High Value Targets Marked for 'Locate and Kill' Strikes via RC-12s
By Miriam Adler ·
Targets in Central America and Korea were reduced to "emitters" for artillery strikes using a system that turns radio signals into coordinates for first round fire.
The aircraft orbits to the rear and parallel to the forward line of own troops. From an altitude of 20,000 to 30,000 feet, it doesn't look for people, but for the invisible wake they leave in the air. It is searching for "selected low, mid, and high band radio signals," according to a program description hosted by the FAS Intelligence Resource Program.
This is the Guardrail Common Sensor (GR/CS). It is a Corps Level Airborne Signal Intelligence (SIGINT) system that converts the act of communication into a coordinate. By integrating the Improved GUARDRAIL V, the Communication High Accuracy Airborne Location System (CHAALS), and the Advanced QUICKLOOK (AQL), the system transforms a modified Beechcraft Super King Air—designated as the RC-12—into a predatory ear. The objective is not merely to listen, but to locate.
"Locate and Kill"
The clinical language of the FAS mirror does not hide the lethal intent of the hardware. The documentation specifies that the CHALS-X system provides the targeting capability required to support a Division Commander's requirements to "locate and kill the enemy." It does this by providing the "precise location of High Value Targets (HVTs)."
There is a terrifying efficiency in the transition from a radio wave to a crater. The record notes that by mixing airborne systems with ground-based systems, the military can locate enemy weapon systems and units regardless of whether they use "conventional or modern radios." The result is a set of coordinates "sufficiently accurate for first round fire for effect by organic artillery.
In this workflow, the human being on the ground is reduced to an "emitter." The process is stripped of its physical violence and reorganized as a data problem. The system uses Time-Difference-Of-Arrival/Differential Doppler (TDOA/DD) techniques, utilizing advances in electronics to shrink the processing hardware. What once required three racks of computer equipment was reduced to "two boxes which fit into a standard 19 inch rack." The machinery of death became more compact, more portable, and more precise.
Document imagery from irp.fas.org From the files: irp.fas.org
20,000-30,000 Feet
The operational structure of the GR/CS is a study in remote execution. The aircraft themselves—the Airborne Relay Facilities (ARF)—are "manned only by the pilots during a mission." The actual intelligence work is done elsewhere. The equipment is "remotely controlled by operators in the Integrated Processing Facility (IPF)."
This separation creates a profound distance between the operator and the target. The IPF serves as the control, data processing, and message center. Information is processed and then reported to "joint consumers" via a TRIXS broadcast. This data is then pushed to Commanders Tactical Terminals (CTTs), providing "near real-time SIGINT and targeting information" to tactical commanders throughout the corps area.
The system is designed for "Deep Battle" and "Follow-on Forces Attack support." It is a tool for reaching far behind the front lines to strike targets that believe they are out of range. The record indicates that the entire system, minus the aircraft, is "C-130 transportable," allowing this capability to be dropped into any theater of operations with rapid deployment capability.
Document imagery from irp.fas.org From the files: irp.fas.org
Central America and the Inter-German Border
The Guardrail system has been a constant shadow over several decades of conflict. According to the record, the system provided coverage along the inter-German border from 1972 through 1990 and has been active in Korea from 1974 to the present.
Of particular note is the system's deployment in Central America from 1983 through 1994. During those years, the "locate and kill" capability was operational in a region defined by brutal counter-insurgency campaigns and state-sponsored violence. The record does not specify which "High Value Targets" were being tracked in the jungles of Central America, only that the system was there.
Two systems were also deployed to Southwest Asia during Operations DESERT SHIELD and DESERT STORM. By 1994, the system had evolved further, with the XVIII Airborne Corps system featuring a "remote relay capability" that allowed aircraft to be deployed forward while the ground processing facility remained in the continental United States (CONUS).
As the technology advanced, so did the connectivity. The later iterations of the system, such as the GRCS System 1 (AN/USD-9C) and System 2 (AN-USD-9E), added the capability to operate worldwide via the GRCS Tethered Medium Earth Terminal (TMET) and the Direct Air to Satellite Relay (DASR) aircraft (RC-12Q). This effectively removed the last geographic barrier, allowing the United States to listen and target anywhere on the globe in near real-time.
The FAS mirror lists various personnel designations for the operation of these vans, specifically mentioning MOS 98C, 98D, 98G, 98J, and 98K. It leaves us with a final technical detail: the system's reliance on UNIX-based workstations and fiber-optics distributed data interfaces to ensure that the signal reaches the artillery battery as quickly as possible. The record stops at the delivery of the data, leaving the actual impact of that "first round fire for effect" to the archives of the battlefields.