Anyone who tries to compare GPS devices, can get overwhelmed by the
large variety of receiver types and features. But if you have a clear idea of
what you want from your GPS system, the required features will be
obvious. And hopefully this brief GPS comparison guide will help sort out the
best GPS system for you.
Although GPS receivers come in a number of different forms, they
all share a basic navigation function. With the aid of the orbiting
GPS satellites, the GPS equipment will locate exactly where it, and
you, are. The various GPS devices mainly differ in their intended use, the
features they include, and whether they're self-contained or part of
Basic GPS Handheld Receivers
The simplest GPS equipment system is a hand-held GPS. Less than $100 will get
you basic GPS handheld receivers that are just as accurate as
more expensive models with added features. If you're looking for a portable GPS
system for outdoor activities, like hunting, fishing, or hiking,
a simple unit maybe all you need.
The main difference between basic GPS handheld receivers and
more advanced GPS devices is what they show on their display screens. Advanced
receivers can show electronic maps that have the same features as a paper map.
But basic GPS units can only plot points on their otherwise blank screen. Your location
is one of the points and the other points represent locations in the area that you've
previously marked, called "waypoints". The receivers with
electronic maps also display waypoints, but the waypoints are displayed on a map.
However, even a simple handheld can provide:
- Your location, elevation, and estimated position error.
- The ability to plot your position and subsequent movement on its screen.
- The speed, direction, and distance you've traveled.
- GPS satellite information including the number accessed, their location, and
- The ability to connect to a PDA or laptop computer with mapping software,
and provide the location data.
GPS Handheld Receivers with Map Display
Like other modern electronics, as the prices of GPS handheld receivers have
dropped, their features have expanded. And so now, most handhelds include
the ability to display maps on their screen. Some GPS devices can only display
a map which is built into the unit. These permanent maps are called "basemaps"
and show the general points of interest for an area, such as major roads, rivers
More sophisticated models let you also display precision maps which are
available from various sources. These electronic maps are detailed enough to make finding a
city street address easy. The maps can be bought from both GPS device manufacturers
and regular map makers. The data for the maps is downloaded and stored either in a GPS
handheld's internal memory or a programmable data card.
An offshoot of handheld GPS receivers is the GPS watch. A GPS wrist
watch has the same functions as a basic handheld, but in a much smaller case.
GPS watches have a display usually less than half the size of handhelds and
their reduced memory means that fewer waypoints can be stored.
And even the batteries usually have a shorter life than those for basic GPS handheld
devices. So unless you're obsessed with size, a GPS watch is probably not your best
GPS for PDA
Among the many accessories available for PDAs today, is the capability for GPS.
You can get GPS for Palm or GPS for Pocket PC operating systems.
Adding GPS functioning to a PDA can be done in two basic ways. Either you can connect
a GPS receiver to the PDA with a cable or wireless, or use a PDA GPS receiver that mounts
in a CompactFlash memory slot.
Even with separate GPS equipment, a PDA can add several important benefits.
The typical PDA has a screen area that's 2 to 3 times larger than the
average GPS handheld. And if you're trying to read the screen while traveling
in a car, boat, or plane, this extra size can be a real help. The PDA
also increases map storage capacity, even if the handheld can already
display maps. Further, there are software navigation programs for PDAs
that include voice commands to help guide you to your destination.
Laptop GPS provides further improvements to the benefits of PDA GPS. A laptop's
large screen and increased memory allow for unlimited mapping capabilities. And
similar to a PDA, laptop GPS is achieved by either connection
to a separate GPS receiver, or by using a GPS PCMCIA card. A laptop
is able to run the most sophisticated mapping software while having the
clearest display. But at the same time, a laptop's larger size and
higher energy requirements, limit where it's practical to use.
As the price and size requirements keep decreasing, GPS receivers
will show up in more and varied electronic devices. One result may be
an electronic equivalent of a swiss army knife with more functions than most people
would ever need. But there are certain features that can be worth getting.
For instance, if you need the highest location accuracy possible,
look for receiver models that work with the Differential GPS (DGPS), or
better still, the Wide Area Augmentation System (WAAS).
And if you want higher accuracy with elevation measurements, get a unit
with a built-in altimeter. Another handy feature to have with GPS receivers
is an electronic compass. This is because regular GPS devices display
direction only after you've moved from one point to another. But even
with an electronic compass, it's also a good idea to carry a mechanical backup.
And keep in mind the more features you get, the faster the batteries
will need replacing and you'll need to carry more spares or a recharger.