Littoral Surveillance Radar System
The Littoral Surveillance Radar System (LSRS), recently designated the AN/APS-149, is a active electronically scanned array (AESA) surveillance radar, currently used on several P-3 Orion aircraft, originally maritime patrol aircraft, which, with the end of the Cold War blue-water focus, have been increasingly used in littoral and overland operations. There is considerable speculation that this system, or a variant, will go onto next-generation surveillance aircraft.  While it is termed a "surveillance" radar, it is intended to provide sufficiently accurate information for the targeting of intelligent weapons, such as the AGM-84 SLAM-ER. In 2010, a large-scale Joint Surface Warfare (JSuW) demonstration, providing targeting updates to air- and ship-launched weapons ranging from Joint Direct Attack Munitions to AGM-84 Harpoons.
The radar probably uses the "tile" AESA technology of the F-18 Super Hornet and Joint Strike Fighter radars, which also provide high-resolution Synthetic Aperture Radar (SAR) and Moving Target Indicator modes.
On October 4, 2006, the Boeing-Raytheon Advanced Sensor Technology Team received a Defense Acquisition Executive Certificate of Achievement.  They performed 2800 hours of testing, apparently based at Love Field in Dallas, before achieving early operational capability in 2005.
In FY 2008, the U.S. Department of Defense cancelled the budget for the planned E-10A C3I-ISR aircraft, which was to replace and consolidate a number of existing programs on weary airframes, such as the E-8 Joint STARS. Not cancelled, however, was the P-8 Poseidon, initially designated as the replacement for the P-3 Orion. The P-8, which recently entered operation, was originally planned by its manufacturer, Boeing, to use a modified commercial Boeing 737-700 airframe. In 2003, however, they changed the platform to the longer 737-800, giving only the reason that it would support a "classified capability". At the same time, they placed the P-8 weapons bay in the rear fuselage. The LSRS antenna array is believed to be long and shallow, fitting the lengthened forward fuselage of a 737-800.
A P-8 with LSRS may be a viable alternative, on a modern aircraft, to the E-10 and its planned radar. The Air Force had also been evaluating the E-8 Joint STARS, originally for land surveillance, for traditionally Navy maritime and littoral missions.
While the system remains highly classified, it has been reported that it has the ability to detect individual people as well as vehicles. Pod-mounted LSRS units, attached to P-3 aircraft, were used in Iraq. "LSRS systems “are a national asset. The testing community becomes a second priority when an LSRS is needed for real-world operations, and I’ll leave it at that,” said Navy Capt. Mat Winter, who hopes to adapt precision missiles to receive updates from sensors including LSRS. "
- Bill Sweetman (May 17, 2007), Not-Quite-Secret Radar, McGraw-Hill Aviation Week blog
- "Advanced Sensor Technology Team awarded Defense Acquisition Executive Certificate of Achievement", Defense Acquisition and Logistics Excellence, March-April 2007, p. 79
- Stephen Trimble (11 October 2010), "US Navy to keep some P-3Cs, despite replacement by P-8A", Flight International
- Keith Button (1 January 2009), "Revealing radar: U.S. Navy partially lifts shroud on insurgent-tracking system", C4ISR Journal