Not-Quite-Secret Radar

New to the not-quite-secret file is the Raytheon-Boeing Littoral Surveillance Radar System (LSRS), a wide-aperture active electronically scanned array (AESA) surveillance radar that is now operational on P-3 Orions flown by VP-46 out of Whidbey Island. LSRS has been used in exercises in the Pacific and operationally in Southwest Asia. It's been mentioned in Jane's and a number of spotter sites, notably the Netherlands-based P-3 Orion Research Group which estimates that at least five aircraft have been modified.

The Boeing-Raytheon team -- the program's umbrella name is Advanced Sensor Technology (AST) -- accomplished 2800 hours of testing, apparently based at Love Field in Dallas, before achieving early operational capability in 2005, according to this official publication (pdf, last page).

LSRS is designed to provide targeting-grade tracking of moving targets on land and at sea. In September, one of the LSRS P-3s supported a test of the Navy/Boeing SLAM-ER missile against a moving target, a simulated SA-10 missile launcher, at China Lake;  follow-on tests were to use the same combination of systems against a maneuvering ground target. In 2010, LSRS is due to support a large-scale Joint Surface Warfare (JSuW) demonstration, providing targeting updates to air- and ship-launched weapons ranging from JDAMs to Harpoons.

Raytheon's role in LSRS is an upset of Northrop Grumman, which had previously dominated Navy trials of moving target indication (MTI) radars through the Gray Wolf and Hairy Buffalo demonstrations. (Both were Norden-legacy programs, Gray Wolf on an S-3 and Hairy Buffalo on a P-3.) LSRS presumably uses the "tile" AESA technology used successfully on the Super Hornet and JSF radars and also has high-resolution synthetic aperture radar (SAR) modes.

But the impact of LSRS may run beyond the Navy. In early 2003, Boeing changed its proposed design for the Multi-Mission Maritime Aircraft (MMA), using the 737-800 as the basis for the aircraft instead of the shorter-bodied 737-700. (MMA is now the P-8A Poseidon.) At the same time, Boeing located the MMA's weapon bay in the rear fuselage. The change was to accommodate a specific, classified capability, Boeing said. Given that Boeing is on the LSRS team it is not hard to guess what that capability is. The long, shallow LSRS antenna is sized for the P-8A's long, low-slung forward fuselage.

Meanwhile, the USAF's planned follow-on to the E-8 Joint STARS, the E-10A, was canceled in the FY2008 budget, and the USAF is still studying the cost of adapting the E-10's radar to the JSTARS platform. With LSRS, though, the P-8A is a modern, long-range, jet-powered platform with an AESA MTI radar and the necessary back-end systems - computers, operator consoles and communications - to support it. Moreover, the USAF has increasingly been evaluating the Joint STARS in the maritime and littoral environment.

--Bill Sweetman

(Photo credit:  Tim Lachenmaier)