Questions tagged [radar]
Anything related to RADAR (RAdio Detection And Ranging) systems and radar signal processing.
103
questions
0
votes
1answer
17 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 ...
1
vote
0answers
36 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)...
0
votes
0answers
28 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 ...
0
votes
0answers
75 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
39 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
45 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 ...
0
votes
0answers
14 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 ...
0
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0answers
52 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 ...
0
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0answers
30 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. ...
0
votes
1answer
50 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?
0
votes
3answers
96 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
votes
1answer
43 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 ...
1
vote
1answer
71 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 ...
0
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0answers
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 ...
3
votes
1answer
101 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
88 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
50 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) = |\...
1
vote
1answer
42 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
117 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 ...
0
votes
0answers
37 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 ...
0
votes
0answers
31 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 ...
1
vote
0answers
75 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 ...
0
votes
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 ...
2
votes
0answers
45 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 ...
1
vote
2answers
119 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 ...
0
votes
1answer
148 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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0answers
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 ...
0
votes
0answers
24 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 + ...
1
vote
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 ...
0
votes
0answers
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).
0
votes
0answers
36 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 ...
0
votes
1answer
114 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 ...
0
votes
0answers
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 ...
0
votes
0answers
76 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 ...
0
votes
1answer
129 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 ...
0
votes
0answers
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 ...
0
votes
1answer
258 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 ...
0
votes
2answers
462 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 ...
0
votes
0answers
80 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 ...
0
votes
0answers
54 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 ...
0
votes
0answers
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 ...
1
vote
0answers
46 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 - ...
1
vote
1answer
104 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\...
0
votes
2answers
125 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.
0
votes
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?
...
0
votes
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 ...
0
votes
2answers
651 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.
...
0
votes
1answer
132 views
References ISAR - Inverse Synthetic Aperture Radar [closed]
Anybody know a reference to start understanding ISAR? Book or article.
Thanks!
1
vote
1answer
156 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 ...
1
vote
1answer
197 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(...
