Babur Cruise Missile - Database

[Zarvan]

We haven't test Babur for really long time hope to see long range version and also Naval Version.

 

[amardeep mishra]

Check PAC and AERO websites. Pakistan produces various types of radar altimeters. No need to set your self up for failure by starting every thing from scratch like DRDO

Hi there!
Dont you think it is always wise do to your background research before writing any comment? Dont you think one should first be READY TO LEARN and what is happening elsewhere! In case you,got you never read any research literature from DRDO ,i would gladly post them here- have got many of them!

But both Babur and Raad are fitted with 2d/3d pitot tubes. Your article does not cover working and purpose of pitot tubes in missile.

@shaheenmissile
Hi there!
I did not include pitots because they are very very simple devices that are used to measure "STAGNATING PRESSURE"(and that stagnating pressure is compared with static pressure buildup at close to the tip to get a measure of "velocity"). Pitot tube is like the very first thing any control engineer studies in his course(We studied that pretty much in the beginning of our course- 3rd semesters)- anyway,since you have asked about it,i will explain that in DETAIL!

 

[Bossman]

Hi there!
Dont you think it is always wise do to your background research before writing any comment? Dont you think one should first be READY TO LEARN and what is happening elsewhere! In case you,got you never read any research literature from DRDO ,i would gladly post them here- have got many of them!


!

Are you a retard or what. This is a website and you are dealing with anonymous people and not trying to defend your Phd. thesis. Why should I research before I write, I know DRDO is total failure. I have listed their failures many time before and that is what India is the biggest weapons importer in the world. It does not even have a domestic primary trainer in service. Weren't you the one talking about how great DRDO is because it can bake epoxy or something? Baking epoxy will not defend your country

 

[AUz]

Babur II with 1500km range on our submarines would give Pakistan a very lethal strike capability....

 

[amardeep mishra]

@shaheenmissile

Here i will briefly explain the pitots and how they are typically employed for velocity measurement-
As you can clearly see in the pictures,the pressure at the tip of the pitot is known as stagnant pressure and the velocity of air at this junction is zero.Static pressure taps are located around the circumference of the tube to obtain the static pressure reading.These two pressures are fed to manometer type system to provide the differential pressure- it is the differential pressure we are interested in,because the velocity is a function of square root of differential pressure and is given by the expression-
v= SQRT(2*(differential pressure)/rho)
When pitots are used in missiles and aircrafts the static pressure reading can be used to measure the altitude- if altitude is to be measured with an error of say 30m ,then the static pressure must be accurate to 0.5%! But here is a catch that most of the people tend to ignore while talking about pitots in relation to missiles and aircrafts and that is the pitot is SUSCEPTIBLE to misalignment as the missile's angle of attack changes this is known as "mis-alignment of tube axis with velocity vector"
There is also an elegant solution to this problem- and that is achieved by having static pressure taps aligned at +/-37.5 degrees with the axis makes it independent of the angle of attack(AoA is nothing but the angle subtended by velocity vector or velocity of air with tube axis) alpha in the range from -2 to 12 degrees!While this method is only effective for alpha ranging between -2 to 12 degrees,a more flexible approach is by designing single vane(rotating type) that adjusts the static taps in +/-37.5 degrees with respect to the velocity vector.
Till now i have assumed the velocity to be confined in only one plane,but what if velocity vector changes plane with changing pitch and yaw of aircraft or even otherwise?what do we do then?- here is the solution
The solution lies in making a "multi-vane(usually a 5-tap sensor)" pitot mounted on a gimbal system is used(first pioneered in american X-15) that provide complete rotational freedom to adjust the static taps with respect to cross flow vector.By measuring the rotation of gimbals,these systems can also determine the direction of velocity!

Determination of AoA and yaw onboard flight vehicles is often accomplished by "vane type probes".These devices are essentially one or two axis weather vanes with suitable damping to reduce oscillations and with motion pick-ups to provide electrical angle signals.Agin gimbaled is best suited for high velocity/high alt applications as it has a gimbal that automatically align itself based on error signal generated by differential pressure P1-P2 and P3-P4(5-tap sensor)

When a pitot is employed in an incompressible fluid,the above eqn that i have mentioned doesnt hold good(although it may be sufficiently accurate if the mach numbers are low- i.e for subsonic regime).
For supersonic regime though where(N>1),a compression shock wave forms ahead of the pitot tube.Between this shock wave and the tube end,the velocity is subsonic.This subsonic velocity is the reduced to zero at the stagnation point. And the differential pressure is now given by a complex formula-
Dp= N^2{(k+1)/2)^(k/(k-1))}*[(2kN-k+1)/((N^2)(k+1)))]^(1-1/(k-1)
Where N is the mach number and k is the ratio of specific heat at constant pressure to specific heat at constant volume!

