Ultrasonic positioning and tracking system

Claim 1

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and wherein placing a plurality of background units in the area comprises placing the background units such that for at least one or more of the background units, there are at least some points in the area to which ultrasound waves cannot propagate from the at least one or more background units within the time window.

Claim 2

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and wherein placing a plurality of background units in the area comprises placing the background units such that for at least one or more of the background units, there are at least some points in the area to which ultrasound waves cannot propagate from the at least one or more background units within the time window.

Claim 3

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; and calculating coordinates of the object responsive to the characteristic, wherein placing a plurality of background units in the area comprises placing the background units such that for substantially every point in the area, ultrasound waves can propagate between the point and at least three of the background units within the time window.

Claim 4

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; and calculating coordinates of the object responsive to the characteristic, wherein placing a plurality of background units in the area comprises placing the background units such that for substantially every point in the area, ultrasound waves can propagate between the point and at least three of the background units within the time window.

Claim 18

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and comprising transmitting a trigger signal to initiate transmission of the ultrasound waves.

Claim 19

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and comprising transmitting a trigger signal to initiate transmission of the ultrasound waves.

Claim 24

A system for tracking an object in a detection area, comprising: at least one first ultrasound transducer, fixed to the object; a plurality of background units, each unit comprising a respective second ultrasound transducer; a central unit, in wireless communication with at least either the first transducer or some of the background units, so as to receive information regarding transmission of ultrasound waves between the first and second ultrasound transducers and to determine coordinates of the object based on the information; and wherein the plurality of background units comprises at least five background units.

Claim 25

A system for tracking an object in a detection area, comprising: at least one first ultrasound transducer, fixed to the object; a plurality of background units, each unit comprising a respective second ultrasound transducer; a central unit, in wireless communication with at least either the first transducer or some of the background units, so as to receive information regarding transmission of ultrasound waves between the first and second ultrasound transducers and to determine coordinates of the object based on the information; and wherein the plurality of background units comprises at least five background units.

Claim 27

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area , each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and wherein placing a plurality of background units in the area comprises placing at least five background units.

Claim 28

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area , each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and wherein placing a plurality of background units in the area comprises placing at least five background units.

Claim 29

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic, wherein transmitting one or more ultrasound waves comprises transmitting ultrasound waves carrying unique identification of the transmitting transducer; wherein transmitting ultrasound waves carrying the unique identification of the transmitting transducer comprises transmitting ultrasound waves which have a distinct frequency identifying the transducer; wherein determining the characteristic comprises determining frequencies of the received waves; and wherein determining the frequencies of the received waves comprises performing an FFT analysis.

Claim 30

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic, wherein transmitting one or more ultrasound waves comprises transmitting ultrasound waves carrying unique identification of the transmitting transducer; wherein transmitting ultrasound waves carrying the unique identification of the transmitting transducer comprises transmitting ultrasound waves which have a distinct frequency identifying the transducer; wherein determining the characteristic comprises determining frequencies of the received waves; and wherein determining the frequencies of the received waves comprises performing an FFT analysis.

Claim 31

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducer to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic, wherein transmitting one or more ultrasound waves comprises transmitting ultrasound waves carrying unique identification of the transmitting transducer; wherein transmitting ultrasound waves carrying the unique identification of the transmitting transducer comprises transmitting ultrasound waves which have a distinct frequency identifying the transducer; wherein determining the characteristic comprises determining frequencies of the received waves; and wherein determining the frequencies of received waves comprises passing the received waves through a plurality of frequency-distinct filters.

Claim 32

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducer to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic, wherein transmitting one or more ultrasound waves comprises transmitting ultrasound waves carrying unique identification of the transmitting transducer; wherein transmitting ultrasound waves carrying the unique identification of the transmitting transducer comprises transmitting ultrasound waves which have a distinct frequency identifying the transducer; wherein determining the characteristic comprises determining frequencies of the received waves; and wherein determining the frequencies of received waves comprises passing the received waves through a plurality of frequency-distinct filters.

Claim 33

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration an the speed of sound is substantially less than the linear extent of the detection are; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and wherein placing a plurality of background units in the area comprises placing at least eight background units.

Claim 34

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration an the speed of sound is substantially less than the linear extent of the detection are; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and wherein placing a plurality of background units in the area comprises placing at least eight background units.

Claim 35

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and wherein calculating coordinates of the object comprises calculating the coordinates of the object independently for each of a plurality of sub-groups of the received waves and averaging the coordinates calculated for two or more of the plurality of sub-groups.

