The nose mounted radar has a circular shape which in overall give more space to use more TR modules , also give better antenna directivity .
The two dimensional array of a nose mounted radar gives more information than a single linear array of sensors... but the individual sensors themselves are just the same... though operating in different frequency ranges.
The horizontal design of the wing mounted radar will reduce the antenna directivity area ,limitation of the cooling system size and the total number of modules ,hence the total transmitted peak power would be away less than any mounted nose radar .
It is not about peak power... American stealth aircraft are stealthy in a narrow frequency range only...
Think of it in terms of infra red and visible light... the F-35 and F-22 have colour camouflage that makes them very very hard to see with a normal digital camera.
The Su-57 has a powerful digital camera that can see fine details and when zoomed in could detect the presence of either aircraft once it knows where to look.
The L band wing mounted array is a thermal imager in this example... the paint they used to camouflage the US aircraft does not work in IR, so both aircraft glow with their heat... just like any other aircraft whether it is stealthy or not.
The L band radar is used for detection and general location and then the nose mounted radar is used to identify and track the stealthy target it might have had trouble finding if it didn't know where to look to start with.
By the way the imagery from MAKS-2009 showing each array employs twelve antenna elements in three quad TR modules .
That would be the export version I would think. I would also think the domestic version will be secret.
The computer will process all the data from active/passive systems like the radars ,OLS or RWR .That's fine but each system has it's own capability and detection range . The L-band is just give a capability which cannot be given easily in the X/Ku-bands .They can also embed the IFF there .
L band radars are not magic and have a few issues, but against stealth aircraft they also have a few advantages. Mixing the results from the nose mounted Ku and Ka band radar, as well as information from the IRST and thermal camera (likely long, medium and short wave IR are used) and you get a system that is harder to fool and produces much better information than any of the sensors could manage on their own.
Yes and they can track it also 60 years ago using their VHF radars but being a land based radar would give more flexibilty to increase the antenna size and provide enough power for it and using multible antennas with different wavelengths like the NEBO system .
Not even close. 60 years ago they had nothing like Container that can detect and track low flying low RCS targets thousands of kms away... NEBO is something different... it supports large SAMs and does not have a dead zone of 900km in front of it where it can't detect anything... NEBO has to detect targets in close and out to decent ranges to do its job...
I guess the same , from 2009 to now it should be fully tested and matured .
The wing mounted systems in the Su-35 are designed for detecting stealthy aircraft and were part of the system designed for Su-57 because that is what it does.... hunts F-22s and F-35s and B-2s.
Putting radar antenna in the wingroot of a fighter plane complicates the design and costs money... I don't think they would bother if it didn't work or show promise to eventually become effective.