WAAS is an acronym for Wide Area Augmentation System. It is bunch of ground based stations that collect correction data using differential techniques. This data is then uploaded to multiple geosynchronous satellites. The data is then beamed down to compatible GPS receivers. WAAS is standard in most GPS units sold in North America and Europe. In Europe they use a equivalent system called EGNOS (European Geostationary Navigation Overlay Service).

When a GPS receiver has a WAAS signal it uses the data in correcting the position already determined by conventional GPS means. This will bring the accuracy of your GPS down to about 3m 95% of the time. Unfortunately GPS is not Global with other systems existing over other continents. The WAAS coverage is intended for Continental USA and Alaska. Because of this there is some coverage overlap in Mexico and Canada. Having WAAS on in an area without coverage will have a couple adverse affects. First your position accuracy could degrade resulting in a error of over 15m. Secondly but less noticeable is a shorter battery life.

As of 2007 new ground stations in Canada and Mexico have come online to increase the WAAS coverage to include all of Canada Mexico.

A tracklog is series of points of where you have been automatically collected by your receiver if enabled. Track logs are a standard feature on recreational handheld GPS devices and marine units but its a feature only found on a few PND's.

What can a track be used for?