Receiver processor for adaptive windowing and high-resolution TOA determination in a multiple receiver target location system
First Claim
1. A method for determining target location in a multiple receiver target location system, the method comprising:
- receiving a tag transmission signal from a tag at a receiver, wherein the tag transmission signal comprises a series of pulses;
determining a coarse estimate of a time-of-arrival (TOA) of the tag transmission signal based on a detection of a pulse of the series of pulses in an adjustable coarse timing window, wherein the coarse estimate is based on a plurality of coarse timing windows;
determining a fine estimate of the TOA based on a detection of the pulse in at least one of a parallel set of fine timing windows; and
determining, using a processor of the receiver, a sub-window resolution of the TOA based on at least one detection transition between consecutive fine receiver windows of at least one of a plurality of pulses and a weighted average of the TOA for each pulse of the series of pulses.
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Abstract
The present invention provides methods for a high-resolution active RTLS tag location determination system that provides for <1 ns TOA accuracy and resolution and significantly reduces the channel effects of multipath interference, even in low SNR applications. To accomplish these objectives, the present invention provides for an iterative and adaptive windowing function in each of the receivers of a receiver grid that captures multiple reflections of multiple transmissions from each of the associated target RTLS tags. The adaptive windowing function is used in conjunction with an asynchronous transmit and receive clock function that effectively increases resolution of TOA detection to levels less than the minimum detection window width associated with each of the receivers in the receiver grid.
198 Citations
17 Claims
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1. A method for determining target location in a multiple receiver target location system, the method comprising:
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receiving a tag transmission signal from a tag at a receiver, wherein the tag transmission signal comprises a series of pulses; determining a coarse estimate of a time-of-arrival (TOA) of the tag transmission signal based on a detection of a pulse of the series of pulses in an adjustable coarse timing window, wherein the coarse estimate is based on a plurality of coarse timing windows; determining a fine estimate of the TOA based on a detection of the pulse in at least one of a parallel set of fine timing windows; and determining, using a processor of the receiver, a sub-window resolution of the TOA based on at least one detection transition between consecutive fine receiver windows of at least one of a plurality of pulses and a weighted average of the TOA for each pulse of the series of pulses. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification