Iran Military Forum

50 kilograms weight, 20 kilometers altitude MANPAD missile with 3 different photodiode detectors can be built in the future.

The current necessity of Special Forces is to have "high altitude" MANPAD (MAN Portable Air Defense systems)
or infantry portable Anti Aircraft missile.

The missile should be portable both by Special Forces infantry and
by Military Stealth Jeep.

Infantry can deploy MANPAD in trench under Camouflage Net. Stealth Jeep can transport missile between
long destination and shoot it as well.

Currently there are 2 MANPADS that have advanced features such as multiple photodiode detectors.

1) 9K38 "Igla" (SA-18). Russian.
http://en.wikipedia.org/wiki/SA-18_Grouse

It was first built in 1983. And has following characteristics.

Weight of full missile is 10.8 kilograms.
Warhead type is Directed-energy blast fragmentation.
Maximum range is 5,200 meters.
Maximum altitude is 3,500 meters.
Flight speed is 600 m/s average and 800 m/s peak.
 
2 seekers used together: Nitrogen-cooled, Indium antimonide (InSb) and uncooled lead sulfide (PbS).

- Lead Sulfide (PbS) at room temperature detects heat radiation at wavelengths of 1-2.5 micro-meters.

- Indium Antimonide (InSb) at 80 K temperature (cooled by Nihtrogen gas) detects heat radiation at wavelengths of 1–5 micro-meters.

Cost was approximately 60,000 - 80,000 USD.

Note: Mid-wavelength Infrared is radiation at wavelengths of 3-8 micro-meters. That radiation is released by jet engine exaust
plume and much less by super-heated parts of jet engine. 3-5 micro-meters radiation also passes through atmosphere. Making
it detectable through air and water clouds.

So if Jet or Helicopter releases Infrared Flares, Igla missile has 2 photodiode detectors that try to destinguish Flares from
Jet itself. However Igla loses battle against Flares since both Igla's photodiode detectors track target in the same wavelength.
1-5 micro-meters. Igla more likely will be diverted by Flare.

Igla and Chinese QW-2 Vanguard both have 2 photodiode detectors. The rest of missiles available on market use only 1 photodiode
detector. And most currently available on market MANPADs are diverted by Flares.

The only MANPAD that offers invulnerability to Flares is Japanese Type 91, Type 92.

2) Type 91, Type 92. Japanese.
http://en.wikipedia.org/wiki/Type_91_Surface-to-air_missile

It was first built in 1991. And has following characteristics.

Weight of full missile is 15.5 kilograms.
Warhead type is Annular blast fragmentation.
Maximum range is 5,000 meters.
Maximum altitude is 3,500 meters.
Flight speed is 600 m/s peak.

2 seekers used together: an advanced imaging seeker operating in Visual wavelength of 0.4-0.7 micro-meters and Infrared seeker
operating in Infrared wavelengths of 3.5-5.2 micro-meters.

Cost was approximately 145,000 USD.

Note: On launch, the Type 91 missile records the target's image shape and is able to ignore defensive countermeasures such as
Flares.

Type 91's photodiode detectors probably have high resolution. Flares can not divert missile once both Visual and Infrared
photodiode detectors record the image shape of Jet.

Also the picture on Visual photodiode detector is in Visual Spectrum and can not be overwriten by picture of Flare (since Flare is small dot that radiates strongly in Infrared Spectrum). Large picture of Aircraft in Visual Spectrum can not be overwritten by small dot of Flare.

So only Japanese Type-91 MANPAD offeres invulnerability to Flares. I think any future MANPAD should have 2 photodiode detectors
Nightvision and Infrared.


Now what future MANPAD is.

50 kilograms missile that has 20 kilometers altitude and 30 kilometers range. It is possible since missile weight is
increased from 10 kilograms to 50 kilograms.

Guidence of missile is 3 seekers:

1 - Laser photodiode detector (where light dot produced on target by illumination laser is used by missile to center on target).
2 - Nightvision Visual photodiode detector. Each target has image shape in Visual Spectrum.
3 - Infrared photodiode detector (that detects Jet engine plumes and overheated Jet external parts, external turbo-jets).

"Future MANPAD" missile remembers and records Target's image shape received from Nightvision (2) and Infrared (3) photodiode
detectors. So missile is not diverted by Flares mostly due to Nightvision image shape of Target.

