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Saving Lives with SABER™

Institute researchers develop situational awareness system to eliminate deadly confusion on the battlefield

by M. LaVarre Bushman and
James A. Moryl

The term friendly-fire is one of the oxymorons of battle -- all military personnel know that incoming fire, whatever the source, isn't friendly. To help prevent this unfortunate incident of war, a team of engineers and scientists at SwRI has developed SABER, an economical and effective solution to the problem of fratricide

LaVarre Bushman (left) and Jim Moryl have worked with SABER™ (Situational Awareness BEacon with Reply) since its inception in 1992. Moryl, who at that time was manager of Tracking Systems in SwRI's Signal Exploitation and Geolocation Division, pioneered the SABER concept with U.S. Navy Commander Austin Boyd and M. Pike Castles, former director of the SwRI Surveillance and Geolocation Department. Moryl, now department director, is the architect of the system's operational hardware, and Bushman is manager of Program Support in the same division.

SABER (Situational Awareness BEacon with Reply) is a sophisticated battle group situational awareness system that is capable of determining the location of beacon-equipped tanks, ships, aircraft, and other military assets worldwide. Using the Global Positioning System (GPS), SABER produces accurate position and platform identification data and sends that information to tactical users and global command and control nodes, where it can be shared to enhance overall communications during military operations. The system relays position information via robust ultra-high frequency (UHF) line-of-sight and UHF satellite communications (SATCOM) channels.

Command and control terminals can be deployed onboard ships, in aircraft, or at ground facilities to receive SATCOM downlinks and line-of-sight transmissions. Terminals acting as network controllers can query individual beacons or program beacons to report automatically. The system architecture can support a global network of 60,000 beacons reporting hourly over a single 25-kHz channel, and reporting up to 16 positions per second on separate 25-kHz channels for line-of-sight networks. Beacons transmit both periodic and on-demand messages that provide tactical and theater SATCOM for friendly force situational awareness. Platforms equipped with SABER allow operators to monitor and display reports from similarly equipped platforms.

SABER beacons also function in an "intent to shoot" and "friendly identification" query and response mode that polls an area to determine the location of friendly elements. "Shooter" platforms -- air, sea, or land-based vehicles carrying weapon systems -- select a target, identify a radius of concern for friendly interrogation, and command the onboard beacon to poll the area with an intent-to-shoot message. For anti-fratricide considerations, the radius of concern generally includes the kill radius and the damage radius of the weapon, which differs for each type of weapon. For example, a weapon may have a kill radius of 30 meters and a damage radius of 80 meters.

On receiving an intent-to-shoot query, all beacons compare their own locations with the target location. Friendly platforms located within the area of concern respond with a "don't-shoot-me" warning message. These messages are displayed on the shooter's terminal as a friendly position location with associated information regarding identification, platform type, and range/bearing from the target.

While other systems in use by the military have some of the capabilities of the SwRI-developed system, SABER is unique in that it offers situational awareness and combat identification, as well as over-the-horizon (satellite) and line-of-sight radio frequency (RF) communications, in a single package. The system can be deployed on a wide range of platforms and can be used by any branch of the U.S. military at approximately one-fourth the cost of existing systems. In addition, it is capable of exchanging information with existing military command and control, communications, and intelligence systems.

The system was first evaluated in a field environment in March 1995. Since then, it has been deployed in numerous training exercises and real-world operations. The first of these was the All Services Combat Identification Evaluation Team (ASCIET) exercise at Camp Shelby, Mississippi, in 1995. The ASCIET organizers select military systems for extensive testing during a joint services war game complete with tanks, ships, helicopters, fighter aircraft, and other combat machinery. SABER was put to the test to demonstrate its friendly identification capability. The result was a resounding success, with no fratricides reported in 8,500 beacon-hours of operation over a three-week period.

In January 1996, 24 SABER units were deployed with the 22nd Marine Expeditionary Unit (MEU) for Operation Joint Endeavor in support of the peacekeeping mission in Bosnia. The USS Guam, flagship of five ships in the Marine Amphibious Ready Group that helped form a 17-ship battle group, was host to the SABER command and control terminal. During the time the 22nd MEU was stationed in the Adriatic Sea, interaction with the Bosnian peacekeeping activities was limited; however, the USS Guam was diverted to an offshore site near the plane crash that took the life of Secretary of Commerce Ron Brown and others, where it maintained a state of readiness with aircraft and SABER systems to provide aerial search support.

