- Raytheon, an RTX business, will begin testing its SPY-6(V)4 radar array at a land based facility in Virginia
- The milestone marks a step closer to backfitting Flight IIA DDG 51s with an advanced AESA radar capability
- This report examines the differences between the two radars in order to grasp the forthcoming improvements in performance
Raytheon is making headway with the rollout of new generation air and missile defence radars onto US Navy ships, the company claim, having delivered and installed a fixed-face array SPY-6(V)4 radar at the land-based Surface Combat Systems Center in Wallops Island, Virginia.
The milestone is just one step in a programme to backfit the new system across all 47 Arleigh Burke-class (DDG 51) Flight IIA destroyers, beginning with USS Pinckney (DDG 91).
Discover B2B Marketing That Performs
Combine business intelligence and editorial excellence to reach engaged professionals across 36 leading media platforms.
At the Virginia facility, the SPY-6(V)4 unit will undergo initial testing along with the power and combat system interfaces; the phase is scheduled to conclude in mid-2028.
The president of naval power at Raytheon, Barbara Borgonovi, explained that the radar will be integrated with its dedicated power system prior to shipboard installation, which means “less time in the shipyard.”
But to what extent does the SPY-6 family differ from the existing SPY-1 in use across the US Navy fleet?
Old and new
“SPY‑1 radars are out there still. They’re no longer in production, but there are SPY‑1 radars that are in the fleet and will continue to operate in the fleet,” said Scott Spence, vice president of naval systems and sustainment at Raytheon, speaking to Naval Technology in early 2025.
While Raytheon begins to backfit Flight IIAs, some older hulls such as Flights I and II will retain the SPY-1 radar due to cost, prioritisation, and severe electrical and cooling limitations that prevent the vessels from supporting the high-power demands of the SPY-6 family.
The latest Flight III destroyers incorporate three Rolls-Royce AG9160RF generators, which produces 4,000 kilowatts of power per unit. Early DDG 51s, meanwhile, use three AG9130RF generators, which produce 2,500 kW each.
Passive and active
The main difference between the two radars is how they generate radio frequencies.
SPY-1D is a passive electronically scanned array (PESA), meaning the system can only broadcast a single radar beam at one specific frequency at any given microsecond. This limits the operator’s ability to handle complex, multi-domain threats.
On the other hand, SPY-6(V)4 is an active electronically scanned array (AESA) providing greater flexibility. The central transmitter is replaced with an array of hundreds or thousands of independent, miniature solid-state transmit/receive modules. Each of these generates its own radio frequency.
Many militaries are making the transition. But the rollout depends on whether a country can afford the hardware integration, the cooling requirements and the microchip supply chains.
This reporter spoke to members of the Italian Air Force on a Nato rotation in Estonia regarding its SAMP/T air defence system in the Baltic country last year. At the time, the force was upgrading its legacy ARABEL system with an experimental AESA array, known as KRONOS.
Gallium nitride
Another crucial difference is the use of gallium nitride (GaN) semiconductor material to power modules in an AESA array.
Rather than relying on one central power source for PESA arrays, an AESA array decentralises power generation to individual modules.
Before GaN, older AESA radars relied on gallium arsenide (GaAs). Switching to GaN provides substantial physical and electromagnetic advantages: higher power density, thermal efficiency and bandwidth.
In May 2026, Raytheon delivered its 13th ground-based, transportable AN/TPY-2 radar to the US military, but it was the first unit to incorporate a GaN array, where earlier units had still used GaAs. GaN technology is said to enhance the radar’s sensitivity, which in turn extends its range, increases surveillance capabilities and enables defence against hypersonic threats.
New maritime environment
SPY-6 extends the capabilities of the existing SPY-1D radar to meet the threats in a congested maritime environment saturated with low-altitude uncrewed aerial systems (UAS) and electronic attack.
Contemporary conflict trends in the Red Sea and Persian Gulf demonstrate the asymmetric advantage of one-way attack UAS in disrupting global maritime trade and the limited deterrence measures implemented by allied navies. The Ukraine-Russia war, meanwhile, exemplifies the contest to influence frequencies and connections in the electromagnetic spectrum.
These new threat forms require unprecedented flexibility in detection, tracking and classification, which the AESA architecture offers operators.
But Raytheon is also seeking to advance AESA further. Using software-defined apertures, an operator is able to command each small block – or “sub-array” – to perform different tasks through software updates, which would traditionally require a physical hardware replacement that takes time and money.
