Well, the problem has to do with our aziz hamwatano and general issue with education system. As in the need to ask without researching the topic just a wee bit So I wont have a coronary at this since it is the same situation as someone who came to class on the first day and asks a rather "coronary" question.
I can relate since in the 6th grade I was too interested in Dinos and in anticipation of history class in that year drew a wonderful T-rex on my Journal. Only to be ridiculed by the teacher who asked if it was Babur or Humayun(damn that woman to the gates of hell) and me feeling rather embarrassed about it and upset that my rather realisitic T-rex was going unnoticed.
The question is not illegitimate and the member is not wrong(or stupid) in asking it so lets not deride that. After all, it is long, pointy and has a rocket motor attached to it which makes it go fast. So as such(like many systems) it does have good potential to become something more than it already is.
To answer it , I am also going to follow the lead of Mastercard Adverts and post prices to things as they happen based on Pakistan specific costs vis-a-vis materials and Labor(along with time). These costs are not mutually exclusive except for time perhaps.
Lets get to the guidance bit later.
While the nasr is manoeuvrable as compared to the other missiles in our arsenal , it is not in any shape to chase after or move around quick enough when hunting aircraft(or ballistic missiles for that matter). As the NASR is currently built for Range and less quick acceleration and speed. As its motor isnt the best in the world and has a generally low specific impulse( simplest to understand as mileage.. as in "Kitnay deti hai"); any tradeoff for greater thrust and acceleration will lead to an adverse effect on range.
As the range on the NASR is already 60-65km at best, that means that with the current motor the maximum it can chase a head on target is around 50km and barely 15km in a tail on chase. Which means that the NASR will need a bigger motor. That could be achieved by adding boosters or changing the primary propulsion system to a better motor or even hybrid rocket/ramjet. That will change the weight, the way the missile behaves and flies which will mean testing of the motor on the ground and in flight.
R&D costs for Changing propulsion: $25 - 35 million, 24 -46 months
Now that we have a better propulsion system that as a benchmark scenario has the same range overall as the NASR at average and can go to 70KM at max. We need to make NASR capable of rapid and accurate changes in direction. Currently, it can make rapid changes somewhat but not exactly accurate. Now I know that Pakistan already has thrust vectoring figured out that compares to Russian tech in the late 1970s that is mated with rather modern processing. So we'll assume those costs are ignored. But a missile like the NASR still needs to have that system adapted for it; this means redesigning the system.
R&D for adapted T/V and additional control system: $15-30 million. 24-48 Months
Guidance and Associated Radar system:
This is the heart of the system. A radar to detect and track targets, and another(or the same) to guide them. The Radar will have to be modern.
To be continued...