AWACS to Get Unmanned Partner?

The future for the U.S. Air Force's AWACS fleet might not be replacement of the E-3s, or even a new radar, but pairing of the aircraft with UAVs to extend surveillance coverage. This would use a technique known as bistatic radar, where the transmitter (the AWACS) and the receiver (the UAV) are in different locations.

According to a new sources-sought notice, the Air Force Research Laboratory plans to flight-demonstrate the AWACS mission performance improvements enabled by using a UAV equipped with an S-band bistatic radar receiver. This will use a conformal load-bearing antenna structure (CLAS) to enable integration of a very large receiver array on the UAV (see previous post).

Bistatic operation offers several advantages. With the smaller and more survivable UAV passively listening closer to the front line, the AWACS with its powerful active radar can be moved further back over friendly territory. This could be a major advantage in a conflict with China, as it would allow the vulnerable E-3s to stand off, making them easier to defend and to refuel.

Photo: US Air Force

As the AFRL notice alludes, pairing geographically separate active transmitters and passive receivers through bistatic operation also helps with electronic protection. Bistatic operation has been tested before with AWACS, using a ground receiver, under the Bistatic Alerting and Cueing program, which was an outgrowth of DARPA's early-1980s Sanctuary bistatic-radar air-defense system project.

As with everything these days, the idea is not new. U.S. and NATO E-3s have already controlled ScanEagle UAVs in exercises and a "Bistatic UAV Adjunct" was at one time proposed for the AWACS fleet. AFRL's test program may be a step in that direction. The Pentagon's FY2012-2014 Aircraft Procurement Plan, meanwhile, says: "the E-3 Airborne Warning and Control System (AWACS) and RC-135 Rivet Joint ISR aircraft will reach the end of their service lives prior to FY 2041. It is possible that advances in UAS designs will allow unmanned systems to replace those aircraft."

Phase 1 of AFRL's planned program would include development of an operational system concept and definition of a Phase 2 flight test program that would demonstrate the CLAS bistatic-radar antenna, receiver, processor and datalinks on a UAV working with a surrogate AWACS radar.

Tags: ar99, unmanned, AFRL