Monday, April 8, 2013

China's Anti-Ship Ballistic Missile & The Lost RQ-170 Sentinel Drone

China’s mysterious Dongfeng 21D anti-ship ballistic missile program, supposedly able to take out American aircraft carriers and other capital ships at distances of up to some 2,000 miles. The DF-21D uses a ballistic delivery concept to send its deadly payload far down-range, and maneuverable re-entry vehicles for its terminal phase of attack. If proven operational, the DF-21D has the potential to deny US aircraft carriers, and their subordinates, access to the strategically imperative South China Sea in whole. This potentially game change weapon system is discussed in a fantastic article posted over at and linked below:

The big question is how effective is this “carrier killer” weapon system really? Is it a deadly over-the-horizon carrier buster for which the US has little defense, or is more of a pipe dream, just another part of the strategic shell game played by China against the US? 

is very hard to try to estimate how reliable the actual missile and warhead is from the “outside looking in,” but we can take a look at the other, less glamorous, yet every bit as important piece of this anti-ship ballistic missile system, that being China’s ability to accurately target American Carrier Strike Groups far over the horizon, to gauge the soundness of such a far-reaching concept. Further, recent events surrounding the loss of cutting edge US unmanned aerial vehicle technology may help us better predict exactly how realistic such a weapon system’s effectiveness may become.

Initially detecting American Carrier Strike Groups can be done using a variety of methods such as advanced over-the-horizon radar (which China is actively developing), traditional maritime patrol aircraft, submarine patrols, surveillance ships and surface combatants, satellite surveillance, and maybe of most potential, long endurance Unmanned Aerial Vehicles (UAVs).


To enhance the possibility of finding what amounts to a needle in a haystack, maritime patrol aircraft would use radar to initially detect an American flotilla, whereas satellites could use infra-red or synthetic aperture radar surveillance, and submarines could use sonar in both passive and active roles.  

In addition, almost all of the platforms mentioned above could theoretically be able to initially detect a battle group’s general whereabouts by using electronic service measures (ESM) that could passively detect a carrier group via “listening” for it’s electronic emissions. 

In reality there exists a cocktail of initial targeting detection capabilities when it comes to locating American flotillas underway in the vast expanses of the Pacific. Yet the capability that seems to be of the greatest interest to the Chinese, as well as militaries around the world, is the use of a Broad Area Maritime Surveillance (BAMS) types of High Altitude Long Endurance (HALE) Unmanned Aerial Vehicles.

Something akin to the American RQ-4 “Global Hawk” type of platform would allow both high-resolution Synthetic Aperture Radar (SAR) with Moving Target Indicator (MTI) capability as well as high-power electro-optical payloads to be brought to bear to scanning massive swathes of the Pacific for prowling American surface combatants. Further, this aircraft, flying above 65,000 feet, would be able to standoff at great distances from the suspected areas where America’s fleet is operating, making it a survivable asset as opposed to predictable satellites, or less capable manned maritime patrol aircraft which are easier to destroy during a time of war.

The reality is that China has built and flown an airframe akin to the RQ-4 Global Hawk as well as a jet powered version analogous to America’s Predator B, otherwise known as the MQ-9 Reaper, as well as other small UAV configurations. 

It would seem that for China airframe design and production is not an issue when fielding such advanced unmanned capabilities. In fact, it would appear that both China’s Global Hawk like HALE UAV and Predator B like designs are actually more advanced in aerodynamically than their approximate American equivalents. 

This can be seen by the Chinese HALE UAV’s use of an advanced, staggered, box type of wing layout, which is optimized for high-altitude endurance efficiency, as opposed to the Global Hawk’s simpler U-2 like thin, straight wing. Further, a smaller UAV, analogous to the layout of the MQ-9 is well-known to be in active testing with PLAAF. 

The major difference between it and it’s American cousin appears to be the use of a jet engine and lower drag airframe design, which really puts the aircraft somewhere between the MQ-9 Reaper and General Atomics’ (the maker of the Predator series of aircraft) new jet powered and stealthy Predator C, also known as the Avenger, when it comes to airframe design alone.

Pictures have even surfaced of what appears to be a Chinese UAV design that is very similar in configuration to that of the stealthy RQ-170 Sentinel and it’s P-175 “Polecat” relative (pictured below), although there is no hard information within the public domain regarding how far along in testing, or even as to what scale this machine really is.

Where China seems to lack in terms of UAV technology is in the realm of advanced data links, autonomous flight controls, and in the case of a BAMS type of concept, a powerful Low Probability of Intercept (LPI) surveillance radar. This is where the RQ-170 Sentinel that came to a soft impact deep inside of Iranian territory may come in extremely handy to the Chinese. Iran has already stated that the Russians and Chinese have examined the drone over a month ago, but as you can imagine there will be a real bidding war over who actually gets their hands on the Sentinel for reverse engineering purposes. 

