Questions tagged [radar]
Anything related to RADAR (RAdio Detection And Ranging) systems and radar signal processing.
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What signal does a CW-Radar using I/Q send?
The last couple of days I read a lot about cw-radars, I/Q modulation and quadrature amplitude modulation (QAM).
But one things, which is never mentioned, really confuses me.
Which signal is really ...
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Communication Channel under Doppler effect
Suppose I have a scheme of a radar station A transmits a signal to sense a car B moving with velocity $v$ and located at a distance $R$. At the same time node B also sends another signal to node A, ...
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Digital signal processing from FMCW rangefinder
I am developing a FMCW rangefinder and have encountered a number of questions regarding digital signal processing.
So I have a sawtooth modulating signal with a frequency of 1 kHz, which is fed to the ...
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Finding SAR baseband recordings?
I'm looking for openly available baseband recordings of synthetic aperture radar signals. Can anyone point me to archives of these? Ideally I'd like to look at the signal from something like AN/FPS-...
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[Kalman filter for radar tracking]: How to handle wrapped speed and/or range measurement model?
The Radar sensor measures range, angle, range-velocity, so it is a non-linear measurement model, and I would use UKF to handle it.
What makes it not straightforward is the wrapping measurements. Both ...
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kalman filter constant accelaration model
i am trying to understand the kalman filter constant acceleration model(CA) through simulations but the results are not as expected but when i did the simulation in similar way for CV model i got good ...
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How to find the bias gradient for localization problem?
I am doing the work to find the cramer-rao bound when the estimator is biased. The algorithm I am based on is from Rethinking Biased Estimation: Improving Maximum Likelihood and the Cram´er–Rao Bound, ...
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Spotlight SAR image formation
I've created a Synthetic Aperture Radar (SAR) simulator and am testing it to ensure its correct operation. One of the last steps is to process the data into a final image, but I'm having trouble with ...
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System instability when using FIR filter in feedback loop for removing targets in FMCW radar return
I have an FMCW radar I am working on where I am also attempting to remove a specific target from the received signal (before it is sampled by the ADC). To do so, during each FMCW sweep, I am ...
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creating range map doppler
I'm trying to create a range doppler map for a chirp signal which has the following parameters:
pri = 5e-6;
pw = 2e-6;
CPI = 0.5e-3;
B = 100e6;
f_c = 40e9;
for one ...
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Phase noise influence on ADC in bistatic FMCW Radar
I am currently studying the topic of oscillator phase noise in frequency modulated continuous wave (FMCW) radar. In my specific case, the radar is implemented on an FPGA (AMD RFSoC). Thus, the echo is ...
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Wrong matched filter sidelobe level for linear chirp despite (invalid ?) energy normalization
I'm trying to reproduce the -13.2 dB sidelobe level typically observed for a linear chirp pulse (cf. for instance this MATLAB documentation page: ...
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What are the hidden assumptions in "Nonlinear Estimation With Radar Observations"?
The paper "Nonlinear Estimation With Radar Observations" (Kenneth S. Miller, Donald M. Leskiw; 1982 IEEE) reports on an improved method for radar tracking with an Extended Kalman Filter (EKF)...
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Radar Signal Modelling based on Channel Estimation
I am a newcomer to digital signal processing. Recently, I have been interested in this question: If we model a reflected radar signal from a target as
$$y(t)=h \ast x(t) + n(t),$$
where $h$ is a ...
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Why is my target showing up with a non-zero centered velocity? I captured this data using the IWR6843A0P using a stationary corner reflector
I need help understanding what I should do to determine why my target is showing up in my Range doppler map with a non-zero centered velocity when I captured my measurement using a stationary corner ...
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Synchronization TX and RX pulses in Pluto-SDR
I am currently working on implementing a FMCW radar for SAR application, I have successfully generated, transmitted, received the CWchrip. But when I move to the calculation of the beat frequency by ...
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SAR and ISAR sampling time
This is a repost of a question that I've previously asked in the EE section of SE. Unfortunately, I've not solved my problem.
I'm seeking insight into the typical values of sampling times or refresh ...
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Continuous wave Doppler radar
I am developing a continuous wave Doppler radar to detect human movement at a speed of 0.2-6m/s. For a radiation frequency of 24.15 GHz, the Doppler shift during longitudinal motion will be equal to ~...
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How does the shape of a FMCW radar work in Python?
I’m a beginner to this field, so sorry if my questions aren’t the best, or if I’m missing information.
Anyways, I’m working with raw data samples from a FMCW radar. Basically, a frame constitutes of [...
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Why are polyphase codes doppler tolerant in comparison to bi-phase codes?
What is the logical reason behind this? Why are P1,P2, P3, P4 codes unaffected by doppler shifts?
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I want to transmit a CW signal using SDR could be pluto or hackrf but I haven't used any one of them can anyone help me
I am using HackRF or Pluto SDR for transmission of a CW signal, after reading the documentation of the HackRF one SDR I found out that it transmits data in only 8-bit signed quadrature samples. Now I ...
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doppler tolerant phase coded waveforms
how do i conclude a waveform shows doppler tolerance, say polyphase code-frank code, without the use of ambiguity diagram? we know that it is doppler tolerant and if we check the frequency spectrum of ...
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Chirp pulse train FFT
I'm trying to understand why the Fourier transform of a chirp pulse train looks the way it does.
I will attach the result I get in MATLAB at the end of the question. I tried to develop analytically ...
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Difference between Likelihood Estimation and CRLB Estimation for Cooperative Radar
I do not know if this question fits this stack, but I think it might suit here because it is something related to the radar sensing processing.
The question is about the difference between the ...
