Skip to main content
Share Your Experience: Take the 2024 Developer Survey

Questions tagged [doppler]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
0 votes
0 answers
20 views

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 ...
level2fast's user avatar
0 votes
0 answers
49 views

Doppler radar. Signal to noise ratio

I'm trying to figure out how a continuous wave Doppler radar works. When moving towards the radar, the Doppler frequency should increase, and when moving away from the radar, the frequency should ...
red15530's user avatar
3 votes
1 answer
131 views

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 ~...
red15530's user avatar
0 votes
0 answers
16 views

Comparison channel impulse in DD and TF domains

How can I plot a similar comparison plot in Matlab? My attempt I have tried to create a random function like/ Matlab: rand(M, N) and then take SFFT of it ...
Aid22's user avatar
  • 23
0 votes
1 answer
109 views

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?
user avatar
1 vote
3 answers
270 views

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 ...
user avatar
0 votes
1 answer
84 views

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, ...
Waseem's user avatar
  • 11
0 votes
0 answers
50 views

Can't get velocity right in the range-doppler map of a received signal from 1 target

I have written a code that simulates a target at 400 m and velocity of 100 m/s. I calculated tau_t the time delay due the the range and the velocity, then I created a received signal from the ...
niv's user avatar
  • 1
0 votes
0 answers
29 views

Incorrect velocity in range doppler map

I am trying to simulate tx, rx and if signals and from the if signal, compute the range and doppler of the target. In the function below, when i generate the range doppler heatmap, i am getting range ...
Beez's user avatar
  • 1
2 votes
1 answer
908 views

unambiguous velocity $V_\max$ in radar doppler processing

In literature, $V_\max = \lambda\cdot \operatorname{PRF} / 2$; should it be $V_\max = \lambda \cdot \operatorname{PRF} / 4$, which would be consistent with FMCW $V_\max = \lambda / (4 \cdot T_c)$? ...
Linda's user avatar
  • 49
3 votes
1 answer
164 views

Ambiguity function information

For a course that i'm taking im asked a question about the ambiguity function of a FMCW radar. However i have not found a good source for reading about this so don't quite understand it. I get given ...
cooldanietje's user avatar
0 votes
1 answer
221 views

How does slow-time FFT detect velocity?

The signal processing steps for a pulsed radar are: Fast time matched filter -> Slow time FFT. I cannot understand how is the second step able to detect frequency, because the results after the ...
Processor48's user avatar
1 vote
1 answer
372 views

Doppler Map for a beginner pulsed radar

I have been assigned to simulate a Pulsed radar with Chirps hitting a moving target and then analyzing the data to create a Doppler-Range map. Im having trouble completing some of the "algorithm'...
Processor48's user avatar
1 vote
0 answers
233 views

FMCW radar IQ data constellation

I am trying to replicate the basic method of vital signal detection based on FMCW radars I found in classical literature on the subject. The issue I am facing at the moment is that of IQ data DC ...
obatala100's user avatar
1 vote
0 answers
375 views

range-doppler map of FMCW radar

I have created a 2D matrix with L as the number of samples and K as the number of chirps. Now I am trying to plot the Range-Doppler response which doesn't correspond to the correct range and velocity ...
SARA NASIR's user avatar
1 vote
0 answers
582 views

How to estimate Range, Doppler and Angle with FMCW MIMO Radar?

I am trying to obtain the range, Doppler and angle of arrival estimation with an TDM MIMO FMCW radar. Actually, I have completed this process. In doing so, however, a few things remained unclear. ...
abdullah A's user avatar
1 vote
1 answer
920 views

FMCW Radar Doppler Ambiguity related to Nyquist theorem or exceeding the distance frequency or both

I have been reading about doppler ambiguity and I have two explanations for its occurrence that I can't relate to each other. 1st Explanation: In the stationary case (radar and target are stationary) ...
Mour_Ka's user avatar
  • 125
1 vote
1 answer
695 views

Doppler shift in satellite communication systems

Does someone have a table with doppler shift range for satellite communication systems? Is it S band or X band? I have seen somewhere, but I can't find it.
FrimHart64's user avatar
3 votes
1 answer
239 views

Derivation of Clarke's Doppler power spectral density

I am reading Wireless Communications by Andrea Goldsmith. I have some issues in the derivation of Clarke's Doppler power spectral density given there. 1)For beginning the autocorrelation of the in ...
UserHuffmann's user avatar
1 vote
3 answers
5k views

range-doppler map to range-velocity map conversion

UPDATE 2.0 I think I've managed to produce the correct range-velocity map. I'm struggling with analytically calculating the range which I expect to see on the range-velocity map. Could someone please ...
E. Ginzburg's user avatar
0 votes
0 answers
43 views

What does Doppler Fast/Slow Items? How do they relate to Micro-Doppler Signature?

