Questions tagged [radar]
Anything related to RADAR (RAdio Detection And Ranging) systems and radar signal processing.
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2answers
30 views
In case of using a Doppler radar, do we have to use IQ demodulation to find the direction of a target?
I want to know the way to find the velocity of a target by using a doppler radar.
I read some paper about it,
In summary,
send rf signal to a target
receive the reflected signal from the target.
...
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1answer
34 views
References ISAR - Inverse Synthetic Aperture Radar [closed]
Anybody know a reference to start understanding ISAR? Book or article.
Thanks!
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0answers
18 views
Space-time filtering vs. beamforming
Say I have a dense linear array of sensors in space and an acoustic signal propagating through them.
In this case, how would delay-and-sum beamforming compare to space-time filtering by masking the ...
1
vote
1answer
80 views
Light Detection and Ranging (LIDAR) Range Bias Compensation with Light Dependent Resistor (LDR)
I have a distance sensor (VL53L0X), which measures the distance to an object. It is placed outside. I currently do 100 measurements in the best available range mode, then I take the median and insert ...
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0answers
29 views
FMCW radar 3D FFT for DOA estimation
I'm dealing with transformation of coordinates after I do the 3d FFT doa estimation.
Data below is a car in front of the radar board, and the angle of arrival is "0", 50m.
Left image is the row has ...
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1answer
53 views
Doppler Shift of Phase Coded Pulse Compression Waveform
Suppose I want to transmit the signal:
$$ x(t) = g\Big(\frac{t-t_{0}}{T}\Big) \cdot \cos(2 \pi f_{0} t + \theta_{0}) + g\Big(\frac{t-t_{1}}{T}\Big) \cdot \cos(2 \pi f_{1}t + \theta_{1}) $$
Where $g(...
2
votes
1answer
274 views
How to Calculate the Ambiguity Function
(Maybe this should be on Stackoverflow instead ...)
What is the best way to calculate the ambiguity function? There are different implementations out there for Python (like PyTFTB or from ...
2
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1answer
38 views
motion compensation for range migration algorithm
Is there a simple to follow explanation of how to do second order motion compensation for range migration algorithm?
The one described in Carrara et al is for the ideal case. For the Extended Omega K ...
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1answer
82 views
2D CFAR detectors
Constant False Alarm Rate is an adaptive detector used to distinguish between true and false detections. There are many types of CFAR and the number of these detectors reaches 25 like (CA-CFAR, OS-...
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0answers
66 views
Is there a situation when maximizing SNR doesn't also maximize probability of detection?
The problem I'm working on is signal detection of a radar signal, but I suspect this problem shows up in many different branches of signal processing.
Background:
From [1], the factor $I_f$, by ...
-1
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1answer
209 views
FMCW Radar Signal Processing Flowchart / Ambiguity Function
I Read many papers on signal processing for pulsed and FMCW radars, taking the FMCW type, the signal processing start after mixing the received and transmitted signal, the result of this operation is ...
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1answer
137 views
Radar video signal and matched filtering
In order to make my question more clear and give more details
I'm trying to understand the processing signal procedure in radars,i understood till this moment that a transmitter generates a signal ...
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2answers
457 views
Deriving the resolution equation of an FMCW radar
I am interested in the equation that depicts the resolution of an FMCW radar. I write the same below.
$\Delta d = \frac{c}{2b}$
First I would like to have an intuitive explanation to the above ...
2
votes
2answers
76 views
Compressive sensing and sparsity
We apply compressive sensing to reconstruct a signal if it is sparse in the original domain or has a sparse represetation in some basis.
How we may know a if a signal is sparse or has a sparse ...
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2answers
151 views
DOA - 1D Music Algorithm
I am currently working on a MUSIC algorithm for DOA of RF emitters in 3D.
At the first stage, interested to apply the 1D MUSIC using a linear array of 4 antennas, and estimate only the azimuth of the ...
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0answers
72 views
Spectrum of received signal from radar fm-cw
I obtained actual data from a researcher, consisting of a matrix composed of several received signals from an up-ramp fm-cw radar.
Wouldn't be reasonable to plot the spectrogram of a ramp up and ...
