Pulse-Doppler Radar | Understanding Radar Principles

Рік тому

This video introduces the concept of pulsed doppler radar. Learn how to determine range and radially velocity using a series of radar pulses.
We cover pulse compression and the matched filter, and how to amplify signal-to-noise ratio (SNR) with pulse integration. We also introduce two of the three axes in the data cube and show the benefits of looking at the data across the so-called fast-time and slow-time dimensions.
Watch our full video series on Understanding Radar Principles:
• Understanding Radar Pr...
Check out these other links:
- MATLAB Example - Doppler Estimation: bit.ly/3I7bzjr
- MATLAB Example - Simulating Test Signals for a Radar Receiver: bit.ly/3yxjp2Y
- MATLAB Radar Designer App: bit.ly/3yzfH93
- What is a Matched Filter? • What is a Matched Filter?
- Free Video Course in Radar Systems Engineering: radar-course.org
- Radar Tutorial (English): www.radartutorial.eu/index.en...
- Want to see all of the references in a nice organized list? Check out this journey on Resourcium: bit.ly/44qKLFw
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КОМЕНТАРІ: 48

@lester289 9 місяців тому

one of the best videos and explanation I have seen in UKposts. Great job!

@MohammadHefny_HefnySco Рік тому

This series of videos is of great value. Thank you for your great offer to make this such useful, informative videos. Really thank you.

@chasenoorda9931 10 місяців тому

Thank you for making this video, it is very concise and informative.

@alexfinkelshtein8066 Рік тому

Great Explanation, thanks

@HenryGhost Рік тому

my god, this video explains so much better and easier the Pulse Radar principle than my master class in germany

@MATLAB Рік тому

Glad it helped!

@famster92 8 місяців тому

TU Darmstadt?

@sachinmurali6413 3 місяці тому

Amazing work....so easy to understand...thanks!

@wangc77 Рік тому

Thank you Matlab! Fantastic Pulse Doppler video. I've been telling young radar engineers for years that Pulse Doppler radar doesn't actually use the Doppler effect. Most radar literature introduce Pulse Doppler Radar by flashing the Doppler equation which is misleading.

@Abhishek-lz5uy Рік тому

Superb Explanation! Expecting one playlist in sequence in more details and practical analysis on dummy data.

@jonathananderson730 Рік тому

The first two Matlab below other links posted by the author would certainly allow you to take that next step.

@marshalllapenta7656 7 місяців тому

This was a GOOD 1

@emrekalfa3333 2 місяці тому

Thanks for the video!

@Pherecydes 6 місяців тому

Absolutely amazing explanation, thank you.

@BrianBDouglas 6 місяців тому

Thanks!

@asellers62 6 місяців тому

Beautifully and masterfully done. Great video that makes me feel smarter than I actually am.

@BrianBDouglas 6 місяців тому

Thanks!

@giovanni4151 2 місяці тому

Fabulous video ❤

@andysar11 Рік тому

Excellent...too good 👍

@vsn4u Рік тому

Excellent explanation with intuitive concept telling. May we request for a video on Spectral analysis of signals comparing them to Time vs. Frequency domains?

@matlabaerospace8544 Рік тому

Yeah I Also want that topic to cover more intuitively

@ugurdemirayak2269 Рік тому

14:38 what happen if the object has an acceleration? In this case our sampling interval will vary in time. I think after sampling, aliasing sinus will not look like a sinusaidal, there will be a distortion, and it will spread around doppler frequency in frequency domain. in such case how will we determine the velocity?

@thurbine2411 5 місяців тому

What is the mixed filter in a receiver? Like what so the construction how does it work? Do you need a computer or could it be done with more simpler radars?

@thejedijohn Рік тому

17:25 When can we expect "the next video on phased array antennas" ? Or is that already released, but under a different playlist. Also, great video series, thanks for the explanation.

@thurbine2411 Рік тому

I think MIT lincoln lab has a series on phased array radars if you want even more info

@lockmat9 11 місяців тому

Do the pulses move in straight lines?

@benyrobert9501 Рік тому

And I still dont found an answer to my guestiion, wich factor makes the SRC PD losse track of the targets?

@sarrafimusic2869 8 місяців тому

14:20 why are you assuming that reflected waves all have same freq ? if the target is getting far from you, the freq you recieve will be lower than what you sent. (dupler effect) Also 50 years ago when jets used pulse-dupler radar (F14) did they use sampling on IQ or they basically calculated the closure rate based on the time shift between pulses. As far as I know we calculate the closure rate based on the difference between Freq_sent and Freq_recieved. Otherwise, assuming that we are on a jet and getting closer to a target which is flying perpendicular to us (radar notch), since we are getting closer to the target, we will still have time shift between each pulse we recieve so we should be able to see the target again ! ... howerver this is not true. But looking into this using dupler effect since target closure rate is 0 in this case, therefore fsent=freceive and this target wont be shown on radar if we are using pulse dupler filter.

