Advanced Extremely High Frequency System
Definition/Scope: The Advanced Extremely High Frequency (AEHF) System is a joint service satellite communications system that provides global, secure, protected, and jam resistant communications for high-priority military ground, sea, and air assets. The system consists of three satellites in geosynchronous earth orbit (GEO) that provides 10 to 100 times the capacity of the 1990s-era Milstar satellites. A constellation of three AEHF augmented by a Transformational Communications Satellite (TSAT) will provide continuous 24-hour coverage. Advanced EHF will allow the National Security Council and Unified Combatant Commanders to control their tactical and strategic forces at all levels of conflict through general nuclear war and support the attainment of information superiority. The AEHF System is a follow-on to the Milstar system, augmenting and improving on the capabilities of Milstar, and expanding the MILSATCOM architecture to enable Transformational Communications and Network-Centric Warfare. AEHF will provide connectivity across the spectrum of mission areas including land, air, and naval warfare; special operations; strategic nuclear operations; strategic defense; theater missile defense; and space operations and intelligence. Description: The AEHF system is composed of three segments: space (the satellites), terminals (the users), and ground (mission control and associated communications links). The segments will provide communications in a specified set of data rates from 75 bps to approximately 8 Mbps. The space segment consists of a cross-linked constellation of three satellites. The mission control segment controls satellites on orbit, monitors satellite health and provides communication system planning and monitoring. This segment is highly survivable, with both fixed and mobile control stations. System uplinks and crosslink's will operate in the extremely high frequency (EHF) range and downlinks in the super high frequency (SHF) range. The terminal segment includes fixed and mobile ground terminals, ship and submarine terminals, and airborne terminals, including the Family of Advanced Beyond Line-of-Sight-Terminal (FAB-T), used by all of the Services and international partners (Canada, Netherlands and UK). The AEHF satellites will respond directly to service requests from operational commanders and user terminals, providing real-time point-to-point connectivity and network services on a priority basis. On-board signal processing will provide protection and ensure optimum resource utilization and system flexibility among the Armed Forces and other users who operate terminals on land, sea, and air. The AEHF system will be integrated into the legacy Milstar constellation, and will be backward compatible with Milstar's low data rate (LDR) and medium data rate (MDR) capabilities, while providing extended data rates (XDR) and larger capacity at substantially less cost than the Milstar system. Each satellite will be launched on an Evolved Expendable Launch Vehicle (EELV) with the first launch planned for April 2008. The AEHF Satellite Communications System will augment and replace the Milstar constellation, improve DoD EHF capability, and enable Transformational Communications and Network-Centric Warfare. The MILSATCOM Systems Wing is responsible for the development, acquisition and sustainment of the AEHF Program.
Broader Terms:Global Command and Control System
Narrower Terms:Wideband Global Satcom Satellite
Related Terms:Advanced Narrowband System