AFAIK China has had OTH radars for over a decade. I believe they used both surface wave and ionosphere bounce systems. Not sure what makes this system unique. As noted, it works as an early detection system in peacetime but would be unlikely to survive any conflict that escalated to the point of air strikes on the mainland. I also wonder how effective it would be in the relatively crowded skies of the region - minimally you'd have to cross check any target detection against regular air traffic to exclude targets that were merely civilian liners. Such a radar will not give you a hard count of the number of targets if they are close together; a flight of four fighters or pair of bombers would likely look identical to a 777.
The novelty is using SIAR.
'A major shortcoming that’s been overcome is that old HFSWR can only tell an object’s general direction and not its precise location. Wei Dongxu, a Beijing-based military analyst, told the Global Times they overcame that “by designing the world's first practical meter wave sparse array synthetic impulse and aperture radar.” In effect, it uses a bunch of HFSWR systems to triangulate where the object is.'
See here too: https://www.research...ture_processing
Is it utilizing backscatter to determine where the objects are? I COULD believe that. It would probably work better on an F117 series aircraft than a B2 or F35, but still. In the kingdom of the blind and all that..