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Questions tagged [radar]

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

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1answer
32 views

Baseband representation of a LFM chirp signal

I need to generate a chirp signal between $f_{start} = -f_{limit}$ and $f_{stop} = f_{limit}$, to compare it to a FrFT generated signal. The FrFT signal of order $\alpha = 0$ is PAM modulated data ...
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1answer
50 views

Omega-K algorithm implementation for synthetic aperture radar

I have been trying to develop Omega-k algorithm for SAR image formation. I am using the equations from chapter 8 in digital processing of Synthetic Aperture Radar data by Cumming and Wong. The steps I ...
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20 views

range resolution FMCW radar influenced by Nyquist?

I am puzzled about this for some time now. According to theory, the max range of a FMCW radar in practice is limited by the sampling frequency $R_{max} = \frac{c_0 T_{upchirp}}{2 f_{BM}}f_s$ Since ...
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17 views

How to find the filter coefficient of matched filter to detect the pulse of a signal?

I would to understand how to find the coefficient of a matched filter. Let's consider we have a signal and the signal is buried in the following noise. we want to find the coefficient of a matched ...
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0answers
14 views

Age of information and measurement rate typical for automotive radar devices

I'm working on an automotive application which uses radar information and I need to create a basic model of the radar to simulate its behaviour. I need to know 2 parameters: -Measurement rate: With ...
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21 views

Precision accuracy radar

in radar systems how does one measure the precision and accuracy on a radar? I'm confused with differen definitions in the references: Richards define (Principles of Modern Radar: Basic Principles - ...
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1answer
55 views

Carrier frequency of chirp signal

I am computing the link budget for a communication-radar (CoRadar) system. The formula for maximum distance, in communication, is: $d_{max} = \sqrt{\frac{P_t}{\tau}\frac{G_t G_{r, comm} \lambda^2}{(4\...
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22 views

FM/CW NOISE RADAR

I am trying to generate the white noise signal which I want to modulate using the sinusoidal wave for the radar-target application. I used fmmod() but I am confused is this right choice. I came across ...
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2answers
58 views

Why having a ridge like Ambiguity Function implies lack of Doppler resolution?

I was wondering why if the AF (Ambiguity Function) has a ridge like form it has low Doppler resolution.
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28 views

Radar - CFAR processing post Digital Beamforming - efficient alternative methods

A radar using a ULA with a large number of elements(for instance N=150 for 1[deg] beamwidth[1]) is being designed. After the Range and Doppler processing, Digital Beamforing is being performed, ...
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1answer
20 views

how can I plot a power spectrum for 150 range bins with 512 fft points [closed]

This is my code for plotting... However when I plot my spectrum data using this code, it is showing only 1 row. How can I plot all 150 rows? Can anyone help me to solve this? ...
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1answer
38 views

How to classify the movement type of a target into two categories(direct motion or else) by using a doppler radar?

How to classify the movement type of a target just into two categories(one is direct motion which is almost straight line movement and the other is anything else) by using a doppler radar with a ...
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2answers
156 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
56 views

References ISAR - Inverse Synthetic Aperture Radar [closed]

Anybody know a reference to start understanding ISAR? Book or article. Thanks!
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32 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 ...
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1answer
102 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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170 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
127 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(...
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1answer
511 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 ...
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1answer
52 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
162 views

CFAR detectors and interference

Constant False Alarm Rate (CFAR) is an automatic thresholding technique. It's situated after the FFT processing in other to detect target peak. This probability of detection depends on clutter and ...
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70 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 ...
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1answer
292 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
193 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
1k 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 ...
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2answers
86 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
224 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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106 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 ...
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1answer
44 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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87 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
137 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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1answer
138 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
73 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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1answer
111 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
86 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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1answer
210 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 ...
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1answer
441 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 ...
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1answer
2k 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 ...
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1answer
496 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 ...
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1k 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
2k 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
99 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
649 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 ...
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1answer
2k 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 ...
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0answers
88 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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1answer
292 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 ...
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2answers
195 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 ...
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1answer
481 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 ...
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1answer
1k 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
2k 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 ...