THE ROYAL Air Force's next generation of strike aircraft is likely to be designed with multiple radar-antenna-arrays located around the airframe. This will provide a "radar picture" considerably larger than at present.
The Future Offensive Aircraft (FOA), now in the conceptual-design phase, will include a series of low-observable features, and a traditional large-diameter radar bay in the nose is unlikely to be available. The aircraft could be a joint French/German/UK project.
The $150 million GEC -Thomson-DASA Airborne Radar consortium is working on an airborne multi-function solid-state active-array radar (AMSAR) which could be used on projects such as the FOA and a mid-life update of the Eurofighter EF2000.
Flight testing of a prototype of the X-band radar is scheduled to begin in 2002.
Prof John Roulston, technical director at GEC-Marconi Avionics, says that "side arrays" provide several opportunities and advantages. He says that the FOA radar-antenna technology "...is really very important".
With FOA liable to have an "irregular shape", the ability to compensate for limited radar space in the nose section by using multiple-aperture options becomes increasingly important.
Roulston says that antenna arrays could be placed along the front of the shoulder area of a blended wing/fuselage, or on the forward lower section of the fuselage. Appropriately placed active arrays could also provide rear-hemisphere coverage.
Roulston says that moving towards multiple arrays for strike/attack and air-intercept radar applications (rather than pursuing the Russian approach of mounting electronically scanned antenna on gimbals) offers size and cost advantages, as well as an increased "look area". The trend is away from big aircraft, he notes.
The EF2000 and the Dassault Rafale are earmarked to benefit from the AMSAR as part of mid-life update programmes to replace the current ECR-90 and the RBE2 radars, respectively.
Multiple radar-arrays also offer offensive and defensive advantages to fighter aircraft. As well as rear-hemisphere coverage, they could also increase the action-manoeuvre area for aircraft involved in beyond-visual-range missile engagements.
Tracking the target and providing updated information using an antenna array placed elsewhere than in the nose section would allow the pilot greater flexibility in moving the aircraft, and increasing the so-called F-Pole: the distance between the launch aircraft and the target at the time of missile impact.