Use of blink counts to locate movable tagged assets
First Claim
Patent Images
1. A method of locating a movable asset that is tagged with an active tag, the method comprisingusing a plurality of receivers spaced apart in two dimensions to simultaneously listen for a periodic signal from the active tag without interrogating the active tag;
- determining blink counts for those receivers that receive the periodic signal;
using the blink counts as distance estimators between the active tag and each of the respective receivers based on the following;
di˜
k*RBCIi
where di is the distance estimator from the active tag to an ith receiver, k is a constant, and RBCIi is a received blink count indication for the ith receiver; and
calculating the location of the active tag using the respective distance estimators of the active tag from each of those receivers that receive the periodic signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of locating a tagged movable asset comprises determining blink counts for receivers in a plurality of zones, and selecting one of the zones according to a comparison of the blink counts.
-
Citations
22 Claims
-
1. A method of locating a movable asset that is tagged with an active tag, the method comprising
using a plurality of receivers spaced apart in two dimensions to simultaneously listen for a periodic signal from the active tag without interrogating the active tag; -
determining blink counts for those receivers that receive the periodic signal; using the blink counts as distance estimators between the active tag and each of the respective receivers based on the following;
di˜
k*RBCIi
where di is the distance estimator from the active tag to an ith receiver, k is a constant, and RBCIi is a received blink count indication for the ith receiver; andcalculating the location of the active tag using the respective distance estimators of the active tag from each of those receivers that receive the periodic signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
-
18. A system for locating an active tag within one of a plurality of spatial zones, where each of the spatial zones includes a plurality of active tag readers having omni-directional antennas, the system comprising a processor programmed to:
-
determine a received blink count indication for each of the readers, select the one zone using each blink count indication as a measure of length of signal path from a corresponding receiver to the active tag, computing a distance estimator between the active tag and each of the plurality of active tag readers in the one zone based on the received blink count indication for each of the plurality of active tag readers in the one zone, and determining an x location of the active tag and a y location of the active tag based on a weighted average of the distance estimators between the active tag and each of the plurality of active tag readers in the one zone.
-
-
19. A system for use with a plurality of spatial stalls arranged in an N×
- M grid, where N>
1 and M>
1, the system comprising;a plurality of tagged assets located in at least one of the stalls, each asset tagged with an active tag, which periodically transmits a wireless signal including an identifier; a plurality of sets of multiple readers, each set located within one of the stalls; and a processing system for determining locations of the assets with respect to the sets of multiple readers, including; aggregating received blink count indications from each set of multiple readers for each one of the stalls, comparing the aggregated received blink count indications, and selecting one of the sets and, therefore, one of the stalls according to the comparison, computing distance estimators between each active tag and each of the readers in the selected set based on the received blink count indications for each of the readers in the selected set, and for each active tag, determining an x location and a y location based on a weighted average of the distance estimators between each active tag and each of the readers in the selected set. - View Dependent Claims (20, 21, 22)
- M grid, where N>
Specification