Common Questions - Global
Positioning System Devices
Discussion of GPS use in Air, Water,
Land & Vehicle Tracking
Overview of GPS
Technology
• GPS stands for Global Positioning System
• The system is an orbiting constellation of 24
satellites
• Allows a public or government user to fix
their position anywhere in the world with a
high level of accuracy
GPS Software
Packages
• GIS Software
– GIS – Geographic Information Systems
– Use in surveying, construction, civil
engineering, marketing and biology
research fields, among others
– Allows for precise organization of data by
geographic location
Software Packages
• Navigation
– Systems available for street, marine,
and aviation navigation uses
– Some packages combine all of these
capabilities into one program
– Door to door routing for US, Canada,
and Europe depending on software
and maps
– GPS integration allow for moving
map display and upcoming turn alerts
in most software
– Detail level and area coverage
available on the PDA vary depending
on the software
Dedicated GPS Units
• Pro
– Longer battery life
– More rugged design
• Waterproof
• Buoyant
• Impact Resistant
• Con
– Limited storage for maps and other data
– Limited or no software upgrade capability
– Software generally not as capable
PC/PDA Based GPS
Systems
• Pro
– Software and Maps can be updated
– Greater storage capabilities
– Software has greater capabilities
• Con
– Will not work without PC or PDA
– Shorter battery life
Differential GPS Systems
• Allows for much greater position accuracy
– Down to the inch in some cases
• Requires additional hardware to receive
differential signal
• Differential signal broadcast from accurately
surveyed positions around the country
• Differential signal available for free in many
areas
Differential: WAAS and LAAS
• WAAS vs. LAAS
– WAAS stands for Wide Area Augmentation
System
– Two satellites in Geostationary orbit broadcast
correction information for the GPS system
– Improves accuracy to 3 meters for users in the
continental US
– LAAS stands for Local Area Augmentation
System
– Provides greater than 1-meter accuracy near
many major airports
Competing GPS Systems
• Galileo GPS System
– Proposed GPS system from Europe
– Total of 30 satellites in Earth orbit
– Scheduled to be ready in 2008
• GLONASS
– Russian GPS system
– Accurate to only 57 meters at best
– Total of 24 satellites in orbit
Future of Triangulation Systems
• E911 Cellular System
– By Dec 31, 2005, cellular operators must be
able to locate 95% of 911 calls placed from
cellphones
– A variety of methods will be used to
accomplish this, depending on the cellular
vendor
• GPS
• Multipath Fingerprint
• Enhanced Observed Time Difference
Future of Triangulation Systems
• GPS-enabled phones
– Not just for emergency purposes, these
phones will allow you to send your
location directly to friends and family
Vehicle Tracking Products
• T-Mobile Pocket Tracker
– Track other vehicles or be
tracked anywhere where
there is cellular service
– Takes advantage of
Internet connection
provided by cellular
T-Mobile PocketTracker
service provider
Vehicle Tracking Products
• Pocket Tracker
– Add tracking
capabilities to any
PDA with an internet
connection and GPS
receiver
– Uses GPS Receiver
and wireless
communications card
iPaq Pocket Tracker
Vehicle Tracking Products
• Satellite Tracker
– Track a container or
vehicle anywhere on
the planet
– Uses satellite
communication along
with GPS technology
to report its position to
the tracking station
Satellite Tracker
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