User's Guide

CHAPTER 7 USING GPS
ALH-900X USER’S GUIDE
DOC. CONTROL #8102114-000 REV A
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Chapter 7
Using GPS
The ALH-9001 handheld reader contains an internal GPS module for finding the geographic
location of the handheld reader. The GPS service requires line-of-sight visibility with at least four
of the constellation of orbiting GPS satellites, so the speed of the initial fix and the accuracy of all
data depend greatly on the quality of the signal from the orbiting satellites. Being inside of or in
between buildings, under tree cover, or near heavy electrical machinery can degrade the quality of
the GPS data.
The GPS receiver appears as a serial Com port, COM6, with a baud rate of 9600.
Executing GPS Demo Program
Find an open place outdoors to check your GPS signals. Depending on your actual environment,
the time to receive a fix and location data is different - about 3-10 minutes is typical. After receiving
a GPS fix the first time, it takes less time to receive GPS data on subsequent attempts.
The Alien GPS demo software is accessible by the Alien GPS icon on the unit’s desktop, or it can
be launched directly from the Start menu.
[Start] > [Program] > [Alien Demos] > [GPS]
Starting the GPS demo program.
Start/stop receiving GPS data with the
button. Watch raw NMEA data in the
lower window. Wait outside for a
satellite fix, and then observe decoded
data in the fields at the top of the
screen.