US Navy's High-Resolution Radar Can See Individual Raindrops In a Storm 161
coondoggie writes "The U.S. Naval Research Laboratory (NRL) researchers said recently that a Navy very high-resolution Doppler radar can actually spot individual raindrops in a cloudburst, possibly paving the way for new weather monitoring applications that could better track or monitor weather and severe storms. According to an NRL release, the very high-resolution 'Mid-Course Radar' was used to retrieve information on the internal cloud flow and precipitation structure. The radar was previously used to track small debris shed from the NASA space shuttle missions during launch. 'Similar to the traces left behind on film by sub-atomic particles, researchers observed larger cloud particles leaving well-defined, nearly linear, radar reflectivity "streaks" which could be analyzed to infer their underlying properties,' NRL stated."
useful.... (Score:5, Funny)
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At least you know what just hit you.
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Signal? Meet noise!
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Huge data set? Meet filtering and modern data-processing!
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.... not to mention keeping stealth aircraft out of the rain. Hey jim! There appears to be a load of raindrops travelling horizontally at Mach2, I wonder what that could be?
Re:useful.... (Score:5, Insightful)
What it means is stealth is now meaningless technology, paying megabucks for a stealth fighter is simply throwing the tax payers money away. Once you can accurately track moisture in the atmosphere, then tracking ex-stealth aircraft is simply a matter of searching for and pinpointing areas of the sky not behaving like other areas of the sky. Specifically those areas of the sky which show a disturbance of where the aircraft has been, contrails http://en.wikipedia.org/wiki/Contrail [wikipedia.org] and where the aircraft actually is shock and compression waves http://en.wikipedia.org/wiki/Shock_wave [wikipedia.org], even subsonic compression of the atmosphere by the passage of an aircraft substantially alters the amount of moisture in close proximity to the aircraft.
The US Navy might as well announce to the world, don't waste your money on the F35 or F22, what you want is a high durability aircraft. Stealth is utterly meaningless especially when the shape impacts durability and performance. Basically the only real defence is flying really low, as fast as possible and being the smallest target possible (cruise missile). Once you get above ground clutter, you'll announce your position, even if you stop and hover, your past passage will show up as well as your thrust plumes, jet or propeller.
No such thing as 'atmospheric' stealth no matter how advanced your technology unless of course you can jam or shut down the detection technology with even more 'advanced' technology (you can guess who I mean), the microchip being such an desirable target for at range energy fluctuations.
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Stealth aircraft use electrogravity tech to reduce their weight by a significant amount. You are incredibly misinformed.
Re:useful.... (Score:4, Insightful)
This may not yet be useful for real-time air defense purposes. The actual equipment my not be field mobile. Not to mention that getting data and analyzing over time it is one thing. Doing that while an aircraft comes at you at Mach 1.2 is a little different. Especially when it has a bomb or an anti-radiation missile with your name on it.
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If your jamming radar, why do you need a stealth aircraft???
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For several reasons:
1) once radar is 'jammed' they know something is up and launch planes that have their own radar
2) They will quickly determine where the jamming is coming from, so you need aircraft entering before or at a different area.
3) Decoy
4) To evacuate the target area through another countries air space without alerting that country's general populace.
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The return of the A-10?
Re:useful.... (Score:4, Insightful)
Scientists could detect the individual particles because of a combination of the radar's3MW power, narrow 0.22 degree beamwidth, and an unprecedented range resolution as fine as 0.5m. This combination of radar attributes allows researchers to sample a volume of cloud about the size of a small bus (roughly 14 m3) when operating at a range of 2 km.
In other words, if you know where the stealth aircraft is to within the region of a small bus, this thing can find it!...so long as it isn't more than 2km away.
This radar is completely worthless in finding a stealth aircraft, or any aircraft at all for that matter. As presented, it doesn't even have any uses for that at all. Maybe you could extend it to that, but the narrow bandwidth and high power means it will be pretty well worthless for stealth detection.
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People are well known for being very slow at searching filtering large data sets for an individual piece of information, computers on the other hand are very well known for the exact opposite. Of course this kind of radar could be used to create a continuous national 3 dimensional image of airspace and based upon economies of scale useful for, air traffic control, weather forecasting and alien aircraft detection. So not one radar, but many working together.
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" you can jam or shut down "
that's not how stealth works.
You might want to read up.