0
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1answer
34 views
azimuth extent for range migration algorithm
Is it true that in the Range Migration Algorithm for synthetic aperture radar, the azimuth extent can be said to span the length of the flight path?
This makes sense but also does not make sense. ...
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0answers
78 views
How to remove echo/reflected-sound caused by stationary objects when building a ultrasound based radar
I am emitting ultrasound with a speaker and am trying to track moving objects with a microphone array by detecting doppler shifts. I have succeeded to detect movement. However, to detect the direction ...
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1answer
106 views
Derivation of range migration algorithm
Problem:
In Walter G.Carrara's book on synthetic aperture radar, the equation is presented:
$\Phi(K_X, K_R) = -K_XX_t - R_B\sqrt(K_R^2 - K_X^2) +K_RR_S $ (10.30)
And this is said to come from ...
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0answers
193 views
Getting the velocity in Radar FMCW
I have managed to get the frequency (the beat) frequency from an FMCW. Here is a screen shot of a wall that's detected by the Radar. I performed an FFT of complex I,Q data.
My questions are 1. How ...
-1
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1answer
110 views
Radar Tracking Algorithms
I would like to know the algorithms to get the angle, range, distance.. so I'm planning to do antenna tracking. What should I do in basic steps to track objects using that module ?
what algorithms ...
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1answer
66 views
Scan shallow water
I need to scan a shower tray with & without the water running to assess the puddling at the drain, then export a point cloud or surface. Sonar & Laser dont seem to be able to deliver, can ...
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0answers
22 views
Is it possible to find a signal that reduce the PSLR without expanding 3dB main lobe for autocorrelation?
Considering a signal $s(t) = rect(t/T_p)exp(j\theta(t))$, the autocorrelation is $ACF=IFFT(s^2(f))$. It's possible to construct the $\theta(t)$ to get a signal which has the same 3dB main lobe as the ...
1
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1answer
93 views
Designing an efficient curve-matching algorithm
I'm currently designing a curve-matching algorithm and as I already explored many ideas I'm requesting your help. So, if you got some advices about how to handle this problem, feel free to answer!
...
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1answer
74 views
Increase Radar Detection range using Modulation
I have been reading about pulse compression which helps with the range resolution.
In my application I do not need to measure the range of the object however I am more interested in boosting the SNR ...
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0answers
784 views
Convert RGB image to meaningful data
I am trying to extract data from images and convert them to meaningful data. The images are mostly obtained from weather radar and have been transformed into some opaque numbers. I am trying to use ...
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1answer
123 views
Phase of FMCW linear chirp
I'm doing a project involving FMCW linear chirp signals.
Given the phase
$\phi = 2\pi\frac{k}{2}t^{2} + 2\pi f_{c} t + \theta$
where $k$ is the frequency increase rate.
When transmitting ...
0
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1answer
352 views
Probability of False Alarm versus SNR
I'm currently testing the performance of an energy detector using two tests. One test involves finding the optimal threshold to achieve a probability of detection(Pd) of 0.9 and a probability of false ...
1
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1answer
1k views
Simulation of FMCW radar in frequency domain
I would like to simulate a FMCW radar in the frequency domain. I used the code (Matlab) I attached below. Specially I am interested in the phase spectrum of the beat signal. In a further research I ...
2
votes
1answer
351 views
Radar Pulse Compression Gain (PCR)
Assume a monostatic radar is transmitting a pulsed waveform. The pulse has been modulated by a Barker code with$\ N$ chips or bits. The waveform chip rate is $\tau_c $, the radar receiver's detection ...
0
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0answers
819 views
Correct Radar Range Equation for SNR at Detection
Assuming you'd like to estimate the probability of detection of a target for a monostatic radar.
For estimating detection SNR of a monostatic radar for given target rcs signature, do you use the ...
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2answers
1k views
Is it possible to make 3D point cloud with RADAR?
Is it possible to make 3D point cloud with RADAR? Both LIDAR and RADAR are EM waves, but with different wavelength. So, if it is technically possible to make point clouds with LIDAR, why is it not ...
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1answer
73 views
Is it possible to get the velocity vector for tangential movement using radar?
When an object appears towards the radar sensor or goes away from the radar sensor, there is a change in the phase shift of the frequency and from that, the velocity can be inferred.
So, I have two ...
