In order to improve the accuracy of the position calculation, Polar G5 and G1 GPS sensors utilize the Wide Area Augmentation System (WAAS). WAAS is an extremely accurate navigation system in North America. It is widely used e.g. in aviation to enable precision approaches for airplanes. WAAS Wide-area Reference Stations, which are located on the earth, monitor and collect information on the GPS signals and then send correction messages to the two Wide-area Master Stations. These two master stations then send the message forward to geostationary satellites, which in turn send the correction signals to WAAS-enabled GPS receivers, like Polar G1 GPS sensors.
Polar G1 sensors need to be in FULL Power mode in order to utilize the WAAS signals. G5 utilizes the WAAS signals all the time.
G5 and G1 GPS sensors can also utilize the European Geostationary Navigation Overlay Service (EGNOS).