Wide Area Augmentation System (WAAS) is an FAA satellite based navigation system designed to become the future primary means of civil aircraft navigation. It was commissioned to assist with guiding aircraft without the help of an ILS (Instrument Landing System) – even in poor visibility conditions.

In the WAAS system, the standard GPS service is augmented with corrections for time, the GPS satellite orbits and the ionosphere.  These augmentations enable the WAAS system to meet the very stringent aviation requirements for accuracy, availability and integrity.  Quarterly performance reports have shown that the WAAS system generally meets or exceeds these requirements. The performance reports also reveal that one of the greatest challenges for WAAS is maintaining continuous APV (Approach with Vertical Guidance) availability during extreme geomagnetic storms.

Small plane owners may want to understand regular GPS outages. They might not know much about WAAS or they might want to know "What is WAAS and how is it better than my regular GPS?"