In this episode, Lucas and Luna explore how mobile apps are using on-device AI for real-time indoor navigation, a technology that helps users find their way inside large buildings like airports, hospitals, and shopping malls without relying on GPS. Lucas breaks down the core challenge: GPS signals are weak indoors, so apps must fuse data from Wi-Fi, Bluetooth beacons, and phone sensors to estimate precise location. He explains how machine learning models running on-device can combine signal fingerprints and step detection to achieve accuracy within a few meters. Luna asks about the practical hurdles, including the initial mapping effort and the risk of signal drift. Lucas shares how companies like Google and Apple are integrating these capabilities into their mapping SDKs, and how retail chains are using it for turn-by-turn directions to specific stores. The hosts discuss a real-world case: the Mall of America, which deployed indoor navigation across its 5.6 million square feet. They also touch on privacy advantages of on-device processing and future possibilities like AR overlays. The episode gives listeners a concrete understanding of how indoor navigation works under the hood and why it's becoming a standard feature in mobile apps.