Maryland Bar Bulletin
Publications : Bar Bulletin : February 2005

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"GPS Can Lead the Way"
By John Anderson

Over the river and through the woods
Only 22.5 more miles
to Grandmother’s house to go
We know the way
To turn the sleigh
Even with the signs all covered
with snow

Once a luxury item, GPS devices are quickly becoming an affordable addition to your technology arsenal. Whether or not you need one should be the first question you ask yourself before you rush out and get one. But if you get lost as often as I do, it could certainly keep you from having to stop and ask for directions (which I never do, anyway).

The GPS Satellite System
The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. GPS works in any weather conditions, anywhere in the world, 24 hours a day. There are no subscription fees or setup charges to use GPS.

Also called NAVSTAR (the official U.S. Department of Defense name for the system), GPS satellites was originally intended for military applications, but in the 1980s the government made the system available for civilian use. The first GPS satellite was launched in 1978, and the full constellation of 24 satellites was achieved in 1994. The orbits are arranged such that there are in fact always at least four satellites visible from any point on the surface of the earth. If signals from four or more of these satellites are picked up by a GPS device, it can determine its location with reliably high accuracy (15m, or 50 feet, horizontally, and 100m, or 328 feet, vertically).

GPS Receivers
GPS receivers can be installed in your car, and they now come as an option on many new vehicles. You can also get receivers that you can place on your dashboard, ones that connect to your laptop and interact with street map software and, of course, handheld devices that you can use on camping trips and other explorations where your car or power cord just can’t reach.

GPS devices are now available for as little as $100. The low-end devices provide basic features such as current position, distance and direction to a set point, current speed, trip distances, track logs, while the more expensive devices provide map features, such as showing your current location on a color map display. Also, they can guide you to a given address. They also have bigger, more sensitive antennas for faster response.

A good recourse for finding an affordable device can be found at, which features a large selection of GPS devices and accessories and software, including GPS wristwatches for prices much lower than you would expect.

Using Your GPS
So, what can you actually do with this new gizmo? Will it dramatically change your life? Probably not, but when you aren’t trying to find the shortest route to Aunt Linda’s (I knew I should have taken that left turn at Albuquerque) you can have a lot of fun.

To start using your GPS effectively, you will have to know about waypoints. What’s a waypoint? Well, I’m glad you asked. Sometimes called landmark, a waypoint provides the coordinates (e.g., latitude and longitude) of a geographic location and is given a name. The location could be a road crossing, a mountain peak or the best parking spot at the mall. You can set these waypoints yourself or download them from directories available online.

Now, let’s have some fun…


GEOCaching ( – This is a GPS treasure-hunting game where, armed only with your GPS device and coordinates, you can locate treasures that others have hidden in unusual places. This is a great family event and many Caches are located right in your backyard.


Hiking – Don’t get lost. Mark waypoints along your way through unfamiliar territory or with the right maps plan out your hike by downloading a route of waypoints to guide your trip. You can also mark that secret fishing hole so that you can find your way back to it next time.


Boating – Boaters, especially seagoing ones, have long used GPS for navigation, but even if you are just taking your canoe out on the lake, you can use GPS just the same to find your way along unfamiliar shorelines.


Car Travel – Several commercial units for cars display your position on a map, which is very helpful for travel in unfamiliar cities, on back roads and at night. And should you break down in a remote area, you can report your exact location by cell phone.


Golfing – You can measure distances of your best shots (we won’t talk about the other ones). There is even special software available to help you out.


Hang Gliding – Yes, you heard me correctly. While vertical precision is not sufficient (100m) for altitude determination, GPS will provide your horizontal position during your flight and at your landing point.


GPS Drawing – Huh? GPS drawing is “digital mark making” using GPS satellite navigation technology. GPS receivers can automatically record where you have been as a digital dot-to-dot line. The drawings are of journeys captured using GPS receivers. They were created by treating travel like a geodetic pencil or a cartographic crayon. Visit to see the designs created by skydivers, city dwellers and trips through corn mazes.

GPS to the Rescue
Miniature GPS receivers are now available in cell phones and when making an emergency phone call can provide the position of the caller to police and rescue personnel.

Where Can I Get One?
You can find these devices in just about any electronic store, but you should probably shop around to find the device that will be the best match for you and your needs. It will also give you the chance to learn the lingo and read some of the FAQs of GPS devices. Some of the most popular brands include Garmin (, Lowrance Electronics ( and Magellan (

GPS is Not Big Brother
Is your GPS spying on you? There is a popular misperception that GPS is a “tracking” technology and that it can be used to monitor someone’s whereabouts.

In reality, a GPS receiver is just that, a receiver. It knows its location (latitude, longitude, altitude, compass heading and speed) anywhere on Earth, within about 50 feet.

There are companies that produce GPS-based tracking devices that couple a GPS receiver with a wireless transmitter on a cellular network. These devices relay the position of a device to a tracking center. However, if you purchase a handheld GPS receiver at a sporting goods store or a car GPS receiver at an electronics store, you need not worry.

So as you begin to explore, leave the bread crumbs behind and start setting your waypoints.

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Publications : Bar Bulletin: February, 2005

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