The curious case of Nasr's terminal guidance

[CriticalThought]

sorry ...??? am not getting your point ....

Inertial navigation is for guidance how it could limit the range ...???

Because it's not accurate at larger range. You wouldn't see that pin point accuracy. But if you are willing to trade accuracy, then there should be no problems if something else doesn't present a limit.

 

[HRK]

Because it's not accurate at larger range. You wouldn't see that pin point accuracy. But if you are willing to trade accuracy, then there should be no problems if something else doesn't present a limit.

IF I am not wrong Beidou is already incorporated with NASR, so what you are suggesting must not be the reason for relatively short range of NASR as compare to other 400 mm artillery rockets and missiles

 

[Safriz]

Because it's not accurate at larger range. You wouldn't see that pin point accuracy. But if you are willing to trade accuracy, then there should be no problems if something else doesn't present a limit.

Those days are gone when mechanical gyroscopes were used for internal navigation and induced large errors
Now with electronic gyros the accuracy is far better

 

[CriticalThought]

IF I am not wrong Beidou is already incorporated with NASR, so what you are suggesting must not be the reason for relatively short range of NASR as compare to other 400 mm artillery rockets and missiles

Do you have a reference for that?

 

[Osiris]

Why so much hype over a missile, which in essence is a Multi barrel guided rocket with just 70 Km range. I believe even A100 outranges Nasr

It would be much greater achievement, if Pakistan were to successfully test the tactical nuke(design of which has never been tested btw) it is suppose to carry.

Because without that tactical nuke, Nasr just another short legged, guided rocket, with very a mediocre payload capacity, Pakistan has better missiles.

 

[Safriz]

thnx ....

39 cm it mean we can assume it + 400 mm (I am more inclined towards 400 mm )
if its length is + 7000 mm
If its warhead weight either >200 or <250 kg
and total weight is around + 1,200 kg

than the question arise why Nasr missile have such less range .... ???

We need to look at the role Nasr is supposed to play.
It's a weapon system designed to be used when Pakistani forces are on the back foot and Indians are advancing and Pakistani military has no means to stop the advancing enemy forces .
So
It's not MLRS and is not supposed to do MLRS job. It's job is to reliability punch a hole in Indian advancing columns who have the upper hand and have access to all sorts of offensive and defensive weaponry .
While Pakistani forces are being pummelled and out of oppositions.

I'm that scenario you need a very reliable weapon which can dodge enemy defenses and cause fairly larger scale damage
In my opinion nasr is pre programmed to make multiple trajectory changes during the flight so that the enemy radar cannot reliability track it and cannot predict its position in the next few tens of seconds for successful interception by a BMD.
However doing so costs kinetic energy which is the only force keeping nasr airborne . The burnout time of the weapon as per my observations is about 10 seconds and there is no power source to propel the missile after that and has to use the kinetic energy. The MLRS follows a parabolic trajectory which is an efficient way of using the kinetic energy from burnt out rocket fuel to get to maximum range. But nasr loses energy while making the multiple in-flight maneuvering Hence low range but very high reliability.
Range does not matter in the scenario in which nasr will be used as in that scenario out armed forces will be fighting a losing battle and enemy will be already close by .
Nasr will be the last ditch effort to punch a hole in enemy lines get behind them Cut off supplies and attack from behind and try to turn the tables
At that time Pakistan will already be on the way of losing the battle and in response to using nasr if India starts an all out nuclear exchange It won't matter for us as we would be already on the way to our doom.
With a tactical nuke mounted on nasr Pakistan will cause an air burst of high energy neutrons covering an area of 2-3 square kilometers per missile mainly disabling Indian ability to advance any further

 

[hussain0216]

Why so much hype over a missile, which in essence is a Multi barrel guided rocket with just 70 Km range. I believe even A100 outranges Nasr

It would be much greater achievement, if Pakistan were to successfully test the tactical nuke(design of which has never been tested btw) it is suppose to carry.

Because without that tactical nuke, Nasr just another short legged, guided rocket, with very a mediocre payload capacity, Pakistan has better missiles.

