The system incorporates either a communication high-accuracy airborne location system (CHAALS) or a communication high-accuracy location system - exploitable (CHALS-X) to achieve precision target locations for its COMINT system.

Each aircraft is remotely linked to an integrated processing facility on the ground. The GR/CS system #1 operates in direct-tethered mode or ground-tethered satellite remote mode. GR/CS system #2 is finishing production and will add the extended direct-tethered and direct aircraft-to-satellite remote modes of operation as well as single aircraft untethered mode. Both systems can be deployed in a two-van configuration by C-130 aircraft.

A ground relay facility is being developed that will modernise and replace the GR/CS integrated processing facility. The ground relay facility will be a downsized, repackaged version of the processing facility that will improve its deployability and mobility, upgrade its capabilities and allow split-based operations.

Airborne reconnaissance low
ARL is a multifunction, day/night, all-weather reconnaissance intelligence asset developed and fielded by the army in support of a requirement for a low-profile intelligence aircraft. It is a modified DHC-7 fixed-wing aircraft with SIGINT and IMINT mission payloads controlled and operated via onboard multifunction workstations.

ARL supports operations in low- to medium-intensity conflicts and performs domestic relief and humanitarian aid. Because it is self-deployable and self-sustaining for seven to ten days, it can be used as a force projection asset. It can be redeployed quickly wherever and whenever needed.

Currently there are three ARL configurations: the ARL-IMINT (ARL-I) with an imagery payload consisting of a forward-looking infrared (FLIR) sensor, an infrared line scanner (IRLS), and a daylight imagery system (DIS); the ARL-COMINT (ARL-C) with a conventional communications intercept and direction-finding payload; and the ARL-multifunction (ARL-M) with communication intelligence (COMINT), imagery intelligence (IMINT), and moving target indicator/synthetic aperture radar (MTI/SAR) subsystems. Two ARL-M systems with MTI/SAR capability were delivered and fielded to US Forces Korea in September 1996. The third was delivered a year later.

In December 1996, the army procured two further ARL-M systems with delivery scheduled in December 1998. The COMINT subsystem on the ARL-M, called Superhawk, provides an electronic support measure capability for intercept, identification and location of communications signals. The IMINT subsystem on the ARL-M includes an infrared line scanner, a forward-looking infrared sensor and a daylight imaging system.

The ARL-M also integrates a moving target indicator/synthetic aperture radar capability that detects and tracks moving targets at long stand-off ranges and provides medium image-resolution synthetic images of fixed targets. The MTI radar is multi-mode, performing wide area MTI, single-beam scan and narrow sector search for improved tracking and probability of detection.

Intelligence collected on the ARL can be analysed and recorded on aircraft workstations in real-time or stored on-board for post-mission processing. During multiple platform missions data can be shared between co-operating aircraft via an air-to-air data link to allow multi-platform COMINT geo-location operations.

The ARL is capable of downlinking to existing ground stations and portable ground terminals. The ARL-M can downlink its MTI data to the joint STARS medium ground station module (MGSM). The same capability exists for the joint STARS common ground station that will replace the MGSM.

Upgrades under investigation include improved sensors, a high-speed common data link (CDL) compatible data link and other payloads. Approved updates now include block upgrades to the radar system and additional dissemination links.

GR/CS and ARL are complementary sensors. GR/CS stands off and flies in the beam for communication intelligence (COMINT) and electronic intelligence (ELINT). ARL flies low to create conventional imagery intelligence (IMINT) or higher to take advantage of its radar sensors such as moving target indicator (MTI) and synthetic aperture radar (SAR). GR/CS and ARL systems are at the ground commander's disposal, providing situational awareness in near real-time. Detecting the enemy through emissions across the electromagnetic spectrum, they look at the battlefield in depth. And GR/CS's real-time location of targets means commanders have an unprecedented vision of the battlefield.

GR/CS performs COMINT and ELINT missions daily in Bosnia. In terms of availability and mission-completion rate, it is the most reliable aerial sensor in the field. GR/CS and ARL have supported the army's Taskforce Eagle and NATO's implementation and stabilisation forces in the execution of their missions. GR/CS and ARL both fly sorties in Korea. In future they will evolve to a more powerful platform, the aerial common sensor (ACS).

Aerial common sensor
ACS will provide the warfighter of Army XXI and army after next (AAN) with information superiority and battlefield situational awareness. It is an integrated multi-intelligence system containing sensors such as COMINT, ELINT, MTI, SAR, daylight imaging system (DIS), forward looking infrared (FLIR), foliage penetration (FOPEN) and measurement and signature intelligence (MASINT). ACS will capture and analyse data based on a commander's needs. It will use a reconfigurable suite of sensors to capture SIGINT and IMINT information from several aircraft simultaneously and will locate targets with precision to support present and future weapon systems.

ACS will be a powerful force multiplier in the 21st century, creating information dominance on tomorrow's battlefield.