Launching tripod has Illumination Laser that is detected by Laser photodiode detector (1). So Soldier can correct missile course by
Illuminating Target with Illumination Laser.

50 kilogram missile is portable and launched by 1 soldier.

Warhead type is Shaped Charge (extremely lethal and can punch through armor of modern Helicopters. Especially armored one.
Like Europian Union Tiger Helicopter. They say it is armored against 23 mm rounds).

In summary: "Future MANPAD" missile is invulnerable to Flares and can be guided by Laser Illumination. Laser Illumination is
required when soldier decides to guide missile by himself (due to any unpredictable reason). Large altitude allows MANPAD
to be used as defence against all kind of Aircrafts (low and high altitude).

Below is pictures of currently the most advanced MANPAD Type-91, MANPAD Type-93 mounted on Jeep (in future it might
be Stealth Jeep) and MANPAD 9K38 Igla and Igla mounted on Jeep.

It is unknown what Laser wavelengths will be used. However there are many Laser types
that can overwrite at least 2 types of Photodiode Detectors at once.

If I would design a system, I would replace the visible wave length diode with a prism and then put an array of diodes in different places behind  the prism.  Then the logic circuit would switch very fast to the next diode that is not saturated.

If Laser Beam has 50 centimeters diameter then it will saturate all Photodiode Detectors in array. Entire prism area will be saturated with large diameter Laser Beam.

See diameter of Tactical High Energy Laser in picture above.

Lasers normally have a limited wave length. A prism will break visible light into separate positions. There is no laser that covers the whole spectrum of visible light.

Laser Beam with large diameter will saturate entire Prism and subsequently all Photodiode Detectors in array.

You are mixing the size of the light source with capability of a prism to separate a light beam. Sun is also a very big source of light but a prism can separate the sun light anyway. The size of the source is not important since the light will enter a very tinny hole and then will be separated.

You need to read some book about light fraction properties. The fraction has nothing to do with the size of the light source. A big prism will make a larger displacement, like rain drops over a huge area that make a large rainbow. The same light source (sun) entering into a tinny prism makes smaller displacement. The displacement of different wavelengths are more dependent on the size of prism and the hole than the size of the light source far away.

Guys this discussion has terrible scientific and technical faults... lots of science fiction in there... somebody with a background will make fun of you ...

I would say get information and designs of the available systems and remove any personal design recommendations....
If you think you have a good idea that all the experts world wide are not using, then please ask why its not being used .. and whats wrong with it

A big prism will make a larger displacement, like rain drops over a huge area that make a large rainbow. The same light source (sun) entering into a tinny prism makes smaller displacement. The displacement of different wavelengths are more dependent on the size of prism and the hole than the size of the light source far away.

On your picture of large diameter Laser Beam hitting the Prism, defracted light saturates half of Photodiode Detectors array.

What is a point of defraction if defracted light also saturates the Photodiode Detectors array like normal light?

What is a point of defraction if defracted light also saturates the Photodiode Detectors array like normal light?

While I think that the idea of a prism is too complicated (other technologies exist) I think I got his idea. A prism will difract light according to its wavelength. The blue will go in a certain direction, the red in another direction, the green color as well, etc.. and since a laser has a specific wavelenght the photodiode would be placed elsewhere in order to avoid the diffracted laser beam. If you know the specific wavelenght that DIRCM/AN/AAQ-24 Nemesis use for its laser you can expect the light to be diffracted toward a specific point and put the photodiode elseqhere. Now I don't know what's the use of a photo diode that receives only the red or blue light (if it's for the visible spectrum and pattern recognition). There seems to be prims that work with IR as well ( http://www.audioplex.com/IRPrism.htm ) but I don't know how it works for the moment.

The seeker however is an advanced imaging seeker operating in both the visual and infra-red frequency ranges: 0.4 to 0.7 micro-meters and 3.5 to 5.2 micro-meters respectively. On launch, the missile records the target's image profile and is able to ignore defensive countermeasures such as flares.

I did try to spot some info on the processor/algorithm but it's in Japanese, at least they refer to another (anti-tank) system in English (Javelin) that use a 64 x 64 pixels image. It's probably limited and not perfect but if the target doesn't vanish from the "screen" briefly ( like a sudden change of altitude) before to reappear it can work somewhat, the geometry of the target cannot change too much in 1/100 of a second. But their  biggest improvement with the  Type 91 Kai is given on the wiki page , "smokeless motor", that one is a killer. The Japanese always make good stuff.

