WAAS GPS

WAAS (Wide Area Augmentation System) is a network of FAA-operated ground stations that corrects GPS satellite errors in real time, bringing positional accuracy to within about 1-3 meters. You can spot a WAAS-capable Garmin unit by the "W" at the end of the model name, for example GNS 430W.

The main benefit for IFR pilots is LPV approaches. LPV minimums can be as low as 200 ft decision height, matching a traditional ILS, but without needing any ground equipment at the destination airport. If you plan to fly IFR, training in a WAAS-equipped aircraft is worth prioritizing.