Questions tagged [radar]
Anything related to RADAR (RAdio Detection And Ranging) systems and radar signal processing.
138
questions
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29 views
mmWave Radars and 2-D point cloud from its IF complex signal
Given we have the IF complex signals from Rx channels, how can we construct point cloud from that?
I have 128 chirps in each frame and total of 8 frames with 4 Rx channels and 3 Tx.
It is AWR1443 ...
1
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1answer
29 views
How do I confirm that range cell migration correction was done correctly? Is there a way to check this graphically without looking at the signal data?
I am implementing the Range Doppler Algorithm for a Synthetic Aperture Radar project and I am at the step where I must perform Range Cell Migration Correction. This step involves creating a sinc ...
0
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1answer
31 views
FMCW radar transmitter signal splitter
An FMCW radar generates a chirp signal in the transmitter. The chirp is transmitted through a splitter device to both the TX antenna and the mixer in the receive path. Some object generates a ...
0
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1answer
30 views
Cut-off frequency for Low-pass filters in Arctangent Demodulation
According to literature, the arctan-demodulation method commonly used in Radio-frequency radar systems is the one shown below:
Is there a rule of thumb regarding the cut-off frequency of these Low-...
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0answers
63 views
Create a Range Doppler Map using “Arbitrary” phase coded Waveforms
This is my first questions I am asking to this community!
I want to understand how to create a Range-Doppler Map (RDM) for a phase/frequency coded radar return using an arbitrary waveform generator (...
2
votes
1answer
90 views
Aliasing in Doppler Radar
my book about RADAR says that:
If a Continuous wave radar sends a sine wave at frequency $f_T$ to a moving object (at speed V), a frequency $f_R$ is received. Their difference is called Doppler ...
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0answers
63 views
Requirement on sampling rate for Doppler shift estimation
What is the requirement of sampling rate on channel impulse response (CIR) for Doppler shift estimation? Suppose that there is a bi-static radar system with perfect synchronization, the receiver ...
0
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3answers
108 views
Is there processing gain for FMCW using heterodyne-style receiver as opposed to matched filter?
Beat signal of a single target will be a sinusoid in the idealized world, so theoretically the signal processing gain of an FMCW pulse correlated with Tx waveform in this way should be analogous to ...
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0answers
10 views
How does one go about choosing a Radar Cross Section for a human when modelling a Pulse micro-Doppler microwave radar?
So as part of a personal project I'm in the process of simulating and making a fall detector using a 2.7GHz microwave sensor with a range of 8m. I've been using MATLAB's example code to simulate each ...
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1answer
38 views
Friendly target identification in radar
How do radar systems identify friendly targets to avoid AA locks during combat scenarios?
Do friendly planes broadcast a known signal or is something else going on?
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3answers
60 views
Beginner Educational Resources
New member here. Recently got hired into a mid level EE position. Have a BSEE but performed more radar performance analysis at a higher system level previously. In my new group we're doing a lot of ...
2
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1answer
91 views
What is the advantage of using a Stepped Frequency waveform over FMCW?
What is the advantage of using a Stepped Frequency Waveform instead of a traditional linear FMCW ?
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1answer
58 views
Can velocity be calculated in first stage FFT?
I understand that, For an FMCW radar, the velocity of a target is proportional to the phase changes at same time instants across the chirps.
I have a MxN data cube with N chirps(columns) & M ...
2
votes
1answer
39 views
Relation between Gaussian derivatives and Gausian-windowed Cosine function
I am doing some research on UWB radars which transmit a pulse given by:
$$
g(t) = p(t) cos(2\pi f_{c}t) = A e^{(-\frac{t^{2}}{2\tau ^{2}})} cos(2\pi f_{c}t)
$$
In some other papers, the transmitted ...
0
votes
1answer
60 views
Expression for Frequency-shifted Gaussian pulse
I am doing some research on UWB radars which transmit frequency-shifted Gaussian pulses. These pulses are given by:
$$
g(t) = p(t)cos(2\pi f_{c}t) = V_{TX}exp(-\frac{t^{2}}{2\tau^2})cos(2\pi f_{c}t)
$...
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0answers
53 views
FMCW range doppler response problem
I'm trying to learn radar simulation using Matlab. I used this example in Matlab
https://www.mathworks.com/help/driving/ug/radar-signal-simulation-and-processing-for-automated-driving.html
But when I ...
