Boeing Highlights Anti-Jam Features Of Wideband Global Satcom

Communications satellites are the glue that holds together America’s global military posture. Without uplinks to orbital relay nodes, there would be no way for ships at sea or warfighters in remote locations such as Afghanistan to quickly and securely communicate with command authorities. The Bush Administration had a plan to provide the entire joint force, even warfighters on the move, with internet-like connectivity through a constellation of “transformational” next-generation satellites. But defense secretary Robert Gates decided to cancel that effort in April of 2009, and military planners have been trying to figure out ever since how to provide far-flung forces with the amount of secure bandwidth they will need in the future.

The Boeing Company is already producing part of the solution, in the form of the Wideband Global Satcom (WGS) system. WGS is a very high-capacity military version of the 702 commercial satellite “bus” that was conceived to replace the aging Defense Satellite Communications System. With over two gigabits per second of carrying capacity on each satellite, a single WGS spacecraft can relay more information than the entire legacy constellation. It also incorporates a variety of other innovations, including 18 steerable beams that allow tailored spot coverage of specific areas on the earth’s surface. WGS will allow the Pentagon to shift much of its communications traffic from commercial satellites to spacecraft under direct military control, potentially saving $200 million annually in transponder leasing fees. Several of the satellites are already in orbit, and appear to be functioning very effectively.

The one area where policymakers have concerns about WGS is in what are called “protected communications,” meaning transmissions that can counter jamming and the electromagnetic pulse generated by nuclear blasts. The Pentagon has developed a different satellite called Advanced Extremely High Frequency (AEHF) to handle the highest-priority protected communications, since the Wideband Global Satcom was not designed to operate in the kind of electromagnetic environment generated by nuclear war. However, Boeing contends that the distinction between protected and “routine” communications has been exaggerated, because WGS has inherent anti-jam features in its basic architecture that could be further enhanced using additional weight and power capacity built into the system.

The company is not arguing that WGS will fare well in a nuclear war. AEHF is uniquely suited to that kind of warfighting environment. But Boeing argues that precisely because AEHF was configured to cope with such stressful contingencies, it is not so well suited to dealing with the more prosaic jamming challenges the joint force now faces on a weekly basis. It lacks the bandwidth to serve some high-capacity users such as airborne reconnaissance systems, its waveforms are difficult to access from mobile platforms, and satellites are maxed out in terms of weight allowances. The latter problem isn’t surprising, since AEHF has technical features that were not included in the WGS design.

Boeing cites the connectivity needs of warfighters on the move as an example of how WGS can be readily adapted to protected-communications requirements. Army mobile users today typically operate at 256 kilobits per second, and WGS has already demonstrated a capacity to deliver information at twice that rate. But with relatively simple modifications, the spacecraft could be upgraded to deliver more bandwidth through small mobile antennas with enhanced anti-jam capabilities. AEHF can deliver eight megabits of capacity to users who have set up fixed ground stations, but major design changes would be required to meet the needs of mobile users. WGS has demonstrated the ability to deliver 400 megabits of data per second to a single user. Boeing therefore contends that while both constellations will play a vital role in future military connectivity, Pentagon planners need to rethink how they approach protected communications with an eye to getting the most bandwidth for the buck.