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HARM
Detecting stealth != attacking stealth (Score:2)
Stealth aircraft have always been detectable on radar, the only question is "how much radar power" and "how close", and that still applies to indirect radar measurements as well. It's still harder to detect changes in moisture vs a B-52-sized hunk of aluminum glinting back at 100 km.
The real point of stealth is that mission planners know what range the stealth aircraft is detectable at, and the range that said aircraft detects its targets, and the range of its weapons. If it lines up, stealth craft launch
An obvious BOFH bonus (Score:5, Funny)
"Boss, I'll need some special equipment to see our data in the cloud ..."
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I appreciate the humor, but on a practical basis, the data analysis must be very similar to that being done at CERN - assuming they are doing serious data analysis. Trillions (ok, here goes, And Trillions) of drop trajectories, etc.
How many raindrops are there in a storm? (Score:5, Funny)
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And, more importantly, if you remove one drop, is it still a storm?
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And, more importantly, if you remove one drop, is it still a storm?
Only if it falls in the woods
Space technology again (Score:2)
So, another solid example of the "Pure science and engineering" stuff that NASA does bleeding into real world applications.
Kind of.
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a) errors in weather forecasting in short times arise, significantly, from the limited data available as inputs ("data assimilation") and the quality thereof, and this sounds like this could easily give
b) the chaos-predicted exponential with time applies to 1) infinitesimal perturbations, and in 2) very long time average over a stationary attractor. In reality the local/finite-time Lyapunov exponents can vary very widely (usually high when there is interesting weather/convection).
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The author was saying that weather forcasting was notoriously inaccurate not (only) due to the ch
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15 years ago my ex-girlfriend used to work on an atmospheric research radar design as a part of her thesis which was capable of seeing individual raindrops. Not sure what's the big deal here.
...Under what circumstances? (Score:3, Interesting)
The Space Shuttle generally flew only under clear conditions (Challenger excepted, of course); I can't ever recall seeing a photo of the Shuttle taking off or landing in the rain.
Light rain, I can see this working, but a proper Texas Downpour (a.k.a. "cow pissing on a flat rock") is probably going to block the signal after 300m of heavy rain, even at higher energies. I'd be curious to hear what kind of rainstorms and what region of the country they were testing this in. Light mist in Seattle is very different from a tropical thunderstorm in Miami is very different from a squall line in Dallas.
Re:...Under what circumstances? (Score:5, Funny)
Might as well karma whore this myself, because someone else is going to, here's a brilliant quote from HHGTTG:
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Light rain, I can see this working, but a proper Texas Downpour (a.k.a. "cow pissing on a flat rock") is probably going to block the signal after 300m of heavy rain, even at higher energies.
Depends how high those higher energies: around 20 kt might improve the visibility for 1-2 km.
Re:...Under what circumstances? (Score:5, Informative)
My friend's dad worked for the radar department at Raytheon for about 35 years. He always told us about this radar array in the panhandle of Texas. The power sent out from the radar array was so high that flocks of geese flying in formation would fly through the field, suddenly would become disorientated and fly in different directions, sometimes crashing in to the ground, effectively scrambling their brains. Once they got out of the field, they would return to normal and form up again. Eventually someone got on to them about this and they would shut down the array briefly when geese were detected. Reportedly you needed to wear special eye wear because the radiation could cook your eyeballs like eggs if you weren't careful (your eyes and testes have not many blood vessels and have trouble regulating their temperature compared to the rest of the body). There are stories about beached whales due to navy sonar tests too, but this is a discussion about atmospheric radar.
;)
Anyways, my point is, you start beaming enough energy through the atmosphere and you can have some unwanted effects. I'm sure the aluminum frame of a Cessna 172 acts as enough of a Faraday Cage against these sorts of things, but with your balls literally on the line, do you really want to test out that theory?
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... with your balls literally on the line, do you really want to test out that theory? ;)
I've had a vasectomy, so I don't particularly care about "sterility" as a side effect.
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That's a nice story that flies in the face of experimental evidence.
Sorry, doesn't happen.
Why don't you tell us the one about using radar to cook a turkey?
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He has several patents to his name in the field of radar technology and still works in retirement with Raytheon as a consultant. I have no reason to question his experiences on the matter.
