Hi
@CriticalThought
I have a paper in AIAA under guidance,navigation and control. So,let me take this opportunity to briefly explain why such a proposition wouldnt really work in real life without
substantial changes. First off, Hypersonic brahmos is still at least 3-5 years away from induction and pakistan has not designed any indigenous MLRS system as of now. KRL one doesnt count as indigenous one.
MLRS usually comes without any guidance, it is fired at a certain trajectory and is expected to hit a portion of land with certain CEP. The job of the rocket is to impart certain velocity to the warhead so that it achieved a particular apogee. More modern systems like the recent improvements made to Indian Pinaka system also incorporates guidance kit which compensates for any errors resulting in much superior CEP figures vis-a-vis simple MLRS.
Now without wasting any time lets discuss why MLRS type weapon wont be able to intercept a hypersonic missile-
1) Lack of any guidance and control scheme--kindly note the control scheme required to compensate for the errors in trajectory is entirely different from control scheme required to implement some sort of PN or
augmented-PN algorithms for target interception. Pakistan would have to design a controller first and prove it in simulations that it works correctly. The state vectors in this case could be [V,\gamma,x,h] for longitudinal plane.
2) Lets just assume that the hypothetical MLRS is steered to a pre-destined point via a command link from the FCR(fire control radar) and itz active seeker kicks in. The control design can be implemented via assuming either a 2D PN or 3D PN law. Traditional linearized approach along with gain scheduling(a kind of adaptation scheme) can be brought to bear to make things easier. However in order to fully exploit the potential one needs to venture out into the rich world of nonlinear controllers. Some of the prominent nonlinear control strategies that are available in literature(for hypersonic vehicles or interceptors) are adaptive sliding mode control, dynamic nonlinear inversion etc.
3) A tail-controlled or BTT(bank to turn) missile is preferred choice to intercept high-g targets. So the natural choice of control surface would be tail! However augmentation with thrust vectoring would result in superior control authority as implemented in latest PDV interceptor. But it would complicate the control system design. In fact in cases where both thrust fraction and tilt angle are available for control, we run into what is known as "non-affine" in control problem.