Seeing as the Chinese are really the best reverse engineers in the world and have deep pockets, it is almost a given that they will obtain firsthand knowledge of what treasures the “Best of Kandahar” has hidden inside its smooth, boomerang like frame. Regardless of how invisible to radar the RQ-170 design truly is, what is packed inside, the very guts that make it accomplish it’s unique and highly challenging missions, may be just what China needs to make their UAV’s currently in development strategic game changers in the Pacific Theatre, especially when paired with their budding Anti-Ship Ballistic Missile program.

The RQ-170′s stealthy data links are most likely one of the most advanced pieces of equipped that was risked on the aircraft during it’s highly sensitive clandestine missions. Being able to operate semi- autonomously while sending back continuous real-time intelligence information to ground controllers, most likely anywhere in the world, while not being detected by enemy listening posts, is really one of the Sentinel’s greatest tricks. 

There can be little doubt that at a very minimum the hardware that makes this happen, including what is under it’s dual communications “humps,” were left largely intact after its unfortunate fall to Earth deep behind enemy lines. Such hardware would be invaluable to Chinese engineers who have a great need to integrate LPI data links into their HALE/BAMS UAV in order to allow it remain undetected while far from home, and thus allowing it to survive during a time on conflict. 

As we have discussed at length in the past, the RQ-170 most likely uses the same control architecture as the RQ-4 Global Hawk, in particular its advanced ground control station built by Northrop Grumman. Being able understand one side of this circular communications link will no doubt help the Chinese in producing the human interface on the other side. Yet, to the Chinese, the most important piece of hardware most likely aboard the doomed RQ-170 was a miniaturized low-probability of intercept synthetic aperture radar featuring high fidelity moving target indicator capability. A piece of equipment that may truly unlock the DF-21D’s carrier killing potential.

Like the RQ-170′s long lineage of predecessors, including Tacit Blue and Darkstar (more can be read about the Sentinel’s shadowy family tree in the special features linked at the end of this feature), it most certainly was built with radar surveillance over or near denied territory in mind. So what does this have to do with China’s DF-21D anti-ship ballistic missile? A lot actually.

If indeed the RQ-170 was sporting such a radar array, as it appears to have been in the latest high-resolution shots taken of it while operating out of it’s Kandahar airfield nest, whether it be a state of the art Active Electronically Scanned Array (AESA) radar, or even a more dated passively scanned array design featuring LPI capabilities, it may just give China the leap it need in over the horizon, near undetectable, targeting abilities in regards to its DF-21D anti-ship ballistic missile program.

What is most startling about the possibility of the Chinese getting their hands on America’s lost RQ-170 drone is not necessarily the individual systems on-board, but really the cocktail of real-time targeting and network relaying capabilities it possesses which could be almost directly adapted to their HALE/BAMS unmanned airframe. 

An aircraft that is no doubt envisioned to supply their DF-21D anti-ship ballistic missile corps with the real-time, survivable, persistent,  high-fidelity moving target tracking capabilities they may so desperately need in order to make the whole system effective. 

When it comes to targeting of moving objects at great distances, the higher quality of data a remote targeting source can provide the better chance that the weapon applied to that target, especially when launched from thousands of miles away, will hit its mark. If China indeed has access to the RQ-170′s flight control, data link, and sensor systems, there can be no doubt that the quality of such data that their UAVs are able to collect and transmit has leaped years, if not decades, into the future.

In the case of the DF-21D it is not clear how the missile, moving at hypersonic speeds as it’s independent warheads (the DF-21D is known to be eventually capable of packing Multiple Re-entry Vehicles (MRVs) in a single missile) barreling toward their moving maritime victims to be, actually pinpoint, or lock onto their targets. 

Initially, a targeting source, in this case a high-flying, long-range maritime surveillance UAV, would relay the target’s precise coordinates back to a command and control element, which would pass the coordinates off to the ground mobile, or possibly sea-based DF-21D launch element. Minutes after launch, as the rocket hit’s its apogee and before warhead separation, a mid-course update may also be data-linked from the UAV to the missile via satellite relay for more accurate, fine tuned course adjustments. 

Once the warhead separates, it must continue to maneuver toward its target, equivalent in scale to hitting a postage stamp floating in one of the Great Lakes. A terminal tracking device aboard the warhead must then swing into action. This is where the DF-21D’s true capabilities become more of a mystery.

A guided terminal attack could be accomplished using an infra-red sensor in the nose of the warhead, otherwise known as the “re-entry vehicle”, which would direct the final phase of it’s attack. This would occur after initial coordinates of the target were factored in at launch and updated possibly during the missile’s “mid-course” phase. An on-board Infra Red seeker is passive in nature as no electromagnetic energy would have to be used to illuminate the target. 

The infra-red sensor would scan the area where the ship is most likely to be during it’s last tens of seconds of flight, in hopes of locking onto the heat signature of the rapidly maneuvering aircraft carrier or ship. The carrier will be rapidly changing course and speed as US early warning ballistic missile launch detection satellites will surely have detected the DF-21′s initial boost phase and would have alerted the Carrier Strike Group as to the incoming missile, or more likely, missiles. Also the Carrier Strike Group’s AEGIS class Guided Missile Cruisers and Destroyers would attempt to track and engage the missile using it’s limited ballistic missile defense capabilities.

