Military personnel have always needed their communications to be protected. In addition to communications between personnel, however, the military now has to worry about equipment that relies on satellite communication. Signal jamming has emerged as a potential hazard for soldiers, weapons, tanks, and more. To help conquer this threat, EMS Technologies, Inc. (www.ems-t.com) recently completed the first set of beam-forming networks (BFNs) for the Advanced Extremely High Frequency (AEHF) military communications program.

The beam-forming networks will allow a satellite's nulling antennas, which are built by Northrop Grumman, to provide anti-jam protection. The BFNs form shaped patterns on Earth that "null," or zero out, signals from potential jammers. At the same time, they permit friendly users within the coverage area to communicate with the satellite. The anti-jam function occurs autonomously without commands from Earth.

A team from Lockheed Martin Corp. will oversee the development of these communications. Compared to Milstar II communications satellites, the resulting Advanced EHF satellites will provide 10 times greater total capacity while offering channel data rates that are six times higher (SEE FIGURE). Northrop Grumman will deliver the AEHF payloads to the system prime contractor, Lockheed Martin Space Systems. The first AEHF satellite is scheduled for launch in 2007.