Lockheed Martin is proposing the use of two pairs of Active Electronically Steered Array (AESA) radars, mounted in conformal pods on the two sides of the helicopter, providing combined coverage of 360 degrees. Lockheed Martin has been working on this application for five years, developing the ‘Vigilance’ roll-on/Roll-off multi-mission pod that could be carried on the Merlin, as well as other helicopters and fixed-wing aircraft.
Initially the Vigilance pod was fitted with the AN/APG-81 radar from Northrop Grumman – the same radar that will also be deployed on the Royal Navy F-35B. However, in recent years Lockheed Martin (that also develops the F-35) switch to a competing AESA radar – the Israeli ELM-2052 developed by IAI subsidiary Elta Systems. Lockheed Martin has already done design studies for applications of the new AEW pods in other platforms, including Airbus EC725, Mil Mi-17 and Sikorsky/Lockheed Martin SH-60 SeaHawk helicopters, as well as Airbus C-235 and C-130 fixed wing aircraft.
The offer from Thales seems to be the lower cost option. Since the Ministry of Defense already owns the helicopters, radar and mission control systems, the cost involved with upgrading those systems and porting them to the new platform is considered to be significantly lower than the alternative from Lockheed Martin. However, Lockheed Martin claims the added capabilities offered by the AESA radar and Vigilance systems far outpace the performance of current systems used on the Sea King ASaC.7.