We propose that an RF-based personnel tracking system has significant advantages over presently used or contemplated ultrasonic/GPS systems. The proposed RF tracking system uses a central tracking station and multiple RF receivers to sense signals from personnel mounted transponder tags. The tags respond to uniquely coded probe signals by transmitting a second set of time coded RF signals. Triangulation to the receivers using proprietary signal processing algorithms allows accurate location of the tags in 2 and 3 dimensions. Numerical simulations of the algorithms indicate highly accurate distance measurement capability even under very low signal conditions and in the presence of RF reflective objects. The proposed system can seamlessly be interfaced with existing GPS systems to eliminate the tracking loss problem during building entry/exit. Furthemore, the system could also be extended to km distance scales for full coverage of training ranges. Such extensions could eliminate the need for GPS entirely, leading to a lower system cost. In Phase I we plan to develop and build a simple RF system to demonstrate tracking of at least one person. We will also refine the processor algorithms with a view to extending operating range and maximizing spatial resolution under low signal and multipath conditions. The proposed systems has applicability to fire fighter accountability systems, as well as location and tracking of inventories, equipment, and persons in secure facilities and prisons