Alot of work has gone into this and the full strategic nature of the missile has not been revealed

As you say it MAY APPEAR Pakistan has much better missile options
But you wouldnt repeatedly test and fire test and fire a simple 70km rocket

It figures this system is very potent and Pak has alot if tricks up its sleeve

 

[CriticalThought]

Those days are gone when mechanical gyroscopes were used for internal navigation and induced large errors
Now with electronic gyros the accuracy is far better

It would be cost/benefit tradeoff. A very precise RLG would increase the cost and also require higher frequency timing signal to be supplied, which would put design requirements on the rest of the system.

 

[Safriz]

The "Bulls

It would be cost/benefit tradeoff. A very precise RLG would increase the cost and also require higher frequency timing signal to be supplied, which would put design requirements on the rest of the system.

Rlg is not the only thing There are other ways of achieving reliable and accurate gyroscope inputs. Look at your phone It has no RLG but can detect any changes in directions by other types of sensors.
Now where is @amardeep mishra

 

[CriticalThought]

The "Bulls

Rlh is not the only thing There are other ways of achieving reliable and accurate gyroscope inputs. Look at your phone It has no RLG but can detect any changes in directions by other types of sensors.
Now where is @amardeep mishra

Well my phone cost around $400/- and doesn't have military grade technology in it. Military grade equipment needs to pass very high criteria, such as sustaining shocks of 22G, being able to work at wide altitude ranges, similarly temperature ranges etc. We can't compare the mobile phone with Nasr.

That said, what I have stated remains speculation on my part.

 

[Safriz]

Well my phone cost around $400/- and doesn't have military grade technology in it. Military grade equipment needs to pass very high criteria, such as sustaining shocks of 22G, being able to work at wide altitude ranges, similarly temperature ranges etc. We can't compare the mobile phone with Nasr.

That said, what I have stated remains speculation on my part.

Yup Speculation it is.
Same as all of us.

 

[FuturePAF]

Maybe the warhead weight is also higher than what would be preferred, and therefore a limited range.
Secondly; maybe the warhead tech is just right, but the SPD wants a higher yield warhead and is ok with a higher weight to get that higher yield. So not the 5 kt up limit, but a regular warhead put in a smaller tactical system.

The missile also needs to maneuver around enemy defenses to ensure it reaches the target, so adding all the elements up, so get a 400 mm diameter and a 7 meter length; if earlier posts are accurate.

 

[amardeep mishra]

The "Bulls

Rlg is not the only thing There are other ways of achieving reliable and accurate gyroscope inputs. Look at your phone It has no RLG but can detect any changes in directions by other types of sensors.
Now where is @amardeep mishra

Hi,
Gyros are known to have inherent drift as accelerometers have inherent spikyness(over sensitive). Most phones have MEMS based gyros. MEMS based gyros (rate gyro or the rate integrating gyro) have compact footprint however they too are prone to certain finite drifts (measured in degrees per hour of operation) . I've played a lot with MEMS based gyro- written my own kalman/extended kalman codes in python for implementation on raspberry pi based autopilots. Now the reason why you dont see the drift in values in your phone is because you dont continuously operate it for long duration of time. It accumulates error much faster than you think-- thanks to it's drift bias.
The best gyros used for such applications(missiles) are either RLG or FOG (Some of the RLG and FOG designed here are)

. FOGs generally are better and hence more difficult to construct. They have very small drifts and are typically the choice for a lot of weapon systems. You can extract p, q, r, phi, theta, psi from a rate gyro (actually for psi or yaw you'd need a good magnetometer). You can further design an observer to estimate V, alpha and beta. One can use various guidance schemes to implement - if you're using PN guidance then you might not need a GPS however if you're using look ahead schemes then GPS would be requires. The guidance generally kicks in when the missile has reached apogee.
I'll reply to this thread in depth when I have some free time. Rn I'm running late

 

[HRK]

Do you have a reference for that?

no that was the reason I said IF I am not wrong .....

 

[CriticalThought]

no that was the reason I said IF I am not wrong .....

IMHO it would be a bad idea since Nasr would then be prone to jamming and/or spoofing of GPS signals.