Military Sensor/Missile capability

[topol-m]

I don't think a fraction of a second that you can't even imagine let alone dare to measure with anything but automated scientific instruments is going to make any difference.

 

Exactly what I was thinking :) For the speed of light 10, 150, 300 km is nothing so basically there is no practical significance if it goes just one way or goes both ways

[tflash]

Point taken, anyway lockheed Martin seems to like the current IRST effort:

 

http://www.lockheedmartin.com/data/assets/mfc/Photos/MFC_IRST-ProductCard.pdf

[GGTharos]

Yep, a very nice effort...though I think their statement of IRST efficiency compared to radar is um ... overstated.

[tflash]

I find the depicted cones also somewhat optimistic and not consistent with what we know about current IRST systems, but it remains a fact that:

 

- in forward view an IRST gives you an instant image since all heat sources are emitting at the same time and do not have to wait until you paint them with a beam, so while your AESA array T/R modules are multitasking between send/receive and steering your CCD is just registering netto data and feeding them to the system.

- not having to emit means consuming less energy;

- less computing is needed since you do not have to steer the beam nor synchronise send and receive

- "tracking" does not require much more energy, it is mostly algorythmic; radar track means narrower, higher frequency beam

 

One of the problems I guess is that the cooling required to have a sensitive enough sensor consumes a lot of energy, but then again the T/R modules in an aesa array aren't energy champions themselves.

[GGTharos]

I find the depicted cones also somewhat optimistic and not consistent with what we know about current IRST systems, but it remains a fact that:

 

- in forward view an IRST gives you an instant image since all heat sources are emitting at the same time and do not have to wait until you paint them with a beam, so while your AESA array T/R modules are multitasking between send/receive and steering your CCD is just registering netto data and feeding them to the system.

 

That is incorrect. You must scan the IRST to get good SA. And in the end, both instruments 'register netto data and feed them into the system'.

 

- not having to emit means consuming less energy;

- less computing is needed since you do not have to steer the beam nor synchronise send and receive

 

This is not correct. You have to steer the IRST, and being mechanically steered makes it SLOWER than the AESA radar. You are also processing a fairly large image and trying to reject false positives, and this consumes plenty of computing power.

Here's a clue to understand this: MSA radars have been doing this for 40 years now. IIR IRSTs are just starting to become standard NOW.

 

- "tracking" does not require much more energy, it is mostly algorythmic; radar track means narrower, higher frequency beam

 

Not at all true. TWS/SWT modes have been done by radars for a while without sufferage, unless you're talking about the poor old MiG-29A radar implementation. THAT had problems.

 

One of the problems I guess is that the cooling required to have a sensitive enough sensor consumes a lot of energy, but then again the T/R modules in an aesa array aren't energy champions themselves.

 

Radar probably does require more cooling.

[Wilde]

As for the L-Band radar, again, it's not going to be like that. That's hype and I really doubt there's merit to it as an anti-VLO sensor.

 

I believe you're still underestimating it's merits. Those simple L-band radars could work very nicely against VLO aircraft. That is because they most likely are designed to work asymmetrically. Their point is not to detect or track a VLO aircraft in the first place imho. I think what they really are about is to being able to detect the VLO aircraft's datalink emissions and to be able to jam those.

 

This effectively means an enemy VLO aircraft is blind unless it uses it's own X-band radar or tries to get targeting information via datalink. Either way it will instantaneously lose it's VLO characteristic. And in the case of the datalink fed system intended to provide superior situational awareness for a F-35 pilot it could render the whole concept useless too, if the L-band array can jam the datalinks. I wouldn't want to be a pilot in a F-35 in a situation like that.

 

Don't bite me. I don't really know if that's their idea or if their solutions can actually do it. But I would expect an approach like that from them. Russian engineers are not morons.

[GGTharos]

No, they are just cash-strapped.

 

I think that's a very interesting, but also far-fetched proposition for something that is classified as an AESA radar.

[exec]

I find the depicted cones also somewhat optimistic and not consistent with what we know about current IRST systems, but it remains a fact that:

 

- in forward view an IRST gives you an instant image since all heat sources are emitting at the same time and do not have to wait until you paint them with a beam, so while your AESA array T/R modules are multitasking between send/receive and steering your CCD is just registering netto data and feeding them to the system.

Not entirely true. IRST has an instant field of view 7,5x10* (OLS-35). Scanning limits are +/- 90* in azimunth and -15 + 60 in elevation. So, scanning forward sector may taka a while. Basicly using 7,5x10* FOV you have to 'shot' 180 'pictures' to scan all available forward area. I think AESA radar can do all the scanning a lot faster.

 

- less computing is needed since you do not have to steer the beam nor synchronise send and receive

Actually you have to steer the 'beam' (camera).

 

 

One of the problems I guess is that the cooling required to have a sensitive enough sensor consumes a lot of energy, but then again the T/R modules in an aesa array aren't energy champions themselves.

There are other important problems I think:

-short range (forward sector ~35km)

-even shorter range in non-perfect weather conditions

[Wilde]

Basicly using 7,5x10* FOV you have to 'shot' 180 'pictures' to scan all available forward area. I think AESA radar can do all the scanning a lot faster.

 

Of course it can. But it needs to emit radio waves in order to do so.

 

Also there is no need to scan the entire area. Using a dedicated scan pattern narrows the area to scan significantly. For example if you want to scan at ranges >40km for other aircrafts you can effectively limit the angles to about +/- 5º in elevation, because there wont be any aircrafts in space or below the ground. So what you do is more or less sweeping the camera left and right only. It's pretty much the same procedure as how the Americans operate their non-AESA radars.

 

In WVR there are dedicated scan patterns too as you probably know from the game.

[exec]

Also there is no need to scan the entire area. Using a dedicated scan pattern narrows the area to scan significantly. For example if you want to scan at ranges >40km for other aircrafts you can effectively limit the angles to about +/- 5º in elevation, because there wont be any aircrafts in space or below the ground. So what you do is more or less sweeping the camera left and right only.

Well, not exactly, more like +/- 14º, so you'd have to do four sweeps (28 : 7,5 = 3,7), considering that this is optics, it will certainly take some time.

 

And what about the aircrafts that are closer than 40km?

 

 

 

Narrow scan pattern gives you large blind zones.

 

AESA radar scans whole 120ºx120º FOV almost instantenously.

[Wilde]

What's your point? Do you want to read "OK AESA is better!" or what?

 

OK AESA is better!

 

 

...

 

 

As I said there are scan patterns for certain scenarios/situations. Obviously for closer ranges you need to narrow the azimuth you want to scan in order to do it equally fast. All it requires is some brains on the pilot's part. I was simply trying to hint you to the point, that there is no need to "take 180 shots" for a scan as you nicely calculated from some datasheet.

[exec]

What's your point? Do you want to read "OK AESA is better!" or what?

 

OK AESA is better!

 

There is no point, really.

 

I just disagreed with 'instantenous IRST scan' claim. No need to get annoyed.:thumbup:

[SpudmanWP]

While not instantaneous, it is damn fast!!

 

[Mugenjin]

it's a laser light show!

 

:P