Milsatcom is a system of systems that provides balanced wideband, narrowband, and protected communications capability for a broad range of users across diverse mission areas. The anticipated implementation of advanced architectures, supported by heightened connectivity in space as well as on the ground, will enable national security space communications to take advantage of commercially developed Internet-like communications, but with greater assurance and security.
For wideband communication needs, the Wideband Gapfiller Satellite program and the Advanced Wideband System will augment and eventually replace the Defense Satellite Communications System (DSCS). These satellites will transmit several gigabits of data per second—up to ten times the data flow of the satellites being replaced. Protected communications will be addressed by a global extremely high frequency (EHF) system, composed of the Advanced Extremely High Frequency System and Advanced Polar System. These systems are expected to provide about ten times the capacity of current protected satellites (the Milstar satellites). Narrowband needs are supported by the UFO (Ultrahigh-frequency Follow-On) constellation, which will be replaced by a component of the Advanced Narrowband System (see Milsatcom Timeline).
Capacity gains in these systems will also be matched by improved features, such as multiple high-gain spot beams that are particularly important for small terminal and mobile users. Satellite, terminal, control, and planning segments will utilize emerging technology to ensure the best capability for the cost. Coordination among ground, air, and space segments and between government and commercial assets will help ensure deployment of the most efficient, effective, and affordable communications systems.Wideband Communications
Assured capacity is the primary goal of the military's wideband communications sector. Wideband data rates are defined as those greater than 64 kilobits per second, although the line between wideband and narrowband is blurring as commercial data rates to disadvantaged users move higher. The military's wideband requirements are currently supported by DSCS and the Global Broadcast Service, as well as commercial systems. These military systems, together with the planned Wideband Gapfiller satellites, will form the Interim Wideband System, which will eventually give way to the Advanced Wideband System.
Wideband Gapfiller Satellites
The Wideband Gapfiller Satellite program will provide the next generation of wideband communications for the Department of Defense (DOD). The constellation will supplement the military X-band (roughly 7–8 gigahertz) communications capability now provided by the Defense Satellite Communications System and the military Ka-band (about 20–21 gigahertz down, 30–31 gigahertz up) capability of the Global Broadcast Service. In addition, the Wideband Gapfiller Satellite program will include a high-capacity two-way Ka-band capability to support mobile and tactical personnel.
The name "Gapfiller" is somewhat misleading because this very capable wideband communication payload will include state-of-the-art technology and provide a major leap in capability. Preliminary estimates indicate that one Wideband Gapfiller spacecraft will provide transmission capacity up to 2.4 gigabits per second. This capability alone exceeds the capacity of the entire existing DSCS and Global Broadcast Service constellations.
Throughput capacity is divided among nine X-band beams and ten Ka-band beams. Eight of the X-band beams are formed by separate transmitting and receiving phased-array antennas, which provide the ability to shape and scale coverage areas. The ninth X-band beam provides Earth coverage. The ten Ka-band beams are formed by gimbaled dish antennas and include three beams with reversible polarization. (Polarization—the direction of the electric field of an antenna—plays an important part in optimizing reception or reducing the effects of jamming).
Wideband Communications
Assured capacity is the primary goal of the military's wideband communications sector. Wideband data rates are defined as those greater than 64 kilobits per second, although the line between wideband and narrowband is blurring as commercial data rates to disadvantaged users move higher. The military's wideband requirements are currently supported by DSCS and the Global Broadcast Service, as well as commercial systems. These military systems, together with the planned Wideband Gapfiller satellites, will form the Interim Wideband System, which will eventually give way to the Advanced Wideband System.
Wideband Gapfiller Satellites
The Wideband Gapfiller Satellite program will provide the next generation of wideband communications for the Department of Defense (DOD). The constellation will supplement the military X-band (roughly 7–8 gigahertz) communications capability now provided by the Defense Satellite Communications System and the military Ka-band (about 20–21 gigahertz down, 30–31 gigahertz up) capability of the Global Broadcast Service. In addition, the Wideband Gapfiller Satellite program will include a high-capacity two-way Ka-band capability to support mobile and tactical personnel.
The name "Gapfiller" is somewhat misleading because this very capable wideband communication payload will include state-of-the-art technology and provide a major leap in capability. Preliminary estimates indicate that one Wideband Gapfiller spacecraft will provide transmission capacity up to 2.4 gigabits per second. This capability alone exceeds the capacity of the entire existing DSCS and Global Broadcast Service constellations.
Throughput capacity is divided among nine X-band beams and ten Ka-band beams. Eight of the X-band beams are formed by separate transmitting and receiving phased-array antennas, which provide the ability to shape and scale coverage areas. The ninth X-band beam provides Earth coverage. The ten Ka-band beams are formed by gimbaled dish antennas and include three beams with reversible polarization. (Polarization—the direction of the electric field of an antenna—plays an important part in optimizing reception or reducing the effects of jamming).
