GPS

The Global Positioning System (GPS) is a satellite-based navigation system that provides location and time information to receivers on Earth. For accessibility, GPS is foundational to wayfinding apps used by blind and low-vision travelers, enabling turn-by-turn navigation and location awareness through screen readers and voice output. However, GPS has significant limitations for accessible navigation: it is unreliable indoors, inaccurate in urban canyons between tall buildings, and its typical accuracy of several meters is insufficient for pedestrian-level guidance such as finding doorways or crossing points—prompting the development of complementary technologies like BLE beacons and inertial dead reckoning.