The AN/APG-81 is an advanced fire control radar developed by Northrop-Grumman for the F-35 Lightning II. It features both air and surface modes and Active Electronically Scanned Array (AESA) antenna for enhanced performance. The APG-81 radar underwent rooftop integration range-testing phase entering flight testing on a Northrop-Grumman BAC 1-11 testbed aircraft in early 2005. The BAC 1-11 tested its air and surface modes. Northrop-Grumman handed over the first AN/APG-81 active electronically scanned array (AESA) fire control radar to F-35 Joint Strike Fighter (JSF) prime contractor Lockheed-Martin on March 3, 2005. APG-81 radar system will support air-to-air, air-to-surface and electronic warfare modes providing the pilot with all-weather precision targeting and advanced air-to-ground automatic target cueing.
The AN/APG-81 radar is a combination of the proven technologies from the F/A-22’s APG-77 and the F-16E/F’s APG-80 AESA radar systems. The APG-81 features features 1,000 transceivers with the ability to track aerial targets and moving targets on the ground. In the air surveillance mode can detect an airborne target of one square meter Radar Cross Section (RCS) at a range of 150 kilometers. Besides, can track 23 targets in 9 seconds while engaging 19 of them in 2.4 seconds.
AN/APG-81 Drawing on experience with the AN/APG-77 radar for the Lockheed Martin F/A-22A Raptor, Northrop is developing the AN/APG-81 dual mode radar for the F-35 Lightning II. The radar, featuring an Active Electronically Scanned Array (AESA), will be an integral part of the aircraft sensor suite, which includes the Northrop/Lockheed Electro-Optic Targeting System (EOTS) and Distributed Aperture System (DAS) (see separate entries).
The AESA’s solid-state technology and elimination of mechanical movin parts will facilitate greatly enhanced reliability over current Mechanically Scanned Array (MSA) systems. The radar features a ‘replaceable assemblies’ design for faster, easier repairs or upgrades to hardware and software modules. Accordingly, AESA life-cycle costs are expected to be significantly lower than those of MSAs, with almost twice the expected life of the airframe from the AESA.
The APG-81 radar will fulfil air-to-air, air-to-ground and Electronic Warfare (EW) duties for the multirole F-35 JSF. The radar incorporates ‘multi-channel’ receivers and exciters, enabling each discrete radar return to be analysed by every channel for differing parameters, thus significantly speeding up processing time and facilitating multiple functions on a single pulse.
Radar Designation: AN/APG-81
Type: Airborne dual mode radar
Frequency band: X-band range: 8-12.5 GHz
Antenna type: Active Electronically Scanned Array (AESA)
Antenna size: 1,200 element array
Azimuth coverage: +-70º
Elevation coverage: +-70º
Air-to-air maximum range (mode):
Look-up high aspect target: 125 km
Look-down high aspect target: 125 km
Target size: 1 m2RCS
Air-to-air modes: Multi Target Track, Track While Scan,
Air-to-ground modes: Synthetic Aperture Radar, Ground