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Milstar Nulling Antenna Automatically Counters Enemy Attempts to Jam Military Communications

Northrop Grumman-developed nulling antenna for the medium data rate (MDR) payload of the sixth Milstar satellite undergoes check-out in 1999 during final performance tests at Northrop Grumman. The nulling antenna, which automatically detects and screens out enemy jamming signals, makes possible secure, real-time transmission of voice, images, and data among tactical and command forces at rates of 1.544 megabits per second, or more than 50 times the speed of a 28.8 kilobit-per-second computer modem. Each MDR payload carries two nulling antennas, as well as six Northrop Grumman-supplied distributed user coverage antennas which are capable of 1.544-megabit rates but without the nulling capability. The nulling antenna is a key component of the tactically oriented Milstar MDR payload that Boeing Satellite Systems is integrating for Lockheed Martin, the Milstar satellite prime contractor. Milstar Flight 6 is scheduled to launch in 2002.