JF-17 Thunder Multirole Fighter [Thread 5]

[razgriz19]

chinese made probably

what laser guidance do these F-7PG use?

 

[Bilal.]

If i am not wrong but GIDS is being made of ex KRL firms which under KRL were under foriegn sanctions and under GIDS they are not

That's IICS, institute of industrial control systems.

 

[gambit]

Must have something to do with technical aspects. As chinese are using laser proximity fuze in their PL-9 missiles as well as in the latest Pl-5E series missiles which is already in service with PAF and used on JF-17s. A very technical guy may answer that why is one system used on one missile and another system on others.

@gambit

Little help Sir.

Easy...

Laser proximity fusing is based upon laser distance sensor. And we all know the weaknesses of lasers regarding atmospheric phenomenon over distance. Proximity fusing is about the detonation of explosive based upon a perceived distance as calculated by a sensor, be it radar or laser or IR.

The laser have the advantage in accuracy and some designers feels that advantage overrode any atmospheric induced weaknesses, especially when the laser is paired with another sensor that have a wider field-of-view (FOV) than the highly coherent laser beam. That other sensor may be radar or IR. Essentially, that 'other' sensor is the main sensor that will provide the missile with as precise target location as possible, then it is the laser that will provide the fusing system with the distance it needs to detonate. The PL-9 have IR as main, if public information is reliable.

PL-9 - Wikipedia, the free encyclopedia

The missile is fitted with a cryogenic liquid nitrogen gas-cooled IR seeker capable of +/-40 degree off boresight angles.

Inevitably, someone will ask: Why is accuracy in distance so important?

In a highly dynamic two-bodies interception situation, and we are talking about both bodies are maneuverable bodies, not a situation where one body is fixed like a ground based missile silo, we cannot always count on a kinetic kill. So we devised a proximity fusing system where if given enough explosives, the target can be destroyed without our missile even touching it. This led to the reasoning that the closer the missile get to the target, the less explosive is required, and it is sound logic.

What is not in the public domain, as it seems to me anyway, is how the IR sensor and the laser fusing system works together...

1- Does the IR sensor call the laser when target IR intensity reached a certain level?

2- Are both systems active from the moment of weapons release and the laser queue the fusing system when the laser reflector sensor detects a certain level of target reflection?

No. 2 seems rather dangerous since there is always a possibility of some kind of atmospheric <something> that could produce sufficient laser reflection and the missile detonate prematurely.

It is not so much about the type (mission) of the missile that demand the laser. Rather, it is about the designers themselves and how they feel about the concept, which lead to question 3...

3- Reflectivity and how does this affect the perception quotient in order to queue the fusing mechanism?

We know that different materials reflects radar and laser differently. For example...

Reflectance characteristics of selected materials f... [Appl Opt. 1988] - PubMed - NCBI

Abstract

The reflective characteristics of several materials have been examined in an effort to develop a 10.6-microm reflectivity standard for field measurements with laser radars. Measurements on twelve different target materials showed that many materials have components of diffuse reflectivity, specular reflectivity, and retroreflectivity. For each material examined, both the effective Lambertian reflectivity and the beam depolarization were determined. It was also found that because of the strong retroreflection component present with many materials, the practice of estimating the effective diffuse reflectivity from measurements of total reflectivity could lead to erroneous reflectivity values for laser radar systems. One of the preferred reference targets found for 10.6-microm field measurements was canvas tarpaulin.

The surface material could be doped paint to reduce reflectivity and that doping could be deliberate or accidental, meaning the paint was never developed to counter laser distancing sensor but turned out to be highly effective anyway. The designers of the missile that uses the laser must try to take the diverse reflectivity factor into account.

Do not forget flares. Yes, they can affect the laser, which further strengthen my leaning towards no. 1 since flares discharge by the target are usually earlier in the missile's flight in trying to distract/seduce it. Keeping the laser 'silent' until the main sensor reached a certain threshold of target detection and/or successfully negotiated countermeasures make more sense.

Finally, this is not to be equated with laser beamriding...

Systems Help Block Laser Guided Missiles | Systems & Subsystems content from Defense Electronics Magazine

A laser-guided missile consists of six basic sections: the photo sensor (laser seeker) with optical filter, control circuitry, guidance section, fuse, propulsion section, and the warhead with fuse (Fig. 1). Two design topologies are used for laser-guided missiles. In the “beam rider” approach, the missile’s photo sensor detects light emanating from the launch site, such as a ground station or aircraft. The laser beam carries directional data, which the control section interprets to adjust the missile’s steering fins accordingly. In the alternative approach, a missile’s on-board sensors make use of laser-light reflections from a target. The launch vessel beams a laser onto a target and launches the missile, which measures the distance between itself and the target via the on-board sensors. Control circuitry is used to adjust the missile’s navigation equipment for accurate delivery of the payload.

