Canoeing.com Definition: A GPS unit allows canoeists to identify the coordinates of their current location, navigate from point-to-point with bearings, and plot waypoints or keep track of a route as they go. A portable and waterproof unit with a long battery life is best for paddling, however a wide range of styles and options are available. Select a unit with specific navigational needs, desired battery life and budget in mind. Large, illuminated and/or color screens can be great navigational aids but increase price and drain battery life. Antennas also impact performance and budget. A quad helix is most common and works best in areas of dense tree cover, but a flat patch antenna works well in an open setting and tends to be less expensive. In general, built-in antennas will be less likely to break or damage but an exterior antenna can be repositioned for better coverage. And when accuracy is critical, look for WAAS (Wide Area Augmentation System) compatible units for up to 3 meters of accuracy.