Military Embedded Systems

Secure satellite communications for warfighters on the move


June 14, 2017

Mariana Iriarte

Technology Editor

Military Embedded Systems

Mobility, beyond-line-of-sight (BLOS) capability, and data security requirements drive military satellite communications development today. Enabling these capabilities will provide warfighters with reliable and consistent communications throughout a mission, whether stationary or mobile.

Today’s warfighters on the move and in the field must be able to count on their communications tools; the same as if they were at home base or some other fixed position.

“Military users have to access the same degree of capability on the move as they would if they were stationary, for all operational stages,” says Rebecca Cowen-Hirsch, Senior Vice President of Government Strategy and Policy for Inmarsat’s U. S. Government Business Unit in Washington, D.C.

When it comes to military communications the reality is that users “can no longer count on predetermined areas or fixed locations, not with the present demands of – for instance – airborne intelligence, surveillance, and reconnaissance (AISR) missions, both manned and unmanned,” she adds. Knowing that they can be deployed at a moment’s notice, “mobility is a capability that is very important in the design of satellite communications.”

In May, Inmarsat – a global telecommunications company – launched its fourth Global Xpress satellite. The launch was accomplished via a “Falcon 9 rocket from the historic Launch Pad 39A at NASA’s Kennedy Space Center in Florida; SpaceX launched the Boeing-built Inmarsat-5 F4 (F4) to add further capacity and coverage to the Global Xpress network, as well as in-orbit redundancy,” Cowen-Hirsch says.

What the Inmarsat-5 satellites provide is worldwide communications coverage through fixed and steerable beams. As the demand for coverage surges, those beams can be adjusted in real time. Inmarsat-5 satellite will enable users’ capabilities to include secure and high-speed communications in land, air, and sea services, as well as multinational coalitions.

What Global Xpress ensures is the “the maximum rate of portability and availability possible in Ka-band. When combined in a hybrid network with Inmarsat L-band, Broadband Global Area Network (BGAN), it delivers signal resilience and frequency diversity to support even extreme situations, such as adverse sea conditions.” The goal, according to Inmarsat: “to take advantage of both Ka-band and L-band to get critical information through.” (See Figure 1).


Figure 1: Inmarsat Global Xpress is interoperable with military satellite communications. Image courtesy of Inmarsat.

(Click graphic to zoom by 1.9x)




Whether it’s on the move or at military base, warfighters “need to be able to have the same degree of capability and that’s for all types of operation,” Cowen-Hirsch says. This is because military operations can be unpredictable and “they really need global connection. They need to be able to have, whether it’s a training in [the] CONUS [continental United States] or a mission in the middle of the Pacific at sea, or whether it’s traversing from across the Atlantic into Central Command Area of Responsibility, they need to be able to have that global connection and capability.”

BLOS communications connectivity is key

Military operations and missions are notoriously unpredictable, so companies like Inmarsat plan ahead to mitigate any loss of connectivity and retain reliability, especially when dealing with BLOS operations.

BLOS operations “demand both ubiquitous and uniform coverage,” Cowen-Hirsch says. “For example, when users take off in one location and fly across ten different consecutive spot beams in our system, they will not lose connectivity, and they will not have to manually relocate their antenna-pointing. This is done autonomously, so that the system automatically and seamlessly traverses through the spot beams.”

For the president of the United States, BLOS communications will enable communications with leaders around the world. In 2014, Raytheon won the contract that started the ball rolling on that capability. The U.S. Air Force Life Cycle Management Center/HNSK at Hanscom Air Force Base in Massachusetts is the contracting activity for the Family of Advanced Beyond Line-Of-Sight Terminal (FAB-T) program, according to information from Raytheon. FAB-T delivers secure, airborne communications.

In 2015, the FAB-T program achieved Milestone C and engineers proceeded with the low-rate initial production of communication terminals for the program. Under contract, Raytheon engineers are producing airborne and ground terminal variants. In a statement released by Raytheon, officials explained the terminals provide “access to and command and control communication links to the Advanced Extremely High Frequency (AEHF) satellite communications system.”

