General Dynamics demonstrates advances in on-the-move satellite communications

News Report

As illustrated in a recent press release, General Dynamics C4 Systems recently completed the first demonstration of secure voice and data communications via the Mobile User Objective System (MUOS) satellite-communications waveform. The demonstration used the Joint Tactical Radio System (JTRS) Handheld, Manpack, Small Form Fit (HMS) two-channel networking radio (AN/PRC-155), running the MUOS waveform software, to transmit encrypted voice through a MUOS-satellite simulator to the MUOS ground station equipment that will soon be deployed in Sicily.

The Technology

MUOS is a is a next-generation narrowband tactical satellite communications system designed to significantly improve ground communications for U.S. forces on the move. The system will enable secure, mobile networked communications worldwide, in even the most-austere environments. MUOS consists of four geostationary earth orbit satellites with an additional on-orbit spare, and a fiber optic terrestrial network connecting four ground stations around the globe. Each satellite will feature two payloads that enable the system to integrate with the existing architecture while upgrading military users to the new wideband code division multiple access system, which will provide mobile warfighters point-to-point and netted communications services at enhanced data rates and priority-based access to on-demand voice, video and data transfers.

The new waveform is termed the MUOS Common Air Interface (CAI), a Software Communications Architecture compliant modulations technique for the Joint Tactical Radio System (JTRS) terminals. User terminals will be in fact provided by the U.S. military under the JTRS program, with an emphasis on handheld, soldier-worn units. For users, the MUOS system will provide familiar cellular phone-like services with the satellites acting as very tall “towers” to allow warfighters on the ground to communicate directly with each other and their commanders virtually anywhere in the world.

The flow of information between users when MUOS is operational will be much different than today’s systems. Users will communicate with the satellite via UHF WCDMA links and the satellites will relay this to one of four ground sites located in Hawaii, Norfolk, Sicily, and Australia via a Ka-band feederlink. These ground sites are interconnected to switching and network management facilities located in Hawaii and Virginia. These facilities identify the destination of the communications and route the information to the appropriate ground site for Ka-band uplink to the satellite and UHF WCDMA downlink to the correct users. Network management will feature a government controlled, priority-based resource management capability that will be adaptable and responsive to changing operational communication requirements. Additionally, MUOS will provide access to select Defense Information System Network services, a voice and data capability that has not been available to UHF MILSATCOM users on prior systems. For satellite telemetry, tracking and command, MUOS will use the existing control system operated by the NavalSatelliteOperationsCenter at Pt. Mugu, California with the Air Force Satellite Control Network as a back-up.

When MUOS is fielded it will serve a mixed terminal population. Some users will have terminals only able to support the legacy waveforms while other users will have newer terminal able to support the MUOS CAI. In anticipation of this, each MUOS satellite carries a legacy payload that will continue to support legacy terminals, allowing for a more gradual transition to the MUOS WCDMA waveform.

For the time being, development of the MUOS waveform remains on track for completion in the third quarter of 2012. By year-end, the MUOS capability will be available on the General Dynamics' AN/PRC-155 manpack radio, the first MUOS terminal that will be available to soldiers. The AN/PRC-155 is a two-channel, software-defined radio capable of network-centric connectivity and legacy interoperability, supporting advanced (SRW, MUOS) and current-force (SINCGARS, SATCOM, HF, EPLRS, etc.) waveforms.

General Dynamics' AN/PRC-155 Two-Channel Networking Manpack Radio

Other radio vendors are keeping close tabs on General Dynamics’ progress developing the MUOS waveform through the JTRS Open Information Repository, a resource designed to link vendors to open-source software initiatives. Harris, for example, plans to provide MUOS capability through its Falcon III AN/PRC-117G tactical satellite radios. Those software-defined, multiband radios used in ground vehicles and command posts were redesigned in 2010 to become MUOS-compatible. Once the MUOS waveform is ready, Harris will begin loading it onto approximately 10,000 AN/PRC-117G radios fielded..

The Context

Lockheed Martin is the MUOS prime contractor and system integrator, and was awarded in 2004 a $2.1 billion contract to build the first two satellites and associated ground control elements by the U.S. Navy’s Space and Naval Warfare Systems Command (SPAWAR) (competing against the Raytheon team).

General Dynamics is leading the development and deployment of the MUOS ground system that provides communications and control interfaces between the MUOS satellites and existing and future U.S. Department of Defense terrestrial communication networks. General Dynamics also is providing the wireless protocol for communication between those networks and the MUOS satellites.

References: General Dynamics (1,2,3), Gunter's Space Page (4), DefenceTalk (5), U.S. Navy (6), Space News (7)