From what I read, the USAF is going for 27 E-7A Wedgetail AWACS which will replace the E-3 Sentry. The satellite based radar system will most probably work in conjugation with the AWACS.
It's part of their "we screwed up" program. Their original plan was the E-3 will be upgraded and will be available until 2035, in time for the constellation to be ready. They had to change the plan when they realized the E-3 can't reliably fly that long, especially in the much more hostile environment of the West Pacific. So the E-7A will bridge the gap between the E-3's demise and the arrival of satellites, which is only expected to start from 2030. It's unknown when a global constellation will be ready, but once it's ready, most of these jets will become pointless.
The E-7 wasn't an air force program, Boeing developed it for the export market. The USAF became so desperate that they had to improvise by buying existing tech. This urgency is being seen in all services. If they had planned for it, we would have seen a more robust design based around more radars with a proper 360 deg capability on a much larger airframe.
The E-7's 737 has an MTOW of just around 80T versus 240T of the A330 or 160T of the E-3. For their own program, they would have chosen the 250T 787 or 300T 777 instead, or at least a 767 (200T).
Even the IAF has currently chosen a narrow-body design with limited capabilities, like the USAF. Otoh, Air India One is based on the 777-ER, which weighs 350T.