Vote for this video by social sharing!
Synthetic Aperture Radar is a technology which was invented in the 1950’s to enable aircraft to map terrain in high detail. It uses the motion of the radar and some fancy mathematics to get much higher detail images than should be possible from an antenna small enough to fit on an aircraft.This process has been extended to satellites and applies to not just the earth, but to other terrestrial bodies in the solar system, notably Venus and Titan which are eternally shrouded in clouds.
For further reading I suggest looking at NASA’s SAR Handbook
https://gis1.servirglobal.net/TrainingMaterials/SAR/SARHB_FullRes.pdf
And if you want to look at real SAR data the Alaska Satellite Facility has lots of public data
https://asf.alaska.edu/
Commercial images in this video come from
Capella Space – https://www.capellaspace.com/
IceEye – https://www.iceye.com/
Ursa Space – https://www.ursaspace.com/
Synspective – https://synspective.com/
I thought he said “it sees through clothes” instead of clouds 🤣😅
So if I pay enough I get a 3d picture of area 51
Why do I *have* to click anything with “weird trick” in the title?
Thank you. Your perspective is always appreciated by me.
16:01 I see what you did there!
Waiting for the day when you say: “Hello, it’s Scott Manley here! … Or is it?” **vsauce music starts**
Anyone remember the show “Continuum”?
I wonder if you could use this to find gold nuggets near the surface given how strongly it reflects radar…
“Generally you can’t see inside most buildings” ,,,,, YET !
I work with SAR images, we use it for tracking ships and oil pollution at sea
“I’m Scott Manley, making applied science accessible!” Thanks for the super explanation in this video! Very useful. 👍😎
1:18 “the radar satelites can work at night and they can work through clothes” … creeps
I love how YouTube asked for feedback… “was this video informative, useful, entertaining, calming?” Well yea, it’s Scott Freakin’ Manley! Even if you have no applicable use for SAR, he told you to fly safe, and that alone is useful…
It’s amazing how much influence one can contain in a generation. Continue forth, strong-willed men and women will strive because this moment differentiates the strong from the weak.
Amazing technology, I can only imagine what classified tech’s flying around.
Wow, thank you for this video! It’s a really comprehensive introduction to a subject I’d never even heard of until now. Definitely one to bookmark and watch again.
Man, I love his Accent .. God bless and a happy New Year to ya’ll
25 years ago I was an imagery analyst in the US Army and we used SAR imagery. Back then resolution was measured in feet, this new stuff blows my mind.
Is that TD-3 in the background ?
and SAR is a very important tool to detect oil spills at the surface of the water (VV)
SAR does not actually use the “instantaneous” doppler, or the frequency shift due to the velocity in the relativistic sense. It does use phase shifts over time. I’m a SAR subject matter expert if anyone has questions.
I did two theses on polarimetry and also read into the radar aspect. It’s great to hear about this topic again and it brings back that excitement about all the things you can do in remote sensing. I find it hilarious how radar tech works: you can first record the data without “lens”, then afterwards run it through a “lens” to get your image. (Fourier transform is in essence what a lens does.) It doesn’t work in the visible yet, because we would need to record the electromagnetic field amplitudes, which are oscillating to quickly.
One way to foil this intrusive type of satellite is to emit your own interfering radar signal.
Now I know how dogs feel when they listen to people talk…
Scott, could you do a presentation on “electro tellurics”–In the 80’s-I could map subsurface details down to about 16k feet with less than 1 meter detail-( structural mapping for oil exploration)-blew the socks off many skeptics. Thanks for your channel!
Maybe the folks wearing tin foil hats were on to something. It sure seems like we are getting bombarded by all kinds of space, planes, drones, and cellphone tower electronic wavelengths constantly. Now if someone can explain this 5g paranoia I’ll decide if I need a hat…or suit.
I absolutely love how whole heartedly nerdy scots back drop is there is something so fun about someone being 100% genuine.
