US Navy plans EPX

From Aviation Week

U.S. Navy Plans EPX Intel-Gathering Aircraft

Feb 22, 2008

By David A. Fulghum

The U.S. Navy is asking three companies each to design an aircraft that can conduct simultaneous intelligence-gathering missions that were considered impractical, perhaps impossible, even a couple of years ago.

In particular, the Navy wants a single, EPX aircraft that can use a powerful radar and at the same time operate an array of sensitive receivers that can collect faint electronic emissions or communications from hundreds of miles away. The multisource information would be fused to locate and identify objects of interest as fleeting and elusive as the low-power cell and satellite telephones used by terrorists and insurgents.

Requirements for an EP-3 replacement would add “organic systems that can do accurate, definitive targeting,” says Paul Summers, Boeing’s director of airborne signals intelligence campaigns. “Radar will be part of the sensor suite.” What’s not defined is the type of radar or how it would be used. That means the “field of regard, instantaneous field of view, power out and range” also haven’t been determined, Summers says.

Lockheed Martin adds mystery to its effort by saying it will “draw on the depth and breadth of its Advanced Development Programs” (ADP) organization which gained fame as the “Skunk Works” and of late has specialized in stealthy, unmanned aircraft.

“Expendable systems,” which may include stealthy unmanned air vehicles small enough to be launched by EPX to fly into enemy air defenses, are “becoming smaller and more capable than ever before,” says Frank Blesi, ADP’s EPX study lead. “By ensuring that EPX can employ expendable systems in the basic concept design, we reduce the cost and risk of integration.”

The Navy’s refinement and apparent expansion of its requirements since last summer has shocked contractors.

“It’s a changed doctrine with new capabilities that include electro-optical/infrared [sensors], synthetic aperture radar/inverse SAR, maritime moving-target indicating, multi-intelligence targeting, wideband satellite communications and searching for [global war on terrorism]-type signals,” says Dennis Hayden, Northrop Grumman’s EPX campaign manager.

The need for a simultaneous active/passive system is part of a just-released set of requirements from the Navy with which teams led by prime contractors Boeing, Lockheed Martin and Northrop Grumman are wrestling.

Two advanced technologies under consideration for EPX are the active electronically scanned array (AESA) radar (with greater range and target discrimination than manually scanned radars) and widespread use of conformal antennas attached to the aircraft’s exterior.

“Radar is going to be a must,” Hayden says. “Any product, sensor or system that can perform multiple jobs [like AESA arrays for sensing, electronic attack and wideband communications] will be attractive.”

L-3 Communications’ business development liaison to Northrop Grumman, Ted Klapka, notes, “It’s safe to say it will be a flying antenna. But it will look less like an F-22 or F-35 [whose wing and tail leading edges are packed with sensors]. Those have stealth requirements—EPX not so much. There are more cost-effective ways to give yourself large apertures. We’re looking at conformal arrays. We’ll probably end up putting an aperture on just about every square inch of the airplane that we can because, with the [new Navy] requirements, it will take some head-scratching to figure out how to accommodate them all.”

Boeing is also exploring antenna innovation.

“One of our trade studies is to look at phased and conformal arrays for radar, communications and general broadband applications across the platform,” says Summers. “The drawings we released show conventional antennas. But the Navy has us looking at lots of enhancements to that antenna layout. Major structural mods to accommodate in-structure arrays are going to be limited. We’ll do things to minimize impact to physical structures, so we’re looking at a pretty broad selection of conformal arrays for various frequency bands. You’ll see configurations migrate to something that looks a little less conventional.”

All those antennas need management.

“Needless to say, that presents unique electromagnetic compatibility issues,” Summers notes. “The program will require a lot of dedication to basic physics so that the platform can provide a broad array of wideband passive sensors as well as an active array.”

Moreover, Klapka adds that “there are going to be a number of new mission areas—some that were previously classified and some that didn’t exist until recently.”

Industry officials won’t discuss details, but some of the new missions being considered include information operations, electronic attack and network exploitation.

In the past, there were emitter aircraft—such as the Air Force’s EC-130 Compass Call or E-8C Joint Stars—and passive, listening aircraft such as the RC-135 Rivet Joint and EP-3 Ares. No aircraft could both emit and listen because the noise from radar or electronic attack would overwhelm the receivers. But passive electronic surveillance has to be continuous to build an effective order of battle that details what is emitting and from where.