The 22nd MEU continued its support mission in the Mediterranean theater, where SABER was successfully used in Exercise Destined Glory off the coast of Sardinia. This exercise allowed the MEU to practice amphibious assault operations with military representatives from allied nations in a two-week training mission and showcased SABER's ability to provide reliable communications links and accurate position reports.

The 22nd MEU was slated for additional exercises in the Adriatic and Mediterranean Seas, but the mission was interrupted in April 1996 by the Liberian crisis. The USS Guam was diverted to the eastern Atlantic off the coast of Liberia for Operation Assured Response to support the evacuation of noncombatants during the civil unrest in Monrovia. The system was used successfully to track rescue helicopters on their routes to and from designated landing zones in Monrovia. More than 70 American citizens and approximately 300 Liberians seeking asylum were rescued during the operation.

The system met its next challenge during ASCIET '96. The focus of this exercise was interoperability with other U.S. military systems. For the first time, SABER was integrated with command, control, and communications systems and computer and intelligence networks such as the Army's Enhanced Position Location Reporting System; the Air Force's Situational Awareness Data Link on F-16 Falcon fighter aircraft; and the Army's Grenadier Brat, a COBRA (Collection of Broadcasts from Remote Assets) system. Data were fed into a common picture of force positions and provided to aircraft, ships, and ground forces as well as to the Battle Group Command Center and the Joint Task Force Command Center.

The SABER system allows tactical commanders as well as individual shipborne, airborne, and ground-based platforms to locate and identify friendly forces. The system taps the global positioning system and ultra-high frequency satellite communications for location data on each of its platforms. An integrated beacon package broadcasts this information and the identification data to computer terminals. SABER provides both line-of-sight and over-the-horizon tracking, as well as proven interoperability with a number of other military systems.

This connectivity was accomplished through the development of a flexible gateway between two datalink protocols -- the Joint Maritime Command and Control Information System and the Officer in Tactical Command Information Exchange System. Situational awareness data were also reformatted for compatibility with another datalink protocol for rebroadcast to E-2C Hawkeye and F-14 Tomcat aircraft. When ASCIET '96 was over, SABER had successfully completed all interoperability test objectives.

Enhancements to extend the line-of-sight radio horizon of SABER in ASCIET '96 included the deployment of two repeaters -- one on a 250-foot tower and one on an aerostat that was tethered at 5,000 feet. When RF signals are sent to a repeater, an RF receiver processes the signal and the information is then sent to the transmitter for rebroadcast on another frequency. These relays increase the over-the-horizon communications capability when satellite channels are unavailable as a result of high usage or restricted access.

SABER also participated in the Hunter Warrior Advanced Warfighting Experiment, a U.S. Marine Corps exercise held this March at Twentynine Palms, California. Serving as the primary tracking system for 12 ground platforms and 18 rotary wing aircraft, the system provided reliable 24-hour-a-day position updates on SABER-equipped platforms to the Expeditionary Combat Operations Center at Camp Pendleton and to the Global Command and Control System at Twentynine Palms. Next on SABER's schedule of deployments is a Joint Warfighter Interoperability Demonstration in the summer of 1997. The Department of Defense has called for completion of 200 units in 1998, with a follow-on plan for 1,000 units.

Planned enhancements include use of the COBRA waveform, encryption of data, and implementation of the highly accurate Y-code GPS receiver. The COBRA waveform will reduce the RF signature of the beacon and spread the energy across a wider bandwidth. Data encryption will make it nearly impossible for enemy forces to interpret SABER information, even if they have an intercept capability. The Y-code GPS receiver will increase position accuracy for SABER-equipped platforms. To date, system applications have been oriented primarily toward the military and the use of military satellites. Under consideration is extending this capability to the commercial arena by using surrogate satellites, repeater units deployed in devices such as tethered and stratospheric balloons that are capable of "station-keeping" to maintain position for the SABER repeater for long periods of time. These options would allow over-the-horizon operations without the need for an expensive, dedicated satellite channel. An added advantage is the decreased RF power required to close the RF link, as compared to that necessary to communicate with a geostationary satellite some 22,000 miles out in space.

Commercial applications include directing emergency vehicles and other resources to crisis areas by determining which are nearest the crisis. Other uses include fleet management of commercial cargo in trucks, trains, ships, and aircraft, as well as security tracking of VIPs and high value items.

Published in the Spring 1997 issue of Technology Today®, published by Southwest Research Institute. For more information, contact Joe Fohn.

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