White Bear Technologies RoamEO GPS Pet Location System - Manual (Page 8)

6
GPS Basics
The Global Positioning System (GPS) was launched in 1995 by the
United States Defense Department. Twenty-four satellites orbit at 10,900
nautical miles above the Earth, passing overhead twice daily. At least
four of these satellites are in view nearly anywhere on the Earth at
all times.
GPS requires signal reception from three satellites in order to
determine a latitude and longitude position, known as a 2D fix. Four
satellites are needed to determine position and elevation. This is a 3D
fix. In 2003, in order to provide an additional degree of accuracy to
GPS, the Federal Aviation Administration developed a program called
Wide Area Augmentation System (WAAS) that complements GPS.
WAAS is not always available to GPS users because of the position
of the satellites. RoamEO will automatically receive WAAS signals,
if available.
Please remember: for GPS to work effectively, it must have a
clear view of the satellites in the sky in order to receive their
signals. Unlike television or radio signals, GPS works at very high
frequencies. As a result, GPS reception can be easily effected by
tree foliage, buildings, your body, and any other cover that blocks
the sky.
To help achieve the maximum per formance from RoamEO,
we recommend:
1. If possible, power up RoamEO outdoors.
2. If powering up RoamEO outdoors, maintain some distance from
buildings and stay out from under foliage if possible. Af ter gaining
an initial GPS lock, RoamEO will probably maintain a lock even if
operating under these conditions.
3. If indoors, it may require a few minutes to acquire a GPS lock. To
improve your ability to gain a GPS fix, stand as close to a window
as possible so that RoamEO has at least a par tial view of the sky.
It is unlikely that you will be able to achieve a GPS fix from an
interior room in the house or the basement.
You can check the status of the GPS reception on the GPS Receiver
Toolbar. For more detailed information on the GPS status, refer to the
GPS Status Screen.