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DIY Synthetic Aperture Radar
An anonymous reader lets us know about a DIY synthetic aperture radar built for $240 in parts (give or take). Here's PDF slideware from the Ph.D. student's research. "Using a discarded garage door opener, an old cordless drill, and a collection of surplus microwave parts, a high resolution X-band linear rail synthetic aperture radar (SAR) imaging system was developed for approximately $240 material cost. Entry into the field of radar cross section measurements or SAR algorithm development is often difficult due to the cost of high-end precision pulsed IF or other precision radar test instruments."
The cake is a lie.
I'm part of a team who did something similar (We're presenting it at IEEE MWSCAS, it's much less cool than this, though). We built several thousands of dollars worth of test equipment using cheap junk and came out with stuff that was just as good. DIY folks have been doing this for decades, of course, but PhD students are now starting to publish these things. This is a big deal, and means that legitimate researchers can pick up this work and very easily enter a field of research their institutions may have previously been unable to fund. Our school has always just enlisted students to design and build all of our test equipment, but still. This is good.
I didn't RTFA, but I certainly hope they've open-sourced their backend interface software and hardware designs as well. Of course, if you're disassembling a microwave, you can hardly patent the technology. Closing off access to your work kind of defeats the purpose in science, though.
When you're afraid to download music illegally in your own home, then the terrorists have won!
This could fall into the hands of terrorists.
Citizens are consumers. We are passing Intellectual Property laws, to ensure that they remain so, and do not make the mistake of becoming producers.
This man's brilliance sets another difficult example and precedent, which will be hard to contain or dismiss! I suggest a patent law-suit against him, and a criminal charges based on illegal production of weaponizable technology.
"Speaking the Truth in times of universal deceit is a revolutionary act." -- George Orwell
that the a Ford Mustang would be so stealthy! Seriously compare the image of the car on slide 21 to all the other targets they tested this thing on.
Can you mount this on your car? Maybe torch the guy who cut you off in traffic?
I want to delete my account but Slashdot doesn't allow it.
A strange thing happened shortly after this equipment was assembled and tested. I noticed that whenever I got angry, my skin would turn green and I would tear off my clothes.
This seems to be from 2006/7...
"A National Instruments PCI-6014 data acquisition card triggers radar pulses and digitizes the video data". http://sine.ni.com/nips/cds/view/p/lang/en/nid/11442 With a $700 (not counting accessories) data acquisition card.
Am I the only one who read "GOATSE with pushpins" and thought that it sounds a lot more painful than the regular goatse?
You just got troll'd!
I'll wait for the DIY portal gun thanks :)
but I did not feel like getting a headache like I always do reading webpages with white text on a black background.
That total cost of 240$ is based on them acquiring used material at a radio swap meet, not scavenging it from old stuff I could find in my attic, and definitely no buying from some online supplier. That is, w/o a lot of luck, time, and knowledge- there is no way I could duplicate this effort with ease.
and this thread swallows it's own tail! well done, /. !
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
Just saying, because the material is from 2006/2007...
Let’s get old junk and put it all together in a university lab with (essentially) unlimited resources and see if we can build something. ( of course half a lifetime of physics and engineering study doesn’t hurt)
DIY is great - but is it worth a Ph.D.? I don't think so. I hope the guy did something more fundamental than the summary might lead you to believe.
The tyrant will always find a pretext for his tyranny - Aesop
I worked for a company started by a person who did SAR research in school. His project was based off an earlier one done by my current business partner at the time. A small rail track is still mounted on top of the engineering building at the university from these projects.
The big difference with what that company, www.ImSAR.com, is doing and anyone else is the size. The system they developed is 2lbs and smaller than a shoebox. At the time, the next smallest system was 50 lbs. This little box can fly a a payload on an 18 pound UAV. Check out the website for some pretty cool images of the unit and generated SAR images. IEEE Spectrum magazine did a cool piece on it in the Jan 2009 issue.
The system was running an ARM with montavista and did realtime (within a few seconds) calculations to transmit the video down to the observer. The antenna is a printed PCB and is mounted on a gimbal that moves using RC airplane control servos. To test the thing quickly, we'd hop in a car and mount it to a bracket on the window and go cruise around town. Definitely got some strange looks doing that. The boss even was once stopped by the cops because of "suspicious activity" that had been reported. Since then, they've now build a small RC plane that can fly it around for quick testing instead of a car.
