Next-Generation Military GPS
To Stay Loud and Clear
by Mal Gormley
05/12/00 04:07:41 PM U.S. EDT
The MITRE Corporation says a new technique under development will enable military users of the Global Positioning System (GPS) to continue receiving accurate navigation signals in the face of an adversary’s jamming. Called M Code, the new signal will be broadcast at a much higher gain, or volume, than is currently utilized by GPS transmitters.
MITRE consulting engineer John Betz, who heads up the new signal development effort, says M Code will use the same 1575 MHz frequency assigned to current GPS signals. Betz spoke recently with AviationNow in an exclusive interview.
Betz says that despite the increased signal gain, the M Code signals will not interfere with civilian GPS users, as some GPS developers have worried. The code would benefit civilian users by discouraging adversaries from transmitting spurious GPS signals in an effort to reduce military GPS accuracy.
The military is still studying whether or not to broadcast M Code signals in selected areas when necessary. The limited broadcast would use spot-beam transmitters on next-generation GPS satellites, which are slated for launch within two years. The U.S. has already switched off the GPS “selective availability” code, which degraded the system’s accuracy for civilian use (see related story).