S. Korea pushes to have stealth-detection radar in 2020s

DAEJEON, South Korea, Oct. 23 (Yonhap) -- South Korea is eyeing stealth-detection radars to counter radar-evading aircraft by its Asian neighbors flexing their muscles for possible future warfare, the Air Force chief said Wednesday.

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Stealth detection is a matter of signal to noise. Use multiple radars, and you increase the SNR.

Well that'll put 'em about thirty years behind everyone else, so big deal.

They want stealth-detecting radar? The old Isayev S-125 Neva system (NATO reporting name SA-3 Goa) designed in the '60s was successfully used in 1999 to shoot down an F-117 Nighthawk stealth "fighter." By extending the wavelength of their radars and using them only in 17-second bursts (to avoid NATO SEAD/Wild Weasel strikes), the Yugoslavian army was able to detect the F-117 under certain conditions, especially when its bomb bays were open. They picked up a Nighthawk on approach to Belgrade, and fired two missiles, hitting with one. The pilot of course ejected and was rescued, but if a SAM system designed in 1961 can shoot down a top-of-the-line stealth aircraft, just imagine what could be accomplished with modern tech and some ingenuity.

reply to post by ShadeWolf


The F-117a shoot down was more a function of a lack of stealthy flight than a failing of stealth technology. It flew the same path for every mission and nearly the same timing. Stealth is more than technology, it is also a pattern of behavior. Fighter aircraft notch their flight just in the event someone is tracking the stream left by their exhaust (heat, not contrail). [In a decent computer game, if you run in a straight line, you tend to get shot in the back.]

I have to presume the new technology for the ROK is multistatic. No big deal, but it does take money and engineering.

Note that the Soviet era low frequency detection of stealth aircraft works, but it isn't particularly useful for targeting.

reply to post by gariac


Question, are there system available on the market to a foreign power that are capable of targeting a top tier stealth aircraft and directing a SAM to it?
If they are going to look at the available tech. if said system does exist and then make a decision then I can see the need for the request to their Joint Chiefs of Staff to look over seas for the system. If such a system doesn't exist yet (to the knowledge of foreign govs.) then why go throught the pony and dog show and just build their own system since the "tech. to detect" is well known.

reply to post by Sammamishman


My understanding is they synchronize and correlate conventional radar equipment. They run fiber optic cable between facilities and establish something on the order of PTP. When you sync facilities, you can run cross-correlation analysis on the return.

Schemes to increase SNR are pretty old hat. They just aren't cheap. You combine N sources, and the SNR is improved by the square root of N. So you add 3 more receivers to the one you already have make it twice as good. I suppose they can crank up the RF level too.

gariac
reply to post by ShadeWolf

 

I have to presume the new technology for the ROK is multistatic. No big deal, but it does take money and engineering.

Multistatic radars work, but they don't give you vectors, just presence. With some work, you can identify as well, but they do much better at detection than tracking.

The cross-correlation is more for identification. If you've got a plane that has axes that it's got bigger RCS on, you can get tracking info that way as well. With multistatic systems, it's possible to do something like a SAR in reverse to get more data from the reflections as well.

OTOH, if you're using newer GaAs phased array systems like a big ground based AESA, you can get the return up by just throwing a wad of power at it.

eta - if the stealth design reflects oncoming radar signals in other directions that can be received from off-axis ground stations, you can sometimes use a multi-static system to pick up the off-axis reflections and get tracking info that way. The older stuff like the F-117 would be more vulnerable to off-axis monitoring.

reply to post by gariac


Yep you are going to have to get into the "grass" to find that target as its RCS is going to be "seen" by a radar system as noise of the system. By using multiple radars and then processing the received returns into one, it would give a better chance of finding that "diamond in the rough" so to speak.

Typical systems have a minimal determinable signal of about -110 dB (that is insanely small) but is still detectable and when you utilize multiple returns from different stations and then process them, you can most likely find the target.

reply to post by ownbestenemy


-110dB needs some reference point. For instance -110dBc meaning relative to carrier, -110dBm as in power, usually with 1mW into 50 ohms. Note a good cell phone can function on a RSSI of -110dBm. I've had service with as low as -114dBm on UMTS.

In reality, if they were going to attack the ROK, the enemy would be jamming the radar. Until the F-35, the USN never had any stealth capability.

They put the Pave Paws on steroids post 9/11. They operate in the 70cm ham band, though if you ask the Navy, they would say the hams operate in the Pave Paws band. I believe that frequency is low enough to detect stealth aircraft.

reply to post by gariac


Received return strength on which a standard radar receiver can "see" a target from the grass/noise of the system and background.

I apologize for the vagueness of if. -110 dBm. Pico-watt range in regard to the return of a "seen" target by a typical radar system. I am talking typical landing systems, auto-track which have a different standard that shouldn't be discussed here.