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Questions tagged [radar]

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

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58 views

Root MUSIC and solution of conjugate palindromic polynomials

The root-MUSIC algorithm gives direction of arrival angles directly and avoids the computational overhead of computing the MUSIC estimator curve (see Direction of Arrival Estimation using a Root-MUSIC ...
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1answer
46 views

How is ESPRIT pronounced?

I'm implementing high resolution DOA algorithms including ESPRIT for radar systems. The word ESPRIT is obviously an acronym but, even so, how is it pronounced? Is the second i long like "ESPREEE" as ...
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34 views

Combining two images with different resolutions?

I am attempting to combine two radar images, each of which is a 3-dimensional cube with a range dimension, an azimuth angle dimension, and an elevation angle dimension. One image has high azimuth ...
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2answers
45 views

Doppler Shift and the Pulse Repetition Interval

Suppose that I have a signal $x(t)$ consisting of $N$ pulses at a given frequency $\omega_{c}$. I space them $T$ seconds apart, ie the Pulse Repetition Interval (PRI) for the waveform is $T$. Now ...
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1answer
40 views

Advantages and disadvantages in term of radar performance of LFM chirp

Which are the advantages and disadvantages of a LFM chirp regarding its radar performance?
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19 views

How to create test vectors for wideband beamforming aplications?

I'm trying to create test vectors for a beamforming algorithm I'm simulating in Matlab. I have a complex signal and I want to create the signal as seen by each antenna element. This will allow me to ...
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17 views

Zero delay cut of LFM complex chirp

I am computing the zero delay cut of the ambiguity function a LFM chirp: $\chi(\tau = 0, \nu) = \int_{-\infty}^{\infty} u(t) u^{*}(t)e^{j 2 \pi \nu t} dt = \int_{-\infty}^{\infty} A e^{j(2 \pi f_0 t + ...
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2answers
43 views

Matched Filters for attenuation detection?

I have been reading about matched filters and I'm interested in possible uses for them, I have seen they are used very often in radar, in such a way that you send out a signal, and then you read the ...
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21 views

Why the ideal ambiguity function (AF) for radar has the maximum in (0, 0) and zero otherwise?

I was wondering why is the ideal AF has zero value in all the function except in (0, 0).
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24 views

RRC filter or rectangular pulse shaping filter in LFM chirp signal

I am working with a LFM up chirp signal, and I wanted to embed some data on it using a BPSK constellation. My doubt was, ¿should I use a RRC filter, like in usual communications schemes, or should I ...
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47 views

Question about FMCW range-velocity plot

I am working on plotting range-velocity heatmap of the receiving FMCW signal. I actually have already plotted. However, I do not really understand the mapping relationship between Doppler FFT bin and ...
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25 views

Automotive Radar Simulation

I am looking to simulate a radar channel and a waveform to test some ideas from other signal processing domains on automotive radar. However, I have no experience with the typical automotive radar ...
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49 views

FMCW radar beat resolution with target spectral width, non-linearity and receiver resolution

The question is about resolution of FMCW radars whcich send triangular frequency waveform, receive it's echo then mix it with sent signal, extract beat frequency. The beat frequency is proportional to ...
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1answer
85 views

Real signal from I,Q, sample rate and center frequency

I am given a recording of an ionosonde sounding. The signal $S$ is represented as a series of I/Q pairs at a sample rate $F_{sr} = 10\,\text{MHz}$. I am told that the center frequency of the ...
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46 views

Doppler shift in police radar

I don't understand how the radar frequency can be extracted from this diagram : (source:https://copradar.com/rdrparts/) and specially i don't understand what is the role of PLL and IF circuits and ...
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1answer
113 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
191 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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56 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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27 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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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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33 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
70 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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25 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
84 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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45 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
22 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
54 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
332 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
93 views

References ISAR - Inverse Synthetic Aperture Radar [closed]

Anybody know a reference to start understanding ISAR? Book or article. Thanks!
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42 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
133 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
335 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
153 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
705 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
59 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
191 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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0answers
74 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
362 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
250 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
2k 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
97 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
270 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
140 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
59 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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111 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
158 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
161 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
78 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
160 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
97 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 ...