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Guardrail/Common Sensor (GRCS)

Program History

Guardrail/Common Sensor (GRCS or GR/CS) was a seventh generation Guardrail product improvement program. The major requirements for the program included integration of the Advanced Quick Look (AQL) electronic intelligence (ELINT) system and the Communications High Accuracy Airborne Locations System (CHAALS). The objective was an integrated signals intelligence (SIGINT) capability that would permit the retirement of the aging RV-1 Mohawk aircraft with the Quick Look II ELINT system. The GRCS system was to provide full SIGINT on a single platform and would add targeting accuracy. Although the development of AQL and CHAALS were on-going programs under separate contracts, the GR/CS program got underway during the first quarter of FY85.

Other GR/CS upgrades included receiver pooling, digital intercom and digital temporary storage recording (DTSR), a greater aircraft payload capacity in order to carry the added subsystems, and the larger ELINT pods. Integration of the highly accurate Global Positioning System (GPS) equipment into the airborne navigation system was needed to support the TDOA capability. The RC-12K, with its larger PT-67A engine, was expected to become the new GRCS aircraft.

Due to schedule considerations, however, 6 RC-12D aircraft were modified to a RC-12H configuration for the initial GRCS System 3. System 3 was fielded in Korea to replace the aging Guardrail V system, which was in need of refurbishment and the 1960's vintage RU-21H's were not going to last much longer with the mission work load being flown in that theater. This meant that although System 3 had been tested with EDM AQL and CHAALS units, it was fielded without these subsystems. As a result the system was also referred to as GRCS (Minus) or GRCS (-).

Another upgrade to the GRCS system was the inclusion of 4 mission computers, rather than 1 computer, to handle the COMINT, AQL and CHAALS loading and to provide a back-up computer. Two of the 4 computers would be to support the AQL and CHAALS ground processing, while the fourth would back-up any failure of the Main System Computer (MSC) or backup the ELINT computer. This feature added a lot of reliability to the system by eliminating some single point failures.

The AQL program started in 1984 and underwent engineering design testing in 1985. The engineering design models were integrated and tested on the Systems 3 and 4 aircraft at Electromagnetic Systems Laboratory, Inc (ESL). The flight test program proved the AQL equipment to be accurate and it provided timely ELINT reports. This application of ELINT on a multi platform system with combined SIGINT capability was considered successful. Production AQL units built by ESCO were integrated on System 4 in the 1992 time frame.

The CHAALS development program had begun in 1972 as a joint Army/Air Force initiative. IBM developed the coherent processing and emitter location capability, while ESL developed the equalized Time Difference of Arrival (TDOA) receiver. Initial programs in the 1970's were the Emitter Location System (ELS) and the Mini ELS. This led to an 1980 flight test of the Coherent Emitter Location Test bed (CELT). CHAALS was a productive outgrowth of these programs. A Global Positioning System (GPS) was integrated into GRCS to achieve the required navigation accuracy for TDOA/DD measurements. Also, a third data link was necessary to support 3 aircraft missions that were required for the CHAALS TDOA/DD operations. New pods that could support both COMINT and ELINT simultaneously were developed for the Guardrail/Common Sensor platform along with a flight test and certification program.

GRCS 3 was deployed to the Republic of Korea in October 1988, on schedule. GRCS System 4 deployment was delayed until the Spring of 1991, so that production AQL and CHAALS units could be integrated and tested prior to fielding to the V Corps' 1st Military Intelligence Battalion (Aerial Exploitation) at Wiesbaden, Germany to replace the existing Improved Guardrail V aircraft.

Several quick reaction capability (QRC) enhancements were checked out in GRCS System 4 prior to fielding, then fully integrated in the field later in the year. These QRC upgrades added capabilities that were shown to be operational shortcomings in the Iraq conflict in early 1991. These included Lowband intercept, Upward frequency extension with programmed multi-channel demodulation, Special Radio Exploitation (SRE), a proforma capability and integration of a TIBS interface. Although not fully integrated into the Main System Computer (MSC) software, these PC based QRC software upgrades provided an important increased capability that might well be needed for any re-deployment to support insurgence or special operations around the world.

