Since the First World War, airplanes have acted as Close Air Support (CAS) for infantry, though it's been a rocky marriage marked by poor communications and difficult teamwork. DARPA's Persistent Close Air Support (PCAS) project aims to improve coordination between air and ground forces by means of a digital system that works up to seven times faster than regular paper maps and voice radio instructions, and with greater accuracy.

CAS has the reputation as the biggest guns readily available to support infantry and other ground forces, but it's also notorious for being imprecise; only able to concentrate on one target at a time, dependent on voice directions, and needing up to an hour to call in an air strike on a target.

PCAS hopes to overcome these limitations by introducing real-time situational awareness and allowing closer cooperation between ground forces and almost any type of aircraft. The system has automated, digital, real-time coordination capability, and can work with rail-launched munitions, digital data links, and uses advanced software in support of ground forces.

Developed in cooperation with Raytheon Missile Systems, Bell Helicopter, Rockwell Collins, Kranze Technological Solutions, L-3 Wescam, and AeroVironment, PCAS is based on two components. The first is PCAS-Air, which a modular Smart Launcher Electronics (SLE) device that is plug-and-play, can run tactical software, and can be installed in almost any aircraft.

According to DARPA, PCAS-Air is able to handle not only weapons management, but intelligence, surveillance and reconnaissance (ISR), and communications, as well as integral navigation, and high-speed data transfer. It works in conjunction with PCAS-Ground, which allows PCAS-Air to communicate with ground forces, and provides situational awareness by means of mapping software installed on commercial Android tablets. Together, the two sides of PCAS can synchronize forces, map friendly units, recommend travel routes and selection of weapons, as well as their deployment.

DARPA claims that PCAS makes for closer, faster CAS that is more precise and easier to use even under full combat conditions, and also reduces the risk of friendly fire casualties and collateral damage. In addition, it allows the use of smaller munitions placed more precisely on smaller, multiple, or moving targets.

Another advantage of the system is that it can be quickly adapted to a wide variety of aircraft – an operation that usually takes months. DARPA says it's able to do this because the system uses commercial IT parts, a digital architecture, open interfaces, service-oriented software, element modularity, and mobile software. Also, PCAS is a system-of-systems approach, which means that it can work with a wide variety of platforms and is difficult to disable because knocking out one component merely degrades performance.

The agency says that PCAS was developed from conception to field testing in 120 days. It was previously tested in 2013 by US Marine forces in Afghanistan and Iraq using a component of PCAS-Ground called Kinetic Integrated Low-cost SoftWare Integrated Tactical Combat Handheld (KILSWITCH). Since then, the Marines have deployed thousands of the devices for testing and have noticed distinct improvements in navigation, situational awareness, fire coordination, and communications.

On March 27, the first major test of PCAS was carried out as part of a air-ground training exercise. This tested a full-scale prototype of PCAS as part of the the US Marine Corps training exercise Talon Reach in the southwestern United States and was the first time such a capability has been integrated with military aircraft.

In the exercise, the Marines used PCAS-Ground to identify a target next to an unmanned truck and relay its position to an MV-22 Osprey tilt-rotor aircraft equipped with PCAS-Air. This allowed the aircraft, ground forces, and command to confirm the target, coordinate an attack, and execute it in real time.

In this case,the attack consisted of a modified Griffin missile with a dummy warhead fired from 4.5 mi (9 km) away. This missile struck the target directly and DARPA says that it would have been destroyed had the warhead been live. Normally, such an exercise using conventional maps and radios would take half an hour, but PCAS was able to complete it in four minutes. This is even less than the six minutes that DARPA had been aiming for.

The Marines also used PCAS-Ground to coordinate a night ground attack. The KILSWITCH tablets allowed the Marines to synchronize with a small unmanned air vehicle (UAV), which provided ISR and radio relay capabilities. This let the Marines determine the location of friendly forces within seconds and improved coordination between the two Marine groups involved.

"On its first try, the full PCAS prototype system showed we could use a modular, system-of-systems approach to adapt an aircraft to provide close air support, and deliver that capability via real-time coordination with ground forces," says Dan Patt, DARPA program manager. "The successful tests point the way to a new model in which the addition of close air support, communications and live ISR support functions to any aircraft would be straightforward, and ground forces would have on-demand access to situational awareness data, modern network-enabled communications and a synchronized digital model of the evolving battlefield."

DARPA is now working on adapting the PCAS system to unmanned aircraft and as well as demonstrate it using a US Air Force A-10 Thunderbolt II attack aircraft.

The PCAS system is discussed in the video below.

Source: DARPA

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