Civilians who navigate using the Global Positioning System (GPS) will benefit
from a tenfold improvement in accuracy within a decade.
The next generation of GPS satellites will broadcast two additional signals.
Since the atmosphere distorts different frequencies in different ways, a
receiver can compare multiple signals and correct for the distortion.
The first of the extra signals will be at a frequency now used for military
GPS—which will ease fears that it might interfere with other satellite systems
(This Week, 1 February 1997, p 5).
The frequency of the second signal will be chosen in August.