I did this exact thing in 1984 in grad school for MSEE. Only it didn't require quite as much hardware as he used.
At the time it was hush-hush because it was for Air Force to use on new bomber construction - B1 with stealth-like attributes.
Cost more too. May have to revisit now that can find cheap parts.
God bless the Can-Do attitude at MIT (and elsewhere, I suppose). I wish they hadn't thrown my application away, and hope that the totally-awesome-just-not-MIT school that I'm going to will support this kind of thing.
I'm impressed with what this guy found at a hamfest. We don't see much microwave gear in Silicon Valley surplus any more. eBay, though, has a decent selection of microwave horns, low noise amplifiers, mixers, and waveguide. It looks like anybody could get the necessary parts in small quantity. New, though, those parts are expensive, so building low-cost robot vision systems this way is hard.
Also, when your "garage machine shop" has a Bridgeport milling machine, you're way above the usual home shop level. Still, if there's a TechShop in your town, you can get access to such machines.
A big problem working in this area, even if you know what you're doing, is that the test gear you need costs more than the thing you're making. Reading the design notes, some of which are on Air Force Research Lab stationery, indicate that the hamfest parts were tested and characterized using reasonably good test gear. And this was an MIT student, with access to MIT labs.
I ran into that building a small LIDAR in the early 1990s. The parts cost wasn't too bad, but I needed access to about $20K in test gear to debug the thing.
It's still amazing a humble little bat accomplishes essentially the same thing except with sound, especially given the computational resources fourier transformations require.
(And we're out of beta; we're releasing on time!)
That could use stuff like this. I have been working with a group of British archaeologists at the Mellor Archaeological Trust for a few years and they have a superb site - but much of it is either impossible to excavate or too expensive. So they started working with Ground Penetrating Radar. Interesting novelty toy, but it only tells you where it might be interesting to dig, it doesn't really help avoid digging.
At the SC2005 supercomputer show, I saw demonstrated reverse tomography techniques. Ah, this looks better. Being able to take the output an generate a visual representation. Problem is, ground isn't uniform so you've a lot of refraction and reflection to contend with. Possible solution - the game Black Box. If you know where you put the rays in and know where you get the rays out, with sufficient rays you can determine where things must have been to produce those results.
Next problem: Objects aren't of uniform shape and size, and signals aren't transmitted vertically downwards. The result is that the output will be scattered in all kinds of directions, where those directions depend on which direction the radar is facing. Solution - have many receivers, some at fixed points and the regular one on the GPR set.
Next problem - the signals used are bloody weak, but the depths you need to scan to are incredible. It isn't possible to build a single receiver large enough to pick up the extremely faint signals you're going to get at any depth. At great depths, sacrificing the fine detail for any detail at all seems reasonable. That means turning the collection of receivers into one large virtual dish.
And this is where the article comes in. Interferometry is a great technique for a constant signal, but radar is pulsed. You need something analogous for radar systems, which is your synthetic aperture radar.
You do the scan of the ground as a grid once for directional sensitivity and then again for signal sensitivity.
There is, of course, one other problem and it's big. The same set of results can come from multiple possible sources. It should be possible to use herustics to try and find potential solutions, and then conduct further scans which either eliminate or confirm those possibilities.
Isn't this a lot of work? Yes. It's a hell of a lot of work. But the site involved has too many areas of extreme interest where non-intrusive scans MIGHT get permission, but where any kind of digging - so much as a teaspoon - would get you hung, drawn and quartered. And then forced to watch Bob Monkhouse reruns.
To me, this is why the paper is interesting. It tells me if this kind of vision is even possible, it tells me something about what the requirements are, and it tells me whether it would be more cost-effective to actually do it or wait.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
$150 to $450 on EBay, but still your point is valid.
Even if it is $700, his point still doesn't invalidate the researcher's point: technology which the conventional wisdom holds is only available to organizations with large budgets is actually available at what are essentially middle-class consumer prices.
The point isn't that you can do it for precisely $500 or $700 or $1200 or $2000 or $5000. The point is if you know someone with reasonable engineering skills and you can raise a few thousand bucks, you can build this stuff.
If nothing else, this has significant ramifications for asymmetric military conflicts...
Tweet, tweet.
I can't hardly wait 'til someone hacks together DIY ultrasonography in the garage. The difficulty level would seem on a par with SAR, if that...