A major radar upgrade for the Northrop Grumman B-2 stealth bomber fleet is progressing, with its most high-risk component - a Raytheon active electronically scanned array (AESA) antenna - now lighter, cheaper and more effective than planners expected.

The B-2 antenna requires two advances for the critical transmit/ receive modules, which are four times more numerous on the B-2 than on any other aircraft and need much more miniaturisation. Northrop Grumman and the US Air Force also required Raytheon to integrate the AESA antenna with the aircraft's existing processors and liquid cooling system.

But the gamble has appeared to work out in favour of the contractor. Although the radar upgrade has created an overall weight increase for the aircraft, the 4,000 transmit/receive modules on each B-2 are projected to be below weight by 7.7kg (17lb) per aircraft, says Rich Auerbach, Raytheon programme director for the B-2 modernisation programme.

Under a $388 million contract awarded to Northrop Grumman in early September, the first modified B-2 will enter flight tests in 2006. A production go-ahead is due in February 2007, with deliveries for all 20 remaining B-2s complete before 2011. The AESA antenna is needed for the B-2 to operate legally without interfering with new commercially available frequencies.

Northrop Grumman is in early discussions on a potential upgrade to a high-resolution synthetic aperture radar to enhance targeting imagery by a factor of 10. The upgrade will require the air force to fund a new programme to modernise the aircraft's internal electronics, however, including processors and routers.



Source: Flight International