ROME — As the market grows for infrared search and track (IRST) sensors that can function like radars on fighters, one American firm has signed a deal with a European counterpart that will bring to the US infrared technologies already honed on the Eurofighter.

Northrop Grumman has launched a partnership with Italian firm Selex ES under which Selex's infrared know-how will enter the US and possibly be turned around for export products for Foreign Military Sales customers.

"Selex has partnered with Northrop Grumman to bring IRST to the US," a Northrop Grumman spokeswoman told Defense News, adding that further details on the applications for new IRST products would be announced in May.

The deal pushes into the US market the technology Selex has worked on for the Eurofighter's PIRATE (passive infrared airborne tracking equipment) sensor, for the European Neuron UCAV technology demonstrator, and, most recently, for Sweden's Gripens.

As passive sensors, IRST systems cannot be jammed like radar, nor do they give away the position of the emitter, like radar. They are also a useful complement to radar when it comes to tracking aircraft with a low radar cross-section. Even if the target aircraft are nearly invisible to radar, they it will generate heat thanks to air friction, as it flies, leaving an infrared signature.

IRST can be used for air-to-air, air-to-ground and land-based tracking, although one down side is that humidity and clouds can interfere with results, unlike radar.

One US analyst said that IRST had not received much attention from the Pentagon over the past few decades.

"The US has lagged on development after getting a strong start in the 1980s when Lockheed Martin put a system on F-14s," said David Rockwell, senior electronics analyst at the Teal Group. "The US dropped back for 20 years, but IRST is potentially a huge market," he added.

"There was a requirement for IRST on the F-22 but the program was cut due to lack of funding, while the IR sensor that Northrop Grumman has put on the F-35 is 360 degrees without an equivalent long-range search-and-track sensor," he said.

In February, Lockheed Martin unveiled its Legion IRST pod, which it claimed will bring long-range infrared tracking to fourth-generation aircraft like the US Air Force's F-15 and F-16 fighters.

The 500-pound pod carries the firm's IRST21 sensor, which was approved for low-rate initial production on the Navy's F/A-18 Super Hornet in January.

An Air Force request for proposals is now expected for an IRST to mount for mounting on the F-15C, with a 2018 delivery date.

A Lockheed official has said the pod-to-pod communication allowed by its Legion pod could also facilitate communication between newer and older fighters.

"If they enter the market, Northrop Grumman and Selex could benefit if the US wants competition, but today Lockheed has the market sewn up. However, it is unlikely Northrop will benefit from the same combination of market factors — including immediate needs after 9/11 — that made Litening successful in the US," he added.

On the other hand, Rockwell said there could be a large market for adding pods to existing fighters around the world, just as US firms are now marketing active electronically scanned array (AESA) radar upgrades for fighters.

Northrop Grumman has already had racked up real success by teaming with Israel's Rafaele to market its Litening targeting pod. It also has a track record with Selex. The Italian firm, which is a unit of Finmeccanica, has long supplied components for Northrop Grumman's directional infrared countermeasure system. (DIRCM).

Selex has meanwhile worked on the PIRATE air-to-air sensor for the Eurofighter, which can act as an IR camera or a passive radar operating in the 8-12 micrometers IR band.

Other contracts have followed. The firm built an air-to-ground IRST sensor for the European Neuron UCAV and a sensor for the Turkish Navy in 2012. The Italian Navy has requested a multiheaded version of an IRST for its new multifunctional vessels. A version is already on board Italy's Cavour carrier.

Selex has used the testing of its sensors to improve work on polishing the algorithms that used to ensure the IRST can exclude false signals and identify vehicle or vessel types tracked.

This month, Saab awarded Selex a production contract to supply 60 Skyward-G IRST systems for its Gripen E fleet, and Selex is also expected to supply the system to go on board Brazil's Gripens.

Selex is also supplying its AESA radar, identification-friend-or-foe IFF and decoy systems to the Gripen, making it responsible for 30 percent of the aircraft's avionics.

Meanwhile, the firm is waiting for an order to upgrade the PIRATE sensor on Eurofighters.

The Skyward system, which weighs 40 kilograms and consumes about 380 kilowatts of power, projects images onto the plane's head up display.

Likely to interest Northrop is Selex's parallel work on a pod version for use on existing aircraft.