0
votes
0answers
25 views
Beamforming and AoA with a small number of elements
So I have an antennae array with only three elements. I want to know what kind of beamforming and AoA estimation I can do with such a small number of elements.
I understand that there are lots of ...
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0answers
66 views
How does the Hilbert Transform extract the in-phase and quadrature phase components of a real passband signal?
I am taking an intro to radar signal processing course and we are discussing the Hilbert Transform and how it take a real input and its output is analytically complex. I'm trying ) how a radar ...
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1answer
40 views
SAR spotlight raw signal database
For practicing spotlight processing, i am looking for I/Q baseband signal from a SAR airborne or spaceborne system. In my research I have only found processed image from :
eoweb geoportal https://...
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0answers
38 views
Advice on generating stable FMCW waveform
I am trying to derive parameters for a triangular FMCW waveform such that the phase of the signal has consistency from one period to the next. Perhaps this is arbitrary and feel free to tell me so, ...
0
votes
1answer
53 views
How is a Particle Filter used to Estimate Parameters of a State Transition Function?
In the tutorials on particle filters that I have seen, it seems that the state transition function is already known. This example from Matlab, for example, states the the Plant or State Transition ...
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33 views
Transceiver for TDoA measurements
Could someone advise me on some module for making the TDoA position system for my research work? I need to have measurements with an accuracy of a few meters. It equals a bandwidth of about 20 MHz. I ...
2
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0answers
58 views
Compressed Sensing in DOA processing
I'm trying to apply the compressed sensing theory (CoSaMP algorithm) to the DOA estimation in FMCW ULA (made of 48 elements). In the dechirped signals processing I use a first FFT to solve the range ...
1
vote
1answer
51 views
What is the importance of signal bandwidth in radar systems for velocity and localization estimation
So I know about the basics of doppler shift which relates the velocity of a moving object with the frequency carrier shift seen at the reciever.
But, I don't understand the importance of the ...
1
vote
1answer
78 views
DOA for bistatic radar
Consider a circular antenna array (UCA) with $N$ antenna elements as part of the CW bistatic radar system.
For each element we receive a signal of length $L$: $x_n[k]$, $k=1...L$, $n = 1...N$.
Оne of ...
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0answers
41 views
Pulse Width and Duty cycle in Gaussian pulses
I have a pulse-based radar which transmits frequency-shifted Gaussian pulses. The Gaussian pulse ($p(t)$) is given by:
$$
p(t) = V_\text{TX} e^{\frac{-t^2}{2 \tau ^2}}.
$$
The frequency shifted ...
0
votes
1answer
80 views
Distortion in phase difference measurement using FFT
I am doing distance measurements by transmitting a 100 kHz tone and receiving it and measuring the phase difference.The distance is simulated by a delay simulator which is very precise (around 10 psec)...
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1answer
629 views
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2answers
194 views
Radar for Vital Signs – Matlab Simulation
Interested to design and simulate FMCW radar for Vital Signs sensing.
The initial signal parameters are(1):
When using the following Matlab code to generate the waveform:
...
3
votes
1answer
124 views
MTI RADAR, DSP algorithm question
Im new to RADAR signal processing.
I using this doc for ref: https://www.mathworks.com/help/phased/examples/ground-clutter-mitigation-with-moving-target-indication-mti-radar.html
I trying to rebuild ...
0
votes
2answers
120 views
What is the best to confirm that the output of a matched filter for a linear FM chirp is correct?
I have written a matched filter in matlab to compress a linear FM chirp signal and would like to confirm that the results of my range compression. My question is what is the best way to do this? I ...
1
vote
1answer
55 views
Radar type application for narrow band only?
Not sure if this is the proper forum to ask this question, but still I am trying my luck.
I am looking for an application (in any area, medical, defence, or any other area) if exist, such that we want ...
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0answers
41 views
How do you perform range compression of SAR data on a 2D matrix?
I am building a Matlab program to process RADARSAT-1 data that came with this book.
The book describes the steps to creating SAR image as follows
I am currently implement the range compression step. ...
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0answers
30 views
How can i identify number of return of the ping in the sonar?
