We have developed the tech by ourselves.Full access to the performance or the technology? It's 30 years old now anyway.
I fully understand how IRST works and so does a Super Hornet pilot:That's not actually sensor fusion. And it won't help, because when cued it will still see nothing.
There's something you need to understand about how IRST works, it's basically an optical telescope, scanning very small windows at range. It's slow and it can be out-manoeuvred by a stealth fighter that already knows where you are. But if NGAD is capable of Mach 4-5 at over 30km altitude with distributed radar, AIM-260 will wipe out any Su-30 or Su-57 out from >200km away.
The IRST is a “stealth equalizer” says the former Super Hornet pilot I interviewed, adding that the high quality IRST which the Block III and other U.S. fighters employ can “pick up gliders as well as F-117s, B-2s, F-22s and F-35s even in the forward quarter at well over 100 miles.”
So B-2, F-22/35 can be picked over 100 miles away even in frontal aspect(subsonic).
According to Super Hornet pilot, this capability of new IRST is "holy s h i t":
That’s the holy **** capability the IRST brings,” he concludes.
So as per a Super Hornet pilot, IRST(new gen) is:
1. Stealth Equalizer
2. Holy s h i t.
Link: U.S. Navy Just Got Its First New F/A-18 Super Hornets — Here Are The Key Upgrades
So it is not me who doesn't understand how IRST works but it's you who is undermining its efficacy. Like it or not, IRST would continue to evolve to the point that your stealth/VLO advantage is fully nullified.