A full-scale development program is underway to develop a version of the U. S. Navy's Boeing P-8A Poseidon maritime patrol aircraft (MPA), fitted with a long-range, high-resolution surveillance radar. It could provide a ready-made, Navy-funded replacement for the aging Joint Stars while potentially performing maritime targeting missions.

The Raytheon Advanced Airborne Sensor (AAS) project, which has been under contract since July 2009, has received Milestone B approval for development and production planning and is proceeding toward critical design review.

Boeing received a $277 million contract in February to modify the first P-8A, aircraft T-1, for aerodynamic and structural tests of the AAS radar pod, which is carried under the fuselage. Those tests are to be completed by August 2016. The radar itself, a much-modernized evolutionary development of the Raytheon APS-149 Littoral Surveillance Radar System (LSRS) is to be tested on a P-3C Orion, the current carrier for the APS-149. The value of the radar development contract has not been disclosed.

The Navy's goal is to acquire an undisclosed number of AAS systems and A-kits (parts that are attached to the aircraft to support the radar) and to configure some P-8As to carry the radar. Initial operational capability dates are also secret, but Boeing/Navy P-8A briefings suggest it is likely to follow the 2016 fielding of the P-8A's Increment 2 upgrade.

The P-8A radar plan has been in the works for almost a decade, but has been shrouded in secrecy because its predecessor, LSRS, was a black program—a classified and unacknowledged effort. To this day, although some AAS-related contracts have been announced, the program has no publicly visible budget. None of its elements has been competed or subjected to a formal analysis of alternatives process. AAS is managed by a one-program office, Advanced Sensor Technology, under the direction of Rear Adm. Don Gaddis, program executive officer for tactical aviation at Naval Air Systems Command.

LSRS itself was developed by the former Texas Instruments unit of Raytheon, which has historically provided Navy patrol aircraft with their search radars. The program started in the late 1990s or early 2000s and attained early operational capability in 2005, carried on P-3Cs flown by patrol squadron VP-46 out of NAS Whidbey Island, Wash. After the program was mentioned (apparently accidentally) in an unclassified document, and the modified aircraft had been photographed in transit to and from the Middle East, a small amount of information was released.

It is known that the LSRS P-3s have been extensively used both to support combat operations—not only for the Navy—and for tests and demonstrations, including tracking both land and maritime moving targets for engagements by stand-off missiles.

Based on active, electronically scanned array technology, LSRS has been assessed as far superior to the older APY-7 carried by Joint Stars. The antenna is double-sided, so the aircraft can scan simultaneously to left or right, and the radar can interleave ground moving target indication (GMTI) and synthetic aperture radar (SAR) modes rather than being restricted to one mode at a time.

AAS is expected to be more capable than LSRS, and will include new features such as NetTrack, developed by the Defense Advanced Research Projects Agency, to track high-value targets—for example, key insurgent personnel and their vehicles—in high-clutter environments, by using high-range resolution radar measurements. AAS has what Boeing describes as “weapon-capability” accuracy, and Boeing illustrations and videos show aircraft directly striking ground targets with Small Diameter Bombs.

However, the system could also have potential for maritime operations. In 2004, the USAF used Joint Stars to guide datalinked weapons onto ship targets in the Resultant Fury exercise, using technology from the Affordable Moving Surface Target Engagement project. The latest Naval Aviation Vision report, published in March, discussed development of a follow-on strike weapon to replace Harpoon and SLAM-ER, which will be “net-enabled” and a maritime interdiction version of Tomahawk—both of which would be designed to exploit long-range, high-resolution targeting from other platforms.

Plans to develop this version of the P-8A started in 2003, before Boeing was selected as the winner of the Navy's Multi-mission Maritime Aircraft (MMA) program. At that time, Boeing changed the basis of its MMA design from the 737-700 to the longer-bodied 737-800 and introduced an aft weapon bay and two forward-fuselage centerline hardpoints. At the time, Boeing would only say the design was to accommodate a classified Navy capability, but in fact, it was to accommodate the antenna of the LSRS.

The inter-service politics of the program are intricate. The Navy is apparently willing to dedicate some of its P-8s to a largely overland, joint-service mission, possibly to maintain support for its large MPA force, while Boeing sees potential for selling up to 15 air-ground surveillance versions of the P-8A to the Air Force to replace Joint Stars. The USAF “is really fighting to not put any more money into large-platform GMTI,” says one observer. “I can't honestly see how they win that fight in the long run. It's too easy for the Army to claim they absolutely need GMTI and the Air force must provide it.”