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Questions tagged [radar]

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

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Motion compensation for stripmap SAR

I am trying to perform motion compensation for an airborne stripmap SAR data following the book Synthetic Aperture Radar Processing by Franceschetti and Lanari. The algorithm flowchart is on page 145. ...
Rifat Afroz's user avatar
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1 answer
664 views

Range Compression

How exactly is the SAR image resolution increased by the linear frequency modulation of the transmitted signal and further by the compression of range and azimuth?
Na5H's user avatar
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3 answers
113 views

3D model from high speed videos?

Is there a way to convert or somewhat replicate RADAR data from a set of given high speed videos taken from multiple angles. The problem is quite ill defined but the task I have in hand is to ...
sspatole's user avatar
-1 votes
1 answer
501 views

How to perform dechirping of SAR image in MATLAB?

I have the transmitted pulse and the raw SAR image before range compression (dechirping). I understand the pulse compression its a convolution along the columns but I am not able to make it work. I've ...
benr's user avatar
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1 answer
1k views

Synthetic Aperture Radar (SAR). How to do Range Compression?

I am trying to perform range compression to a raw SAR image [fast times, sensor position], Dr in code. I have the transmitted signal (chirp), g in code, and literature says range compression is ...
benr's user avatar
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0 answers
72 views

modelling radar system for image generation

I am trying to find or derive some model for radar using python and blender which should hopefully create a simulation of what a radar image of the blender environment would look like. I have been ...
O. M.W.'s user avatar
5 votes
1 answer
2k views

Radar signal processing flow chart

I'm new to Radar in general, and I'm studying RADAR using online resources. I came across the following slide which shows the process flow of the Radar signal processing. The thing I don't get in ...
Jung_Zheng's user avatar
2 votes
2 answers
298 views

Pulse Doppler Radar: time delay in down conversion

My understanding of Pulse Doppler Radar is the system measures Time Of Flight for the pulse. My confusion is that during the down conversion process prior to ADC the lowpass filter causes some time ...
FourierFlux's user avatar
-1 votes
1 answer
323 views

Coherent Radar -- How do we justify it?

How can we justify doing coherent radar when the phase of the return is unknown? For instance, after a reflection, assuming a stationary target, we should get something akin to: $$ x_{rx}(t) = |\...
the_src_dude's user avatar
2 votes
1 answer
176 views

Minimizing Time Sidelobes with Pulse Compression

I am trying to compute a compression filter function to minimize the error from a a desired pulse compression result. The usual approach to doing this is to minimize the RMS error of the the ...
Jim's user avatar
  • 265
3 votes
1 answer
260 views

FFT strong signal in middle frequency bin

I've developed a radar that I'm using to determine the distance to remote objects. It uses a custom PCB with an onboard FPGA that performs the DSP algorithms. The data from it is then plotted on a ...
MattHusz's user avatar
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0 answers
152 views

Range Migration Algorithm in FMCW MIMO RADAR

I’m using a FMCW MIMO radar [77-79 GHz] with a virtual linear array made of 48 channels. I’m wondering if the adaptation of the range migration algorithm (typically used in SAR processing) is ...
Luca Romano's user avatar
1 vote
0 answers
128 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 ...
Mark Pedley's user avatar
0 votes
1 answer
69 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 ...
Mark Pedley's user avatar
3 votes
1 answer
371 views

Combining two Images with Different Resolutions into Higher Resolution Image

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 ...
Sean Holloway's user avatar
1 vote
2 answers
537 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 ...
The Dude's user avatar
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1 answer
930 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?
DaDSPGuy's user avatar
  • 182
1 vote
2 answers
92 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 ...
Stephen Jackson's user avatar
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1 answer
83 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).
DaDSPGuy's user avatar
  • 182
0 votes
0 answers
106 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 ...
DaDSPGuy's user avatar
  • 182
0 votes
1 answer
764 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 ...
Spen1210's user avatar
0 votes
1 answer
971 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 ...
Lars Ericson's user avatar
0 votes
1 answer
2k 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 ...
DaDSPGuy's user avatar
  • 182
1 vote
2 answers
2k 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 ...
Rifat Afroz's user avatar
1 vote
0 answers
152 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 - ...
Felipe's user avatar
  • 155
1 vote
1 answer
301 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\...
DaDSPGuy's user avatar
  • 182
0 votes
2 answers
281 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.
DaDSPGuy's user avatar
  • 182
0 votes
1 answer
63 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? ...
hari chandana's user avatar
0 votes
1 answer
82 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 ...
Sinecosine's user avatar
0 votes
2 answers
3k 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. ...
Sinecosine's user avatar
0 votes
1 answer
263 views

References ISAR - Inverse Synthetic Aperture Radar [closed]

Anybody know a reference to start understanding ISAR? Book or article. Thanks!
Felipe's user avatar
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1 vote
1 answer
295 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 ...
fsp's user avatar
  • 113
1 vote
1 answer
494 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(...
The Dude's user avatar
  • 632
2 votes
1 answer
3k 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 ...
ronnyworm's user avatar
3 votes
2 answers
158 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 ...
matthew's user avatar
  • 95
1 vote
1 answer
753 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 ...
Issa's user avatar
  • 127
1 vote
0 answers
114 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 ...
Robert L.'s user avatar
  • 2,222
2 votes
1 answer
881 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 ...
Issa's user avatar
  • 127
0 votes
1 answer
426 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 ...
Issa's user avatar
  • 127
5 votes
2 answers
8k 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 ...
Denis's user avatar
  • 223
2 votes
2 answers
170 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 ...
Issa's user avatar
  • 127
3 votes
2 answers
975 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 ...
SenSen's user avatar
  • 113
0 votes
0 answers
298 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 ...
Francesco Pegoraro's user avatar
0 votes
1 answer
188 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. ...
matthew's user avatar
  • 95
0 votes
0 answers
239 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 ...
Deep Mind 's user avatar
2 votes
1 answer
241 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 ...
matthew's user avatar
  • 95
-1 votes
1 answer
256 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 ...
Andre Ahmed's user avatar
-1 votes
1 answer
122 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 ...
R. Knight's user avatar
2 votes
1 answer
565 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! ...
Louis Lac's user avatar
  • 378
-1 votes
1 answer
156 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 ...
Ktuncer's user avatar
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