Garmin GPS 100 - Manual (Page 107)

When all GPS satellites have been deployed, 3D coverage with good
geometry will be available 24 hours a day worldwide. Until then, there may
be periods of time when only 2D coverage is available with occasional
outages in coverage.
A.3 GPS RECEIVER DESIGNS
Until now, most GPS receiver designs could be categorized as one of three
types:
· Continuous Receivers typically consist of five or more channels with
each channel dedicated to the tracking of one satellite. Receivers with
this design provide the highest performance but are also large,
expensive, and consume more power. A high dynamics vehicle such
as a fighter aircraft typically requires a continuous receiver.
· Multiplex Receivers typically consist of a single channel which
rapidly sequences through five satellites at a four millisecond rate.
Receivers with this design provide high update rates but suffer from
degraded signal tracking capability. For example, a multiplex receiver
may not reliably track satellites at low elevation angles.
· Sequential Receivers typically consist of one or two channels which
sequence through multiple satellites at a rate much slower than that
of the multiplex receivers. Receivers with this design provide good
signal tracking sensitivity at low cost, but lack high update rates of
continuous receivers.
GARMIN’s MultiTrac TM design represents a major breakthrough in GPS
receiver technology. Using this proprietary technology, the GPS 100
provides high update rates and tracking capability similar to continuous
receivers, but consumes far less power and space. This design can handle
any navigation situation from the palm of your hand to the cockpit of a fast
personal jet.
In addition to MultiTrac TM , the GPS 100 incorporates the latest innovations
in software design. As a result, this feature packed Personal Navigator TM is
extremely easy to use. The unit tracks all visible satellites and provides the
user with continuous navigation information. Satellite transitions, data
collection, and acquisition of newly launched satellites are all automatically
handled by its built-in intelligence.
A-2