GPS watches, are watches that can link to the network of satellites known as the "Global Positioning System". By receiving a satellite signal they can determine your precise location on earth. A relatively new concept in sports watches, the addition of GPS technology has given sports watches, especially fitness watches the ability to measure speed, distance and height above sea level - an ability athletes ten or twenty years ago would only have dreamed about. With much more precise information at their disposal, performance athletes now have a lot more real-time information at their finger tips that they can use to their advantage both in training and competitive events.
There are generally two levels of sports GPS watches available for athletes to choose from:
Speed & Distance (2D GPS) Speed & Distance + Elevation & Routes (3D GPS)
The first GPS watch type is the cheaper of the two measure linear speed and distance only. It measures speed, pace and distance, but not elevation or height information.
The second type does include height information provides a lot more power to runner or athlete user given its extra features. Height information can be used to calculate ascension and descent ion rates and a watch with this ability can even offer height alerts when an athlete passes a certain height limit.
Often known as 3D GPS, this kind of system is often also capable recording route information, meaning a runner can have their watch record location data at short, repetitive intervals along their run which are stored in the watch's data banks and can be later transferred to a personal computer for viewing in a 3D software program. Many GPS watches now use wireless data transfer features that facilitate data transfers, removing the need to fumble around with data cables.
A 2D GPS system is quite limited and given that GPS consumes battery power at a rapid rate and suffers when large objects obstruct its link to the satellites, often a footpod unit might as well be used. Accelerometer foot pods are on par with a GPS watch's accuracy, but do not suffer its deficiencies. Many people do not understand a 2D GPS's limitations, so when they purchase a "GPS watch" expecting the full package, they are often left wanting.
When you purchase a GPS watch, always ensure that it is providing the functionality that you want. Many cheaper systems are 2D, in particular entry-level watches from Polar and Suunto, so don't be tempted by these cheap offerings, unless you know its what you really want.
