Navigating the Latest GPS UnitsPoint by Point

Contractors may have to find a new excuse for showing up late to work. Locating the jobsite has never been easier, thanks to the availability of feature-packed, surprisingly affordable GPS devices.

GPS units utilize the Defense Department's Global Positioning System, or "Navstar," a civilian-accessible network of 24 satellites. By latching on to any three satellites at the same time, a GPS receiver can calculate its location anywhere.

GPS technology is a boon for contractors of all sizes, and there is a mind-boggling array of products available. Here is a look at what pros can expect to find with units costing $600 or less.

What's Available

GPS products run the gamut not only in price, but also in functionality, usage, and features.

Handheld receivers are intended primarily for outdoorsmen marking a hiking route or favorite fishing spot. Handhelds are more about walking (point-to-point navigation) than driving (turn-by-turn navigation), but you can find hybrids that will get you through a weekend in the Rockies and a workweek in your Sierra.

Vehicle-oriented personal navigation devices or personal travel assistants are what most people think of as GPS. They are used primarily to get turn-by-turn driving directions and find pre-programmed points of interest, such as gas stations, hotels, and restaurants. Unfortunately, even though many are shirt-pocket portable, they usually lack the pedestrian/walking features found in handheld receivers.

Every major U.S. cell phone carrier now offers GPS services and phones with GPS features. Typically, you'll pay about $10 a month (for Verizon and Sprint) for consumer service, and $20 to $25 a month for commercial and tracking capability; that's on top of a required data plan. A cell phone with GPS can be a great alternative to a dedicated device. It does as good a job with driving directions, and since it can get real-time information from the cellular network, traffic alerts and points of interest can be updated continuously. These devices also let contractors take advantage of lower-cost fleet-tracking services.

There also are GPS kits and laptop and PDA add-ons that turn your laptop or PDA into a