Claim 36

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and wherein calculating coordinates of the object comprises calculating the coordinates of the object independently for each of a plurality of sub-groups of the received waves and averaging the coordinates calculated for two or more of the plurality of sub-groups.

Claim 37

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and comprising repeatedly recalculating the coordinates of the object at a refresh rate that is substantially greater than the quotient of the speed of sound divided by the extent of the area.

Claim 38

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and comprising repeatedly recalculating the coordinates of the object at a refresh rate that is substantially greater than the quotient of the speed of sound divided by the extent of the area.

Claim 39

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducer to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less then the linear extent of the detection area; determining a characteristic of the record ultrasound waves; calculating coordinates of the object responsive to the characteristic; and wherein transmitting one or more ultrasound waves comprises transmitting waves from one or more transducers fixed to the object, and wherein receiving the ultrasound waves comprises receiving the waves at the transducer fixed to the plurality of background units.

Claim 40

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducer to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less then the linear extent of the detection area; determining a characteristic of the record ultrasound waves; calculating coordinates of the object responsive to the characteristic; and wherein transmitting one or more ultrasound waves comprises transmitting waves from one or more transducers fixed to the object, and wherein receiving the ultrasound waves comprises receiving the waves at the transducer fixed to the plurality of background units.

Claim 41

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and wherein determining the characteristic comprises determining a Doppler shift of the waves.

Claim 42

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; and wherein determining the characteristic comprises determining a Doppler shift of the waves.

Claim 43

A method for calibrating an object tracking system, the system comprising a plurality of background units, each unit including an ultrasound transducer for ultrasonic sensing of the position of the object, said method comprising: placing at least three of the background units in respective locations having known position coordinates in a surveillance area; placing additional background units in other locations in the surveillance area; determining position coordinates of a first one of the additional units by transmitting ultrasound waves between the first additional unit and the at least three units having the known position coordinates; and determining position coordinates of a second additional unit by transmitting ultrasound waves between the second additional unit and the first additional unit.

Claim 44

A method for calibrating an object tracking system, the system comprising a plurality of background units, each unit including an ultrasound transducer for ultrasonic sensing of the position of the object, said method comprising: placing at least three of the background units in respective locations having known position coordinates in a surveillance area; placing additional background units in other locations in the surveillance area; determining position coordinates of a first one of the additional units by transmitting ultrasound waves between the first additional unit and the at least three units having the known position coordinates; and determining position coordinates of a second additional unit by transmitting ultrasound waves between the second additional unit and the first additional unit.

Claim 49

A system for tracking an object in a detection area, comprising: at least one first ultrasound transducer, fixed to the object; a plurality of background units, each unit comprising a respective second ultrasound transducer; a central unit, in wireless communication with at least either the first transducer or some of the background units, so as to receive information regarding transmission of ultrasound waves between the first and second ultrasound transducers and to determine coordinates of the object based on the information; and comprising wireless receivers coupled to the first and second ultrasound transducers, which receive a trigger signal to initiate the transmission of ultrasound waves between the transducers.

Claim 50

A system for tracking an object in a detection area, comprising: at least one first ultrasound transducer, fixed to the object; a plurality of background units, each unit comprising a respective second ultrasound transducer; a central unit, in wireless communication with at least either the first transducer or some of the background units, so as to receive information regarding transmission of ultrasound waves between the first and second ultrasound transducers and to determine coordinates of the object based on the information; and comprising wireless receivers coupled to the first and second ultrasound transducers, which receive a trigger signal to initiate the transmission of ultrasound waves between the transducers.

Claim 65

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; wherein calculating the coordinates of the object comprises transmitting the determined characteristic to a control unit over a wireless link; and comprising identifying a background unit from which the control unit has not received the characteristic and requesting re-transmission of the characteristic via another background unit in a vicinity of the identified background unit.

Claim 66

A method of tracking an object within a surveillance area having a predetermined linear extent, comprising: fixing one or more ultrasound transducers to the object; placing a plurality of background units at known positions in the area, each unit comprising an ultrasound transducer; transmitting one or more ultrasound waves between the object and the plurality of background units; receiving those of the ultrasound waves that propagate between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area; determining a characteristic of the received ultrasound waves; calculating coordinates of the object responsive to the characteristic; wherein calculating the coordinates of the object comprises transmitting the determined characteristic to a control unit over a wireless link; and comprising identifying a background unit from which the control unit has not received the characteristic and requesting re-transmission of the characteristic via another background unit in a vicinity of the identified background unit.