Which type of navigation aid relies on multiple ground stations to enhance accuracy?

Ground Based Augmentation Systems (GBAS) enhance navigational accuracy by utilizing multiple ground stations that work together to provide precise location information to aircraft. These systems help correct errors in satellite-based navigation systems, such as GPS, by transmitting differential correction signals. By comparing the signals from multiple ground stations, GBAS can determine the actual aircraft position with higher precision, improving safety and reliability for approaches and landings, especially in poor visibility conditions.

In contrast, radio beacons primarily provide basic navigational signals but do not incorporate multiple stations to improve their accuracy. Visual markers are physical indicators used mainly during visual flight rules (VFR) operations and do not involve any technological enhancement for navigation accuracy. Charted visual flight paths are established routes for aircraft to follow but are not a type of navigational aid that relies on ground stations to enhance precision. Thus, GBAS stands out as the correct answer due to its reliance on a network of ground stations for improved accuracy in navigation.