Raytheon is moving ahead to demonstrate more rapid and accurate close air support after finalizing a contract with the U.S. Defense Advanced Research Projects Agency (Darpa) to continue the Precision Close Air Support (PCAS) program.

PCAS has been modified to shift the emphasis from automating close air support by enabling ground forces to control the weapons on unmanned aircraft. Instead, the program has been focused on transitioning technology to manned CAS aircraft.

The original plan was to demonstrate unmanned CAS using a Fairchild A-10 converted to optionally piloted mode by Aurora Flight Sciences. Now PCAS will be demonstrated using a manned A-10, says Dave Bossert, Raytheon program manager.

“The fundamental goal is still the same: to decrease the timeline by a factor of 10 from a request for fire to an effect on target — from 60 min. to 6 min. for an A-10 20 nautical miles away,” he says. “And we will still use the A-10, but not optionally manned.”

The modified program comprises two elements. PCAS-Air is the airborne system, providing the interface between the aircraft and the joint terminal attack controller (JTAC) on the ground. PCAS-Ground is the JTAC kit, including Android tablet computer, head-up display and radio.

PCAS will provide improved communications and situational awareness for the JTAC and CAS pilot, with all-digital messaging and shared displays of sensor imagery, targets, weapons and their effects.

“The PCAS-Air piece was the A-10. Now it is “Smart Rail” electronics small enough so that anything that can carry the Hellfire missile can be PCAS-Air-enabled,” Bossert says. “We are platform-agnostic, sensor-agnostic and radio-agnostic.”

The Smart Rail includes a computer that hosts the PCAS algorithms, a GPS/inertial navigation system, and it talks to the JTAC via a dedicated data-link radio and to the aircraft sensors and an Android tablet in the cockpit via an interface box.

“Tight coupling of the JTAC and pilot is key,” Bossert says, with PCAS providing the JTAC access to computing power and high-resolution sensors on the aircraft without the Smart Rail being part of its operational flight program. “It is separate from, but hosted on, the aircraft.”

Raytheon’s modified $12.9 million Phase 2 contract will culminate in a critical design review in November, and Bossert says there is a “high probability” Darpa will proceed into the 18-month, $25.5 million Phase 3 flight demonstration.

The program changes reflect a shift in focus for near-term transition of PCAS to manned CAS, from unmanned. “One of the original sponsors when we started was the MQ-X [unmanned aircraft] program. There is no MQ-X anymore,” he says.

“The primary focus was never the optionally piloted A-10, and it became somewhat distracting,” he says. Instead of enabling the JTAC to directly control weapons on an aircraft, PCAS is most likely to transition as an autonomous decision aid for the pilot. “Manned CAS has the biggest need,” he says.

“It will be part of their situational-awareness decision aids, showing recommended actions for both the pilot and JTAC,” Bossert says. “For the PCAS demo we still plan autonomous weapons employment, but a pilot will fly the A-10 and be able to override the autonomy.”

The live-fire demos in 2015 will involve the A-10’s gun, a Joint Direct Attack Munition GPS-guided bomb, a Laser Maverick missile, dual-mode laser/GPS weapon and 2.75-in. rocket.

After the demo, PCAS will be able transition “to any fixed-wing, rotary-wing or unmanned aircraft that can carry Hellfire [or larger weapons],” Bossert says.