It can pin point the location of a low observable object if its large enough..
You are not understanding... radar cross section has nothing to do with the actual size of something... it is an indication of how reflective that something is.
If you create a corner reflector you can make something that reflects radar back to its source like a light reflector on the back of a car reflects back the headlights of your car.
If you decorate the front of your aircraft with corner reflectors you could have a radar cross section measured in kilometres if you wanted to.
Russia uses its old SAMs as targets for air defence training and they take things out like the HE payload and the guidance radar in the nose if it has one and so they just have a sheet metal nose which is actually quite stealthy compared to a radar invisible nose cone with a big flat round radar antenna reflecting back a big radar signal.
The Peniye system is based on the SA-6 SAM and uses three standard missiles on the standard TEL, and with a sheet metal aerodynamic nose fairing the RCS of the missile is 0.1 to 0.3m squared. With the original radar transparent nose cone the radar waves from the enemy radar go straight through and hit the flat surface where the radar antenna in the missile would be and of course radar shining back from a flat surface like that is 1m square. Putting a luneberg lens or corner reflector in the nose with the radar transparent nose cone can get a radar cross section of 3 to 5m square.
In terms of light the sheet metal fairing redirects the light in all directions so it isn't exactly bright coming back at you. With the flat surface and radar transparent dome it is like a flat shiny surface reflecting the light back, and with the corner reflector it looks like you put the reflector from a car in there... it actually looks like there is a light inside that is shining back at you.
The thing is that L band radar is not the same as the high frequency radar used to find and track targets... it is like the difference between normal visible light and heat, so stealth is camouflage paint that makes the target hard to see, but in L band the entire aircraft or object just reflects the signal... the whole thing glows and energy is not redirected in other directions because of the stealth shaping of the object.
To get the same accuracy as a 2m diameter X Band radar, You would need it 6m large.
A stealth object stands out like any other object in its field of view stands out... and the angle precision is good enough to be able to point the main radar at it and find it with a powerful burst, or the IRST could be directed at the target to find it too.
Then it will track and search exactly like an X band radar with more range however. But it will need more power because of that wavelength..
Finding stealth aircraft with an L band does not need extra power because the wavelength is too long to be redirected by the stealth shaping of the target so the entire beam sent to the target is returned to the radar antenna. At Ku or Ka band much of the energy is redirected away from the source radar so more power is needed to detect a stealth target, but with L band there is no degrading of range.
One of the reasons why It is not particularly employed as a frequency band in the radar of a fighter jet (Fighter jet radars are already multi-band btw, they dont operate from 1 band only) is because of the size of the thing...
A 2D array of elements would be a ridiculous size and would not fit well in the nose of a fighter and more importantly would take up space that can be used by a more useful radar like a Ku or Ka band set.
If you are having trouble understanding look at this... this is NEBO.
From right to left is the high frequency radar on a truck and then a low frequency radar on a truck and then high frequency and low frequency.
NEBO is the mobile version... the static version can look like this:
They are not doing a L Band radar for the main search and track radar.. It is gonna have terrible resolution..
Nobody said they were. The L Band AESA radar is a single line of elements along the leading edge of the wing, as part of the leading edge flap I believe so it can be moved to mechanically scan vertically while horizontal scan would be electronic.
I dont know if you have played around with CST Suite or ANSYS HFSS but shaping that lobe is not easy..
I am confident the Russians know exactly what they are doing...
That western audiences don't understand is honestly a good thing because if they realised how exposed western stealth fighters are going to be against Russian air defences there would be panic and then there might actually be changes and solutions that matter a damn.... but I wont hold my breath.
Most of the best beam shaping is through trial and error and not some straight forward mathematical formula like Electronic beam steering.
With the ground based NEBO system they take AESA radars of different frequencies and process their signals through some computers and can have astounding results against a range of objects.
Not ideal for very small targets, but for big targets pretending to be small like a stealth fighter or stealth bomber they are amazing.