• What is a GPS unit and why do you need one?
• Big brother is watching
• Fun and GPS games
• What to look for in a GPS
• How the GPS works
• More than one system
• Location, location

Fun and GPS games

Like to travel? Fancy a bit of sleuthing? With a personal GPS receiver you can do both. The popularity of personal GPS units has even resulted in a new "sport" called Geocaching. Sort of like a high-tech treasure hunt, Geocaching involves using a GPS receiver to find a "geocache" (or "cache") placed in a specific (and sometimes difficult) location, the co-ordinates of which are posted on the Internet. A cache is typically a small, waterproof container containing a logbook and a "treasure". Don't get too excited yet — the "treasure" is usually not valuable at all, but finders still get a thrill from getting to it first. Geocaching is spreading worldwide. For more info, check out Web sites like www.Geocaching.com, www.Terracaching.com and www.Navicache.com.

What to look for in a GPS

Assuming that you are looking for a GPS unit for personal use, it will most likely be either an in-car system or a personal, handheld device. You may travel a lot and/or have a bad sense of direction, or you might just want to take advantage of the growing range of practical applications for this handy technology. In any case, here are a few things to bear in mind when shopping around.

TomTom's GO930 includes software to syncronise with a PC or Mac

To help determine what sort of unit you need, consider the following:

• Do you regularly reach for the street directory or travel to unfamiliar areas? You are a prime candidate for a GPS unit.
• Do you often drive alone?
• Do you primarily drive your own car or do you rent? A fixed in-car system is of little use if you can't take it to another vehicle. Go for a portable in-car unit. Examples of these include the TomTom GO 930, Mio Moov 370, Navman S300T and the Garmin nuvi 265W.
• Do you use a mobile phone, PDA or notebook computer? If so, consider an add-on to give it GPS functionality. Many mobile phones are now shipping with built-in GPS receivers. Even if your phone doesn’t have one of these built-in, there are a range of GPS receivers that can be added on to give it this functionality, such as the Nokia LD-4W, and the QStarz BT-Q1300.
• Do you want a compact unit that you can take with you anywhere?
• For in-car use, go for a unit with a large (at least 3.5in) and high quality display, such as the TomTom XL.
• Go for a unit that can be upgraded (with more memory, extra/new maps and software upgrades — often via an SD or microSD card slot) and preferably one that can be linked to a PC or notebook via a USB connection for downloading new information. The TomTom ONE (4th Edition) includes the TomTom HOME software, allowing easy connection to a PC or Mac.
• Will you use it primarily while boating? Specialist marine GPS units offer features you won't find in a land-based unit — like fish finders, depth sounding, information on buoys and navigation aids, and coastline charts designed more for boating than driving.
• If you go for a marine-type unit, or are going to be outdoors, check that the unit you select is water resistant.
• Using a handheld GPS or mobile phone while driving is difficult and dangerous (and most likely illegal). Make sure it can be mounted securely for in-car use.
• Do you need a continuous power supply for a GPS? If so, look for additional battery packs or a car cigarette lighter adapter for recharging and continuous power. And make sure your GPS has an internal battery.

Mobile phones with GPS are becoming more and more popular. A wealth of mobile phones now include built-in GPS receivers, including the Apple iPhone 3G, LG Arena and Nokia 5800 XpressMusic.

An example of GPS navigational software running on a mobile phone

If you have a smartphone, it can easily be transformed into a navigational unit by installing a software package such as CoPilot Live 7. The convenience of using your mobile phone as a GPS is its portability – it is available in your pocket, anywhere, anytime. A GPS-enabled mobile phone is ideal if you are navigating on foot, as you won’t have to carry around a chunkier, heavier in-car unit.

The dith GPS is that they often have a small display without touch-screen operation, so general use isn't as polished as a portable in-car unit with a touch screen.

So, when you think of the range of features and uses a GPS unit provides, with prices starting around only a couple of hundred dollars, you can see why they are quickly becoming the must-have high tech item.