Questions tagged [radar]

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

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13 views

Detect number of targets from the FMCW data matrix

Currently, I already have an FMCW data matrix which was acquired by the SISO radar. Based on this data matrix, I want to estimate number of targets in it. And then I can apply some blind source ...
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35 views

SAR processing images fft with Matlab [closed]

I am investigating processing of SAR images right now, it is new for me. From Magellan images (1024x1024), I have to determine the Doppler Centroid. For that, I have to compute the azimuth spectrum (...
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42 views

Stolt interpolation and ifft in range migration algorithm

I am using range migration algorithm for focusing stripmap synthetic aperture radar data. I have successfully tested my algorithm using the following steps after range compression (similar to this ...
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29 views

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. ...
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1answer
43 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?
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3answers
94 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 ...
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1answer
36 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 ...
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1answer
59 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 ...
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21 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 ...
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1answer
85 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 ...
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2answers
79 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 ...
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1answer
48 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) = |\...
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1answer
40 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 ...
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1answer
113 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 ...
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34 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 ...
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27 views

MIMO FMCW radar - back-projection

any suggestion how to start implementing the back-projection algorithm in a FMCW MIMO radar? Currently I'm using 2D FFT to get radar image, I would try time-domain algorithms to improve the overall ...
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74 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
50 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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42 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
104 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
111 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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25 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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23 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
55 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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30 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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34 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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94 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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34 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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73 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
121 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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52 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
224 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
405 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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77 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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47 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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44 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
93 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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28 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
111 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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49 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
25 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
62 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
559 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
119 views

References ISAR - Inverse Synthetic Aperture Radar [closed]

Anybody know a reference to start understanding ISAR? Book or article. Thanks!
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1answer
152 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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1answer
183 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
943 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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2answers
85 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
269 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 ...