I am writing a fake function which is actually doing active pinging (basically SONAR). I am little confuse here about how to identify the number of sonar return i got ? Let's say i am continuously ...
0
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1answer
131 views
FMCW Radar using FSK Superimposed LFM ramp
While reading the datasheet of the ADF4159 I came upon a section describing how to create an FMCW ramp with FSK superimposed to "enable unambiguous (distance and velocity) multitarget detection&...
0
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1answer
125 views
Cant find Doppler shift with LFM signal
Im stuck on this one. I hope someone helps me!
Problem: I need to find Dopler shift with array of reflected chirps.
I have bursts of chirps which then i sampled, and calculated fft.
Im suposed to ...
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vote
1answer
803 views
Generating IF signal for FMCW radar
I am trying to generate a signal that represents mixer output of FMCW radar. I am using MATLAB and already tried out this tutorial. There, Phased Array System Toolbox is used to showcase how FMCW ...
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0answers
87 views
How to calculate FMCW Radar Chirp STFT?
I have received signal from FMCW Radar which is of the shape [128x64] = [Number of samples per chirp x Number of chirps per cycle] and i want to calculate the stft
i am calculating it with stft ...
0
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1answer
85 views
Why does my I/Q data from radar are not centered?
I am working on the IQ raw data from FMCW radar. I plot the I and Q data, they seem to be strongly shifted from the center. And the amplitude of I and Q also varies. I don't understand why it looks ...
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0answers
49 views
Does a time varying gain (AGC) mitigate clutter in radar signals?
Trying to implement an MTI filter for flatland clutter in a radar received pulses.
However, after the matched filter output instead of implementing directly the MTI filter, I normalized with an ...
0
votes
1answer
120 views
DSP based FMCW radar
I have an SDR receiver I'm interested in making into a FMCW radar. The bandwidth is somewhat narrow as it only samples at 64 MSPS.
There is a problem in that without a bunch of embedded programming ...
1
vote
4answers
58 views
Doppler frequency when down-converting a receiving signal
Suppose we have a monostatic radar system, with only one target crossing at a speed $v$ at the main lobe of the antenna. The Doppler frequency for this case will be given by
$
f_d = \frac{2v}{\lambda}...
0
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1answer
105 views
FMCW radar: Linear phase change determination with sinusoidal decomposition
I am struggling to understand how linear phase shift can be determined with a transform whose main purpose is to determine frequencies rather than rate of change of a function.
In FMCW radar, ...
3
votes
1answer
688 views
Is it fast time or slow time for the delay in the ambiguity function domain for radar signal?
I am confused about the delay concept in the ambiguity function. The FFT of slow time is the doppler frequency. However, people usually relate the range-doppler domain with the ambiguity function ...
0
votes
2answers
100 views
Coherent detection in radar and radio signals
Coherent demodulation\detection is usually done via matched filtering in RF signal processing. In radar signals, coherent integration can be done if the phases of the returns are known. In terms of ...
0
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1answer
22 views
Is it possible to detect or localize movement of objects using LPWA (or LPWAN) such as LoRa, DASH7, NB-FI?
Assume that there is a moving human in the room without any device (or receiver). Is it possible to detect or localize movement of objects using LPWA (or LPWAN) such as LoRa, DASH7, NB-FI by analyzing ...
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0answers
46 views
Sign of manifold vectors in monostatic phased-array radar
I am reading some notes where the impulse response of phased-array to is given by;
$$
\beta S(\theta, \phi) \bar{S}^H(\theta, \phi) \cdot \delta(t-\tau)
$$
where
\begin{align}
\bar{S}(\theta, \phi)...
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0answers
87 views
Identify an obstacle in front of the radar
I use the K-LC6 24 GHz microwave module in the linear frequency-modulated signal mode to determine the distance to moving objects. But if I put a barrier in front of this radar while it is moving, I ...
0
votes
1answer
97 views
Digital beamforming and phase shift stage insertion
I have read some literatures about the different topologies of beamforming and it came to my mind a question : where is applied the phase shift for each channel depending on the type of topology/...
0
votes
1answer
61 views
Is it possible to observe more area in azimuth than physically traveled in stripmap SAR?
I have been examining stripmap SAR algorithms, mainly Range Migration Algorithm. When I check the textbook examples so far I always saw the data trajectory is larger than scene that is observed. An ...
