Hemisphere GPS Crescent A100, Руководство пользователя

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2: GPS Overview
The basics -
WAAS is a free service of the FAA that allows regular GPS positions
to be improved to a DGPS level of accuracy. Tests using a Crescent
A100 have shown better than one-meter accuracy. WAAS is
available everywhere in the U.S., including Alaska, Hawaii and
Puerto Rico. It can also be picked up in some of the border areas of
Mexico and Canada. There are no subscription charges incurred
when using WAAS.
EGNOS is a similar service that is available in Europe and Western
Russia.
Automatic SBAS tracking -
The Crescent A100 will automatically scan and track the satellite
signals. This automatic tracking allows you to focus on other
aspects of differential operation without the need to tune the
receiver. The Crescent A100 features two-channel SBAS tracking
that provides an enhanced ability to maintain a lock on a SBAS
satellite when more than one satellite is in view. This redundant
tracking approach results in more consistent tracking of a SBAS
signal when in an area where signal blockage of a satellite is
possible.
e-Dif -
A Crescent A100 that is equipped with Hemisphere GPS’ e-Dif
capabilities can operate anywhere in the world where normal GPS
signals can be viewed. e-Dif can be used anywhere on the globe
where a GPS lock can be achieved.
Hemisphere GPS developed e-Dif for our customers who are not
able to receive other types of differential signals due to location or
budget.
875-0163-000 (Crescent A100).book Page 22 Tuesday, November 13, 2007 11:29 AM