Guardrail/Common Sensor (GRCS)
System 2 / Objective System / Guardrail 2000
Guardrail Common Sensor System 2, also known as the Objective System or Guardrail 2000, is nomenclatured as the AN/USD-9(V)D Special Purpose Detection System. System 2 is a Corps asset that collects and accurately locates SIGINT signals in real time and disseminates high value, target accuracy, intelligence in near real time. The system is designed to provide vital information on the targeted area of interest for mission scenarios that cover: 1) peace time reconnaissance search and collection operations (PRSCO)/training missions and 2) battlefield tactical operations in various levels of conflicts.
Major capability enhancements to the System 2 payloads expand the signal set capability and adds important mission flexibility to the system with its "Unified Architecture". The ARF architecture assists in the efficient acquisition, location, signal processing and expedites situational analysis of signals of interest. The IPF operators can now obtain information from the ARF via task oriented queries, by using predetermined signal environment filters or by manual operation.
System 2 is capable of operating against a large set of signals using multiple band antennas and supports modern modulation types over a wide range of COMINT and ELINT frequency bands. Baseline System 2 mission assets provide the operators with the resources to acquire, identify and copy a combination of conventional signals and exotic signals. Automated and manual analysis of collected data allows a more rapid response to tasking from tactical consumers. The preprocessed collected data is used to turn raw intercepts into usable intelligence reports which are disseminated over a variety of communications nets.
The GRCS System 2 is composed of a set of SIGINT sensors and a shared modular processing package which resides in the airborne segment. It has a System 1-like IPF that provides the ground based command, control, and processing segment which resides in a set of transportable IPF shelters. A support segment provides various storage, maintenance, and support facilities. The sensor package consists of COMINT and ELINT antenna and receiving systems with powerful back-end processing capabilities.
The system remote and local data buses are bridged together in a way that is transparent to system operation. This architecture efficiently provides system functions that include manual and automatic signal acquisition, SIGINT signal intercept monitoring and signal recording, emitter location and targeting, signals processing and analysis, system control and mission planning, and intelligence reporting capabilities. The system is physically defined as three segments (Ground, Airborne and Support).
The Airborne Segment is the remote sensor that is linked to the Ground Segment. Both the ground and airborne segments interface with GPS satellites to provide precision time tags and location information for the collection and processing of signals. During a standard mission, system operators perform the functions of signal activity monitoring and system control, signal acquisition, collection, location processing, signal processing, data analysis, and reporting within the Ground Segment. The system supports multiple reporting links such as the CTT which relays TACREPS, TACELINT reports, voice comms and has the protocol for TIBS, TRIXS and TRAP/TADIXS-B. MSE, Autodin, secure phone and secure fax capabilities are also part of the dissemination capabilities.
The ground segment consists of 4 primary subsystems. The subsystems are functional equipment groupings which have different functions but similar levels of hierarchy. The IPF Platform, Communications, IPF Information Distribution, and IPF Control and Processing subsystems.
The IPF Platform Subsystem consists of the physical vans, racks, cabling, climate control, power distribution, lighting/security equipment and biological/chemical protection. It also provides the various life support, safety and HUMINT accommodations. The Platform Subsystem physically supports the IPF mission electronics. The Communications Subsystem consists of all equipment utilized for data link transmissions to and from the airborne segments, communications self test, reporting and external net connectivity. The Information Distribution Subsystem provides the FDDI fiber optic networks with its standard protocol that allows information to be passed from one node to the next within the system. This subsystem includes all servers, local area networks, and programmable adapter modules that interface the FDDI LAN to with non-FDDI standard or mission peculiar devices. The Control and Processing Subsystem consists of all of the elements which provide for executing the mission functions including the Universal Workstations.
The System 2 IPF was based on the System 1 IPF distributed architecture. Changes to the ground system were limited to those related to new system requirements that rippled into the IPF design. Major architectural changes were primarily to the ARF and AGE. All System 1 functionality was retained, but various enhancements were added.
System 2's airborne unified architecture was a technology transfer that used state of the are technology that includes MCM techniques, RISC processors, and fiber optic buses. These were all interfaced into a unified system to provide a flexible system that has allocable processing to the various priority functions performed in payload, including conventional signals and LPI capabilities. This a shared asset approach to signal collection and distributed on-board signal processing.
System 2 featured a new generation CHALS-X COMINT TDOA system. CHALS-X features modern VME based ground processing and expandable on-board processing. It has provisions for future air to air operation that will result in a significantly reduced CHALS-X link data rate, which is needed for a daisy chained air-to-air link and a future direct satellite relay.
The Enhanced AQL ELINT used on System 2 uses a common CMC architecture type airborne processor and a single panel antenna array for reduced weight. It includes antenna provisions for a drop-on receiver that was to support WB dwell-scan operation over an expanded frequency band. Has planned future expansion that would provide expanded on-board processing that supports reduced link bandwidth needed for direct satellite relay.
System 2 featured a new generation interoperable Multi-Role Data Link (MRDL), which includes ground based Modular Interoperable Surface Terminal (MIST), the portable GSE in the MMV , and the airborne Guardrail Dual Data Link (GDDL). The GDDL is a dual channel Ku band version of the X band MIDL. The GDDL has provisions for air-to-air link-up between platforms concurrent with air-to-ground operation. A major improvement in the MRDL is its variable serial data rate at its I/O.
Automatic on-board recievers included in System 2 search and hand off to intercept receivers is enhanced to support several new signal acquisition scan plans. A Wide Band Multi-element direction finding system is also fitted. This 6 channel direction finding system replaced the older 2 channel switched baseline system. The system uses 6 wide band tuners that are routed through Digitizer, FFT's and signal processors using a fiber optic network. The wide band front-end is required to support LPI processing. Automatic search rates are increased by a factor of 1000.
System 2 is able to acquire, track, locate and copy Low Probability of Intercept transmissions. It can simultaneously locate LPI and conventional emitters. One platform is seized for copy when multi-search and direction finding functions are in progress.
System 2's identification processing was been transferred from the IPF to the payload. This resulted in a factor of 3 increase in capacity and supports reduced link bandwidths required for the planned future satellite relay.
In System 2 IPF Link PAM's were upgraded to support the bulk serial MRDL interface and provide the system communications control. An airborne data link PAM was added to support the airborne link interface. Additional workstation software changes were incorporated to support the new CHALS-X and LPI.
System 2 also involved the upgrade from the RC-12N to the RC-12P aircraft. The RC-12P featured new pods with a single panel ELINT array and drop-on receiver antenna provisions were added. These aircraft incorporated the unified architecture racks, cables and fiber optics provisions and provides weight reductions.
The System 2 aircraft also allowed for onboard preflight checkout. The CMC architecture and the new generation MRDL and CHALS-X have self test and fault indicators. The on-board bus structures support end to end test of system functions and interface to monitoring panel that displays system health and failure modes during preflight check-out. This new feature allows autonomy for quick deployments and expedites premission testing.
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