Multi-path mitigation in rangefinding and tracking objects using reduced attenuation rf technology

Abstract

Methods for determining a LOB of one or more user equipment (UE) in a wireless system employing Time Difference of Arrival (TDOA) is described. TDOA techniques are based on estimating the difference in the arrival times of reference signals from multiple receivers or from multiple emitters to a receiver. A particular value of the time difference estimate defines a hyperbola between the two receivers on which the handset may exist. When the distance between the receiving antennas is small relative to the distance of the emitter source (the handset) being located, then the TDOA is equivalent to the angle between the baseline of the sensors (receivers antennas) and the incident RF energy from the emitter. If the angle between the baseline and true North is known, then the line of bearing (LOB) and / or angle of arrival (AoA), can be utilized to determine the location of the UE.

Description

[0001] Cross References to Related Applications [0002] This application claims the benefit of US Provisional Patent Application No. 61 / 736,458, filed December 12, 2012, entitled "MULTI-PATHMITIGATIONINRANGEFINDINGANDTRACKINGOBJECTSUSINGREDUCEDATTENUATIONRFTECHNOLOGY." technical field [0003] The present embodiments relate to wireless communication and wireless network systems and systems including RTLS (Real Time Location Service) for radio frequency (RF) based identification, tracking and location of objects. Background technique [0004] RF-based identification and positioning systems for determining the relative position or geographic location of objects are commonly used to track single objects or groups of objects as well as to track individuals. Traditional positioning systems have been used for position determination in open outdoor environments. Typically RF based Global Positioning System (GPS) and Assisted GPS are used. However, conventional positioning system...

AI Technical Summary

Problems solved by technology

Also, with active DAS, the optimal accuracy (lower error limit) is limited to 50 meters

Finally, Chen et al. do not address the impact of multipath on positioning accuracy in indoor environments, where multipath is most severe (compared to outdoors) and in many cases produces much larger (2X -4X) positioning error

[0024] Modifications to indoor wireless network antenna systems as taught by Chen et al. are not always possible due to the enormous effort and cost involved in upgrading existing systems

Furthermore, in the case of active DAS, the optimal theoretical accuracy is only 50 meters, and in practice this accuracy is significantly lower due to RF propagation phenomena including multipath

Images