Patent attributes
Described are systems and techniques for determining a position of one or more people within a physical environment, such as an aisle in a fulfillment center. In some instances, the aisle is instrumented with a plurality of radio frequency receivers (RFRXs), active infrared transmitter-receiver pairs (AIRTRPs), and passive infrared (PIR) proximity sensors. A radio frequency-emitting tag carried by the user is detected by the RFRX to determine an identity and approximate position along the length of the aisle. Data indicating obscuration of beams from one or more of the AIRTRPs provides further refinement as to position along the length of the aisle. Data from the PIR provides disambiguation as to which side of the aisle the user is on. Accordingly, the user may be identified and precisely positioned in the aisle.