Picture Courtesy- "Measurement systems application and design"- Ernst doeblin| dhanesh n Manik

 

[Bossman]

@shaheenmissile

Here i will briefly explain the pitots and how they are typically employed for velocity measurement-
As you can clearly see in the pictures,the pressure at the tip of the pitot is known as static pressure and the velocity at the junction is zero.Static pressure taps are located around the circumference of the tube to obtain the static pressure reading.These two pressures are fed to manometer type system to provide the differential pressure- it is the differential pressure we are interested in,because the velocity is a function of square root of differential pressure and is given by the expression-
v= SQRT(2*(differential pressure)/rho)
When pitots are used in missiles and aircrafts the static pressure reading can be used to measure the altitude- if altitude is to be measured with an error of say 30m ,then the static pressure must be accurate to 0.5%! But here is a catch that most of the people tend to ignore while talking about pitots in relation to missiles and aircrafts and that is the pitot is SUSCEPTIBLE to misalignment as the missile's angle of attack changes this is known as "mis-alignment of tube axis with velocity vector"
There is also an elegant solution to this problem- and that is achieved by having static pressure taps aligned at +/-37.5 degrees with the axis makes it independent of the angle of attack alpha in the range from -2 to 12 degrees!While this method is only effective for alpha ranging between -2 to 12 degrees,a more flexible approach is by designing single vane(rotating type) that adjusts the static taps in +/-37.5 degrees with respect to the cross flow vector.IN modern times though "multi-vane" pitot mounted on a gimbal system is used(first pioneered in american X-15) that provide complete rotational freedom to adjust the static taps with respect to cross flow vector.By measuring the rotation of gimbals,these systems can also determine the direction of velocity!

Determination of AoA and yaw onboard flight vehicles is often accomplished by "vane type probes".These devices are essentially one or two axis weather vanes with suitable damping to reduce oscillations and with motion pick-ups to provide electrical angle signals.Agin gimbaled is best suited for high velocity/high alt applications as it has a gimbal that automatically align itself based on error signal generated by differential pressure P1-P2 and P3-P4(5-tap sensor)

When a pitot is employed in an incompressible fluid,the above eqn that i have mentioned doesnt hold good(although it may be sufficiently accurate if the mach numbers are low- i.e for subsonic regime).
For supersonic regime though where(N>1),a compression shock wave forms ahead of the pitot tube.Between this shock wave and the tube end,the velocity is subsonic.This subsonic velocity is the reduced to zero at the stagnation point. And the differential pressure is now given by a complex formula-
Dp= N^2{(k+1)/2)^(k/(k-1))}*[(2kN-k+1)/((N^2)(k+1)))]^(1-1/(k-1)
Where N is the mach number and k is the ratio of specific heat at constant pressure to specific heat at constant volume!

View attachment 178956

Thanks for your cut and paste job. Who are you trying to impress? I think you have some very deep rooted insecurities or I would say lack of education that you are trying to compensate for.

 

[amardeep mishra]

Thanks for your cut and paste job. Who are you trying to impress? I think you have some very deep rooted insecurities or I would say lack of education that you are trying to compensate for.

Oh really?you have no idea about my experience or my qualifications,and yet you talk like that- impressive!

Yes indeed the picture has been taken from "Measurement systems application and design"- Ernst doeblin| dhanesh n Manik,However the description is all mine- i still dont understand your point- either way,i am not going to reply to your posts any longer because of the simple reason that you seem to be oblivious to industrial research taking place in india and insulting my intelligence
If you care to read my explanation ,no where have i mentioned that the pics are mine- in fact have given due credit to the author as well

 

[Bossman]

Oh really?you have no idea about my experience or my qualifications,and yet you talk like that- impressive!

Yes indeed the picture has been taken from "Measurement systems application and design"- Ernst doeblin| dhanesh n Manik,However the description is all mine- i still dont understand your point- either way,i am not going to reply to your posts any longer because of the simple reason that you seem to be oblivious to industrial research taking place in india and insulting my intelligence
If you care to read my explanation ,no where have i mentioned that the pics are mine- in fact have given due credit to the author as well

Obviously I don't know your experience and qualifications and that is my point in the first place. Who are you trying to impress? The person you are exchanging messages with on this board might be 12 year old kid and there are many. As far as industrial research in India is concerned, I have not doubt that it is taking place but it doesn't seems to be contributing significantly to the country's defense. It is attitude of people like you who are responsible for the problem. They are taking a lot of pride in undertaking esoteric academic research but they cannot translate it into operational defense products. Every major Indian defense project has been a failure. You are even importing small arms ammunition.

 

[shaheenmissile]

@amardeep mishra have a look at this pic of Raad ALCM. What can you say about these "Appendages".

 

[amardeep mishra]

have a look at this pic of Raad ALCM. What can you say about these "Appendages"

Hi @shaheenmissile
That seems to be some sort of wind vane for velocity/angle of attack(AoA is basically the angle subtended between the wind velocity vector and zero lift line) measurement. It works on the same principle as i have mentioned above(i.e differential pressure method).However in certain cases,ANEMOMETER type sensing instrument is used to measure the flow.(Anemometers work by loss of heat due to convection~higher the loss higher will be the flow of fluid around the hot wire).Normally "constant current" type anemometers are preferred over "constant temperature" type.
Btw,i have composed a detailed analysis of TERCOM guidance,in case anyone is interested,i can post it here!