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1answer
442 views
How is angle of arrival estimated?
I have simulated a phased array antenna. I have also simulated a point source. I don't get how to calculate pseudo spectrum vector without using the position of the source. Algorithms such as Capon ...
2
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1answer
1k views
Time-Bandwidth Product
The following text is cited from a textbook, "Spotlight Mode Synthetic Aperture Radar: A Signal Processing Approach", I would like to ask if anyone knows the proof to the following statements, as the ...
4
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0answers
83 views
Finding the parameters and endpoints of a sinusoid
Suppose I have some signal
$$
s(t) = n(t) + \left\{\begin{aligned}
&0 &&: t < t_0\\
&A e^{i (2 \pi f t + \theta_0)} &&: t_0 \le t \le t_1\\
&0 &&: t > t_1
\...
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0answers
221 views
Pauli decomposition of polarimetric SAR data
I am working these days with Pol SAR and I have read up on the Pauli decomposition and how it can help to detect the signal power which has been acquired over a single or odd number of bounces, two or ...
0
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1answer
226 views
Radar Imaging Method
I've been working with an FMCW Fast Chirp radar transceiver. Mainly, I've been looking at the Doppler range map but really it is not suitable as there is only one point per range/ speed and I want to ...
0
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2answers
169 views
Should the transmitted signal be continuous in FMCW?
I am a novice in this field and working on respiration detection through near ultra-sound between $18 \textrm{kHz}$ and $20 \textrm{kHz}$.
In the referece article and other radar use articles, the ...
3
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1answer
386 views
Array Signal Processing: What are snapshots in Direction of Arrival estimation?
I do have an overview of basic radar signal processing chain [Data cube, 3 stages of FFT, Range, Range-Doppler map, coherent/non-coherent integration, coarse DoA etc.].
I am now trying to understand ...
0
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1answer
799 views
FMCW Radar: Need for Second stage FFT for velocity determination?
I have understood that for the purpose of Range determination, the samples of the beat frequency are first assembled per chirp. The beat frequency is directly proportional to the range of the ...
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0answers
1k views
FMCW radar FFT processing
I'm working on the processing of raw FMCW radar data.
In my case the radar works in the [6.014-7.76] GHz band (I have 187 frequency points starting from 6.014 GHz and ended with 7.76GHz) and the data ...
0
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1answer
609 views
How to reduce spectral leakage?
We are looking at FMCW radar ADC signals and converting from the time domain to the frequency domain in order build a range doppler map but want to have the best signal to noise ratio possible.
In ...
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2answers
1k views
How to interpret an Ambiguity function
I need to evaluate several different waveforms regarding their doppler tolerance, for use in a radar application. So I came across something called the Ambiguity function.
The following picture shows ...
2
votes
1answer
166 views
High performance DSP processor with better on-chip memory
I am currently using a combination of 4 ADSP 21469 because of the complexity and huge chunk of code that I currently have. BOOT and application will execute from external Flash memory. The code for ...
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0answers
94 views
What is the unit of radar cross-ambiguity function for signals with given power?
I am trying to write my own radar simulator in MATLAB. In contrast to other simulators I found (Levanon etc.), my goal is to provide exact results with respect to signal power, antenna gains, path ...
2
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0answers
145 views
Help detecting target in pulsed radar signal
This signal is from the Pasternack $2.4\textrm{ GHz}$ development kit. The saved signal appears to be the pulsed waveform. It is sampled at $20\textrm{ kHz}$ for $4130$ points. I recorded a ...
3
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1answer
1k views
Radar SNR for a LFM Waveform
How do you estimate the detection SNR for a radar transmitting an LFM (chirp) waveform? I'm looking for an SNR equation that is a function of chirp bandwidth and compressed (or uncompressed) ...
4
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2answers
1k views
Radar terminology - Specific meaning of “video signal”
In the radar literature, particularly in older references, the term "video signal", "downrange video", or just "video" is used to describe the radar signal at a certain point in the processing chain. ...
2
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1answer
2k views
Radar signal processing - Difference between range gate/range bin
In learning about radar signal processing, I see two different terms that sometimes seem to refer to the same thing, but sometimes different things:
Range gate
Range bin
Usually, I interpret both to ...
