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. One embodiment describes systems and methods for the zone tags to automatically determine their position location. Another embodiment describes systems and methods to detect that a zone tag has been moved and to determine the new position of the moved zone tags. Another embodiment describes systems and methods whereby mobile tags determine a list of zone tags with which to make range measurement for determining the mobile tag's position location.

Abstract: A position location system based on a wireless local area network such as an IEEE 802.11 network is described. The system determines position of mobile tags attached to assets or people. IEEE 802.11 enabled zone tags are installed to assist in positioning. The system aligns frame timing of zone tags to that of an associated basic service set (BSS). The system computes the frame timing offsets between adjacent BSSs, and utilizes the frame timing offsets in scheduling range measurements between zone tags and mobile tags. A set of zone tags which are in close proximity of a first zone tag and able to receive signals from the first zone tag is identified. Frame timing of all zone tags in a network are aligned.

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.

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. One embodiment describes systems and methods for the zone tags to automatically determine their position location. Another embodiment describes systems and methods to detect that a zone tag has been moved and to determine the new position of the moved zone tags. Another embodiment describes systems and methods whereby mobile tags determine a list of zone tags with which to make range measurement for determining the mobile tag's position location.

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.

Abstract: A position location system based on a wireless local area network such as an IEEE 802.11 network is described. The system determines position of mobile tags attached to assets or people. IEEE 802.11 enabled zone tags are installed to assist in positioning. The system aligns frame timing of zone tags to that of an associated basic service set (BSS). The system computes the frame timing offsets between adjacent BSSs, and utilizes the frame timing offsets in scheduling range measurements between zone tags and mobile tags. A set of zone tags which are in close proximity of a first zone tag and able to receive signals from the first zone tag is identified. Frame timing of all zone tags in a network are aligned.