By no means 'in the know', but I can copy and paste something I wrote a while back;
There are a handful of good options for the RAF's E3 replacement. Here are the two most realistic;
- Boeing E-7 Wedgetail
- Saab / bombardier global eye.
Let's compare the top 2 options;
Both are fixed panel arrays, bringing all the benefits of electronic beam forming, but only the Boeing manages 360 degrees of coverage, global eye only has side panels resulting in 300 degrees of coverage.
Both feature big panels facing sideways, with the Boeing featuring additional panels facing forward and back & these are less sensitive.
The Erieye ER on the global eye is the more technically advanced radar, it's the only gallium radar in the air, yeilding far greater energy transmitted per kilogram. Importantly, gallium radars are supposed to perform better in the lower frequencies, which is more effective against today's low observable aircraft.
The Boeing is bigger, which importantly allows more operator stations, whilst the smaller globaleye features 5 station cheaper, it is cheaper to buy and run.
Mission endurance is very similar, with the global express flying higher and faster.
The global eye feature some nice additional features, with an optical sensor and another radar on its belly it's has a mid range maritime surveillance role, as well as a ground moving target indicator to support land forces. The Boeing has nothing comparable.
Importantly both exists and both are already flying. The E7 is in service with the Australian's, who are very positive about its performance, as wll as turkey and Korea. The global eye has only been ordered by the UAE, and the first one is currently on flight trials.
Price is difficult to tell, but indications are the E7 is significantly more expensive than the global eye.
Other options are;
- The IAI conformal AEW aircraft, which is similar to the SAAB system, but with additional sensors so give 360 degrees of coverage. However the radar tech is likely less sophisticated than the SAAB
- The Japanese ordered the E2D hawkeye but optimised for land operations with a bigger fuel tank, could be an outside option.
- The E-3 upgrade is another option, costing a lot of money for a decade of extended service. It is a big capable system, but lack some of the electronic trickery that modem electronically scanned systems can achieve. About the only advantage is probably a lower friction entry into service.
- The Airbus option, the only advantage of which is derisking the aircraft for the French and Germans.