Laser Guided Missiles?

[lamborgini8]

Just been wondering, what kind of lasers are used for laser guided missiles. The logical thing to use would be an IR laser but what about the power of them? What about the colimination of them? I would guess it would have to be incredibly well coliminated to stop it being seen as a gigantic IR blob a few miles away that nothing can be guided by.

 

[Bionic-Badger]

Actually a blob might not be so bad if it can still be observed. If it were a tiny dot, it might not be located from a distance especially if the surface isn't too reflective. Laser guided weapons don't have a huge range either. For example the Hellfire missile has a 7km range, which is easily within the range of lasers that the army can strap to their helicopters.

Remember also, that they're not using the low powered lasers we use. The 500mW green lasers we salivate over are chump change compared to the lasers they can employ. Think in terms of watts, generated by actively cooled gas lasers. They can also tune them to IR wavelengths that aren't absorbed so easily by the atmosphere for greater distance and collimation. Still, they're not perfect; the lasers are still affected by weather, heat, and other factors that can misguide the missile.

 

[lamborgini8]

Actually a blob might not be so bad if it can still be observed.  If it were a tiny dot, it might not be located from a distance especially if the surface isn't too reflective.  Laser guided weapons don't have a huge range either.  For example the Hellfire missile has a 7km range, which is easily within the range of lasers that the army can strap to their helicopters.  

Remember also, that they're not using the low powered lasers we use.  The 500mW green lasers we salivate over are chump change compared to the lasers they can employ.  Think in terms of watts, generated by actively cooled gas lasers.  They can also tune them to IR wavelengths that aren't absorbed so easily by the atmosphere for greater distance and collimation.  Still, they're not perfect; the lasers are still affected by weather, heat, and other factors that can misguide the missile.

But are the missiles guided by the dot or can they follow the actual beam? It would make more sence to follow the beam but wouldnt that mean the furthur it gets away and the bigger the beam gets the less stable the missile will become as it trys to follow the beam?

I would assume you can't easily intercept a laser guided missile with another IR laser but if someone had a IR laser with more power than the guided missile then that could cause a lot of problems...

 

[Cyparagon]

Dot. Even if the dot were a few feet wide, that's plenty enough accuracy to destroy a target given the destructive capabilities of your typical bomb.

 

[FrothyChimp]

The laser designators I used to use were Nd:YAG laser systems. Keeping the dot on the target was not easy especially as the distance grew. Any small movement of the designator and the designation point would move off the target. The nice thing, however, is the missiles/bombs, what have you, continue seeking as well as heading toward the original aim point. Once reaquired the weapon continues toward the aim point. Also keep in mind that the aim point was not really a point. The target was "painted" or illuminated by the laser. There is a big blob of light reflected that jitters around on the target. One more thing, you cannot just use any laser to designate a target. To lase a target requires entering a designation code on the designator. This code matches the code entered into the weapon. What this does is modulate the laser output. The weapon looks for the specific modulation pattern and homes in on that designation only. Self designating systems like the AH-64 will have all their hellfires coded the same so they don't need to make any code changes during flight (although I believe these days the hellfire missile is a fire and forget weapon). Forward air controllers will either receive the code directly from the pilot if the communications are encrypted or have to look up the code designation in the air tasking order, or the daily crypto.

 

[Switch]

One more thing, you cannot just use any laser to designate a target

Yea, that's so lame in HL