BLOS communications for Inmarsat fall into the company’s SATCOM solution, which “enables you the ubiquity of coverage,” Cowen-Hirsch notes. The way Inmarsat approaches BLOS with “Global Xpress spot beam architecture that supports a uniform distribution of power allows for consistent, uninterrupted connectivity anywhere around the world. Our ‘SATCOM as a Service’ capability delivers guaranteed data rates to satisfy mission requirements at a moment’s notice. With solid Service Level Agreements (SLA) and Committed Information Rates (CIR), users get what they ask for, and the quality of the acquired service is assured.”

In the past, “Some historical broadcast fixed satellite services that have adequately responded to prior needs by supplying available bandwidth leased on a regional basis,” Cowen-Hirsch explains. However, the military needs on-demand access and a reliable network. Inmarsat’s technology can allow users to “strategically leverage complementary commercial satellite communication capability. This boosts the effectiveness, flexibility and redundancy of military satellite communication (MILSATCOM) systems for dynamic and global unmanned missions. This advanced capability is in contrast to broadcast-centric fixed transponder leases that require precommitment from agencies to acquire large amounts of bandwidth in a piecemeal approach and forces them to ‘guess’ as to how much bandwidth they will need and over which region.”

Mobile User Objective System (MUOS) satellites

In April 2017, users saw the fifth Lockheed Martin-built MUOS satellite operational and delivering BLOS communications for troops. These satellites also enabled communications for legacy ultra-high-frequency (UHF) radios. (See Figure 2).


Figure 2: MUOS-5 is the final satellite that completes the U.S. Navy's network of orbiting satellites and relay ground stations for mobile military forces. Photo courtesy of Lockheed Martin.

(Click graphic to zoom by 1.9x)




The Navy has been looking to replace legacy systems and make the network 16  times faster, with the service’s Program Executive Office for Space Systems and its Communications Satellite Program Office heading the program in San Diego. At Lockheed Martin’s Sunnyvale, California, facility, engineers have been working to test and assemble all five MUOS satellites that are now on-orbit.

The system delivers narrowband communications, according to information from Lockheed Martin. Two payloads onboard the satellites support the Wideband Code Division Multiple Access (WCDMA) waveform capabilities as well as the UHF satellite communications system.

On the ground, General Dynamics – under contract with Lockheed Martin – leads the ground segment of the system with four ground station facilities around the world. Each station is equipped with freestanding antennas that receive radio “calls” that are sent through the MUOS satellites, according to General Dynamics.

Representatives of the Army Forces Strategic Command and the Navy worked together to configure two of MUOS-5 communication payloads, thereby providing additional support for the Navy’s legacy UHF satellite communications mission, according to General Dynamics. The collaboration provides narrowband UHF communications for the military.

The whole point is to provide uninterrupted connectivity and support new WCDMA waveform capabilities, as well as its legacy UFH satellite communication counterpart, says Mark Woempner, director of Narrowband Communications Systems at Lockheed Martin, in a statement released by Lockheed Martin.

While the MUOS network is not fully operational yet, according to a release by Lockheed Martin, the company says that once it is functional users will be able to handle more than 10 times the communications capacity of its legacy system that it is replacing. The fifth MUOS satellite is currently in transition after completing its post-launch trials earlier this year.

The satellite “completed orbit raising and successfully deployed its solar arrays and antennas for mission operations on October 30, 2016,” according to Lockheed Martin. This was the same satellite that had experienced an anomaly during its orbit raising in June 2016; despite this initial difficulty, however, Navy and Lockheed Martin engineers were able to isolate the issue and “deliver MUOS to operational orbit using alternative propulsion.”

Security of highest importance

Underpinning all of this data communication is the expectation of the highest levels of security. “The security elements of bandwidth demands are the same, whether it’s a narrow-band data rate requirement or a high-throughput capability for wideband applications,” Cowen-Hirsch says. “Either way, we take the same defense-in-depth approach and we design that into our system.”

For the warfighter, having secure communications while on the move to not just ensure their safety, but also enable communications without interference, loss of service, and high throughput information – wherever they may be – is crucial.

The challenge to strengthen security capabilities to enable secure satellite communications will continue: “We are constantly evolving in advance or in anticipation of any particular threat,” Cowen-Hirsch says. “Given the unique, geographically based military challenges of the modern age, users seek protected tactical waveforms (PTW) [waveforms designed with frequency-hopping spread spectrum (FHSS) to provide greater antijamming capability].”

Inmarsat continues to invest in new capabilities built to augment MILSATCOM with broader protection and more antijam (A/J) resistance, and to enhance diversity, resilience, and protection, she adds.