User's Manual

CHAPTER 7 USING GPS
ALH-901X USER’S GUIDE
DOC. CONTROL #8102117-000 REV D
43
Chapter 7
Using GPS
The ALH-9011 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.
In Windows Mobile, the GPS receiver is managed by the OS itself, and is accessible either directly
through its COM port (COM6, @9600 baud), or by using Microsoft’s GPS Intermediate Driver. You
can configure many of the low-level connection settings for the GPS receiver using the GPS
control panel (Start -> Settings -> System -> GPS)
Running the 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 in the Alien Demos folder in the Start menu.
[Start] > [Alien Demos] > [GPS]
Starting the GPS demo program, at
the bottom of the Start menu.
Start/stop receiving GPS data with the
button. Wait outside for a satellite fix,
and then observe decoded data in the
various fields around the screen.