Satellites and secure wireless evolve to meet new demands

Troops operating in all domains turn to satellite communications (SATCOM) and secure wireless for tactical communications. Responding to an increasing need for instantly accessible, high-speed and secure communications, the Defense Department is evaluating and deploying a variety of new systems in space, on the ground and even in the air.

Satellites

A sign of SATCOM's value the Defense Department can be found in the number of satellite programs being deployed or examined by the DOD. The Mobile User Objective System (MUOS), for example, is a series of next-generation narrow-band tactical satellites designed to significantly improve ground communications for forces on the move. MUOS aims to supply military users with 10 times more communications capability compared to existing systems. Those new capabilities include simultaneous voice, video and data for 3G mobile communications. The first geosynchronous MUOS satellite launched in February.

Iridium NEXT is also expected to provide tactical communications support, as well as routine voice and data traffic. Set to be launched beginning in 2015, Iridium NEXT satellites will supplement the existing Iridium constellation of 66 cross-linked low-Earth orbiting satellites. Iridium NEXT is expected to substantially enhance and extend Iridium mobile communications services by providing higher data speeds, new broadband-oriented services and support for IP technology, all while maintaining backward compatibility with existing handsets, devices and software applications.

Global Positioning System (GPS) III, meanwhile, aims to enhance existing GPS technology with improved position, navigation and timing services and advanced anti-jamming capabilities. The first GPS III satellites, scheduled for launch in 2014, will deliver signals three times more accurate than current GPS spacecraft. They also will provide three times more power for military users, while also extending the spacecraft’s design life and adding a new civil signal designed to be interoperable with international global navigation satellite systems.

It's a SNAP

Even the most powerful and flexible satellite technology is useless if troops can't access it at critical moments. Josh Davidson, director of strategic communications at Army Program Executive Office for Command, Control and Communications-Tactical (PEO C3T) at Aberdeen Proving Ground, Md., believes that SIPR/NIPR Access Point (SNAP) satellite terminals will play an increasingly vital role in field communications over the next few years. The terminals are designed to provide beyond-line-of-sight communications to small units at remote forward operating bases, many of which are currently unable to use line-of-sight radios due to issues with terrain or distance. Complementing the SNAP systems are larger Deployable Ku Band Earth Terminals (DKET) terminals. The first SNAP earth satellite terminals and DKET terminals went live in January using X-band military radio frequencies with military satellites, Davidson said.

"SNAP satellite terminals are designed for use at small combat outposts, while DKETs are geared for larger hub locations," Davidson said. "SNAPs are like the spokes of the wheel, while DKETs provide the hub to extend networked mission command to the tactical edge."

The Ka-, X- and Ku-bands are radio frequencies used for satellite communications. While the Ka- and X-bands are used on military satellites, the Ku-band is used on commercial satellites. Because the DOD has high efficiency requirements, using the Ka- and X-bands is more efficient and effective than using the Ku-band, and there is a significant cost savings by not having to lease expensive commercial-satellite time. The Ka- and X-band certification for the SNAP satellite terminals was completed in June 2011, and the certification for the larger-size DKET terminals was achieved in September 2011.

SNAP terminals also have the ability to provide communication links even when satellite access isn't possible. Serving as a tropospheric scatter terminal, the SNAP Tactical, Transportable, TROPO (3T) system can shoot a microwave up to the tropopause, a thin buffer zone located between the troposphere and stratosphere. "The microwave shot bounces off the tropopause, where it is collected on the ground by a second SNAP 3T," Davidson said. This method enables secure, high-speed communications up and over terrestrial obstructions between sites.

According to Davidson, SNAP 3T is expected to decrease the Army’s reliance on costly and signal latency-prone military and commercial satellites. "SNAP 3T also provides significant cost avoidance at very low risk by using and repurposing current Army products that have already been proven successful," he said.

Network-centric Waveform

Another step forward in the evolution of satellite communications is the Network Centric Waveform (NCW) being developed under Warfighter Information Network-Tactical (WIN-T) Increment 2. The WIN-T Increment 2 and Increment 3 architectures will utilize NCW for most satellite communications services.

According to Davidson, the waveform is compatible with virtually all transponder-type satellites, which represent the majority of the communications satellites in use today, including the Wideband Global SATCOM (WGS) constellations. NCW supports a heterogeneous network of SATCOM terminals with varying antenna sizes, power levels and mission requirements, ranging from large-antenna strategic terminals to small tactical mobile terminals with antennas as small as 18 inches in diameter.

"The NCW waveform is highly dynamic and adaptive and automatically adjusts to changing network conditions and traffic demands," Davidson said. "In addition, the NCW offers a spread spectrum modulation mode that will permit the WIN-T SATCOM On-The-Move (SOTM) terminals to operate over virtually any commercial satellite worldwide."

MIMO and LTE

Satellites aren't the only communications platforms undergoing rapid changes; DOD also is focusing on next-generation terrestrial network technologies. Multiple-input and multiple-output (MIMO) and Long Term Evolution (LTE) technologies, both of which support high-level encryption, are two of the most promising systems.

While most antennas are single input/output, MIMO leverages multiple antennas to both transmit and receive, increasing communication performance, as well as spectral efficiency. MIMO is an integral part of LTE, a secure wireless communications technology supported by a number of commercial carriers. It increases data throughput for both mobile phones and data terminals. LTE supports download rates up to 299.6 Mbs and upload rates up to 75.4 Mbs (with 4x4 antennas using 20 MHz of spectrum). "By looking into technologies such as MIMO and LTE, the Army hopes to leverage new technologies and integrate them into Army networks to provide soldiers with the best available capabilities," Davidson said.

Flying Mesh Networks

Unmanned aerial vehicles (UAVs) also are beginning to play a role in delivering secure communications to troops in virtually any geographic location. Jericho Defense, located in Palmetto Bay, Fla., has developed N.COM, a proprietary software-driven technology that that uses UAVs to deliver ad hoc secure mobile mesh networks to the tactical edge. "Think of it as a robotic mesh network," said Dale Leary, the company's CEO.

Mesh technology helps troops by being extremely, rugged, adaptable and expandable. Yet mesh configurations are often difficult to deploy in areas where troops move rapidly and frequently. N.COM is designed to address this problem. "The future of battlefield networking is in mobile, self-healing meshes," Leary said. "What we've done is create an aerial extension of the mesh."

N.COM supports broadband throughput without the need for backhauls, said Leary. "You can actually just have a commander launch a network to know what his team is doing," he said. "You can even put cameras on the helmets of the [troops] so that he can see where they are and what they're seeing. "