So much for stealth (Score:5, Interesting)
If you can detect indvidual raindrops, I suspect detecting a marble sized radar target flying near or over the speed of sound is no problem whatsoever. While this radar is probably too big to put in a fighter a datalink from a ground based version to the fighter will solve that problem quite nicely.
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While this radar is probably too big to put in a fighter
But not a Navy ship. Which is also likely to have directed energy weapons in the near future too.
Since an enemy sailor on deck has a larger RADAR profile than a raindrop, being one within visible range of one of these US Navy ships will be very bad for your health. With just a little bit of automation, a 'killall' command takes on new meaning.
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While this radar is probably too big to put in a fighter
You can say that again. I don't know if you have seen a tico [wikipedia.org] but the old version of this could never get up in the air, much less on a fighter. (there are a total of four of those huge octagonal panels.)
Re:So much for stealth (Score:5, Insightful)
Detecting a stealth aircraft and being able to identify what you've detected as a stealth aircraft are two completely different animals.
I think that any "marble sized" object travelling near mach-1 would be suspicious
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It could be a bullet.
Or even atom ant [wikipedia.org]
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Careful he might make you stand and deliver... what?
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Indeed. I've never heard of any fighters or self-powered munitions being that small.
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Clarify: i'm looking at the hole in the rain where the object is, not the radar cross-section of the object itself.
So yea, it might look on the scope like a marble, it's also got a jet-fighter or cruise-missile shaped hole in the rain around it, and they would apparently be able to see this now.
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Detecting a stealth aircraft and being able to identify what you've detected as a stealth aircraft are two completely different animals.
I think that any "marble sized" object travelling near mach-1 would be suspicious
Radar is not nearly as high resolution as you seem to think it is. It's not going to be tracking a single marble sized object and be able to determine that it's traveling mach-1 and, thus, is likely a stealth aircraft. Sure it makes sense in your imagination. But reality differs.
Yes you can it's called doppler and it allows you to measure the speed of the object fairly easily, just like a cops radar gun.
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Yup, and doppler can be really sensitive because you can just filter out anything that isn't moving above some threshold velocity. That does mean that things moving tangentially to the radar can be hard to detect (something exploited by fighters when they evade radar-guided missiles).
I'm sure there are a bazillion refinements these days, but the principle is pretty simple. You generate a radar pulse, then take the returned pulse and mix it with the output signal. The return pulse is slightly different in
Military Obsolescence. (Score:3, Insightful)
>Doppler radar can actually spot individual raindrops in a cloudburst,
A raindrop, you say? Like what, a big one? Ok, that's 5mm across for the largest type. From here: http://hypertextbook.com/facts/2001/IgorVolynets.shtml [hypertextbook.com]
It's only a matter of time that other countries develop "weather radar" as pinpoint as this.
The F22 and F35 radar cross sections have been compared to a metal marble and a metal golf ball, respectively. Their "stealth technology" has just been rendered obsolete.
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BMO
Their Stealth technology has been obsolete since b (Score:4, Informative)
Their Stealth technology has been obsolete since before they came out, as long as you can use a heavy-ass ground (or ship) based radar system. Russian S400 "Triumf" deals with stealth just fine, and so does S300 with minor mods. And by "deals" I mean shoots down stealth aircraft from beyond its missile range. That's why we haven't attacked Iran yet. That's not the point of stealth. The point of stealth is that _other planes_ can't see you, and you can take them out from way beyond _their_ radar range.
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Nope. The Fokker E.III was a fighter.
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*: The name of the fighter's mothership shall be left as an exercise for the reader.
Re:Their Stealth technology has been obsolete sinc (Score:5, Informative)
The point of stealth is to take out their radar sites. People declare that it's easy for radars to detect and shoot down stealth aircraft, but how easy is it for a stealth aircraft to blow up a radar site? I have to point out that no one has figured out how to make a stealth radar site yet. Think about this: the radar beam has to travel to the target, reflect, then travel back to the radar site to be detected by the radar. If the target has a bunch of antennas, it can detect the radar much earlier than the radar can detect it.
