Indoor Navigation encompasses the technologies and systems that provide wayfinding, positioning, and routing guidance within enclosed spaces where satellite-based positioning (GPS) is unavailable or unreliable. It relies on alternative positioning signals such as Wi-Fi fingerprinting, Bluetooth beacons, Ultra-Wideband (UWB) ranging, visual markers, inertial sensors, and lidar-based spatial maps. Indoor navigation is critical for large venues such as airports, hospitals, shopping centres, factories, and warehouses where occupant or asset routing improves operational efficiency and user experience.
Overview
- GPS accuracy degrades dramatically indoors due to signal attenuation through building materials; indoor positioning systems (IPS) fill this gap.
- Bluetooth Low Energy (BLE) beacons are the most widely deployed indoor positioning infrastructure due to low cost and ubiquitous smartphone support.
- Ultra-Wideband (UWB) time-of-flight ranging achieves 10–30 cm accuracy for precision use cases such as industrial robot guidance and contact tracing.
- Standards such as IPS (Indoor Positioning System) and the W3C Geolocation API are converging to improve cross-vendor interoperability.
Key aspects
- Multi-technology fusion: BLE + inertial measurement unit (IMU) dead reckoning is a common hybrid approach.
- Floor-level disambiguation remains challenging; barometric pressure sensors and visual markers assist.
- Map data must be kept current as building layouts change.
- Privacy considerations arise when tracking individuals; consent and anonymisation are required.
- AR overlays via head-mounted displays or smartphone cameras augment turn-by-turn navigation.
Mechanisms
- Wi-Fi fingerprinting: compares received signal strength patterns against a pre-recorded map of radio signatures.
- UWB time-difference-of-arrival (TDOA): measures sub-nanosecond pulse arrival times between anchors and tags.
- Pedestrian dead reckoning (PDR): integrates step count and heading from IMU sensors to propagate position.
- Lidar SLAM: builds and localises within a 2D or 3D floor plan in real time.
Applications
- Hospital staff and equipment tracking to reduce search time.
- Airport terminal wayfinding for passengers with flight connections.
- Warehouse pick-path optimisation for logistics operators.
- Museum and gallery exhibit discovery for visitors.
- Emergency responder positioning inside fire-affected buildings.