Another key post fielding QRC upgrade to GRCS System 4 was the Smart File Cabinet/FasTrack "smart mapping workstation". This product improvement program employed 2 Sparc SUN workstation terminals and successfully reused and expanded, a very large set of existing graphics software. It included ESL developed IR&D software for terrain mapping/mission planning, as well as geographic data bases developed by the US Government that were necessary to support this important system enhancement. Eventually, TIBS was interfaced to these workstations to provide the system with external multi-sensor data.

Some minor impacts to the GRCS System 4 schedule and fielding were experienced along the way due to the large amount of GFE. Integration of CHAALS and AQL presented some challenges, but the operational goals of the program were achieved. Some field modifications to the GFE ELINT software was required and some CHAALS support software for mission monitoring were deemed to be necessary post fielding upgrades.

The GRCS System 4 was delivered with 8 platforms. The ninth platform and its payload was held back to support flight certification for the RC-12N aircraft with its new multi function display (MFD) that enhanced the cockpit MMI. The aircraft was also needed to support various System 1 (the Objective System) next generation product improvements.

By 1994, the ever increasing advancements in computer technology compressed the cycles of hardware obsolescence to a couple of years. Processing power increased by an order of magnitude with each generation, performance per dollar increases even more rapidly. With this extra processing power, signal processing, data sorting, very wide band fiber optic buses, embedded training and all sorts of capabilities became available to the Guardrail system during GRCS development. International standards were also coming on line to control and define computer interfaces. These standards along with software languages that include development standards, now make software reusability a reality. Since it was no longer practical to control the future availability of particular computer hardware, nor would one want to limit system capabilities and speed by doing that, it became apparent that a different approach to avoiding obsolescence was required.

ESL, under IR&D, and on other joint programs, such as the advanced SIGINT Fireworks program, put forward 2 initiatives to resolve that dilemma. The first, was the application of a real time tactical system processing architecture that was based on use of international standards and use of the 7 layer, Ada protocol. The second technology advancement was the Advanced Tactical SIGINT Architecture (ATSA) initiative that employed a "unified architecture" that was bus oriented and employed all Ada software in a shared asset payload. In this manner, the architecture and the software standards became the basis for the system, not the vintage of computer hardware. As new computer and bus technology came along, so would the method of adapting to the established standards. As new languages come along, they would also be required to be compatible with Ada "objects".

The new airborne distributed unified architecture shifted away from the traditional philosophy of integration of dedicated hardware subsystems with typically non-reusable software that was very difficult to upgrade and that was usually not compatible to new generation computers. Rather ATSA uses shared assets and established standards to define all interfaces, and became an open system architecture that could accept capabilities from anyone who followed the "rules." Distributed, unified architecture was the driver for the Guardrail System Technology Insertion Program, part of the GRCS. Onboard assets had bus structures that were bridged to the ground facilities bus via the data link and were synchronized so that signal data can be re-constructed whenever tasking required it.

GRCS System 1, also known as the Hybrid System, provided the distributed processing Integrated Processing Facility (IPF) that was also downward compatible with older Guardrail system payloads and planned Air Force systems. System 1's payloads were identical to the GRCS System 4, except it had extended coverage, lighter weight intercept receivers and had an improved interference reduction system that was required by agile on-board avionics radios and the TRIXS Relay. The System 1 program started in September 1991.

System 2, also known as the Objective System, on the other hand, focused on a new on-board architecture designed to deal with the evolving signal environment and at the same time furthered reduces weight. Use of common modules and Ada software from an on-going development program, formed the basis for the new "Unified" Guardrail system payload architecture. The System 2 payload was designed around a wide band signal fiber optic "Data Flow" bus, an FDDI bus, and a synchronization fiber bus. This technology had been already designed and laboratory tested. Shared general purpose processors were being used to perform signal processing and on-board data base management. These modules used established standards or were participating in establishing standards where they did not yet exist. The newest generation of the Interoperable Data Link, CHALS-X and AQL ELINT were being employed in the system as were wide band, multi-channel tuners and active antennas. Although ELINT equipment was not initially unified, it was moving toward that goal by integrating airborne ELINT processing into the common, distributed processors. This phase II portion of the program started early in calendar year 1992, with major follow-up ECP's.

Other planned upgrades as of 1994 included embedded training, advanced smart map sensor management support, automated multi level security reporting, expanded proforma exploitation and integration of the three channel CTT with its multiple interfaces and protocols. These protocols include compatibility with TRIXS, TIBS, TRAP/TADIXS-B It potentially can communicate via Satcom nets.

