Gambit
From your last post one may assume that given enough testing time, the DF-21D may become a more effective weapon(if the guidance issues which do seem formidable can be sorted out) than a Brahmos.
I do not intend to call it superior as to me these are still apples and oranges.. but when I say more effective I refer to a perfected(if such a term may apply) DF-21D with a unitary warhead being more effective than a Brahmos at killing a carrier.
However.. compared to a carrier, a Arleigh Burke may not be such an easy target for a DF-21D as it would be for a Brahmos.
From a sensor perspective, if I was instructed by the customer to focus in on the sensory perception, radar or IR, of an 'aircraft carrier' type signature, it would be an easy task -- for me. The physical dimensions of this ship poses no credible challenges once its sensor characteristics, radar or IR, is produced and acquired.
For the guidance engineer, the technical hurdles are enormous, sensor target and flight controls inputs updates are real time dynamic variables whose compensatory methods, from said guidance engineer, cannot trespass the millisecond barrier, in other words, whatever his methods are to compensate for weather phenomenon that may block the sensor's view of the target or that the flight controls system detected a course deviation, they must be within milliseconds of receiving those variables. Target updates can be one millisecond or one hour and it does not matter, his methods must process each update within milliseconds and send the appropriate commands to the flight controls within milliseconds. Flight controls do not have that luxury, to keep the vehicle in stable flight, the FLCS system must monitor air data, gyros, accelerometers, and surface deflections and positions, at all time. If there is a course deviation detected, and there will be, the FLCS system must query the guidance section for instructions, the guidance engineer's methods must respond within milliseconds.
For the flight controls system engineer, his problems are equally enormous because he must deal with mechanical variables, such as materials and manufacturing defects. Those variables inevitably exists and will introduce system noise, which can give erroneous data regarding the flight control status itself, which in turn will query the guidance section for instructions, which can give compensatory instructions that will fail the mission. The problem here is that because the guidance section have no way of telling if the query for instructions is valid or not, the guidance engineer
MUST have complete trust that whatever query he receive it is a valid one, hence his methods will automatically assume that
ALL queries are valid.
From a system engineering perspective, we cannot have Sensor, Guidance, and FLCS second guessing each other. That would create chaos within the system. FLCS and guidance engineers work much more closely with each other than with Sensor, often times a person may be both, not merely work on/with both, if he is talented enough. Sensor provide the mission goal, so to speak, and everyone else must work to accommodate that mission. Guidance and FLCS must have complete trust that the goal provided is a valid one and that is why a missile can be misled by decoys. It is Sensor's responsibility to discriminate between the true and the false.
The above technical hurdles are applicable to all weapons systems, be it missiles or dropped 'stupid' bombs. They only differ in terms of complexity.
In a ballistic approach to the target, speed is a 'one-way' variable in the sense that since gravity is the source of motion, any loss in speed cannot be regained. Closing speed compensation algorithms need not and are not as sophisticated as when speed can be 'throttled' or is 'two-way'. A thought to consider: Given the high speed approach of the ballistic method, the system will have very limited time to compensate for any corrections required. So from this perspective, is it really necessary to have as capable a sensor/guidance/FLCS integration as thought? No.
However, when the customer's requirement is that we are using a non-nuclear explosion to destroy an already difficult target, then said integration must adapt some of the complexity level of if speed is a 'two-way' variable because we must attempt to have 100% successful impact in every missile launch. Unlike a fixed land target, sensor target updates of this moving object must increase. The guidance section is now receiving more course deviations information from sensor and must send appropriate compensatory commands to FLCS to correct the flight path, and given the high closing speed between warhead and target, course corrections must have near instantaneous response.
There are two reasons why we must have a 'near instantaneous response' capability:
- High closing speed between two objects.
- Short distance between two objects.
Both situations give us 'compressed response' time.
GBU-12 Paveway II - Wikipedia, the free encyclopedia
Paveway II laser guided bombs use what is known as "bang bang" guidance. This means the bomb's fins deflect fully, rather than proportionally when it is attempting to guide to the laser spot. For example, if it sees the laser spot and determines that it should make a change it deflects its fins until it has over-corrected and then it deflects back the opposite direction creating a sinusoidal type of flight path. This type of guidance may be less efficient at times.
The Paveway bomb uses bang-bang guidance because of the 'short distance' situation. I am very confident that the DF-21D guidance system uses bang-bang guidance because of the high speed situation, not entirely like the Paveway bomb but as part of a composite guidance system. The bang-bang guidance method require a very tough FLCS but that does not mean it must be durable. This is meant to destroy itself, after all, so what is there the need to have durable mechanical devices. They just need to be tough enough to withstand extreme stresses in their short time of existence.
The situation is different for the cruise missile. Even though both ballistic and cruise missiles are technically 'aircrafts' the latter is more so. Its speed variable is 'two-way' in that if it must maneuver due to terrain, its speed will be lost and regained when the FLCC throttles up again. Its sensor/guidance/FLCS integration algorithms will inevitably be more sophisticated. Its FLCS must be both tough and durable for mechanical devices, especially if the weapon is designed to compensate for decoys because it must ignore the deception if it recognized such and to try to reacquire the true target. The ballistic approach does not allow this capability.
Efficacy - Wikipedia, the free encyclopedia
Efficacy is the capacity to produce an effect.
So how does all this mumbo-jumbo related to 'efficacy', which is to stop an aircraft carrier from producing attack aircrafts? It is well known that given time, we can correct for errors, which includes deceptions. The subsonic approach give us that capability, at the cost of time, of course.
gulfnews : Tomahawk cruise missile used for long-distance precision strikes
Radar detection of a flying Tomahawk, whose range could exceed 2,500 kilometres is difficult because of the missile's small radar cross-section and low altitude flight.
That is the intended distance for the DF-21D so distance is not an issue for the cruise missile design itself, be it the Tomahawk or the Brahmos models.
To date, despite what the Chinese members here may say, there is no credible data on the success of the ballistic approach to destroy a moving target, even one as slow moving like a ship, whereas for the cruise missile, from the early Exocet to the more sophisticated later Tomahawk, we have plenty of data of these weapons' ability to acquire moving target.
So if we define 'efficacy' here as to stop an aircraft carrier from producing aircrafts, then the DF-21D will take the seat
PROVIDED that it must have at least comparable successes in hitting its targets as the cruise missile design. The impact of
ONE unitary warhead will force an aircraft carrier to at least have a long respite if not complete cessation of air operations.
But if we define 'efficacy' here as to hit a ship, be it the large aircraft carrier or the smaller destroyer type, then given what we know of missile guidance technology, see 'mumbo-jumbo' above, and cruise missile successes, then the Brahmos must be given priority. Some opinions I have heard is that the Indians have given that capability more hoopla than it deserve, however, when taken into tactical situations such as proximity to an adversary, as in 'next door neighbor' type, that Mach capability will be more valuable in the long run. The Brahmos is a more flexible weapon than the DF-21D but at the cost of immediate potency upon hitting a target.
Going back to the first paragraph...
From a sensor perspective, if I was instructed by the customer to detect as wide a range of 'ship type' sensory perceptions, radar or IR, as possible, from an aircraft carrier to a cruiser to a dingy, the task would have much greater difficulty but still quite 'doable'. We already can do that. But once I handed off these signals to Guidance and FLCS, the burden of making the concept into a workable weapon falls upon them. The reverse applies to me as well. If Guidance and FLCS present to everyone the successful response required regardless of Sensor inputs, hypothetical or real, then the burden falls upon me to provide the final piece to produce a working weapon.