 

[Jungibaaz]

Hi @shaheenmissile
That seems to be some sort of wind vane for velocity/angle of attack(AoA is basically the angle subtended between the wind velocity vector and zero lift line) measurement.

That's exactly what it is.

@amardeep mishra have a look at this pic of Raad ALCM. What can you say about these "Appendages".

 

[amardeep mishra]

@shaheenmissile

The equation for Anemometer type sensors for velocity/flow measurement is-
(i^2)*R=hA(Tx-Ty)
and h=a+b*sqrt(v)

Where i = current through the wire
R= Resistance of the filament
A=Area
Tx-Ty= difference in temperature between fluid and the filament
h=film coefficient of heat transfer which is a function of fluid velocity

Here i'd like to point out that from a purely industrial application perspective a normal anemometer type sensor cant be directly installed on an aircraft as the reading of anemoemter is inherently non-linear as can be seen from the equation above.Hence there is a need to linearize the circuit by placing it in the feedback path of a op-amp.Or by using software algorithms that take int account the non-linear equation

 

[Bratva]

Babur stats board in Ideas 2008

 

[Indus Falcon]

Any updates on Babur2 and Babur Sub launched version?

@Horus @Rashid Mahmood

 

[Kurlang]

@The Deterrent
@Oscar

We all very well know the importance of INS+GPS package for guidance of missiles.I will begin my analysis from briefly describing the INS+GPS and then eventually building on TERCOM and DASMAC guidance schemes. I have certain reservations regarding pakistani access to accurate maps- but i am guessing china would provide these to pakistan?
There are Two GPS/INS integration approaches commonly used. These are

(a) the tightly coupled integration approach, which yields higher accuracies; and
(b)the loosely coupled integration approach used for short time and/or ranges,yielding lower accuracies
Normally the GPS receiver of the missile is interfaced with
(1)altimeter
(2)flight control system,
(3)the INS’s serial/digital interface,
(4) and the carrier aircraft/launching platform

The navigator (i.e., dynamic navigation equations), consisting of a 15-state Kalman filter(in case anyone of you want an elaborate analysis of how KALMAN filters are used to fine tune/filter various sensor outputs,i can provide an indepth analysis as well- for more advanced readers- Amardeep Mishra), is normally updated by the onboard navigation computer every 50 milliseconds (or a 20-Hz rate),while the GPS is updated at1-Hz rate.The GPS will normally consist of a 8-state Kalman filter,so that both the INS and GPS Kalman filters operate in a cascaded mode.Inertial aiding provided to the GPS receiver- tracking loop is at a 10-Hz rate. (Note that the INS is of the strap down class. Thus,the basic strap-down INS algorithms that maintain the body-to-level-axis transformation matrix and transform the body-axis velocity increments to a locally level coordinate frame can be performed at a rate of 50 Hz, while the basic INS algorithms can be performed at an iteration rate of 10 Hz.).

A significant characteristic of the ALCM is the high accuracy at long missile ranges provided by its terrain correlation updated navigation system. In order to implement a terrain correlation updated navigation system, reference terrain elevations must be stored in the missile’s computer prior to launch.This elevation data must be gathered, stored in ground computers, precisely selected for each mission, stored in the carrier aircraft, and transmitted to the missile prior to launch. More specifically, the missile’s navigation and guidance unit uses a terrain contour matching (TERCOM) system that periodically updates the missile’s inertial navigation system by comparing terrain over which the missile flies with stored mapping data.

Now here is the trouble,where does pakistan sources,such an "elevation data"?In USA's case,this data is collected by Defense Mapping Agency-Aerospace Center (DMAAC).In india's case this data is gathered by most probably the RISATs in orbit(more preferabbly by RISAT-2 that has an x-band AESA SAR that can map very very accurately)
View attachment 178759

The above figure shows visually the steps involved in planning a test mission from launch
point (Point 0) to the target (Point 6). The planner first selects a path from launch to the target in the horizontal plane that passes through the required maps (maps 1 and 3, in the example). In the horizontal plane selection, the mission planner takes into account the terrain over which the missile will fly,special test objectives,and distance between maps. The mission planner has two ALCM simulation tools (or modules) available to aid him in planning missions. These are
(a) the clobber analysis module
(CAM), and
(b) the navigation accuracy module (NAM)

Both these programs reside in a ground-based computer. CAM provides the capability to the mission planner to compute either probability of ground clobber given a specified ground clearance, or ground clearance given a specified probability of clobber. CAM can operate in a rapid mode or a slower mode that provides more detailed results. NAM predicts accuracy and map crossing probabilities along the route of the mission from launch to target. Each of the horizontal maneuvers or any missile mode or speed change requires a missile waypoint. A waypoint is defined as an action point.
The vertical profile is then selected. Here again, a waypoint is needed for each vertical change either in terrain following or barometric hold. Once the mission is selected and all way point and maps defined,the defined mission is inputed to the mission data preparation system

Firstly, I really liked your avatar as it reminds me of the polar & spherical coordinate system I studied long long time ago in the course of electromagnetic theory. You talked about the controls system and application of adaptive signal processing however it is a defense form, I think people would not appreciate your efforts - though they should.

At least i do appreciate your effort.