You don't get it.
violet 380–450 nm
blue    450–475 nm
cyan    476–495 nm
green 495–570 nm
yellow 570–590 nm
orange 590–620 nm
red    620–750 nm

This is the visible spectrum. All the diffracted rays will strike a different point. The laser however has a very narrow band. If it is  3.5-5 µm  ( 3500 to 5000 nm) it will go to a different point where your photodiode is absent. If your laser has a band 560-580 nm, you put your photodiode elsewhere just to receive the green or the blue light. This is normal light, sunlight that has a normal intensity, not the intense laser light, it's not the light from a jammer, it's a part of the the light received from the sun, light that rebounded on the object. It's not dangerous for the diode. Now I don't know why I'm getting into such details because I don't believe that a prism is a good idea anyway, but for different reasons.

I used the prism as an example to demonstrate one simple way to defeat saturating laser beams. You can also shield different diodes with different colored filters to achieve the same effect or by using an array of diodes that are sensitive to a narrow but different wavelengths.

Numbers is concentrating on the strength and diameter of the laser beam to convince us that the prism solution does not work. He does not realize that the laser beam cannot reach all the diodes because diffraction concentrate the laser light on one or two diodes and the rest of the diodes will receive the day light as different colors and can work without any problem. This prism solution will work in pattern recognition as well because even in one color the intensity differences make contrasts and it is possible to recognize the pattern based on these different contrasts. For example in green zoom of the prism the picture of the airplane become different green areas with different intensities.

If you have one of the old fashion video projectors that have three color lamps, you could watch a movie only with one or two lamps working. The colors become strange but you could see the movie anyway.

"Spider Umbrella" Stealth Anti Air missile.

"Spider" technology is 2 meters missile wings with Photodiode Detectors on them.
"Spider" technology stops Large Diameter Lasers from saturating missile's Photodiode Detectors.

Future Aircrafts and Helicopters might start to use "Point Defence".

Point Defence's sensors consist of small Phased Array Ragar, Visible and Infrared Photodiode Detectors.
The Point Defence Gun will probably be 4 x AK-47 with 7.62×39 mm caliber bullets.

4 x AK-47 fire on approaching missiles and destroy them before missiles hit the Aircraft or Helicopter.

The missile in order to avoid Point Defence and hit the target Aircraft must use Stealth Technologies.

Below is the list of known Stealth Technologies:

1) To avoid Phased Array Ragar missile body should be covered by multiple layers of plastic.
Multiple layers of plastic should be in shape of cone to reflect Radar Beam to the sides of
missile and not back to Radar (Stealth Technology).

2) To avoid detection by Visible Photodiode Detector missile must have
smokeless motor and be painted in color of surrounding terrain.

If missile flies on top of terrain, it is hard for Visible Photodiode Detector
to detect painted missile on top of similar coloured terrain.

3) To avoid detection by Nightvision (Near Infrared) Photodiode Detector missile shoud be painted by
paint that includes sand particles. Then missile will be not distinguished from desert terrain.

4) The hardest is to make missile Stealthy in Infrared Spectrum.

To avoid detection by Infrared Photodiode Detector missile should have
"Unfolding Plastic Umbrella" on missiles's front cone.

When unfolded conical "Umbrella" will hide missile exaust heat that is discharged behind
"Umbrella". "Umbrella" should have 1 meter diameter and be highly sloped to decrease Air Drag.

Of course the Air Resistance drag on missile will be higher due to 1 meter in diameter sloped "Umbrella".
However the drag can be off set by more powerful missile's engine.

"Umbrella" is good decision because Air behind "Umbrella" offers exelent heat insulation.
Air is one of the best heat insulators.

However in future more powerful Point Defence's sensors can be used against Stealth Anti Air missile ("Spider Umbrella").

It is quite possible that in future "Spider Umbrella" missile will lose to Point Defences in
"1 on 1" challenge.

But because missiles are 100 times cheaper than Aircrafts and Helicopters, 10 multiple missiles
can be launched against Aircraft or Helicopter equipped with Point Defence.

Point Defence might lose "1 on 10" challenge.

Below are the pictures of less sloped Umbrellas. The missile's Umbrella will be highly sloped to reduce the Air Drag.