Beamriding missiles generally have kinetic kills as the goal and the laser beam provide the 'pointer' or guide towards the target. In an air-air situation, it is not (yet) possible to have a third party provide constant laser illumination of the target for the missile to latch on to the beam. The PL-9's laser system seems to be of the latter design -- use of target reflections.

 

[Arsalan]

09.. inducted in 2009..
It is an operational aircraft sourced for testing.

so this pretty much confirms that even the BLK-I will be fitted with IFR probes at some stage. Thanks!

 

[SQ8]

so this pretty much confirms that even the BLK-I will be fitted with IFR probes at some stage. Thanks!

All JF-17's essentially have room for growth to include software and hardware improvements. Its modelled after the F-16 and so follows its philosophies.

 

[graphican]

so this pretty much confirms that even the BLK-I will be fitted with IFR probes at some stage. Thanks!

A quick question: does that mean the prototype we saw was for block-I only or the same fixed IFR would be used for block-II as well. A constantly visible (fixed) IFT contributes to RCS and as we are improving block-II on avionics, weight-carrying capacity etc, one may think it would also improve on RCS.

What is your learning on that?

 

[Dazzler]

A quick question: does that mean the prototype we saw was for block-I only or the same fixed IFR would be used for block-II as well. A constantly visible (fixed) IFT contributes to RCS and as we are improving block-II on avionics, weight-carrying capacity etc, one may think it would also improve on RCS.

What is your learning on that?

blk 2 will have a fixed IFR, there is not enough room for a retrectable IFR, no light/medium fighter can accommodate it hence the fixed IFR.

 

[Tempest II]

... ... there is not enough room for a retrectable IFR, no light/medium fighter can accommodate it hence the fixed IFR.

 

[Tacticool]

Why would these rich GCC states be keen?

I think Pakistan is lobbying this time. At least some political maturity is shown.

 

[alimobin memon]

A quick question: does that mean the prototype we saw was for block-I only or the same fixed IFR would be used for block-II as well. A constantly visible (fixed) IFT contributes to RCS and as we are improving block-II on avionics, weight-carrying capacity etc, one may think it would also improve on RCS.

What is your learning on that?

two possibilities
1. Block 1 and 2 have fixed IFR
2. Block 1 Design does not facilitate itegrated IFR so it will have fixed. Block 2 as seen in pac video has some structural changes might have integrated IFR.

 

[nomi007]

Well your thinking doesn't matters as i am well aware that American LGUs / LGBs are very much integrated with F-7P / PGs, and for many years now. China doesn't makes such designed LGU kits nor Pakistan is making Laser Guidance kits. AWC recently started to make Chinese ToT FT series glided bomb kits with INS/Satellite navigation, which you just saw in that Takbir series bomb kits.

kia baat hai ap ki aqal e saleem ki
when did usa give LGUs / LGBs to pakistan

 

[Donatello]

kia baat hai ap ki aqal e saleem ki
when did usa give LGUs / LGBs to pakistan

I think he meant the JDAM kits for 1000/2000lb bombs, which are an improvement over laser guided ordnance.

GPS-INS type navigation seems to have an advantage as the aircraft can release these at a stand-off distance, rather than waiting for laser guidance from the aircraft, which can be hindered during bad weather.

 

[nomi007]

I think he meant the JDAM kits for 1000/2000lb bombs, which are an improvement over laser guided ordnance.

GPS-INS type navigation seems to have an advantage as the aircraft can release these at a stand-off distance, rather than waiting for laser guidance from the aircraft, which can be hindered during bad weather.

bro usa never allows us to modified or even to install our equipments on their aircrafts

 

[Donatello]

I believe the Mirage/F-7 used Aim-9 Sidewinders on them.

But yes, you are right. For that reason, Pakistan is moving away from USA towards China.

The only option left in the west is Europe. But they have limited offering and at times, expensive.

 

[Tempest II]

kia baat hai ap ki aqal e saleem ki
when did usa give LGUs / LGBs to pakistan

Here is some news and I don't think these were tthe first: Press Releases and Communiques - Dec 2007

Raytheon Wins $161M Paveway Contract for Pakistan