IR Seeking Guidance for a Missle Project

[Tracey3]

So I am starting brainstorming on my engineering project. I am quite set on creating IR guided rocket I am not very knowledgeable yet with wavelengths and optical sensors and there is one question that bothers me.

How and why laser guided missiles don't track the sun? Also if anyone has any schematics on how its done, It would be appreciated as I unfortunately don't have an AGM-65 Maverick lying around the house to dismantle

 

[berkeman]

So I am starting brainstorming on my engineering project. I am quite set on creating IR guided rocket I am not very knowledgeable yet with wavelengths and optical sensors and there is one question that bothers me.

How and why laser guided missiles don't track the sun? Also if anyone has any schematics on how its done, It would be appreciated as I unfortunately don't have an AGM-65 Maverick lying around the house to dismantle

Fun project! There is a difference between laser guidance (as in your title) and IR/heat-seeking guidance (what you ask about in your post). Can you say what the difference is, and which you are asking about? I can adjust your thread title if needed.

 

[Tracey3]

Fun project! There is a difference between laser guidance (as in your title) and IR/heat-seeking guidance (what you ask about in your post). Can you say what the difference is, and which you are asking about? I can adjust your thread title if needed.

My bad for being unclear, I am referring to IR seeking which would seek out IR light emission rather than one that would follow a guidance beam. If you wouldn't mind adjusting the title I would appreciate it.

 

[berkeman]

How and why laser guided missiles don't track the sun?

I did a Google search on Why Doesn't an Aim-9 Sidewinder Missie Track the Sun? and got some good hits. Here is one of the better ones:

https://www.reddit.com/r/explainlik..._come_heat_seeking_missiles_dont_go_straight/



EDIT/ADD: https://en.wikipedia.org/wiki/AIM-9_Sidewinder

 

[berkeman]

See also the shoulder-launched Stinger missile: https://en.wikipedia.org/wiki/FIM-92_Stinger

 

[CWatters]

How and why laser guided missiles don't track the sun?

The target is designated by someone/something pointing a laser at it and the missile homes in on the reflected signal. The reflected signal is quite weak so it has to be amplified. It's quite hard making a high gain DC amplifier so the laser is modulated to produce an AC signal. That makes it easier to amplify the reflected signal and easier to filter out the sun which is essentially DC.

I imagine that if each target designator used a slightly different AC signal (or data was encoded in it) you could designate and launch multiple laser guided missiles at the same time and they wouldn't get confused as to which target they should hit.

Edit: Using AC is a common instrumentation trick.

 

[davenn]

The target is designated by someone/something pointing a laser at it and the missile homes in on the reflected signal. The reflected signal is quite weak so it has to be amplified. It's quite hard making a high gain DC amplifier so the laser is modulated to produce an AC signal. That makes it easier to amplify the reflected signal and easier to filter out the sun which is essentially DC.

I imagine that if each target designator used a slightly different AC signal (or data was encoded in it) you could designate and launch multiple laser guided missiles at the same time and they wouldn't get confused as to which target they should hit.

Edit: Using AC is a common instrumentation trick.

that is laser guided, not IR heat seeking that the OP is wanting to know about

check out Berkeman's links for good infoDave