All the systems except for Guardrail System 2 had been fielded by 1996. GRCS System 2 was in the Engineering and Manufacturing Development phase in California at that time, expected to be fielded during FY97. The Northrop Grumman Mission Systems-developed GRCS System 2, also called Guardrail 2000, was to be a key component of the Army's next-generation Aerial Common Sensor System that would provide battlefield commanders with the world's most advanced tactical surveillance data for the 21st century. Guardrail 2000 was the seventh generation of successfully fielded Guardrail systems over the span of 29 years. Previous versions had been used to provide enemy location information during Desert Storm and to support the Bosnia peacekeeping effort. The system, comprised of a twin-engine Beechcraft airplane and a ground station that remotely controlled the flow of intelligence data, formed the foundation for the Army Corps intelligence collection and serves as a critical element of the national intelligence collection infrastructure.

By the end of the 1990s, GRCS System 4 was operating in Europe with V Corps, System 3 was operating in Korea in support of US Forces Korea, System 2 had been fielded to XVIII Corps, and System 1 had been fielded to XVIII and III Corps. System 1 had been fielded to XVIII Corps in 1994 with a remote relay capability that allowed forward deployment of aircraft while the ground processing facility remained in CONUS. In Europe Guardrail systems had supported Operation Joint Endeavor ENDEAVOR and XVIII Corps had deployed the system in support of the combined Exercise Atlantic Resolve.

In 2000, the Aerial Common Sensor (ACS) program was initiated, a joint US Army-US Navy program intended to provide a common replacement for Navy's EP-3E Aries fleet and the Army's Guardrail system. The Army also hoped that the new system was allow for the replacement of the Airborne Reconnaissance - Low (ARL) system. The ACS program was canceled in 2006. In its place, the US Army initiated the Enhanced Medium Altitude Reconnaissance and Surveillance System (EMARSS) program, which was intended to leverage work that had been done in fielding QRC systems in support of the Global War on Terror and subsequently Overseas Contingency Operations. EMARSS was itself cancelled in 2012. This renewed focus on an improvement program for GRCS. The GRCS upgrades included expanded frequency ranges, a capability to locate signals in both stand-off and stand-in modes, and an adaptive beam-forming antenna array that was capable of locating emitters in the dense signal environments. Collectively, these capabilities, making use of an improved RC-12X aircraft, provided a unique tactical focus to prosecute modern networked targets encountered in the era of persistent conflict. The development of the RC-12X and further GRCS upgrades was to ensure that the system would remain operational until 2025.

The purpose of the Guardrail Modernization Program was to significantly improve the system's tactical Irregular Warfare capability, while maintaining its Full Spectrum performance. The Guardrail Modernization program included 3 main efforts: cockpit modernization, external aircraft modifications, and payload upgrades. Initial planning established an overall schedule to integrate all of these efforts, while minimizing impacts to existing Guardrail operations in support of Operation New Dawn and Operation Enduring Freedom.

The GR/CS modernization effort provided A-Kits for the fleet of 14 RC-12X mission aircraft with capabilities that would allow GR/CS to keep pace with a flexible enemy. Communications High Accuracy Location Subsystem-Compact (CHALS-C) provided precision geo-location and supported Theater for Net-Centric Geo-location (TNG) Architecture Cooperative Operations. Enhanced Situational Awareness (ESA) provided modern airborne COMINT subsystem and infrastructure. High Band COMINT (HBC) provided enhanced capability to intercept, locate, and exploit high frequency COMINT signals. Special Signals (SS) provided enhanced X-MIDAS hardware architecture and capability to intercept and exploit special signals. ELINT was standardized in a P-Pod configuration on 14 aircraft and provided AQL processing B-Kits.

In addition, to meet the requirements of the surge of American forces into Afghanistan in 2009, a additional system to be coupled with the GR/CS and RC-12X in development, called ZIONBOBCAT, was delivered in theater within 4 months of approval of the initiative. ZIONBOBCAT delivered high performance active/passive signal intelligence capability for 8 RC-12X aircraft operating in a high-density-emitter environment over mountainous terrains.

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Page last modified: 20-07-2012 13:50:05 ZULU