A n00b Radar Question...

[B3LA]

I had this mad idea the other day...

The old radars dishes in the nose cones are now
divided into a multiple array of many small units.

Stealth works by either absorbing radar waves or
reflecting as little back as possible.

A larger dish should be able to give a better echo.

The nose cone of a jet fighter has to be reasonable
small due to aerodynamics (and other reasons).

So....I was thinking about the the way Astronomers
nowadays with computers and careful alignments link
several observatories together to make a giant virtual dish.
Couldn't the same be done on a fighter jet ?
A line of these small radar units along the front edge of
the wings and up on the tailfin as well.
Combined they would make a much larger virtual dish and
thus get better readings on stealthy adversaries ?


...Or is this what they mean when they talk about sensors all
around in the fuselages of the F-22/F-35?

 

[Feanor]

What's even more interesting is that they link together multiple radars from different fighter jets to exchange information with each other as well as with an airborne command post....

So yes. That is part of what they mean with the additional sensors.

Though please don't confuse IR sensors with radars, as the F-22 and F-35 carry both.

 

[Todjaeger]

I had this mad idea the other day...

The old radars dishes in the nose cones are now
divided into a multiple array of many small units.

Stealth works by either absorbing radar waves or
reflecting as little back as possible.

A larger dish should be able to give a better echo.

The nose cone of a jet fighter has to be reasonable
small due to aerodynamics (and other reasons).

So....I was thinking about the the way Astronomers
nowadays with computers and careful alignments link
several observatories together to make a giant virtual dish.
Couldn't the same be done on a fighter jet ?
A line of these small radar units along the front edge of
the wings and up on the tailfin as well.
Combined they would make a much larger virtual dish and
thus get better readings on stealthy adversaries ?


...Or is this what they mean when they talk about sensors all
around in the fuselages of the F-22/F-35?

You seem to be describing (the astronomical reference anyway) a VLBA; Very Long Baseline Arrray. The arrangement of dishes positioned in such a way to allow the array to capture very high amplitude signals IIRC.

I will give it some thought, though I do not (currently) believe such an arrangement would be workable aboard aircraft, at least not in an arrangement like a VLBA.

-Cheers

 

[Aussie Digger]

I had this mad idea the other day...

The old radars dishes in the nose cones are now
divided into a multiple array of many small units.

Stealth works by either absorbing radar waves or
reflecting as little back as possible.

A larger dish should be able to give a better echo.

The nose cone of a jet fighter has to be reasonable
small due to aerodynamics (and other reasons).

So....I was thinking about the the way Astronomers
nowadays with computers and careful alignments link
several observatories together to make a giant virtual dish.
Couldn't the same be done on a fighter jet ?
A line of these small radar units along the front edge of
the wings and up on the tailfin as well.
Combined they would make a much larger virtual dish and
thus get better readings on stealthy adversaries ?


...Or is this what they mean when they talk about sensors all
around in the fuselages of the F-22/F-35?

I suppose it could be done that way, but one major problem would seem likely to occur:

The ability to "concentrate the beam". With small arrays spaced out over the aircraft it's going to be difficult for the arrays to generate much in the way of power...

Aircraft cooling systems are going to have to be significantly spread out over the aircraft as well and this may well create weight and fuel penalties as a result.

As they say, there's no such thing as a free lunch...

 

[Feanor]

I think he's referencing the concepts of additional AESA arrats in different parts of the aircraft, and simply using a poor analogy.

 

[B3LA]

Well...a little bit of both actually....
The old placement of the radar was a natural choice due to its size
and purpose : to look straight ahead.
But with the new AESA radars it should give designers new freedom.

Copied from the web :

------
AESA radar, Active Electronically Scanned Array, refers to a radar that
is built up of many small antenna elements into a large antenna.
Each individual element can be controlled, facilitating many functions.
Previously, the radar was a mechanically controlled antenna that
illuminates one area at a time.
An AESA radar can quickly scan larger areas, monitor more targets
simultaneously and allow the pilot to operate with more flexibility.
--------

My original thought was to achieve a better scan of stealthy objects by
adding arrays at different and greater angles (arrays placed at wings
and fin tip) than what the cluster in the nose can achieve.
Working together and carefully synchronized, they should be able to
build a better echo.

This is not as when a wingman lights up a target so that the leader
passively can lock on to it.

But I guess arrays could also be placed around the fuselage, aimed
left, right,down,up and backwards to keep a 360 by 360 degree check
of the entire surrounding ?