[grkvlt]

Also interesting are the resolution targets, using sets of black and white bars at varying widths in both X any X orientation, to determine the spatial resolution i.e. how high frequency a component could still be imaged separately as lines, similar to TV test cards. These are discussed in various blogs [1][2] with some amazing picures. I think these were for both satellite imaging and spy-plane (U2 and SR-71 plus less exotic surveillance systems) and not just the USA. This article [3] shows some satellite test targets in the Gobi desert, presumable for Chinese (PRC) spy satellites, and also has a cool picture of the world's largest compass rose, at Edwards dry lake bed, as well as explaining the crosses from the original article, and talking about radar altimeter targets (another dry-lake bed) that are mapped to centimetre accuracy in altitude for calibrating GPS and other systems.

I find it a really interesting area of industrial/scientific archaeology, with some fascinating stories.

[1] http://www.clui.org/newsletter/winter-2013/photo-calibration... [2] http://www.bldgblog.com/2013/02/optical-calibration-targets/ [3] http://www.atlasobscura.com/articles/landscapes-made-for-sat...

[kweks]

I recently visited the Chinese ones. It tools a good day or so of driving off road (after two weeks of driving to get into the area) to reach them.

Totally in the middle of nowhere, and quite amazing to see.

[fapjacks]

Awesome! Did you by any chance blog about your trip (with photos)?

[mauvehaus]

Ironically, they all came out blurry...

[toomanybeersies]

Those tri-bar patterns are fascinating. I'd imagine that American surveillance equipment would be able to discern all but the smallest couple of squares.

They'd easily be able to read registration numbers on aircraft, probably almost be able to discern specific small arms (e.g. count the number of RPGs and AK-47s sitting on some tarmac somewhere). Amazing.

[rangibaby]

USSR "trolled" the US by painting windows on top of a plane or helicopter while it was under development. I can't remember the exact one will have a look around.

[grkvlt]

I'm sure I've also read about this, but can't find any links at the moment. The art of Maskirovka [1] (deception and camouflage) is still part of Russian military doctrine. Interestingly, the US also does something similar with planes like the A-10, which has a 'fake cockpit' painted on its underside, so that it is hard to determine the orientation of the aircraft visually. This is actually patented [2] and has been applied to various different aircraft, see the pictures accompanying this answer [3] on stackexchange.

[1] https://en.wikipedia.org/wiki/Russian_military_deception [2] https://www.google.com/patents/US4448371 [3] http://aviation.stackexchange.com/questions/2078/what-is-the...

[rangibaby]

According to wiki the one I was thinking of was the Ka-50

> The single-seat configuration was considered undesirable by NATO. The first two Ka-50 prototypes had false windows painted on them.[19] The "windows" evidently worked, as the first western reports of the aircraft were wildly inaccurate, to the point of some analysts even concluding its primary mission was as an air superiority aircraft for hunting and killing NATO attack helicopters.[20]

[todd8]

I don't think that even LEO Spy Satellites have that resolving power. Of course, that information would be classified. Does any HN reader know what a reasonable guess at their resolving power would be? I would love to know.

[grkvlt]

Commercial satellite imagery is available at 0.25m resolution these days, so assuming an order of magnitude better that gives around 2.5cm resolving power, or one inch. I think I've heard about 5cm quoted somewhere, as well. So, maybe just good enough to detect the difference between small-arms, and certainly enough to read identification markings on an aircraft, or to determine the name of the newspaper, but not to read its headlines.

[toomanybeersies]

I wonder what the real limit is for resolution, due to the distortion of the atmosphere.

I guess that by taking multiple photos in quick succession from slightly different points you could reconstruct a clearer image. It's not my field at all though, so I may just be randomly guessing.

[Swizec]

Future archeologists are going to have so much fun with these. They're not gonna say it's aliens, but it'll def have been aliens.

[noir_lord]

It would be kinda fun to do these crazy scale things and have no reason to do them with the intention that our distant ancestors will be as confused as hell but then I look around at the modern world and think they'll no doubt think that anyway.

[Swizec]

If you're into that kind of stuff, read Mark Lawrence's books. It's set in post-modern times where our civilization is known as The Builders. Complete with ghosts coming out of unintelligible machines and talking about how stupid everyone is these days.