Systems and Methods of Location and Tracking

Abstract

A position location system is described for determining position of mobile Tags attached to assets or people. Zone Tags are installed in the venue to assist in position location estimation of mobile Tags. Time is divided into intervals, each interval comprising at least one range measurement sub-interval, and an idle sub-interval where zone Tags and mobile Tags go to sleep to save power. A zone Tag or mobile Tag is designated as the anchor network element. The anchor network element contends and seizes the communications channel at the beginning of each interval to start the range measurement phase. Mobile Tag position location estimates are made periodically. Between the periodic range measurement based position estimates, mobile Tag sensor readings are used to update the mobile Tag's position location. The period between range measurement based position updates is adjusted based on the statistics of the differences between the range measurements based position estimate and the sensor based position updated.

Dependencies are inferred from the claim text.