notice this technology
can "see" ceramics!
Posted on 10/21/2004 1:57:36 PM PDT by theFIRMbss
I wonder if this type of sensing could negate stealth technology? Needless to say, we're heavily invested in stealth.
The question is whether it can be jammed...
It would have no bearing on stealth aircaft - at least not in an operational sense. Stealth is designed to fool radar frequencies.
Visual stealth, OTOH, hasn't been made public yet. But it's definitely here.
Passive millimeter wave imaging considerations for tactical aircraft
Abstract:
Air Force, Army, Navy, and NASA Research Laboratories, in addition to major aerospace companies, are considering millimeter wave (MMW) imaging technology as an enhancement to sensor suits on both occupied and unoccupied vehicles. This is a review of the basic technology involved in MMW imaging and some of the programs and products that might benefit from passive day or night imaging through mist, haze, fog, clouds, smoke and/or dust. Potential applications include UAV surveillance of ground vehicles, airborne approach to airfields, tankers, flight leaders, and detection of airborne targets, including stealth aircraft.
wow, a Glock 7!
Any electromagnetic signal can be jammed. From ELF to EHF - all you need is to transmit the corresponding signal to cancel the other one.
It's when you have multiple signals and their harmonics riding a carrier wave that jamming becomes more difficult.
Interesting post!
I didn't think there was a natural source for millimeter wave radiation. The article kept mentioning passive millimeter wave processing, but never mentions the source of the radiation.
Im curious about the image of the cars. Is there an active source and what we are seeing is the millimeter reflection?
Peaking my interest here ...
Anyone with a physics background that can answer some questions here ?
But if it's in visual or passive sensing range, it's too late.
This is not a radar configuration. You can find electromagnetic energy throughout the spectrum, though we usually call it "noise." This method uses the "noise" as a source and performs incoherent imaging on the return.
So in a sense energy is "reflected," but it's the ambient signal that's reflected not an active radar signal.
Also, 94 GHz is selected as the frequency in order not to be absorbed by water vapor in the atmosphere.
I've read of "passive"
systems that monitor wide
areas. Perhaps
multiple units
can be forward-placed, and then
integrated well . . .
I follow everything you said, and that makes sense. But the source question still plagues me. What in nature would emit 94 GHz radiation that could be reflected and detected? ... Are you saying that the radiation, being just background, is atomic? ... or cosmic, or solar?
See what Im saying ???
It's not all reflected, some of it's emitted. Shiny objects tend to reflect the sky, which (if clear) is very cold. "Dull" surface objects are glowing at that wavelength, due to their temperature. Heat them up enough, and you'll start to see significant glowing at visible wavelengths.
when gets to the passive-meter stage, the world will end.
Everything, including you! See Planck's equation.
You really have me interested now ... I worked with IR at Wright Pat when I was in grad school. The EO group had active millimeter wave systems they were conducting experiments on ... I thought I remember one of the folks telling me there were no natural sources of millimeter wave radiation ... and all work was active ...
Of course, that was in the early 1980s ...
I will surely waste a few hours tonight on the internet reading some stuff.
Thanks for the info ...
See Krauss, "Radio Astronomy" for more info.
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