Awesome breakdown of the challenges of indoor navigation! One thing I was curious about... given that many modern phones now have UWB radios built in, was UWB ever considered as part of the solution stack? From what I understand UWB can get to sub meter accuracy, and I know it's used in several sports applications where precise tracking is really critical.

Is the constraint more about infrastructure (installing anchors, device compatibility, power) or something else that made you lean towards WiFi + SLAM fusion instead?