Android 9 Pie introduced support for indoor positioning by utilizing 802.11mc. Wi-Fi Round Trip Time (RTT) allows the system and apps to "measure the distance to nearby RTT compatible Wi-Fi access points." This week, Google released a "WifiRttScan App" for developers via the Play Store.
Location derived from GPS is not correct in closed, indoor settings. Google has previously explored beacons as an alternative, with its latest attempt at indoor positioning, using the IEEE 802.11mc Wi-Fi protocol. The accuracy can be within 1 to 2 meters if a device is able to measure the distance to three or more access points. The RTT APIs in Android 9 and above allow an app to utilize indoor positioning.
Use cases involving helping people navigate shopping malls, stadiums, conferences, or other appropriate big venues. In addition to in-building navigation, other new experiences include:
- Fine-ground location-based service: disambiguated voice control (for example, "Turn on this light")
- Location-based information: (eg "Is there special offer for this product?") [1
Developers, OEMs and researchers can use this tool to validate target metrics that enable the development of positioning, navigation and context-aware applications based on the WiFi RTT API.
The 2.5 MB app (and Wi-Fi RTT) requires users to give the Location permission to display a list of RTT-compatible APs of SSIDs and BSSIDs. Tapping opens a granular list of Access Point Ranging results that indicate range (in meters) and latitude / longitude / height, if available.
WifiRttScan App is available on the Play Store and requires a supported Android 9+ device.  Check out 9to5Google on YouTube for more news: