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US Army Developing Encrypted Radar Waveform (thestack.com)
An anonymous reader writes: The U.S. army is working on an innovative technology for masking radar emissions in contested territory and environments with heavily congested radio bands. Effective radar system performance is critical in military operations, yet remains a challenge in locations under attack or in areas of high traffic density. Army researchers have now developed a noise-encrypted radar waveform called Advanced Pulse Compression Noise (APCN), which can be tuned in real-time to allow users to adjust radar performance depending on their surroundings. Research scientist, Mark Govoni explained: 'Having the ability to transmit a radar waveform that's continually changing, one that never repeats itself, and looks like noise, is extremely difficult to intercept....and remains anonymous to radar detectors.'
Stay out of high noise areas maybe?
How about anti-radiation missiles?
So they discovered FHSS. Good for them!
(Also, they may be able to mask the radar pulses, but "encrypt"? Really?)
How can I believe you when you tell me what I don't want to hear?
Ultra-wide band radios for consumer use died a death of 1000 cuts at the hands of the FCC due to certain 'agencies' not wanting anyone pissing in their private pool. Its really sad to see how little unlicensed consumer spectrum exists and the seemingly insurmountable hurdles one must clear to get an experimenters license to make use of anything else. Pass me some ketchup for these freedom fries.
Catching speeders.... since vehicle radar detectors won't work for attempting to detect the the encrypted radar signal.
Passave array radars are ...passive. They use existing electromagnetic radiation (tv broadcasts, radio broadcasts, cell phone broadcasts, wifi broadcasts, etc.), in a differential mode (receiving in multiple axis) and using signal processing to passively track other aircraft. You can also use oblique shapes for your own aircraft to deflect signals, and more definitively, use plasma generators on wing leading edges and in front of turbofan inlets. The blurb was a fib though. The signal isn't 'encrypted' in any way. Electromagnetic radiation exists, and you aren't making your own fake signal based on an already existing signal, all you are doing is determining the most effective frequency of transmission given the current medium, and using it to best effect. This is *no* different than what DSL modems do (all day every day), or radiosondes have been determining about the ionosphere for the last 80 years.
The FBI have already asked for a back door.
Noise radars are not a new concept. The biggest challenge is that calculating correlation between noise (or pseudo-noise) and a doppler-shifted, delayed version of the same pseudo-noise is challenging to say the least (basically has no good solution, other than some crazy brute-force).
Some special properties of the pseudo-noise might make it possible again.
Does the FBI know they're using something encrypted? Perhaps Obama should have them subpoena their schematics.
Curtiss-Wright makes a circuit board that would be perfect for this work. This board is an FPGA next to a DAC that can spit out an RF signal whose modulation is about 6 GHz wide, calculated by the FPGA. Using this technology, ANY type of waveform or modulation can be sent to the radar transmitter.
I just ordered (for my radio astronomy job) its cousin, which is all A/D converter, as our radio telescope doesn't have a transmitter, just a receiver.
The determined Real Programmer can write Fortran programs in any language.
Directed energy assaults on humans has been occurring for decades and it cannot be detected. It comes from military over the horizon radar and satellites.
What I know is this sounds like an old technology the Army is trying to puppet as just being developed when they mastered directed energy eons ago.
DrRobertDuncan.com
Why? Their only use would be attack helicopters, which are supposed to be discontinued because drone warfare is easier and cheaper. I can understand the air force wanting to put stealth radar in stealth planes, which currently fly blind. Even the navy can use stealth radar in its landing/coastal vessels. But when does the army need a radar to detect buildings and other vehicles?
Presumably this will come with a backdoor for the FBI, right? Just to keep things, fair, right?
Allow OTA updates only through a program (app) on a smartphone.
This achieves three important things;
1. The car has no remote communication capabilities (update via cable or at worst NFC that can be turned off in hardware!)
2. You can choose if you want to upgrade because you can choose to connect or not.
3. Be a much safer option for updates etc.
Let's not forget other motives manufacturers have...your data. Manufacturers can still get at their precious data for customers willing to share it.
A 'singular oddity' is an event that cannot be explained and only happens when you are alone.
You won't see it either or it will be damn easy to disturb or detect by using the same methods. My signal theory is rusty, and i may be wrong, and I know there are a few schemes with component analysis which allows to detect signal lower than the noise floor on specific bandwidth, but then so can the other detector do. After all you do not need to know the signal is meaningful, you only need to detects that at that bandwidth there is a higher power than expected.
C. Sagan : A demon haunted world:
http://www.amazon.com/gp/product/0345409469/
visit randi.org
Based on the Crystaline cipher no doubt...
http://ieeexplore.ieee.org/xpl...
C. Sagan : A demon haunted world:
http://www.amazon.com/gp/product/0345409469/
visit randi.org
why would you announce such a thing?
nothing to see here - move along
https://en.wikipedia.org/wiki/Low_probability_of_intercept_radar
Similar systems are already deployed. The original implementations were a variation on frequency hopping techniques, but they've been becoming more sophisticated as computing power increases.
