new group we're doing a lot of ...
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125 views

What is the advantage of using a Stepped Frequency waveform over FMCW?

What is the advantage of using a Stepped Frequency Waveform instead of a traditional linear FMCW ?
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74 views

Can velocity be calculated in first stage FFT?

I understand that, For an FMCW radar, the velocity of a target is proportional to the phase changes at same time instants across the chirps. I have a MxN data cube with N chirps(columns) & M ...
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1answer
40 views

Relation between Gaussian derivatives and Gausian-windowed Cosine function

I am doing some research on UWB radars which transmit a pulse given by: $$ g(t) = p(t) cos(2\pi f_{c}t) = A e^{(-\frac{t^{2}}{2\tau ^{2}})} cos(2\pi f_{c}t) $$ In some other papers, the transmitted ...
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63 views

Expression for Frequency-shifted Gaussian pulse

I am doing some research on UWB radars which transmit frequency-shifted Gaussian pulses. These pulses are given by: $$ g(t) = p(t)cos(2\pi f_{c}t) = V_{TX}exp(-\frac{t^{2}}{2\tau^2})cos(2\pi f_{c}t) $...
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74 views

FMCW range doppler response problem

I'm trying to learn radar simulation using Matlab. I used this example in Matlab https://www.mathworks.com/help/driving/ug/radar-signal-simulation-and-processing-for-automated-driving.html But when I ...
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26 views

Beamforming and AoA with a small number of elements

So I have an antennae array with only three elements. I want to know what kind of beamforming and AoA estimation I can do with such a small number of elements. I understand that there are lots of ...
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76 views

How does the Hilbert Transform extract the in-phase and quadrature phase components of a real passband signal?

I am taking an intro to radar signal processing course and we are discussing the Hilbert Transform and how it take a real input and its output is analytically complex. I'm trying ) how a radar ...
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1answer
42 views

SAR spotlight raw signal database

For practicing spotlight processing, i am looking for I/Q baseband signal from a SAR airborne or spaceborne system. In my research I have only found processed image from : eoweb geoportal https://...
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45 views

Advice on generating stable FMCW waveform

I am trying to derive parameters for a triangular FMCW waveform such that the phase of the signal has consistency from one period to the next. Perhaps this is arbitrary and feel free to tell me so, ...
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1answer
55 views

How is a Particle Filter used to Estimate Parameters of a State Transition Function?

In the tutorials on particle filters that I have seen, it seems that the state transition function is already known. This example from Matlab, for example, states the the Plant or State Transition ...
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35 views

Transceiver for TDoA measurements

Could someone advise me on some module for making the TDoA position system for my research work? I need to have measurements with an accuracy of a few meters. It equals a bandwidth of about 20 MHz. I ...
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62 views

Compressed Sensing in DOA processing

I'm trying to apply the compressed sensing theory (CoSaMP algorithm) to the DOA estimation in FMCW ULA (made of 48 elements). In the dechirped signals processing I use a first FFT to solve the range ...
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1answer
62 views

What is the importance of signal bandwidth in radar systems for velocity and localization estimation

So I know about the basics of doppler shift which relates the velocity of a moving object with the frequency carrier shift seen at the reciever. But, I don't understand the importance of the ...
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1answer
87 views

DOA for bistatic radar

Consider a circular antenna array (UCA) with $N$ antenna elements as part of the CW bistatic radar system. For each element we receive a signal of length $L$: $x_n[k]$, $k=1...L$, $n = 1...N$. Оne of ...
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45 views

Pulse Width and Duty cycle in Gaussian pulses

I have a pulse-based radar which transmits frequency-shifted Gaussian pulses. The Gaussian pulse ($p(t)$) is given by: $$ p(t) = V_\text{TX} e^{\frac{-t^2}{2 \tau ^2}}. $$ The frequency shifted ...
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91 views

Distortion in phase difference measurement using FFT

I am doing distance measurements by transmitting a 100 kHz tone and receiving it and measuring the phase difference.The distance is simulated by a delay simulator which is very precise (around 10 psec)...
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1answer
781 views

FMCW Radar - Range-Doppler Plot

The FMCW radar with the following parameters was implemented: ...
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2answers
214 views

Radar for Vital Signs – Matlab Simulation

Interested to design and simulate FMCW radar for Vital Signs sensing. The initial signal parameters are(1): When using the following Matlab code to generate the waveform: ...
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1answer
152 views

MTI RADAR, DSP algorithm question

Im new to RADAR signal processing. I using this doc for ref: https://www.mathworks.com/help/phased/examples/ground-clutter-mitigation-with-moving-target-indication-mti-radar.html I trying to rebuild ...
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2answers
137 views

What is the best to confirm that the output of a matched filter for a linear FM chirp is correct?

I have written a matched filter in matlab to compress a linear FM chirp signal and would like to confirm that the results of my range compression. My question is what is the best way to do this? I ...
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1answer
61 views

Radar type application for narrow band only?

Not sure if this is the proper forum to ask this question, but still I am trying my luck. I am looking for an application (in any area, medical, defence, or any other area) if exist, such that we want ...
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41 views

How do you perform range compression of SAR data on a 2D matrix?

I am building a Matlab program to process RADARSAT-1 data that came with this book. The book describes the steps to creating SAR image as follows I am currently implement the range compression step. ...
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31 views

How can i identify number of return of the ping in the sonar?

I am writing a fake function which is actually doing active pinging (basically SONAR). I am little confuse here about how to identify the number of sonar return i got ? Let's say i am continuously ...
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1answer
142 views

FMCW Radar using FSK Superimposed LFM ramp

While reading the datasheet of the ADF4159 I came upon a section describing how to create an FMCW ramp with FSK superimposed to "enable unambiguous (distance and velocity) multitarget detection&...
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134 views

Cant find Doppler shift with LFM signal

Im stuck on this one. I hope someone helps me! Problem: I need to find Dopler shift with array of reflected chirps. I have bursts of chirps which then i sampled, and calculated fft. Im suposed to ...
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1answer
972 views

Generating IF signal for FMCW radar

I am trying to generate a signal that represents mixer output of FMCW radar. I am using MATLAB and already tried out this tutorial. There, Phased Array System Toolbox is used to showcase how FMCW ...