localization: absolute
- Proximity-To-Reference
- Landmarks/Beacons: ParcTab, Active Badges
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- Angle-To-Reference
- Visual: manual triangulation from physical points
- Radio: VOR
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- Distance-From-Reference
- Time of Flight
- RF: GPS, PinPoint
- Acoustic: Active Bat, Lew
- Signal Fading
- EM: Bird/3Space Tracker
- RF: SCADDS/SCOWR, Niru
- Acoustic: Jer?