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Simulating 32x32 Radar Configuration from 64x64 FMCW Radar Data
I have gathered data using an FMCW Radar with a configuration of 64 chirps per frame and 64 samples per chirp. Now, I'm trying to simulate the data as if it were collected by a radar with a 32x32 ...
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I am trying to plot range of a target in a FMCW radar
I am working on the simulation of FMCW radar, and I am trying to figure out how to plot the target range using the impulse response of the beat signal. I have successfully generated the chirps and the ...
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Range Doppler Graph
The graph includes a peak at zero frequency and some other frequencies. However, my professor says that there should not be a peak at zero. I contend that he is wrong. But my graph is also not right, ...
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How to simulate multiple targets in FMCW radar simulation in python?
I have simulated a FMCW radar for a single stationary target, now the next step in my project is to simulate multiple moving targets. For this I had thought of using doppler shift to show a difference ...
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What does really Time Chirp contribute to Range and Doppler estimation in FMCW radar signal?
As I started researching FMCW radar signals, I discovered a popular reference code for FMCW simulation in Github. One of the most important things that I still don't understand is the parameters ...
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Image generation from Radar (IMAGEVK-74) I/Q signals
I have a millimeter wave radar (IMAGEVK-74). I am new to signal processing and I need to generate images from the radar data.
The specifications of the radar are- it has a 20 transmitter 20 receivers ...
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Calculating k-space coverage from antenna positions
I work with radar and I want to understand which spatial frequencies I can measure, i.e. the k-space coverage, given a set of coordinates of transmitter-receiver combinations. The ideal coverage for a ...
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Why does applying Fourier Transform on point Spread Function yield h(t) which is complex-valued
I wanted to understand why this text talks about applying the Fourier transform on H(f) to obtain h(t). I view Fourier transform as moving from the time or spatial domain to the frequency / spatial ...
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Cannot understand a simple example in Phased Array System Toolbox (MATLAB), regarding FREE SPACE
I am learning about radar and signal processing. I try to run a simple code snippet provided on Mathwork's official website
It is just about FREE SPACE, which I think you know very well, but I am new ...
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SAR Doppler centroid estimation
I read book Comming Wong Digital Processing of Synthetic apperture, where they describe in detail various metods for estimation doppler centroid. Fractional part and resolve ambiguous.
But in tne ...
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Cfar Algorithm Implementation
I am trying to implementation Cfar algorithm to our radar signal processing algorithm. I obtained some output but I want to be sure that is right. Cfar algorithm's output below like, I'm interpreting ...
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How can I apply a phase shift to an LFM pulse?
I am modelling radar scenarios in python and am trying to make a model which retains phase information. To do so, I'm envisioning something which works like this:
Generate samples of an LFM waveform ...
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How to plot a sawtooth chirp waveform using an array of frequency and time for an FMCW radar?
Before switching to use sawtooth I was using sine wave but in sine wave high frequency content was not clearly visible, But I don't have any experience with using sawtooth waveforms. I am going to ...
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FMCW Radar - What's wrong with the transmitted signal model?
I am new to FMCW radar and trying to plot the transmit signal over time.
As you know, the transmitted signal is modelled as:
$$s(t) = cos(2\pi f_c t + \pi S^2),$$
where $S = BW/T_{chirp}$ is the slope,...
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Can you please help me in generating a chirp signal in GNU radio by creating a module of your own?
I am currently working on a FMCW radar using a SDR I have done the simulations in python and am moving towards simulations on GNU radio. In python it was easy to generate a chirp, just use the scipy....
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How to control the Cross-range of a scene for a fixed resolution in SAR image processing?
In order to image a scene with a certain resolution I would have to fly a certain distance. The longer the flight, the better the azimuth resolution. This is determined by the following formula
$$\...
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Which probability density functions to use in a likelihood ratio test for the radar detection problem?
I am trying to understand the radar detection problem in the form of the generalized likelihood ratio test and am having a little trouble with understanding the noise distributions. Perhaps this will ...
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Observing Artefacts along azimuth direction after applying RMA to FMCW radar data
I have simulated 3 scatterers for FMCW radar signal processing using Range Migration Algorithm.
Background:
The Range Migration algorithm steps are as follows:
Applying Azimuth FFT on the raw data
...
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Synthetic Aperture Radar model: Ground reflected energy
My question is related to a theoretical part of the book: Digital Processing of Synthetic Aperture Radar Data, Algorithms and Implementation by I.G. Cumming et al. [Chapter 4. Equation 4.25 (for those ...
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Trimming of Azimuth Frequency Extent After Stolt Interpolation
The space-variant impulse response can be circumvented by collecting SAR data over a larger angular aperture than is strictly needed to achieve the desired azimuth resolution. From Carrara's text, it ...
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Maximum Range of FMCW Radar
I am performing some simulations for FMCW radar for target detection. I am working with a dechirp on receive system. Therefore, the target distance can be determined from the Intermediate Frequency or ...
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FMCW Radar timing of transmission and reception
I have a question regarding the implementation of FMCW radars that seems rather basic to me, but for some reason I am a bit unclear about this.
So I understand that in FMCW radar, transmitter and ...
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Range Gating for FMCW Radars
I have a question regarding on how to select a particular range of interest for the dechirp-on-receive FMCW radar for application within Synthetic Aperture Radar signal processing. If RX01 is the ...
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How can I plot the power spectra of a ST (Stratosphere Troposphere) Radar in MATLAB to estimate the doppler shift
Respected all,
I am trying to plot the power spectra of a ST (Stratosphere Troposphere) Radar to estimate the doppler shift. I am able to obtain a 3D plot between range, FFT point and Power density ...
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Ambiguity function volume
I find myself confused how two properties of the ambiguity function relate to one another.
The properties in question are (presented here from wikipedia, but similar formulas can be found in books by ...
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