We recommend the introduction by Prof. Berthold K.P. Horn of MIT CSAIL. See http://people.csail.mit.edu/bkph/ftmrtt.shtml
For in-depth overview by Prof. Horn of best practices for implementing Wi-Fi RTT see the article “Doubling the Accuracy of Indoor Location: Frequency Diversity“
It combines sound theoretical background with extensive hands-on experimentation and development using WILD and Android.
For more details see:
- 1 WILD units allows ranging from an Android phone.
- 2 WILD units allow ranging from one WILD to the other WILD
- 3 WILD units allow obtaining location from an Android phone (by trilateration – ranging to each WILD device)
- 4 WILD units allow obtaining location from one WILD (initiator) by ranging to the other three (FTM responders)
- 5 WILD units is the recommendation for evaluation. It allows one initiator and four FTM responders (FTM responder redundancy is recommended)
FTM Responder (FTMR) is a WiFi enabled device (usually an access point) that has FTM capabilities. WILD is an FTM Responder that can also act as an FTM Initiator (FTMC).
Multiple FTMR units have to be installed inside a building to enable WiFi Indoor Positioning.