In any war, drones and cruise missiles will be the vanguard of the strike force. The UAVs will fly in to draw fire and jam radars, and cruise missiles will be used to hit anti-aircraft batteries that fire. Sure, in theory the radars can detect stealth aircraft but what about a real electronic warfare environment where we have jammers, target drones, and cruise missiles lighting up any radar site that turns on? The B-2 has its own electronic warfare suite, and as seen above, it can see radar sites much earlier than the radar sites can see them. And don't make any mistake: the radar sites are well within the reach of many of our aircraft. The S400 has a maximum engagement range of 400 kilometers. That is well within the range of the JSOW-ER with a small jet engine that can hit targets from 300 nm. The JASSM-ER has a range of 575 miles, which can be deployed by the B-2.
The B-2 carries the Joint Standoff Weapon (JSOW), which can hit targets from 60 nautical miles. There's a Small Diameter Bomb that can float 60 nmi. Any guy who turns on his radar will have a bad day, guaranteed.
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Except of course neither Raptor nor JSF can carry JSOW-ER, and it can itself be easily shot down by any SAM produced since early 80's, since it's not stealth. The planes that can carry it can be shredded into confetti by S400 from 400km away. And that's the officially advertised range, real range is likely to be greater than that. In addition, S400 has 360 degree radar detection with a range of 600km. So whoever turns on the radar trying to target it is going to have a really bad day, guaranteed.
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You're missing the point when you conclude that "whoever turns on the radar trying to target it is going to have a really bad day, guaranteed." The first part is not true. Killer birds do not have to turn on its radar to find where your radar sites are. It is the S400 has to turn on its radar to detect targets. Killer birds can sit around passively sucking up radiation to hone in on radar sites. Due to the physics of it all, the killer bird gets to detect the enemy radar passively from a much great range th
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Aside from Iraq (which didn't really have much in the way of weaponry), the US has never won a war in which it was a dominant player. Nuff said. All the bells and whistles, and yet the cave dwelling towelheads in Afghanistan are handing our asses to us. What makes you believe that Russians (or Iranians, with Russian weapons) won't be successful at it, in case a conflict breaks out? Why is the US scared shitless of invading Iran and North Korea, or, for that matter any country which has any decent weapons at
ANALYSIS (Score:2)
raindrops are not designed to misdirect observatio (Score:3)
Stealth technologies are designed to change how an object that can be detected by RADAR is seen by it. Through various material changes, positioning of openings, angles, and the like, you can change how you appear on a RADAR and to a point minimize detection range. You do not have to penetrate foreign airspace much to get a bomb on target and drones don't incur the political risk of dead pilots.
Oh I do not doubt that current stealth technology can be rendered obsolete if not already in some cases, however w
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>Explaining what stealth is
Dude... don't do that. We know what it is. And for those who don't, google is --->over there.
>Oh I do not doubt that current stealth technology can be rendered obsolete if not already in some cases, however while we read about breakthroughs in RADAR technology when it occurs we rarely read about stealth technologies until they are implemented or already surpassed.
I was talking about the planes we have built. If you can detect a .5mm raindrop, at 2km, you sure as hell
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Jamming only works for so long, and it pretty much says "HERE I AM" after you "burn through" it. Imagine someone shining a super-bright flashlight in your face. Can't see now? That's jamming. However, put on some welding goggles (burn through the jamming) and suddenly that blinding glare is merely a point of light telling you EXACTLY where that person is.
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And once we do start selling them, I bet we could harass our enemies by shooting golf balls with stealth fighter profile into their air space. That'd be hysterical. Just sit a ship out in international water and use an air cannon or something to fire a constant stream of "stealth fighters" into their airs
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Oh god, I love that idea. ... and then, in the middle of it, you send the actual attack craft. "Guess which one's real, assholes!"
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Oh god, I love that idea. ... and then, in the middle of it, you send the actual attack craft. "Guess which one's real, assholes!"
Probably the one not following a parabolic arc. If the golf ball "chaff" is going fast enough that the arc is undetectable, you don't need the fighters anyway.
Re:Military Obsolescence. (Score:4, Informative)
They claim they can see a rain drop out to 2 kilometers.
Fine. Let that be our upper limit for angular diameter. We shall use the largest rain drop of .005m (5mm, but .005m for the sake of units) mentioned earlier to figure this out. We shall then use the angular diameter to figure out how far a golf ball has to be to be the same apparent size (angular diameter).
Using the large raindrop is our best bet for reality. It keeps us from pushing out the golf ball sphere to ridiculous distances.
Here, let's do some math.