It makes them harder to detect, harder to determine the source if detected, and more resistant to jamming. They can still be rendered useless by powerful broadband jamming, but that is rarely used as it blinds everyone, not just the enemy. Though it should be noted that blinding everyone might be attractive to a less technically advanced side with significantly larger numbers.
Radar detectors would have to adopt Counter LPI/LPD techniques, which apparently do exist:
There's a book on Amazon called "Detecting and Classifying Low Probability of Intercept Radar".
This sounds like it could be beneficial in many areas of signal transmission. I feel it should be opened to the public.
The last thing we need is more military capability. In fact, what we really need is more technically capable adversaries to keep us in check and raise the real cost of us going to war to untenable levels.
So the real answer is ALL of our defense research should be opened to all of mankind. Every last page of it. I would LOVE to see this technology used in commercial drones, in the hands of the public.
"I opened my eyes, and everything went dark again"
Hedy LaMarr (yes) developed spread spectrum frequency hopping for submarine torpedo guidance systems that couldn't be intercepted by the enemy who would then have been able to throw the torpedoes off course. She patented it in 1942. The US Navy started deploying her system in the 1960s during the Cuban missile crisis.
The same technology gives us WiFi, CTCSS/DCSS, FTTC, n-plexing NFM and WFM radio, CDMA, Bluetooth...
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
There are a lot of confused comme ts here, but the concepts are not difficult to understand. The techniques make it extremely difficult to detect an emitter despite what people are saying here. The strategy moves the back and forth in electronic warfare from the realms of commoditization of hardware to the realm of computational investments that are very expensive and favor technologically capable combatents. It isn't exactly a breakthrough, but it has been changing the EW race for some time.
Other methods for detecting and tracking targets are becoming cheaper and more effective now in response, and these methods are making the EW community wary. One field of development is in radar acoustic imaging, where new techniques are being developed to image the air disturbances from aircraft quickly and with high enough resolution to get countermeasures within a half mile or so. The tech is dirt cheap, and these firms are getting purchased by Raytheon, Airbus, etc., and going dark left and right. The technique is useless for detection of ground based threats, but their cost allows large networks to be deployed against airborne threats which are extremely difficult to defeat.
Can anyone with access to the papers share what's new about "advanced pulse compression noise" radar versus classic noise radar?
Noise radar itself, i.e. transmitting white noise and then correlating returns with the original noise signal to find the targets, is not a new technology. I don't doubt there's something new here, but the articles are too light on details to be able to tell what.
Also, bit of a stretch to call it "encryption"... Methinks that was the managers or the journalists.
Folks have been developing Low Probability of Intercept/Low Probability of Detection radar for decades. Spread-spectrum textbooks from the 70s and 80s talk about it. Maybe what's new here is that it's published in the open literature?
With radars, you have the problem that the victim trying to detect the radar sees the signal down by 1/r^2, while the radar itself sees the reflection down by 1/r^4. The radar transmitter has to put out enough power so that the reflection is above the noise floor (after process gain from the pulse compression/noise modulation). So the question is whether the target/victim is far enough away that they can see the signal without doing the process gain.
You can detect the increase in the noise floor with a broadband detector (also called a crystal video), although in a RF dense environment with a lot of emitters, it's tricky.
if you plan to attack Russia, China, or the Borg ship.
Seriously. This is just a variation on WiFi being used for a different application. This was all developed in the 1950's.
GPS operates with a signal at the antenna that is 30-40 dB below the noise floor of the receiver front end. The only reason it can be detected at all is the receiver knows what the DSS sequence is and processing gain brings it up above the noise floor.
The innovation is SDR radios with lots of compute power. Go look at the high end MIMO RF eval boards that Analog Devices offers. The hard part of this is doing it *really* fast. That gets very expensive and difficult very quickly. But the math is still the same.
It is NOT frequency hopping. It's direct sequence spreading using a very fancy spreading sequence and the hardware required to do that. Frequency hopping has the instantaneous power concentrated at a single frequency. You can't jam it, but you can detect it with a wideband receiver. In DSS the instantaneous frequency is very wide which makes the power at any particular frequency very low and thus hard to detect.
The problem is in your definition of "noise floor". I would counter-argue that if you can't receive the signal you don't have good enough hardware. The "noise floor" is a sum over time of all radiation:
- Within the pass bands of any filters (software and hardware)
- Modified by the gain characteristics of the antenna/receiving system (again, software AND hardware)
- Over the time period you are integrating.
The engineering problem is to simply narrow the above until the signal sticks out above the noise floor.
There are many ways to do this, but one very good one would be to look for any signals traveling within certain speed bands. I.e. any aircraft emitting any omnidirectional radiation is just stupid: you should be able filter out noise not on the ground, and not stationary (i.e. speed correlation)
Perhaps the UV background hiss in the Universe could be the carrier for interstellar communications? Using an encryption-key generator, it might be possible to randomly unlock such hidden hidden communications, or use the method to transmit and receive communications using the background noise as the carrier.