I'm working with X4M200 respiration sensor (Sensor Output Datatypes) and in provided link on page 11 it says that it provides recordings with Movement Slow/Fast Items (slow and fast pulsedoppler ...
Robert Syrnicki's user avatar
0 votes
3 answers
1k views

Doppler shift in signals

I have started doing some reading into the effects of the doppler shift on signals. In particular, radar signals from ships moving relative to a receiver. This might seem weird but I understand why ...
Student_987's user avatar
1 vote
1 answer
1k views

Range-Doppler Matrix Cells

I am working on developing an understanding on range-gates and the size of each cell. I haven't had much luck in finding information in how the matrix in the image below is generated, so I have some ...
Afromullet's user avatar
1 vote
1 answer
348 views

Motion detection with FMCW radar

I am studying the work of a microwave rangefinder and faced such a problem, but before that, a preface: I have a microwave module that operates at 24GHz. I use a 1kHz triangle waveform as the ...
red15530's user avatar
0 votes
0 answers
108 views

Generating a 2D delay-Doppler channel matrix

I was wondering if anyone here has any idea on 2D delay-Doppler channel and how to generate the channel matrix? Even a hint or a resource would be helpful. I just want to understand and visualize the ...
Amit Sravan's user avatar
0 votes
1 answer
131 views

Fine frequency correction : grouping and finding max amplitude inside a group

I work on phase and frequency estimation algorithm. Currently I am working on a derivation and determination of the Doppler shift( dF – frequency step). For each dF, The following algorithm was ...
LeeLeeYa's user avatar
2 votes
1 answer
110 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 ...
Mighty Funkster's user avatar
0 votes
3 answers
156 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 ...
Joshua Polley's user avatar
1 vote
1 answer
565 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 ...
Hp179's user avatar
  • 43
0 votes
0 answers
60 views

How is sampling rate affect the Doppler spectrum? Textbook attached

I am studying FWGN model, in the textbook "MIMO-OFDM wireless communication with MATLAB", it says "When oversampled by a factor of $N_OS$, the bandwidth of Doppler spectrum becomes \...
ColinGuolin's user avatar
0 votes
0 answers
69 views

Correcting large frequency offsets at very low data rates

Consider a typical BPSK system running at a baud rate of 1 kbaud/sec - the receiver needs to deal with severe frequency offsets, let's say up to +/- 1 MHz offset and that the frequency offset can ...
user67081's user avatar
  • 723
1 vote
1 answer
779 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 ...
user3921's user avatar
  • 267
0 votes
1 answer
184 views

How to remove frequency offset with RRC as pulse shaping filter

I am working on a project with QPSK modulation format and a RRC filtering at the transmitter (TX) side. The channel introduces a constant dropper shift ($f_d$) to the received signal. To make the ...
Cindy's user avatar
  • 131
0 votes
1 answer
84 views

How to add a frequency offset to a buffer of MPSK signal for simulation purposes?

I need to simulate some channel effect to a buffer of MPSK signal. How to add a frequency offset to a buffer of baseband MPSK signal?
Linda's user avatar
  • 49
1 vote
1 answer
379 views

How to remove the modulation before doing frequency offset estimation?

To use DFT/FFT (or maximum likelihood) method to estimate the frequency offset introduced by the channel, we need to remove the modulation on the received data samples in the front. If the unknown ...
Linda's user avatar
  • 49
0 votes
1 answer
700 views

Why is fourier analysis used in doppler effect?

I am a high school student that carried out the experiment on the Doppler effect to therefore analyze the graph but after doing some research, I saw one of the articles saying “ Fourier analysis is a ...
General MO7's user avatar
3 votes
2 answers
524 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: ...
SenSen's user avatar
  • 113
0 votes
0 answers
110 views

Sound of (sea) waves imitation

I need to create an algorithm for sound of waves. So I imagine it should be a white noise with doppler effect. However I understand doppler is just change of frequency. But white noise have all the ...
Boppity Bop's user avatar
1 vote
1 answer
926 views

Fast/Slow Fading: How are doppler shift and coherence time related?

In the literature I've read that fast fading happens if the bit duration is larger than the coherence time of the channel. The coherence time of a channel is proportional to $\frac{1}{f_{Doppler}}$. ...
scopusd's user avatar
  • 11
3 votes
1 answer
705 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 ...
Michael Rahav's user avatar
0 votes
0 answers
137 views

frequency domain representation of the doppler shift sequence

This is a bit of a weird question. I have a bunch of IQ data. Its a very big file that i cant upload on here. Im working through a few exercises trying to analyse the data. I have plotted the signal ...
Sa_as's user avatar
  • 1
2 votes
1 answer
655 views

Does Radio Communication Have to Account for the Doppler Effect?

I know that radio communications take place in specific frequency bands, and that the doppler effect can cause shifts in frequency when there is relative motion between the source and destination ...
Matthew Inbox's user avatar
0 votes
1 answer
355 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 ...
techno's user avatar
  • 1
0 votes
1 answer
52 views

A-GPS frequency (fd) search ranges

A-GPS is able to reduce the fd search range from several kHz (GPS search range) to several hundred Hz (a-GPS search range). I know the GPS search range has a center at 0 Hz. What is the center ...
Cindy's user avatar
  • 13
1 vote
4 answers
386 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}...
DaDSPGuy's user avatar
  • 182
0 votes
1 answer
91 views

Converting PLL Discriminator into Doppler error

I'm writing a GPS receiver SDR software, and I have calculated the PLL discriminator ouptut as atan(Q_Prompt,I_Prompt) I would like to know the formula that converts the discrminator output to doppler ...
andre's user avatar
  • 103
0 votes
1 answer
33 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 ...
Deep Mind 's user avatar
-1 votes
2 answers
583 views

help to calculate phase shift in certain frequency(identified from FFT)

I am designing a 24ghz doppler radar, with 1TX 2RX. Four adc channel are recording at 25khz, applying 256point FFT on adc of both of RX I and Q, I could identify the target in certain doppler ...
Quing in Vancouver's user avatar
5 votes
1 answer
1k 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 ...
Jung_Zheng's user avatar
3 votes
3 answers
150 views

How to use a FIR on a signal with a drifting central frequency?

I have been working on this subject for a while and I couldn't get a proper answer. I am trying to estimate the phase of the input signal : $x(t)=Ae^{j(at^2+bt+c)}+n(t)+i(t)$ Where $n(t)$ is a ...
Ryan's user avatar
  • 31