Boeing developed the EA-18G Growler mainly to jam radars, but the US Navy has been quietly developing its onboard systems to perform a critical new role in attacks on surface vessels.

A formation of three EA-18Gs has demonstrated the ability to precisely determine the location of a target from dozens of miles away without using radar, says John Thompson, director of electronic attack for Northrop Grumman.

Instead the EA-18Gs use Northrop’s ALQ-218 receivers to pick up emissions from an enemy vessel, Thompson says. Each of the three aircraft in formation will detect the signal at a slightly different time. Using a processing technique called time difference of arrival, computers can calculate a weapons-quality geo-location of a target by measuring those tiny differences in timing, he says.

The existing datalink on the EA-18G is not fast enough to share the signal information between the three EA-18Gs, so the Growlers use the wideband Rockwell Collins tactical targeting network technology (TTNT).

Such a capability means that the EA-18G can find a target without giving its own position away by using a radar, which transmits signals that can be detected. The ALQ-218 is a receiver system, so can collect target information discretely at standoff range,

In the past, similar receivers have been used to detect targets using older processing techniques, such as long baseline interferometry. But those processes were not accurate enough to precisely locate the source of the emitter, so it would be necessary to move closer to establish positive identification or use a radar.

The US Navy first demonstrated the new technique during a live experiment in 2013, Thompson says. An improved version of that capability will be demonstrated again a fleet experiment later this year called FLEX 2015, he adds.

The navy has tasked the contractors to focus the system initially on surface vessels, but it can be expanded to other types of ground or air targets, Thompson says.