Questions tagged [radar]
Anything related to RADAR (RAdio Detection And Ranging) systems and radar signal processing.
124
questions
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43 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
21 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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32 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, ...
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1answer
38 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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32 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 ...
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0answers
51 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
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1answer
36 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
60 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 $L$: $x_n[k]$, $k=1...L$, $n = 1...N$.
Šne of ...
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0answers
27 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
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1answer
55 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
233 views
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2answers
124 views
Radar for Vital Signs ā 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
89 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
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2answers
77 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 ...
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1answer
48 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
32 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
28 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 ...
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0answers
32 views
In FMCW RADAR, how to use signal difference to calculate the position of a new object entered a clutter
Radar setup:
FMCW radar with 1 TX and 2 RX both have IQ channel. So a single (stationary) object's range and angle can be calculated.
Problem:
If two objects are at about same distance but different ...
0
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1answer
86 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&...
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1answer
96 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 ...
1
vote
1answer
372 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
49 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 ...
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0answers
14 views
Advantage of “multi-static” transceiver configuration
Assume I have a system with one mobile station and multiple Transceivers (similar as in a "multi-static" RADAR system), in this example 4 transceivers:
The bit error rate from RTX $i$ to the mobile ...
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1answer
49 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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46 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 ...
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1answer
101 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 ...
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4answers
50 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
68 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, ...
1
vote
1answer
196 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 ...
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2answers
66 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
21 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
44 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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31 views
Block Processing to Plot Phase in Real Time
I am trying to modify an LTFAT demo script that records and plays back streaming audio simultaneously. The objective is to read in the block to a vector, and take the DFT of the block samples, and ...
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0answers
84 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
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1answer
75 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
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1answer
57 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 ...
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0answers
199 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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0answers
37 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
80 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
97 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 ...
0
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1answer
102 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
184 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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0answers
29 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 ...
3
votes
1answer
344 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 ...
2
votes
2answers
128 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 ...
-1
votes
1answer
60 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) = |\...
2
votes
1answer
56 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 ...
3
votes
1answer
155 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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0answers
54 views
Range Migration Algorithm in FMCW MIMO RADAR
Iām using a FMCW MIMO radar [77-79 GHz] with a virtual linear array made of 48 channels.
Iām wondering if the adaptation of the range migration algorithm (typically used in SAR processing) is ...
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0answers
84 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 ...
