Ongoing military operations in Afghanistan and Iraq are putting more emphasis on the need for reliable, robust and bandwidth-rich satcom-on-the-move (SOTM) solutions. The U.S. military and Allied Forces relies primarily on small portable, fixed VSAT terminals which can be deployed rapidly, as existing SOTM programs are limited in number and in scope.
Among other things, the emphasis on keeping out of the line of fire has taken on a new sense of urgency with the mounting number of casualties resulting from improvised explosive devices - IEDs - and the growing number SOTM solutions beyond Blue Force Tracking is enabling U.S. forces to get the job done on the move while minimizing the exposure to enemy fire which might occur when small fixed VSAT deployments take place.
"The greatest influence that the Iraq and Afghanistan deployments have had is to accelerate user acceptance of 'current force' solutions, and the urgency of these deployments had vastly accelerated the acceptance of equipment and systems when appropriate to the deployed warfighters," says Ric VanderMeulen, director of government satellite communications at California-based ViaSat Inc.
SOTM can be accomplished in Ka-, Ku-, L-, Q- and X-bands, though military applications primarily are limited to Ka-, Q- and X-bands via Defense Satellite Communications System satellites, Milstar spacecraft and the planned Wideband Gapfiller and Advanced Extremely High Frequency constellations, says Fred Darlington, director, satellite communications systems at Raytheon Co. "Lower frequency provides better SOTM connectivity through rain and foliage. Higher frequencies have narrower beam widths requiring precise pointing algorithms but are more jam resistant," he says. "As frequency increases, pointing becomes increasingly difficult, and with Ku-band, as a result of spacecraft spacing, there is the potential for locking onto the wrong satellite or satellite sidelobes after loss of tracking."
Existing SOTM systems include the U.S. Marine Corps Systems Command's C2 On-the-move Network Digital Over-the-horizon Relay, or CONDOR system, and the U.S. Army's Mounted Battle Command on the Move system. However, these systems may need to be adapted to meet new requirements from the U.S. Department of Defense that call for lighter, more mobile satellite communications networking solutions which enable interoperability between forces and fully support the Pentagon's Everything over Internet Protocol objectives, which are driven by IPv6 along with the multi-phased Joint Tactical Radio System. With the increased efficiency and addressability that IPv6 offers, Everything over Internet Protocol is critical to the process of netcentric transformation as it pertains to Brigade and Below operations in particular. "SOTM will continue the drive of smaller, cheaper, faster battlefield tools," says David Helfgott, president and CEO of Americom Government Solutions Inc. (AGS), a subsidiary of SES Americom. "Key will be a stable and robust system that will respond to demand and institutionalize the service throughout the armed forces and hopefully become one or more programs of record. This institutionalization could drive Ka- band and perhaps other band SOTM solutions."
AGS has a SOTM system undergoing testing at the Pentagon's Joint Interoperability Test Command, which is responsible for end-to-end interoperability certification of joint C4ISR systems. This service employs a low-profile antenna and the Arclight spread spectrum modem from ViaSat Inc. "The core of the SOTM challenge is to reliably deliver the desired performance levels via a small antenna, without causing adjacent satellite interference," says Helfgott. The operational infrastructure for the system in the continental United States has been operational since early 2006, while AGS expects to have the infrastructure for the Indian Ocean region operational midyear.
Signal blockage is mitigated by using satellites in orbits high enough to prevent most blockage created by natural or man-made obstacles, along with advanced modulation technology used to reinforce connectivity and ensure an immediate reconnection in case of signal loss. "The primary effect of [Operation Enduring Freedom] and [Operation Iraqi Freedom] has been to keep the pressure on the military to bring a reliable solution to the market," says Helfgott, who added that the military has realized video is a key part of collaborative battlefield management tools. "In fact, the need for video is part of the driver to utilize a Ku-band solution as opposed to L-band due to the much higher bandwidth."
Datapath Inc. of Georgia supports the U.S. military's net-centric philosophy by delivering communications networks that include mobile and portable satellite terminals to the Joint Network Node. The company won an $8.3 million contract in September 2005 for operation and maintenance support services on deployable Ku-band earth terminals for the U.S. Army Communications-Electronics Command. "Solutions for the [Joint Network Node] deliver what we describe as Communication on the Quick Halt, which allows forces to stop and within 30 minutes set-up a rapidly deployed terminal to establish connectivity," says Daniel White, vice president of engineering at Datapath. "We will continue to focus on how to deliver increased mobility to the edge of the network. The goal is to create a complete SOTM solution that could provide speeds of greater than 1 megabit per second while traveling at 50 miles per hour."
But meeting the demand high-bandwidth SOTM in a mesh environment using a very small antenna poses a completely different challenge than providing Communication on the Quick Halt, says White. "Most requirements are for a mesh solution that will allow all remote mobile terminals to communicate with all others," he says. "The issue is how to close the satellite link with two small antennas on either end. We think there is a hybrid approach that employs a wireless component along with a satellite piece to give complete functionality and allow for higher speeds." The January acquisition of New Hampshire-based Third Rail Americas Inc. has bolstered Datapath's ability to provide hybrid SOTM/wireless networking solutions, he says.
To be effective, the SOTM systems must have the ability to handle all data rates, including video, White says. "Forces in the field are requesting speeds that are higher than the currently recommended specifications, which in turn require larger antennas. We expect that these specifications will shake out within the year - defined in large part by Warfighter Information Network-Tactical requirements - and that a hybrid satellite communication and wireless terrestrial communication solution will be required to meet the [space, weight and power] required for mobile forces," he says.
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