“Hullo it’s Scott Manley here, the Manly Scott!” ……/chuckle
Your bookcase is the stuff of insane – I love it. Happy new year my man.
Scott: Demonstrating circular back propagation
“Using a clever mathematical trick”
Me: cries in Huygens wavelets and Stolt formatting
Scott why do you have to bring back these painful grad school memories
At around 10:15 you mention that high dielectric constant materials reflect radio waves. In this instance, that’s true, but the more accurate description is that it’s interfaces with a high contrast in dielectric constants. That means that the opposite also works and you can see objects with lower impedance contrast, which is how ground penetrating radar is able to range, and describe, objects underground.
8:48 The next time when I get invited to a party I will just tell them “Sorry, I have to reshape all my lenses.”.
oh i can hear the conspiracy nuts now:
flat earther: these are doctored images, they’re not real!
anti-5g people: omg, they are radiating everyone from orbit!!! How can they get away with this??
“Hello it’s Scott Manley here!” No… 😮
Saving the best for last? I was very much intrigued by the title, and this turned out to be the most educational video of the year!
This was really invented to track people wearing tin hats.
Great, now I can sell pyramidal hats!
I hope scott sits proud on the throne of this channel, a distinguished and successful educator that’s reached millions and millions of people.
man, the FFT never ceases to amaze.
Scott, as an airman on the E-8C JSTARS, I have no comment.
Is it just me or should we all love this shit.
The title absolutely stole my heart, Manley, it was so good! 😂😭🙌🏽💯🎊
Him : SAR synthetic aperture radar
Me : SAR supplied air respirator
“ I want to understand.” Scott, “say no more.”
“Cave Johnson here…”
The fact that they figured out how to do this analogue blows my mind… I understand we do it now with computers, but the people who blazed the trail deserve recognition beyond most. Truly we stand on the shoulders of giants
“This weird trick the banks do not want you to know!”
When I was young, SAR meant search and rescue.
Scott: You must have spent a great deal of time studying up on this. This is one of those watch several times videos. Thanks!
Brilliant stuff. A 16 minute video on a topic I knew almost nothing about, but which I (mostly) understood! No discord channel, no patreons, no researchers, no irritating ads or sponsoship, not even an obvious script! – just a bloke who knows his stuff and knows how to get it across. Thanks, Scott. Great title too!
Another really interesting technology is hyperspectral imaging, which can be used see what things are made of by looking at a wide range of different wavelengths in parallel.
FUN FACT: at the company I work for we developed a system that does the same with ultrasound on metal welds to see welding defects. The technique is basically the same.
Oh there are plenty of military applications. Back in the 1970s when the US first released satellite radar images of subterranean rivers in Egypt, the true message was to tell the USSR “We can see inside your missile silos and bunkers”.
SAR elevation models were extremely important for my research on landslides in southeast Alaska
Fun fact. Water’s dielectric constant changes significantly when it freezes. This is used by radar to determine the amount of ice vs water cover.
I’d say this guy knows his stuff.
first thing to do when you got your own ground penetrating imaging satelite: fly over area 51 and see what’s really there
This is definitely one of the most interesting videos I’ve seen in a while.
You just summed up a 1.5h lecture I had this summer. It’s an exciting topic, isn’t it?
“I’ll be watching you… 🎵”
Some defence applications use image processing of SAR pictures to track moving objects. A helicopter for instance can be hard to be seen on a SAR picture but with multiple pictures you can visualize the rotors, even when it is hovering.
(2:45) A moment of silence for Arecibo.
I came here to see the inside of charlie sheens villa, I went home disappointed.
Man you’re brilliant! I have a graduate EE degree in signal processing and I’ve never learned as much about synthetic radar as your presentation.
Thanks, Scott. That just about the best explanation of the principles of SAR that I’ve seen.
