SHF Super High Frequency

The Defense Satellite Communications System (DSCS), is used by all four military services, as well as a variety of governmental agencies. With a nominal orbital constellation of five operational and two spare satellites(2) five or six satellites of the DSCS II series remain in service since being launched in the late 1970's, and three of the more capable and survivable DSCS III spacecraft, launched in the early 1980's are also operational.

The Defense Satellite Communications System is an important part of the comprehensive plan to meet national military communications needs. As of February 1992, seven Phase II and five Phase III DSCS satellites orbited the earth at an altitude of more than 23,000 miles. The DSCS constellation currently consists of five prime DSCS-3 satellites. The satellites are super high frequency systems capable of providing worldwide secure voice and data transmission.(1)

Users on the ground, at sea or in the air can receive DSCS communications. The DSCS system supports national security users, both DoD and non-DoD. These users include the National Command Authority, the Army, the Air Force, the Navy, the Worldwide Command and Control System, the White House Communication Agency, and the Diplomatic Telecommunications Service. The military uses DSCS for long-haul, high-capacity, wideband, general-purpose communications for multiple users up through theater-level conflict. The system is used for high priority communication such as the exchange of wartime information between defense officials and battlefield commanders. The military also uses DSCS to transmit space operations and early warning data to various systems and users.

The Defense Information Systems Agency manages operational use of the communications capabilities provided by the network of satellites, ensuring proper allocation of frequency and bandwidth to users based upon their requirements. Members of an Air Force Space Command unit, the 50th Space Wing's 3rd Satellite Control Squadron at Falcon Air Force Base, CO, provide command and control for all DSCS systems. The MILSATCOM Joint Program Office at the Space and Missile Systems Center, Los Angeles AFB, CA, is responsible for development and acquisition of DSCS satellites and ground systems.

In response to a validated joint requirement, initial operating requirements were defined in 1972 for a shipboard Super High Frequency (SHF) satellite communications (SATCOM) terminal to provide high data rates for SURTASS T-AGOS platforms and jam-resistant voice and data circuits for major combatants beyond the line of sight (BLOS). The major combatants also required low probability of intercept (LPI), direct access to the Defense Communications System (DSCS), the only SATCOM system that satisfied these requirements.

Since fielding of Extremely High Frequency (EHF) space segment and shipboard terminals for protected communications, Navy's SHF SATCOM requirement has transitioned to unprotected interoperable high capacity voice, data, and video for combatants and flag capable ships, and reliable Joint/NATO-interoperable low probability-of-intercept (LPI), secure information exchange at medium to high data rates for fleet flag ships. Only DSCS SHF continues to provide the required global connectivity among fleet units, Joint Forces, Allied and NATO Forces, and Naval Command, Control, Communications, Computers and Intelligence (C4I) commands. The Operations Requirements Document for Lightweight SHF Satellite Communications Terminals, dated 2 September 1992, pertains to SHF X-Band satellite terminals procured to satisfy these requirements.

References

1. Maj Michael J. Muolo, Maj Richard A. Hand, Maj Bonnie Houchen and Maj Lou Larson, Space Handbook A War Fighter's Guide to Space -- Volume One, AU-18, Air University Air Command and Staff College, (Air University Press, Maxwell Air Force Base, Alabama, December 1993).

2. "Department of Defense Authorization for Appropriations for Fiscal Years 1990 and 1991," Senate Armed Services Committee, 101st Congress 1st Session, part 6, page 141.

News

• Tobyhanna takes on worldwide satellite communications project by Anthony Ricchiazzi TOBYHANNA ARMY DEPOT, Pa. (Army News Service, March 27, 1998) -- Tobyhanna has embarked on a multi-million dollar mission to install and test a wide variety of Defense Satellite Communications Systems at sites located worldwide.