@dirkaminimo4836 8 місяців тому

I really enjoy the way you pack this signal over time in a far more condensed version when compared to my last lecture. My hope is that this channel and one’s like it aren’t affected by the noise to signal ratio of channels that show the latest purse carried by some useless reality TV star, which is eating the brain cells of our children. Epically horrible and I hope some see that time wasted is never recoverable

@joshnel123 Рік тому

I assume the pulse interval is actually 1ms not 1us? 1ms * 55 m/s = 0.055 m

@user-ts7ck4um2w 6 місяців тому

5:50 Is the matched filter used for correlation, right? But it seems to show us convolution.

@BrianBDouglas 6 місяців тому

Wikipedia has a good write up for this if you search for matched filter. "In signal processing, a matched filter is obtained by correlating a known delayed signal, or template, with an unknown signal to detect the presence of the template in the unknown signal.[1][2] This is equivalent to convolving the unknown signal with a conjugated time-reversed version of the template."

@mastertecherock Рік тому

Doesn't the curve of the planet hide the object?

@spencerwyman9541 10 місяців тому

The comment around 2:00 is inaccurate. Modern radars don't avoid ambiguity, they simply use multiple pulse repetition frequencies that allow for disambiguation.

@YYCH2 Рік тому

Why don't we use beat frequency to measure velocity for pules doppler radar?

@jonathananderson730 Рік тому

The beat frequency is typically used to describe the difference in the transmitted and received signals for an FMCW radar. This difference in frequency for FMCW radar can be either induced by range and/or relative velocity of a target return. If you have a stationary target the beat frequency represents range (time delay). If you have a moving target you need another waveform slope (or constant CW tone) to solve for both range and relative velocity. If you have multiple targets you need even more slopes. There are many excellent youtube videos that explain that. In pulsed Doppler radar we observe the phase change of subsequent samples in slow-time (at the same range bin). The rate at which phase changes over your slow-time data gives you a frequency - and you can think of it as a "beat" frequency of sorts, but it only provides Doppler information. In pulsed Doppler radar instead of slopes (FMCW) we have different PRF to resolve range and velocity ambiguities should they exist. Pulsed Doppler radar are usually divided in low-medium-high PRF regimes and have different range/Doppler ambiguity implications. The MIT Lincoln Lab Radar Series I think explains this well. An important but challenging concept to understand is that a radar can receive signals from any direction, at any time, and with any frequency shift (subject to constraints). The radar's designer attempts to solve these ambiguities (or mitigate their occurrences) through various signal processing and hardware design schemes.

@YYCH2 Рік тому

@@jonathananderson730 Thanks for the explanation. I understand pulsed Doppler radar uses the shift of RPF to solve the velocity, but it introduces velocity ambiguity. What I am think of is solving beat frequency on the other hand seems it can resolve velocity ambiguity. And waveform slope doesn't have to be used because pulsed Doppler radar can solve the range by solving the time delay of the receiving signal. So my question is, is my theory correct or is there any difficulty to utilize beat frequency for pulsed Doppler radar? BTW I am not a radar engineer, but a combat sims player who is so curious about how radar works.

@jonathananderson730 Рік тому

@@YYCH2 I'm not sure I get where you are coming from but we can't typically get an accurate instantaneous frequency difference between the receive and transmitted carrier over a single pulse. Often this measurable difference has large errors that make it impractical to attempt to extract the Doppler from a single pulse.

@eddievhfan1984 Рік тому

@@YYCH2 I think I get what Jonathan means. Indeed most RADAR systems utilizing Doppler processing will use the output of a frequency mixer to pass Doppler frequency directly to the signal processing system-this lower-bandwidth signal can be more easily worked with for signal processing compared to the GHz-band raw signals. (After a fashion, the sample rate of the receiver acts as a mixer/filter anyways.) However, both systems will have a similar problem-the sampling rate of the received signal. Since the samples are being taken at the intervals of the pulse width, this puts a fundamental limit on the maximum non-aliased frequency that can be determined (Nyquist-Shannon sampling theorem), which is half that of the sampling frequency. If your Doppler beat frequency is higher than this sample rate, it will alias to a lower frequency and make for ambiguous velocity anyways. That being said, if you wanted to get a more complex spectrum from the pulse for things like non-cooperative target recognition and such, you could theoretically sample at a higher rate than the pulse width, but then you have to deal with more complex interactions between the target and receiver, determining which of the received frequencies is actually due to "real" target motion and not moving parts on the target, and so on.

@YYCH2 Рік тому

@@eddievhfan1984 Thank you so much for the detailed break down.