Martian2
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China's Anti-Stealth Radars and Sensors
The easiest way to detect an F-22 is to look for its electromagnetic radiation emission (e.g. ELINT and SIGINT).
In particular, an F-22 emits:
a. radio communication
b. satellite communication
c. IFF transponder
d. radar emissions
China has three different sensors designed to locate electromagnetic radiation emissions.
1. Chinese NOSS (ie. Navy Ocean Surveillance Satellite) satellite trios.
2. China's YLC-20 passive surveillance radar
3. China's CETC DWL002 Passive Detection System
The NOSS satellite trios are interferometers.[1]
The YLC-20 passive surveillance radar can be used as an individual unit (or in a network as an interferometer).[2]
I have previously covered the Chinese CETC DWL002 Passive Detection System as an interferometer that is about 25 times more sensitive than the original Russian Kolchuga version.
Citations.
1. Rosie Finally Flies: Atlas V Inserts Classified NROL-36 into Orbit « AmericaSpace
"The NOSS...use a technique known as ‘interferometry’ to detect radio transmissions from the ships and ‘geolocate’ them using Time Difference of Arrival."
2. The Chinese great RADAR wall | Defense Update
"The Chinese great RADAR wall
Nov 13, 2014
Airshow China 2014 Photo Report - Air Defense Radars
The YLC-20 is a signals intelligence system detecting RF emitting targets beyond visual range. The system can be used as a single unit or a network of several sensors. According to the Chinese developers, it operates over a wide frequency range and delivers high location accuracy and powerful signal analysis capabilities. Photo: Tamir Eshel, Defense-Update
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Analysis
Why do you need three systems that basically perform the same function? The answer is redundancy.
The Chinese NOSS satellites are likely to be destroyed by American ASATs at the beginning of a serious conflict.
The YLC-20 passive radar is very large and requires a truck to carry the sensor. The control unit would be located on a different truck. To set up an interferometer, you need an atomic clock, fiber-optic cables, experts, and data-processing computers.
To set up a YLC-20 interferometer, a minimum of three trucks are needed. Two YLC-20 detectors and one truck dedicated to controlling the system. I don't know if there is sufficient space for the data-processing computers. It is possible that a minimum of four trucks are needed for an interferometer.
In contrast, the Chinese CETC DWL002 Passive Detection System is a compact unit. All of the equipment needed for a CETC DWL002 interferometer is located on the truck.
Given its size, the YLC-20 has greater detection range. However, to set up a YLC-20 interferometer, it is more complex and requires multiple trucks of equipment.
The CETC DWL002 provides quick regenerative ability. If a CETC DWL002 unit is damaged or destroyed, simply drive a replacement to the front line. However, the downside of the CETC DWL002 is its shorter range due to a much smaller detector.
Also, the YLC-20 passive surveillance radar and the CETC DWL002 Passive Detection System could be complementary and focus on different frequency bands.
Why are we seeing all of these Chinese interferometers? China built an atomic clock in 1972 at the Shanghai Astronomical Observatory (SHAO). However, we had to wait for Chinese supercomputers and processing software. With the Tianhe-2 33.86 petaflop supercomputer, China has demonstrated its mastery in building supercomputers.
Using its experience with civilian interferometers (e.g. China's Deep Space Network and the Yuanwang ship space-tracking radio telescope array), China obviously has experience in writing software for interferometry.
In my next post, I will cover regular radars, low-frequency radars, or infrared detection of stealth aircraft.
More Information.
China has world's second largest satellite fleet at 113 satellites
China's highly-advanced digital CETC DWL002 Passive Detection System
The easiest way to detect an F-22 is to look for its electromagnetic radiation emission (e.g. ELINT and SIGINT).
In particular, an F-22 emits:
a. radio communication
b. satellite communication
c. IFF transponder
d. radar emissions
China has three different sensors designed to locate electromagnetic radiation emissions.
1. Chinese NOSS (ie. Navy Ocean Surveillance Satellite) satellite trios.
2. China's YLC-20 passive surveillance radar
3. China's CETC DWL002 Passive Detection System
The NOSS satellite trios are interferometers.[1]
The YLC-20 passive surveillance radar can be used as an individual unit (or in a network as an interferometer).[2]
I have previously covered the Chinese CETC DWL002 Passive Detection System as an interferometer that is about 25 times more sensitive than the original Russian Kolchuga version.
Citations.
1. Rosie Finally Flies: Atlas V Inserts Classified NROL-36 into Orbit « AmericaSpace
"The NOSS...use a technique known as ‘interferometry’ to detect radio transmissions from the ships and ‘geolocate’ them using Time Difference of Arrival."
2. The Chinese great RADAR wall | Defense Update
"The Chinese great RADAR wall
Nov 13, 2014
Airshow China 2014 Photo Report - Air Defense Radars

The YLC-20 is a signals intelligence system detecting RF emitting targets beyond visual range. The system can be used as a single unit or a network of several sensors. According to the Chinese developers, it operates over a wide frequency range and delivers high location accuracy and powerful signal analysis capabilities. Photo: Tamir Eshel, Defense-Update
----------
Analysis
Why do you need three systems that basically perform the same function? The answer is redundancy.
The Chinese NOSS satellites are likely to be destroyed by American ASATs at the beginning of a serious conflict.
The YLC-20 passive radar is very large and requires a truck to carry the sensor. The control unit would be located on a different truck. To set up an interferometer, you need an atomic clock, fiber-optic cables, experts, and data-processing computers.
To set up a YLC-20 interferometer, a minimum of three trucks are needed. Two YLC-20 detectors and one truck dedicated to controlling the system. I don't know if there is sufficient space for the data-processing computers. It is possible that a minimum of four trucks are needed for an interferometer.
In contrast, the Chinese CETC DWL002 Passive Detection System is a compact unit. All of the equipment needed for a CETC DWL002 interferometer is located on the truck.
Given its size, the YLC-20 has greater detection range. However, to set up a YLC-20 interferometer, it is more complex and requires multiple trucks of equipment.
The CETC DWL002 provides quick regenerative ability. If a CETC DWL002 unit is damaged or destroyed, simply drive a replacement to the front line. However, the downside of the CETC DWL002 is its shorter range due to a much smaller detector.
Also, the YLC-20 passive surveillance radar and the CETC DWL002 Passive Detection System could be complementary and focus on different frequency bands.
Why are we seeing all of these Chinese interferometers? China built an atomic clock in 1972 at the Shanghai Astronomical Observatory (SHAO). However, we had to wait for Chinese supercomputers and processing software. With the Tianhe-2 33.86 petaflop supercomputer, China has demonstrated its mastery in building supercomputers.
Using its experience with civilian interferometers (e.g. China's Deep Space Network and the Yuanwang ship space-tracking radio telescope array), China obviously has experience in writing software for interferometry.
In my next post, I will cover regular radars, low-frequency radars, or infrared detection of stealth aircraft.
More Information.
China has world's second largest satellite fleet at 113 satellites
China's highly-advanced digital CETC DWL002 Passive Detection System
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