Since unicode sucks here, it goes like this:
Angle = 2 x Arcsin(radius of sphere divided by distance)
For a flat circle, it's an arctan but we're not using a flat circle. At this distance and size of targets, it doesn't make much difference, but we're using the correct formula for formality's sake.
Angle = 2x Arcsin(.0025 / 2000m)
0.000143239 degrees, or about .5 seconds (take number, multiply by 3600)
A golf ball is 42.67mm in diameter at a minimum, but let's just truncate this for simplicity and readability, and the error makes the radius of detection smaller. .042m/Sin (.00000413239/2) = 1164km
1164km = maximum effective range to detect a steel golf ball with this radar as long as you can detect the signal (for clarity, I am omitting signal strength and inverse-square law and what it does to detector size).
But then you say "read the article"
>With such small pulse volumes, it becomes possible to measure the properties of individual raindrops greater than 0.5mm
Their minimum raindrop is 1/10 smaller in diameter than the one used in this post. If I had put in .5mm in for calculating angular resolution, I would have pushed out the steel ball 10x the distance, a credulity straining distance.
Stealth is toast. It is obsolete.
QED.
Note: Please do not confuse angle of detection with beam width.
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BMO
Correction. (Score:5, Informative)
I said .042m/Sin (.00000413239/2) = 1164km
This is wrong.
I forgot to use the radius of the golf ball, which is .021
Which gives 582km instead, not 1164km
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BMO
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That is incredibly amateurish. It's the RF engineering equivalent of a marketer explaining how the traditional computer is obsolete because his iPhone can do everything.
'Radar cross section' is an executive summary term that you use to explain concepts to a non-technical audience. It's an analogy. By trying trying to do calculations with it, you're assuming that RF propagates losslessly through the atmosphere, which is very wrong. Radar cross section is a proxy for reflection scattering (S_11 for RF enginee
Radar is not so simple (Score:2)
Cause that's the problem (Score:3)
Seeing individual raindrops, that's the problem with current weather radar technology.
Or could it be that it's already so expensive that they cannot blanket the country like
they need to and there are huge gaps in coverage which makes models less accurate?
-AI
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Stealth technology.. (Score:1)
Remember, stealth doesn't mean a plane is invisible, it just means that the cross section of the plane is just too small to image using normal radar.
Wavelength and TX power? (Score:2)
I wonder about those two almost insignificant characteristics and related health azards.
Any idea?
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Think putting your balls in a microwave.
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If you can see the raindrops (Score:2)
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Stealth aircraft have a large radar signature than raindrops. Most are atleast golf ball sized. If the radar can process so much information (which I doubt), then yeah they can detect stealth aircraft.
So? (Score:2)
I can do that too. What's the big deal?
Great (Score:1)
Now I can't even take a piss in the woods without the government keeping track of the stream?
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Now I can't even take a piss in the woods without the government keeping track of the stream?
Now I can't even take a piss in the woods without the government taxing the stream?
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I've heard about politicians pissing away money on public projects, but this is really a watershed moment.
To see is one thing, to memorize another... (Score:2)
And to manipulate such quantities of data - yet another thing.
And that another another thing is something to think about here. To calculate from raindrop up, or to take chaos theory shortcuts?
I really don't know much about meteorology and chaos theory, but I am sure people thinking about individual raindrop approach do not know, too!
I have a better idea (Score:1)
Oh and by the way, this is impossible and they're lying. If there's a raindrop 500 feet into a pillar of rainfall, chances are it will be blocked so the radar waves would bounce off a raindrop closer to the edge first before even hitting a
A step towards Total Perspective Vortex (Score:2)
Increase the resolution and apply to fairy cake and we're good to go!
Nostradamus predicts (Score:1)
RTFA: the /. header is non-sensical (Score:5, Insightful)
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I imagine the drop size isn't nearly as important as the drop separation as far as resolution goes. The size of two stars viewed in a telescope is vanishingly small (WAY smaller than a pixel), and yet you can easily spot them. What matters where resolution is concerned is their separation. In the case of radar obviously relfectivity matters a great deal, as you basically pointed out.
I'd be interested on the dish size required to address diffraction. Even with a phased array I wouldn't be surprised if th
Waste (Score:2)
Back to the drawing board (Score:2)
Well, I guess that plan to infiltrate earth in tiny spaceships disguised as water drops is out the window now.
Thanks to the US Navy!
Skynet (Score:3)
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