When the Air Force’s E-10 multi-sensor, command-and-control aircraft (now a victim of budget cuts) was designed, service officials wanted a version that also would combine a powerful AESA radar with a very sensitive electronic surveillance system. In addition, the 20-ft.-long antenna was designed for the collateral mission of disabling air-to-air and surface-to-air missiles with bursts of high-power microwaves as a self-defense capability. It would have the offensive capability of similarly disabling stealthy cruise missiles, as well, which it was capable of detecting at tactically useful ranges. The combination was dropped because it was deemed impossible due to cost and improbable due to technology restraints.

The basic problem remains: How to harmonize the use of passive and active sensors?

“Co-site interference on an airplane of this sort is always going to be an issue,” Klapka concedes. “You’ve got to be able to listen all the time. Part of that [is made possible by] being precise in using the spectrum. You’ve got to know when you put energy out, that you can look through it.”

Another way to solve co-site problems is to “use somebody else’s receive apertures” through networking distributed sensors, Klapka says. “As the P-8A [maritime multimission aircraft] and Broad Area Maritime System [unmanned aircraft] get out there, and with the availability of satellites and other systems, we can tap them along the way.”

The Northrop Grumman team, predictably, is focusing on intelligence-gathering systems. They plan to pull on mission management capabilities from the E-8 Joint Stars, signals intelligence from the EP-3 and electronic attack and information operations from the EA-6B Prowler, EA-18G Growler and Rivet Joint.

“The Navy has decided that EPX is a manned aircraft,” Klapka says. “[it] has to complete a mission on its own, but that includes things in the weapons bay or hanging on the wings. We have expendables with wings to deploy and those will be factored in as we go along.” There also is a requirement for level-four control of UAVs that are sure to include stealthy, penetrating designs.

Northrop Grumman officials say they are working their way through a group of about 150 aircraft to see what best meets Navy needs. They are considering a family of sensors and aircraft that might also meet the demands of the Army’s Aerial Common Sensor program and, eventually, the Air Force’s Rivet Joint replacement.

Boeing is somewhat more focused on airframes so that it can leverage the Navy’s previous investment in the P-8A Poseidon patrol aircraft.

“This is a different mission, so there may be some changes required to the air vehicle to accommodate this unique, multi-intelligence payload,” Summers says. “The Navy has already spent a great deal in modifying the 737-800 with the larger -900 wing to be NavAir certified, so it would be foolish of us not to trying to leverage this to the maximum extent.”

Yet another element of the EPX design will be deciding how to staff crews adequately while simultaneously lessening the personnel burden on the Navy. There are two parts to the answer.

Boeing is offering a large aircraft with baseline accommodations for 14 operator stations aft of the flight deck. But there is the option to increase the number of operators to 24-25 persons.

“We’re approaching this design as though it will be a major node in the command-and-control network, including target information handoff to other aircraft such as strikers,” Summers say. “That number could change up or down, depending on workload and tasking studies. Automation will be key to our approach and continue to add capability to the platform.” Since any work station can do any operation, “the Navy can choose at any time to have more comint, elint or radar operators.”

Lockheed Martin, apparently concentrating on a “cost-effective, executable EPX program,” is considering rebuilt EP-3Es, a C-130J derivative or an Orion 21 development of the original P-3 design, Blesi says.

Northrop Grumman’s team has adopted the theme of “dynamic compose-ability.” Roughly, that means aircrews won’t be fixed. Each day the crews can be tailored for very different missions.

“Because of the distributed nature of onboard and off-board processing, we’re looking at a fully integrated, virtual crew with members that are half a world away and that have never met,” Hayden says. That could produce ripples throughout the personnel structure. “Not everyone will have to go through flight training and survival school. Some crewmembers will never have to leave the ground, and that will help the Navy with costs.”

Boeing plans to have an aircraft that is compatible with Air Force refueling airplanes. Northrop Grumman sees problems with relying on another service that’s not part of the planning for EPX.

“It’s not just the refueling system; it’s the force structure in the Air Force,” Hayden says. “Does the tanker force allow for that? I don’t know if they’ve contemplated the need to refuel maritime patrol aircraft while they’re out on station. What would that add to the cost?”