Another way the DF-21D anti-ship ballistic missile’s final phase of attack could be facilitated is by using data links to not only relay the target’s initial coordinates to the missile’s launcher, but to continuously relay it’s exact location as it moves through time and space up to a satellite in orbit and then back down to the missile as it makes it’s final attack run on it’s target. This would maximize the UAV’s data-linking and radar provided moving targeting indicator technology. 

A small antenna that can extend outside the atmospheric effects of a warhead’s violent re-entry may be able to give it the real-time data needed, supplied by a UAV utilizing RQ-170 derived technology, to accurately hit a maneuvering flat top with a high degree of confidence. In this case the UAV, or whatever remote targeting platform is at work would literally tell the warhead where to go via data link right up until it slams through the carrier’s deck at mach 10.

Another and very likely method could be to use an active or passive radar seeker. An active radar seeker, basically a small radar like what is used in medium range air to air missiles, could be effective although such a system sensitivity is limited in range would be somewhat fragile and complex and is susceptible to jamming. 

A more likely alternative, at this time in China’s technological capability at least, would be for the warhead to come up with its final targeting solution as it rips down through the atmosphere via the use an older, more robust form of terminal radar guidance, known as “semi-active” radar homing. Semi-active radar homing, sometimes called “beam riding,” works similar to earlier radar guided air to air missiles, such as the AIM-7 Sparrow, made popular in Vietnam and Desert Storm.

This form of radar targeting utilizes a powerful radar source to “paint” a target with a certain band and frequency of electromagnetic energy. Then the missile itself, equipped with a fairly rudimentary seeker-head that is tuned to “see” the remote targeting radar’s reflected energy, simply recognizes and homes in on the radar energy reflecting from the “painted” target until impact or on-board fusing is triggered. 

This simple, proven, and robust form of targeting would require that a secondary source, in this case a HALE/BAMS UAV, equipped with a powerful radar, paint the target for the attacking warhead during it’s final moments of an attack. Using high-powered, yet compact, AESA or even ESA technology, where a fine yet very powerful energy beam can be pinpointed on a target from a great distance, would allow for such a system to work efficiently. 

Further, the powerful radar toting UAV would only have to “paint” a target continuously for a very short period of time, just mere seconds as the warhead makes its final approach at hypersonic speeds. Once the attack is complete the targeting UAV can go “emissions silent” and change its course to escape reprisal, although it would be most likely outside even an American flotilla’s engagement range in the first place. 

Further, if China can repackage systems derived from the Sentinel’s hardware for such a task info a similar stealthy airframe, it would allow the craft to even closer to an American flotilla. Even if the targeting UAV was subsequently shot down by what is left of a Carrier Strike Group after a massive DF-21D barrage, it would be a tiny price to pay for what would be the most successful maritime strike in some 70 years.

Out of the targeting possibilities listed above, eventually, in around a decade or so, we may see the DF-21D equipped with a varying array of such terminal targeting concepts in order to increase the probability of success when firing a volley against a known enemy surface combatant. In effect, this would make it tougher for the targeted vessel to know how such an attack was being prosecuted against them. 

Further, the use of multiple terminal homing methods would severely complicate the fielding of countermeasures, such as flares or directional infra-red “blinding” devices for IR homing equipped warheads, or chaff and jamming for warheads equipped with radar homing seekers. 

In the end, low probability of intercept data links, both for UAV operation and to target the missile initially, as well as it’s warhead during it’s terminal phase of flight, would be the “holy grail” of such a weapon system, as it would be very hard to decoy or confuse. At that point only active “hit to kill” or laser based defensive weaponry would be able to fend off such an attack, which may be effective against a few inbound DF-21Ds on a good day, but futile against a massive barrage.


Long-range targeting utilizing semi-autonomous Broad Area Maritime Surveillance (BAMS) High Altitude Long Endurance (HALE) UAVs, equipped with Low-Probability Of Intercept (LPI) data links and high power, high-resolution scanned array radars would no doubt be the ultimate enabler and force multiplier that would allow the Chinese DF-21D anti-ship ballistic missile to reach its full potential. 

With the recent loss of a state of the art US drone that was almost certainly equipped with all the components listed above, the Chinese may have been given the massive leap in technology they need, at exactly the right time, to make effective such a dangerous area denial weapon system. 

A system aimed at the very heart of US power projection, its Carrier Strike Groups. With all their power and punch, a US carrier group is only effective when it’s targets are within the range of it’s combat aircraft and it’s cruise missile inventory. An operational DF-21D arsenal, when paired with effective over-the-horizon targeting assistance, denies an American task force useful proximity to the Chinese shore and surrounding seas by a massive margin. 

The need for robust and survivable long range surveillance and targeting is so important to the DF-21D system that I would go as far to say that the RQ-170 scavenged by the Iranians presents such a massive opportunity for the folks in China’s defense apparatus, and such a huge increase in potential risk for the US Navy, that there really is no known precedent. 

In essence, almost the RQ-170′s exact on-board capabilities, even it’s most rudimentary features, may very well have given Chinese weapons designers the invaluable “missing link” they have been in search of to make their prized DF-21D “Carrier Killer” a true operational reality.


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