I worked for one of the premier SAR algorithm shops (we had one of the co-inventors of SAR, a guy we hired out of retirement from Sandia Labs) and one of the cooler things we worked on is differential polarimetry, which enables one to see (for example) whether a road has fresh tire tracks on it vs. the day before – or not, despite no platform being able to actually _directly_ image tire tracks with spatial resolution – no open platform at the time (and possibly even black platforms even now!) have the spatial resolution to do this with conventional EO imaging. But SAR is black magic! See also “targets under trees” or FoPen (foliage penetration), finding submarines by the hump in the surface of the water created by their mass (local gravity!), land subsidence, underground tunneling operations… this is why NRO has been all-in with huge black SAR platforms since at least the 70s. Also, I worked directly – as in, I touched flight hardware – on Magellan, my signature went to Venus!
I need to get my underwater lair project going again… they’ll never find me.
“Begin looking at the world in a different light” love it!
Man I don’t even know what you said. But I like it.
Fourier transforms rule so much of mathematics and science. It is absolutely everywhere.
Wow that was interesting, thank you Scott!
(Doc Brown was always right by saying “Great Scott!”)
SAR, basically the MRI of satellites
There are Terabytes of data from the Sentinel missions publicly available for free, for everyone to use and the data is updated every day. So you can look at SAR images that are only a few days old.
The free software SNAP can be used to process the raw data and extract lots of information that cannot be seen in optical images.
Outro should be said “Spy safe”!
You’re playing Phoenix Point, aren’t you Scott?
I work on radars in the RAF (ground, not space
) and I learned so much from this video!
11:06 Oh noes! Mah secrets!
You freaking blew my mind talking about the optical-mechanical computer that could perform fourier transforms from film data. The engineers of the past were ingenius.
Omg Brian overload right there.
“Figuring out a nations Oil stockpile….” GOT THAT RIGHT
8:22 The fact that you can effectively perform Fourier transforms and other image processing by passing an light through some lens completely blows my mind!
I’m downloading a file from the Alaska Satellite Facility – I don’t know what it is – but it’s going to be great
Roughness of water lets you retrieve near-surface wind fields from radar signals (both SAR and lower resolution scatterometers ala the Jason series satellites…)… Wind waves generate different scattering patterns to larger scale waves (swell and similar).
A great explanation of a very technical subject.
There is also a non-pulse, ultra high resolution type of radar; CWI (Continuous Wave Interferometer) that uses a combination
of SAW (Surface Acoustical Wave) devices as the main detector. Not anything “modern”, this sort of device was used back in the early ’70s (by the military – of course). That might make an interesting complement to this video.
You should not be wearing a tin-foil hat if you want to avoid being seen by SAR
“Rocket scientists are puzzled!”
This video is impossible according to flat earthers.
I listened to every word. I didn’t understand very much of what was said. But he explains the topic of SAR with such enthusiasm that he makes it interesting and the result is: I now have an appreciation for what is going on, as compared to my total lack of knowledge just a few minutes ago. You are a genius and I am an enthusiastic subscriber.
This is the Aperture Science we deserve!
There is some really cool research on techniques for the deceptive jamming of SARs using GANs to generate realistic ‘spoof’ images.
“… look at the world in a different light”
That’s such a manly pun
The image of the little white and black dots being identified as Russian armored vehicles blew my mind, right after you talked about all the shit SAR can’t do lol
“Satellites do this trick, and governments hate them for it!” Page Six
The “were” in the arecibo telescope image is so sad 😭
I’m sure the NSA has a love/hate relationship with these companies since they provide lots of intel, but also prove that you don’t have to be the NSA to afford a spy sat program
2:53 cries a little on the inside
Satellites use this “one weird trick” to see more; rocket scientists don’t want you to know! I fixed your title.
Thought this was Buzzfeed space after reading the title XD
Technology just keeps getting better I cant imagine what resolution would be available within 20 years
I was wondering if you’d do a video explaining this about two days ago. Thanks for reading my mind oh powerful one of the clan Manley!
Hot take: interferometry cool