Patent ID: 8558666

Claim:
A method of location detection, comprising: a plurality of base stations of a location system obtaining information about each of a plurality of tags associated with the location system; designating one of the plurality of base stations as a master base station for each tag, comprising identifying which of the plurality of base stations has a best quality combination of acoustic link and electromagnetic link to the tag; each master base station electro-magnetically transmitting beacons to each of the plurality of tags that the master base station has been designated master, wherein the master base station transmits beacons of different tags at separate transmission times; each tag responding to the electro-magnetically transmitted beacons with an acoustic signal that identifies the tag, wherein the acoustic signal of each of the different tags are separated in time as determined by the separate transmission times of the beacons transmitted to each of the different tags; multiple of the plurality of base stations receiving the acoustic signal of each tag; detection motion of at least one of the tags; estimating a location of each tag based on times of arrival of each acoustic signal of each tag at each of the multiple base stations, and based on location information of each of the multiple base stations; detecting location data points for each tag at a rate that is dependent upon how fast the tag is moving.