Questions tagged [radar]

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

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How to estimate Range, Doppler and Angle with FMCW MIMO Radar?

I am trying to obtain the range, Doppler and angle of arrival estimation with an TDM MIMO FMCW radar. Actually, I have completed this process. In doing so, however, a few things remained unclear. ...
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How to apply MUSIC to FMCW radar IF data?

I'm working on target extraction with raw FMCW ADC data. I arranged my received data in an (numADCsamples x numAntennas x numChirpsPerFrame) radar cube. So far I am using range FFT and doppler FFT to ...
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In radar pulse analysis, why is the PRF of pulse not calculated using Fourier transform?

So, I am fairly new to this, but when going through books on Radar pulses, I noticed that quite often, a formula describing the frequency of the waveform is given. For example, the frequency of a ...
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How to eliminate a cyclic spectrum estimation window artifact?

I am using an implementation of the averaged cyclic periodogram (section 3.2.4 in Antoni, Jérôme. "Cyclic spectral analysis in practice." Mechanical Systems and Signal Processing 21.2 (2007):...
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103 views

Cross Ambiguity Function Peak Width

I am trying to plot the Cross Ambiguity Function of two OFDM signal (1024 subcarriers) reflected from two targets, which are separated by 30m. The problem I am facing that the CAF peak width at the ...
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FMCW Radar Doppler Ambiguity related to Nyquist theorem or exceeding the distance frequency or both

I have been reading about doppler ambiguity and I have two explanations for its occurrence that I can't relate to each other. 1st Explanation: In the stationary case (radar and target are stationary) ...
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DSP based phase shifting in Phased Array systems

Is there a downside to doing phase shifting at basedband in the DSP section of phased Array systems? I suppose you trade off analog components for digital which may be more costly but I suspect modern ...
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SNR estimation from a radar sensor signal

I am using a radar sensor for human activity monitoring which works on 3.18GHz. The received signal by the receiver of the sensor depends on the movements in its area of observation. All the activity ...
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FMCW radar: understanding of doppler fft

I am using fmcw radar to find out distance and speed of moving objects using stm32l476 microcontroller. I transmit the modulation signal as sawtooth waveform and I read the recieved signal in the ...
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3 answers
560 views

range-doppler map to range-velocity map conversion

UPDATE 2.0 I think I've managed to produce the correct range-velocity map. I'm struggling with analytically calculating the range which I expect to see on the range-velocity map. Could someone please ...
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Best way to reach experts in the Synthetic Aperture Radar (SAR) Simulation field?

I'm looking for Synthetic Aperture Radar (SAR) Simulation experts and struggling to find them (context: synthetic data for geospatial applications). I've found a few users in this community who could ...
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What does Doppler Fast/Slow Items? How do they relate to Micro-Doppler Signature?

I'm working with X4M200 respiration sensor (Sensor Output Datatypes) and in provided link on page 11 it says that it provides recordings with Movement Slow/Fast Items (slow and fast pulsedoppler ...
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How to quantify a deterministic system?

So let me layout my question and the thought process on solving it. Say, we have some system, and we want to see how deterministic the system is. By that I mean, I mean if I put some signal (real ...
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Radar Pulse Shaping Filter

For communication signals, a Root Raised Cosine (RRC) filter is often used as the pulse shaping filter. What kind pulse shaping filters (prototypes or window functions or tapers) are used in radar ...
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Removing Attenuator and Real Mixer influence on the received Baseband signal in Radar IQ Transmitter - De-embedding

Radar IQ Transmitter Measurement Setup: Waveform Generator + IQ Transmitter + Attenuator + Real Downconversion mixer + Oscilloscope + Post-processing (Hilbert Transform) With the above arrangement ...
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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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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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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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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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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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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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286 views

3dFFT to compute angle of arrival in FCMW radars

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 arrival (AoA). The scenario is the following. The radar ...
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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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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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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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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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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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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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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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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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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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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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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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2 votes
1 answer
308 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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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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2 votes
1 answer
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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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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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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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2 votes
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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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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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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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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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1 vote
1 answer
206 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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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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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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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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2 votes
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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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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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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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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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