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By: Jason Giacchino
GPS: Don’t Leave Home Without It
Garmin Colorado 400t |
You can almost imagine the scene--sometime in
the distant future a history teacher addresses
his bored class. He unfolds a brightly
colored piece of paper and says, “These relics
were all that early humans had to rely on for
navigation purposes. They were called
maps.”
The kid in the front row will reply “My great
grandfather told me about those things, but I
never pictured them so low-tech. I mean it’s
just a drawing!” And the class will erupt in
laughter at our primitive nature.
Don’t feel too bad, though; we stand at the
crossroads of future technology today. GPS
or Global Positioning Systems have been around
for a few years now and have finally become
affordable enough to earn acceptance by the
masses. What’s more is that companies are
producing units compact and specialized enough
to be marketed for specific applications. The
GPS receiver in your car no longer has to serve
duty as the unit you would take hiking, cycling,
or in our case, ATVing. We can’t be certain
future generations of spoiled brats won’t be
laughing at our expense one day; but thanks to
GPS, it’s getting much more difficult to get
lost today and there’s nothing funny about that.
HISTORY
While today’s GPS units are typically no larger
than a cell phone, the technology can be traced
back to the early 1970s through a series of Air
Force experiments intended to duplicate the
effects of global positioning using ground-based
satellite receivers. It wasn’t until 1978 that
the first GPS satellite was launched into earth
orbit. By 1985, ten more such satellites were
launched into orbit. 1993 witnessed the initial
operational capability of the system and by 1994
a total of 24 satellites orbited the globe. In
2004, the US signed an agreement with the
European Community to establish cooperation with
their upcoming satellite network (Galileo). That
was also the year that Qualcomm successfully
integrated GPS receivers into their mobile phone
systems. The most recent GPS satellite launch
took place in December of 2007 bringing the
total to 31 actively broadcasting satellites.
Magellan eXplorist 100 |
So how do 31 satellites high above the planet
determine exactly where you (or more
specifically, the little gizmo in your pocket)
are located? A typical GPS receiver (the little
gizmo itself) calculates its own position using
incoming signals from four or more GPS
satellites. Why four? At least this many
satellites are needed since the process needs a
very specific local time, more accurate than any
clock can provide. What this means is that the
receiver internally solves for time as well as
position. In English the GPS receiver in your
pocket collects four measurements (one from each
of the satellites above) which it then
translates into more understandable values such
as latitude/longitude coordinates or your
location on a digital map. This is what appears
on your screen. GPS receivers are every bit as
essential to the process as the satellites
themselves as it is the receiver that is
responsible for taking the satellite information
and using triangulation to calculate the user's
exact location. Essentially, the GPS receiver
compares the time a signal was transmitted by
the satellite with the time it was received, and
it is this time difference that tells the GPS
receiver how far away the satellite is.
Believe it or not, there are literally dozens of
different GPS receiver types to choose from.
Among these are aviation models, handheld,
automotive, PC cards, marine, surveying, etc.
For our specific purpose (off-roading) the
handheld unit is the most practical for its
portability, lightweight construction, and
durability. Additionally, handheld GPS receivers
are used because they are battery powered (often
rechargeable) and feature a built-in display.
The display is usually LCD (liquid crystal
display) for low power consumption and can be
either alphanumeric or graphical.
Often times we associate automotive GPS with
in-dash technology (such as On-Star) but equally
popular of late are handheld units that can be
easily mounted to the vehicle’s dashboard for
travel but detached and carried upon arrival.
These units typically make worthy ATV companions
because of their bright screens and easy to
follow navigation tools (such as full graphical
maps).
This day and age has actually witnessed
technology advances that make it possible to fit
a GPS receiver into a device wearable on the
wrist! For runners, bikers, backpackers and ATV
riders, these units offer another popular method
of navigation. The drawback is that due to their
much more compact screens, these devices don’t
usually support GPS mapping capabilities.
Instead they do offer route tracking, as well as
distance, altitude, speed and location data. Of
course, should the user become lost, the
receiver would point rescuers directly to the
wristwatch.
What to Look For
Channels:
When getting ready to buy, you will likely
discover that there are two specific types of
receiver to consider: Parallel Channel and
Multiplexing. The most basic of today’s
receivers will support 8 parallel channels. What
this means is that the unit can scan for a total
of eight orbiting satellites to determine its
position. The more channels a receiver can
support, the more accurate its triangulation of
position becomes. Currently the best receivers
can scan 16 channels, which provide 95%
accuracy.
Multiplexing models are slightly different as
they can switch between tracked satellites on
the fly. Because multiplexing receivers lock
onto a satellite signal for only a short amount
of time, they tend to be less accurate than
parallel channel receivers.
Garmin GPSMap60csx |
Water Resistance
Let’s face it. Those of us who ride in swampy
conditions, through creeks, and get caught in
the rain have to consider a unit that is fairly
water resistant (and shock proof). While few
receivers come completely waterproof, there are
many that offer some degree of water resistance.
This is accomplished at the factory by encasing
the delicate electronics in a plastic or
rubber-based shell. Read the box and don’t
be afraid to ask questions before purchasing.
Running a fragile unit in rough conditions will
quickly destroy the receiver.
WAAS
Many units proudly boast WAAS Technology
Equipped across the package. What does this
mean? While GPS receivers have an accuracy of
roughly 10 meters, a WAAS-enabled receiver can
be accurate within 3 meters! WAAS stands for
Wide Area Augmentation System and in addition to
an array of satellites,WAAS offers connection to
nearby ground stations to provide GPS signal
corrections. These correcting signals literally
improve the accuracy of the GPS receiver’s
position. This technology averages up to five
times more than a non-WAAS equipped unit.
Battery Life
ATV epics often lead riders far from
civilization and since all receivers require
electricity to operate, battery life is a
serious consideration when selecting a receiver.
Most of today’s GPS receivers offer some type of
battery-saving quality to keep you from having
to constantly swap batteries. Many handheld
units use a rechargeable lithium-ion battery
pack (like those found in cell phones and PDAs)
that actually shows a battery-life meter on the
display. With this line of thinking you could
shut the unit down when it is not needed in an
effort to conserve energy. If you decide
on a non-rechargeable model, it wouldn’t be a
bad idea to get into the habit of carrying spare
batteries on long rides.
Maps
Most standard GPS receivers come with only a
base map. So how do you acquire additional maps
or specific maps of your particular area? Some
manufacturers charge extra to unlock maps from
their web sites or sell actual map CD-ROMs that
you install on your computer (then download into
the receiver). Many quality units have a USB
port that allows you to connect the receiver to
your PC, where you can download the latest maps
as they become available. Some even come
packaged with a free CD full of maps as part of
a sales promotion.
Garmin Rhino 530 |
Voice
Many models boast spoken voice navigation
abilities (whereby the unit actually speaks step
by step navigation instructions) but keep in
mind that this is quite an unnecessary feature
for most ATV applications as its main benefit
involves street navigating (not to mention with
helmets on and revving engines, it will likely
be difficult to hear).
In summary, ATV riders have some pretty unique
needs when it comes to selecting a GPS unit.
While many various specializations could be made
to work (automobile portable & automobile pocket
models), the better choices for our unique needs
come from the camping and hiking market segment.
These are the GPS units specifically designed to
be lightweight and rugged for the types of abuse
outdoor use can dish out. Many of these units
are offered in waterproof options as well.
Although sometimes difficult to find, some
companies do produce motorcycle-specific GPS
units, which work exceptionally well for ATV use
because of the fact that they are most often
waterproof, vibration resistant, and best of all
come with unique mounting hardware designed to
clamp down to a motorcycle handlebar.
Finally, if all else fails, fitness and cycling
GPS devices commonly used for walking, jogging,
running, and bicycling can be made to fit the
needs of an ATV rider. While usually cheapest in
price, these tiny units are usually worn on the
wrist (like a watch) and can track variables
such as your speed, distance traveled, pace, and
location. Cycling-specific variants of these
units often come with the mounting hardware that
allows fitting directly to the stem or handlebar
of a bicycle (which can work on many quad bars
as well).
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